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Hill MA, Staut N, Thompson JM, Verhaegen F. Dosimetric validation of SmART-RAD Monte Carlo modelling for x-ray cabinet radiobiology irradiators. Phys Med Biol 2024; 69:095014. [PMID: 38518380 PMCID: PMC11031639 DOI: 10.1088/1361-6560/ad3720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 02/23/2024] [Accepted: 03/22/2024] [Indexed: 03/24/2024]
Abstract
Objective. Accuracy and reproducibility in the measurement of radiation dose and associated reporting are critically important for the validity of basic and preclinical radiobiological studies performed with kilovolt x-ray radiation cabinets. This is essential to enable results of radiobiological studies to be repeated, as well as enable valid comparisons between laboratories. In addition, the commonly used single point dose value hides the 3D dose heterogeneity across the irradiated sample. This is particularly true for preclinical rodent models, and is generally difficult to measure directly. Radiation transport simulations integrated in an easy to use application could help researchers improve quality of dosimetry and reporting.Approach. This paper describes the use and dosimetric validation of a newly-developed Monte Carlo (MC) tool, SmART-RAD, to simulate the x-ray field in a range of standard commercial x-ray cabinet irradiators used for preclinical irradiations. Comparisons are made between simulated and experimentally determined dose distributions for a range of configurations to assess the potential use of this tool in determining dose distributions through samples, based on more readily available air-kerma calibration point measurements.Main results. Simulations gave very good dosimetric agreement with measured depth dose distributions in phantoms containing both water and bone equivalent materials. Good spatial and dosimetric agreement between simulated and measured dose distributions was obtained when using beam-shaping shielding.Significance. The MC simulations provided by SmART-RAD provide a useful tool to go from a limited number of dosimetry measurements to detailed 3D dose distributions through a non-homogeneous irradiated sample. This is particularly important when trying to determine the dose distribution in more complex geometries. The use of such a tool can improve reproducibility and dosimetry reporting in preclinical radiobiological research.
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Affiliation(s)
- Mark A Hill
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, ORCRB Roosevelt Drive, Oxford OX3 7DQ, United Kingdom
| | - Nick Staut
- SmART Scientific Solutions BV, Maastricht, The Netherlands
| | - James M Thompson
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, ORCRB Roosevelt Drive, Oxford OX3 7DQ, United Kingdom
| | - Frank Verhaegen
- SmART Scientific Solutions BV, Maastricht, The Netherlands
- Department of Radiation Oncology (Maastro), Research Institute for Oncology & Reproduction, Maastricht University Medical Centre+, Maastricht, The Netherlands
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Chan Wah Hak C, Dean JA, Hill MA, Somaiah N. The National Cancer Research Institute Clinical and Translational Radiotherapy Research Working Group Workshop: Translating Novel Discoveries to and from the Clinic. Clin Oncol (R Coll Radiol) 2023; 35:769-772. [PMID: 37741714 DOI: 10.1016/j.clon.2023.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 08/30/2023] [Indexed: 09/25/2023]
Affiliation(s)
- C Chan Wah Hak
- Division of Radiotherapy and Imaging, The Institute of Cancer Research, London, UK
| | - J A Dean
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - M A Hill
- Department of Oncology, University of Oxford, Oxford, UK
| | - N Somaiah
- Division of Radiotherapy and Imaging, The Institute of Cancer Research, London, UK; The Royal Marsden NHS Foundation Trust, London, UK.
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Verhaegen F, Butterworth KT, Chalmers AJ, Coppes RP, de Ruysscher D, Dobiasch S, Fenwick JD, Granton PV, Heijmans SHJ, Hill MA, Koumenis C, Lauber K, Marples B, Parodi K, Persoon LCGG, Staut N, Subiel A, Vaes RDW, van Hoof S, Verginadis IL, Wilkens JJ, Williams KJ, Wilson GD, Dubois LJ. Roadmap for precision preclinical x-ray radiation studies. Phys Med Biol 2023; 68:06RM01. [PMID: 36584393 DOI: 10.1088/1361-6560/acaf45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 12/30/2022] [Indexed: 12/31/2022]
Abstract
This Roadmap paper covers the field of precision preclinical x-ray radiation studies in animal models. It is mostly focused on models for cancer and normal tissue response to radiation, but also discusses other disease models. The recent technological evolution in imaging, irradiation, dosimetry and monitoring that have empowered these kinds of studies is discussed, and many developments in the near future are outlined. Finally, clinical translation and reverse translation are discussed.
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Affiliation(s)
- Frank Verhaegen
- MAASTRO Clinic, Radiotherapy Division, GROW-School for Oncology and Reproduction, Maastricht University Medical Centre+, Maastricht, The Netherlands
- SmART Scientific Solutions BV, Maastricht, The Netherlands
| | - Karl T Butterworth
- Patrick G. Johnston, Centre for Cancer Research, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom
| | - Anthony J Chalmers
- School of Cancer Sciences, University of Glasgow, Glasgow G61 1QH, United Kingdom
| | - Rob P Coppes
- Departments of Biomedical Sciences of Cells & Systems, Section Molecular Cell Biology and Radiation Oncology, University Medical Center Groningen, University of Groningen, 9700 AD Groningen, The Netherlands
| | - Dirk de Ruysscher
- MAASTRO Clinic, Radiotherapy Division, GROW-School for Oncology and Reproduction, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Sophie Dobiasch
- Department of Radiation Oncology, Technical University of Munich (TUM), School of Medicine and Klinikum rechts der Isar, Germany
- Department of Medical Physics, Institute of Radiation Medicine (IRM), Department of Radiation Sciences (DRS), Helmholtz Zentrum München, Germany
| | - John D Fenwick
- Department of Medical Physics & Biomedical Engineering University College LondonMalet Place Engineering Building, London WC1E 6BT, United Kingdom
| | | | | | - Mark A Hill
- MRC Oxford Institute for Radiation Oncology, University of Oxford, ORCRB Roosevelt Drive, Oxford OX3 7DQ, United Kingdom
| | - Constantinos Koumenis
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Kirsten Lauber
- Department of Radiation Oncology, University Hospital, LMU München, Munich, Germany
- German Cancer Consortium (DKTK), Partner site Munich, Germany
| | - Brian Marples
- Department of Radiation Oncology, University of Rochester, NY, United States of America
| | - Katia Parodi
- German Cancer Consortium (DKTK), Partner site Munich, Germany
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Garching b. Munich, Germany
| | | | - Nick Staut
- SmART Scientific Solutions BV, Maastricht, The Netherlands
| | - Anna Subiel
- National Physical Laboratory, Medical Radiation Science Hampton Road, Teddington, Middlesex, TW11 0LW, United Kingdom
| | - Rianne D W Vaes
- MAASTRO Clinic, Radiotherapy Division, GROW-School for Oncology and Reproduction, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | | | - Ioannis L Verginadis
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jan J Wilkens
- Department of Radiation Oncology, Technical University of Munich (TUM), School of Medicine and Klinikum rechts der Isar, Germany
- Physics Department, Technical University of Munich (TUM), Germany
| | - Kaye J Williams
- Division of Pharmacy and Optometry, University of Manchester, Manchester, United Kingdom
| | - George D Wilson
- Department of Radiation Oncology, Beaumont Health, MI, United States of America
- Henry Ford Health, Detroit, MI, United States of America
| | - Ludwig J Dubois
- The M-Lab, Department of Precision Medicine, GROW-School for Oncology and Reproduction, Maastricht University, Maastricht, The Netherlands
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Wilkinson B, Hill MA, Parsons JL. The Cellular Response to Complex DNA Damage Induced by Ionising Radiation. Int J Mol Sci 2023; 24:4920. [PMID: 36902352 PMCID: PMC10003081 DOI: 10.3390/ijms24054920] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 02/24/2023] [Accepted: 03/01/2023] [Indexed: 03/08/2023] Open
Abstract
Radiotherapy (ionising radiation; IR) is utilised in the treatment of ~50% of all human cancers, and where the therapeutic effect is largely achieved through DNA damage induction. In particular, complex DNA damage (CDD) containing two or more lesions within one to two helical turns of the DNA is a signature of IR and contributes significantly to the cell killing effects due to the difficult nature of its repair by the cellular DNA repair machinery. The levels and complexity of CDD increase with increasing ionisation density (linear energy transfer, LET) of the IR, such that photon (X-ray) radiotherapy is deemed low-LET whereas some particle ions (such as carbon ions) are high-LET radiotherapy. Despite this knowledge, there are challenges in the detection and quantitative measurement of IR-induced CDD in cells and tissues. Furthermore, there are biological uncertainties with the specific DNA repair proteins and pathways, including components of DNA single and double strand break mechanisms, that are engaged in CDD repair, which very much depends on the radiation type and associated LET. However, there are promising signs that advancements are being made in these areas and which will enhance our understanding of the cellular response to CDD induced by IR. There is also evidence that targeting CDD repair, particularly through inhibitors against selected DNA repair enzymes, can exacerbate the impact of higher LET, which could be explored further in a translational context.
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Affiliation(s)
- Beth Wilkinson
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, 6 West Derby Street, Liverpool L7 8TX, UK
| | - Mark A. Hill
- MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Jason L. Parsons
- Institute of Cancer and Genomic Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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Hopewell JW, Moore J, Villafuerte CJ, Paddick I, Jones B, Hill MA, Tsang DS. Improving the Accuracy of Biologically Effective Dose Estimates, from a Previously Published Study, After Radiosurgery for Acoustic Neuromas. World Neurosurg 2022; 172:e130-e143. [PMID: 36587897 DOI: 10.1016/j.wneu.2022.12.119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/27/2022] [Accepted: 12/28/2022] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To recalculate biological effective dose values (BED) for radio-surgical treatments of acoustic neuroma from a previous study. BEDs values were previously overestimated by only using beam-on times in calculations, so excluding the important beam-off-times (when deoxyribonucleic acid repair continues) which contribute to the overall treatment time. Simple BED estimations using a mono-exponential approximation may not always be appropriate but if used should include overall treatment time. METHODS Time intervals between isocenters were estimated. These were especially important for the Gamma Knife Model 4C cases since manual changes significantly increase overall treatment times. Individual treatment parameters, such as iso-center number, beam-on-time, and beam-off-time, were then used to calculate BED values using a more appropriate bi-exponential model that includes fast and slow components of DNA damage repair over a wider time range. RESULTS The revised BED estimates differed significantly from previously published values. The overestimates of BED, obtained using beam-on-time only, varied from 0%-40.3%. BED subclasses, each with a BED range of 5 Gy2.47, indicated that revised values were consistently reduced when compared with originally quoted values, especially for 4C compared with Perfexion cases. Furthermore, subdivision of 4C cases by collimator number further emphasized the impact of scheduled gap times on BED. Further analysis demonstrated important limitations of the mono-exponential model. Target volume was a major confounding factor in the interpretation of the results of this study. CONCLUSIONS BED values should be estimated by including beam-on and beam-off times. Suggestions are provided for more accurate BED estimations in future studies.
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Affiliation(s)
- John W Hopewell
- Green Templeton College, University of Oxford, Oxford, UK; Department of Oncology, University of Oxford, Oxford, UK.
| | - Joshua Moore
- School of Mathematics, Cardiff University, Cardiff, UK
| | | | - Ian Paddick
- Queen Square Gamma Knife Centre, National Hospital for Neurology and Neurosurgery, London, UK
| | - Bleddyn Jones
- Green Templeton College, University of Oxford, Oxford, UK; Department of Oncology, University of Oxford, Oxford, UK
| | - Mark A Hill
- Department of Oncology, University of Oxford, Oxford, UK
| | - Derek S Tsang
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
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Kaeppler JR, Chen J, Buono M, Vermeer J, Kannan P, Cheng W, Voukantsis D, Thompson JM, Hill MA, Allen D, Gomes A, Kersemans V, Kinchesh P, Smart S, Buffa F, Nerlov C, Muschel RJ, Markelc B. Endothelial cell death after ionizing radiation does not impair vascular structure in mouse tumor models. EMBO Rep 2022; 23:e53221. [PMID: 35848459 PMCID: PMC9442312 DOI: 10.15252/embr.202153221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/15/2022] [Accepted: 06/27/2022] [Indexed: 12/24/2022] Open
Abstract
The effect of radiation therapy on tumor vasculature has long been a subject of debate. Increased oxygenation and perfusion have been documented during radiation therapy. Conversely, apoptosis of endothelial cells in irradiated tumors has been proposed as a major contributor to tumor control. To examine these contradictions, we use multiphoton microscopy in two murine tumor models: MC38, a highly vascularized, and B16F10, a moderately vascularized model, grown in transgenic mice with tdTomato-labeled endothelium before and after a single (15 Gy) or fractionated (5 × 3 Gy) dose of radiation. Unexpectedly, even these high doses lead to little structural change of the perfused vasculature. Conversely, non-perfused vessels and blind ends are substantially impaired after radiation accompanied by apoptosis and reduced proliferation of their endothelium. RNAseq analysis of tumor endothelial cells confirms the modification of gene expression in apoptotic and cell cycle regulation pathways after irradiation. Therefore, we conclude that apoptosis of tumor endothelial cells after radiation does not impair vascular structure.
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Affiliation(s)
- Jakob R Kaeppler
- Cancer Research UK and MRC Oxford Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
| | - Jianzhou Chen
- Cancer Research UK and MRC Oxford Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
| | - Mario Buono
- MRC Molecular Hematology Unit, MRC Weatherall Institute of Molecular Medicine, John Radcliffe HospitalUniversity of OxfordOxfordUK
| | - Jenny Vermeer
- Cancer Research UK and MRC Oxford Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
| | - Pavitra Kannan
- Cancer Research UK and MRC Oxford Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
| | - Wei‐Chen Cheng
- Cancer Research UK and MRC Oxford Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
| | - Dimitrios Voukantsis
- Cancer Research UK and MRC Oxford Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
| | - James M Thompson
- Cancer Research UK and MRC Oxford Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
| | - Mark A Hill
- Cancer Research UK and MRC Oxford Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
| | - Danny Allen
- Cancer Research UK and MRC Oxford Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
| | - Ana Gomes
- In Vivo ImagingThe Francis Crick InstituteLondonUK
| | - Veerle Kersemans
- Cancer Research UK and MRC Oxford Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
| | - Paul Kinchesh
- Cancer Research UK and MRC Oxford Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
| | - Sean Smart
- Cancer Research UK and MRC Oxford Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
| | - Francesca Buffa
- Cancer Research UK and MRC Oxford Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
| | - Claus Nerlov
- MRC Molecular Hematology Unit, MRC Weatherall Institute of Molecular Medicine, John Radcliffe HospitalUniversity of OxfordOxfordUK
| | - Ruth J Muschel
- Cancer Research UK and MRC Oxford Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
| | - Bostjan Markelc
- Cancer Research UK and MRC Oxford Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
- Present address:
Department of Experimental OncologyInstitute of Oncology LjubljanaLjubljanaSlovenia
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Abdelrazzak AB, O'Neill P, Hill MA. Influence of ionizing radiation and cell density on the kinetics of autocrine destruction and intercellular induction of apoptosis in precancerous cells. Sci Rep 2022; 12:7150. [PMID: 35505194 PMCID: PMC9065116 DOI: 10.1038/s41598-022-11253-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 04/19/2022] [Indexed: 11/09/2022] Open
Abstract
Intercellular induction of apoptosis (IIA) represents a well-defined signaling model by which precancerous cells are selectively eradicated through reactive oxygen/nitrogen species and cytokine signaling from neighbour normal cells. Previously, we demonstrated that the IIA process could be enhanced by exposure of normal cells to very low doses of ionizing radiation as a result of perturbing the intercellular signaling. In this study, we investigate the kinetic behaviour of both autocrine destruction (AD) and IIA as a function of cell density of both precancerous and normal cells using an insert co-culture system and how exposure of normal cells to ionizing radiation influence the kinetics of apoptosis induction in precancerous cells. Increasing the seeding density of transformed cells shifts the kinetics of AD towards earlier times with the response plateauing only at high seeding densities. Likewise, when co-culturing precancerous cells with normal cells, increasing the seeding density of either normal or precancerous cells also shifts the kinetics of IIA response towards earlier times and plateau only at higher seeding densities. Irradiation of normal cells prior to co-culture further enhances the kinetics of IIA response, with the degree of enhancement dependent on the relative cell densities. These results demonstrate the pivotal role of the cell seeding density of normal and precancerous cells in modulating both AD and IIA. These results further support the proposition that ionizing radiation could result in an enhancement in the rate of removal of precancerous cells through the IIA process.
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Affiliation(s)
- Abdelrazek B Abdelrazzak
- Spectroscopy Department, Physics Research Institute, National Research Centre, Cairo, 12622, Egypt.
| | - Peter O'Neill
- MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Mark A Hill
- MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB, Roosevelt Drive, Oxford, OX3 7DQ, UK
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Karabulutoglu M, Finnon R, Cruz-Garcia L, Hill MA, Badie C. Oxidative Stress and X-ray Exposure Levels-Dependent Survival and Metabolic Changes in Murine HSPCs. Antioxidants (Basel) 2021; 11:11. [PMID: 35052515 PMCID: PMC8772903 DOI: 10.3390/antiox11010011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 12/10/2021] [Accepted: 12/16/2021] [Indexed: 12/24/2022] Open
Abstract
Haematopoietic bone marrow cells are amongst the most sensitive to ionizing radiation (IR), initially resulting in cell death or genotoxicity that may later lead to leukaemia development, most frequently Acute Myeloid Leukaemia (AML). The target cells for radiation-induced Acute Myeloid Leukaemia (rAML) are believed to lie in the haematopoietic stem and progenitor cell (HSPC) compartment. Using the inbred strain CBA/Ca as a murine model of rAML, progress has been made in understanding the underlying mechanisms, characterisation of target cell population and responses to IR. Complex regulatory systems maintain haematopoietic homeostasis which may act to modulate the risk of rAML. However, little is currently known about the role of metabolic factors and diet in these regulatory systems and modification of the risk of AML development. This study characterises cellular proliferative and clonogenic potential as well as metabolic changes within murine HSPCs under oxidative stress and X-ray exposure. Ambient oxygen (normoxia; 20.8% O2) levels were found to increase irradiated HSPC-stress, stimulating proliferative activity compared to low oxygen (3% O2) levels. IR exposure has a negative influence on the proliferative capability of HSPCs in a dose-dependent manner (0-2 Gy) and this is more pronounced under a normoxic state. One Gy x-irradiated HSPCs cultured under normoxic conditions displayed a significant increase in oxygen consumption compared to those cultured under low O2 conditions and to unirradiated HSPCs. Furthermore, mitochondrial analyses revealed a significant increase in mitochondrial DNA (mtDNA) content, mitochondrial mass and membrane potential in a dose-dependent manner under normoxic conditions. Our results demonstrate that both IR and normoxia act as stressors for HSPCs, leading to significant metabolic deregulation and mitochondrial dysfunctionality which may affect long term risks such as leukaemia.
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Affiliation(s)
- Melis Karabulutoglu
- Cancer Mechanisms and Biomarkers Group, Radiation Effects Department, Radiation, Chemical and Environmental Hazards Directorate (RCE, Formally CRCE), UK Health Security Agency (Formerly Public Health England), Chilton, Didcot, Oxon OX11 0RQ, UK; (R.F.); (L.C.-G.)
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK;
| | - Rosemary Finnon
- Cancer Mechanisms and Biomarkers Group, Radiation Effects Department, Radiation, Chemical and Environmental Hazards Directorate (RCE, Formally CRCE), UK Health Security Agency (Formerly Public Health England), Chilton, Didcot, Oxon OX11 0RQ, UK; (R.F.); (L.C.-G.)
| | - Lourdes Cruz-Garcia
- Cancer Mechanisms and Biomarkers Group, Radiation Effects Department, Radiation, Chemical and Environmental Hazards Directorate (RCE, Formally CRCE), UK Health Security Agency (Formerly Public Health England), Chilton, Didcot, Oxon OX11 0RQ, UK; (R.F.); (L.C.-G.)
| | - Mark A. Hill
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK;
| | - Christophe Badie
- Cancer Mechanisms and Biomarkers Group, Radiation Effects Department, Radiation, Chemical and Environmental Hazards Directorate (RCE, Formally CRCE), UK Health Security Agency (Formerly Public Health England), Chilton, Didcot, Oxon OX11 0RQ, UK; (R.F.); (L.C.-G.)
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Ruan JL, Lee C, Wouters S, Tullis IDC, Verslegers M, Mysara M, Then CK, Smart SC, Hill MA, Muschel RJ, Giaccia AJ, Vojnovic B, Kiltie AE, Petersson K. Irradiation at Ultra-High (FLASH) Dose Rates Reduces Acute Normal Tissue Toxicity in the Mouse Gastrointestinal System. Int J Radiat Oncol Biol Phys 2021; 111:1250-1261. [PMID: 34400268 PMCID: PMC7612009 DOI: 10.1016/j.ijrobp.2021.08.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 08/03/2021] [Accepted: 08/04/2021] [Indexed: 12/18/2022]
Abstract
PURPOSE Preclinical studies using ultra-high dose rate (FLASH) irradiation have demonstrated reduced normal tissue toxicity compared with conventional dose rate (CONV) irradiation, although this finding is not universal. We investigated the effect of temporal pulse structure and average dose rate of FLASH compared with CONV irradiation on acute intestinal toxicity. MATERIALS AND METHODS Whole abdomens of C3H mice were irradiated with a single fraction to various doses, using a 6 MeV electron linear accelerator with single pulse FLASH (dose rate = 2-6 × 106 Gy/s) or conventional (CONV; 0.25 Gy/s) irradiation. At 3.75 days postirradiation, fresh feces were collected for 16S rRNA sequencing to assess changes in the gut microbiota. A Swiss roll-based crypt assay was used to quantify acute damage to the intestinal crypts to determine how tissue toxicity was affected by the different temporal pulse structures of FLASH delivery. RESULTS We found statistically significant improvements in crypt survival for mice irradiated with FLASH at doses between 7.5 and 12.5 Gy, with a dose modifying factor of 1.1 for FLASH (7.5 Gy, P < .01; 10 Gy, P < .05; 12.5 Gy, P < .01). This sparing effect was lost when the delivery time was increased, either by increasing the number of irradiation pulses or by prolonging the time between 2 successive pulses. Sparing was observed for average dose rates of ≥280 Gy/s. Fecal microbiome analysis showed that FLASH irradiation caused fewer changes to the microbiota than CONV irradiation. CONCLUSIONS This study demonstrates that FLASH irradiation can spare mouse small intestinal crypts and reduce changes in gut microbiome composition compared with CONV irradiation. The higher the average dose rate, the larger the FLASH effect, which is also influenced by temporal pulse structure of the delivery.
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Affiliation(s)
- Jia-Ling Ruan
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, United Kingdom
| | - Carl Lee
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Science, University of Oxford, Oxford, United Kingdom
| | - Shari Wouters
- Interdisciplinary Biosciences Group, Belgian Nuclear Research Center (SCK CEN), Mol, Belgium; Molecular Pathology Group, Cell Biology and Histology and Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, Campus Drie Eiken, University of Antwerp, Antwerp, Belgium
| | - Iain D C Tullis
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, United Kingdom
| | - Mieke Verslegers
- Interdisciplinary Biosciences Group, Belgian Nuclear Research Center (SCK CEN), Mol, Belgium
| | - Mohamed Mysara
- Interdisciplinary Biosciences Group, Belgian Nuclear Research Center (SCK CEN), Mol, Belgium
| | - Chee Kin Then
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, United Kingdom
| | - Sean C Smart
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, United Kingdom
| | - Mark A Hill
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, United Kingdom
| | - Ruth J Muschel
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, United Kingdom
| | - Amato J Giaccia
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, United Kingdom
| | - Borivoj Vojnovic
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, United Kingdom
| | - Anne E Kiltie
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, United Kingdom
| | - Kristoffer Petersson
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, United Kingdom; Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden.
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Van den Heuvel F, Vella A, Fiorini F, Brooke M, Hill MA, Maughan T. Incorporating oxygenation levels in analytical DNA-damage models-quantifying the oxygen fixation mechanism. Phys Med Biol 2021; 66:145005. [PMID: 34130265 PMCID: PMC8273901 DOI: 10.1088/1361-6560/ac0b80] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 06/15/2021] [Indexed: 11/28/2022]
Abstract
Purpose.To develop a framework to include oxygenation effects in radiation therapy treatment planning which is valid for all modalities, energy spectra and oxygen levels. The framework is based on predicting the difference in DNA-damage resulting from ionising radiation at variable oxygenation levels.Methods.Oxygen fixation is treated as a statistical process in a simplified model of complex and simple damage. We show that a linear transformation of the microscopic oxygen fixation process allows to extend this to all energies and modalities, resulting in a relatively simple rational polynomial expression. The model is expanded such that it can be applied for polyenergetic beams. The methodology is validated using Microdosimetric Monte Carlo Damage Simulation code (MCDS). This serves as a bootstrap to determine relevant parameters in the analytical expression, as MCDS is shown to be extensively verified with published empirical data. Double-strand break induction as calculated by this methodology is compared to published proton experiments. Finally, an example is worked out where the oxygen enhancement ratio (OER) is calculated at different positions in a clinically relevant spread out Bragg peak (SOBP) dose deposition in water. This dose deposition is obtained using a general Monte Carlo code (FLUKA) to determine dose deposition and locate fluence spectra.Results.For all modalities (electrons, protons), the damage categorised as complex could be parameterised to within 0.3% of the value calculated using microdosimetric Monte Carlo. The proton beam implementation showed some variation in OERs which differed slightly depending on where the assessment was made; before the SOBP, mid-SOBP or at the distal edge. Environment oxygenation was seen to be the more important variable.Conclusions.An analytic expression calculating complex damage depending on modality, energy spectrum, and oxygenation levels was shown to be effective and can be readily incorporated in treatment planning software, to take into account the impact of variable oxygenation, forming a first step to an optimised treatment based on biological factors.
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Affiliation(s)
- Frank Van den Heuvel
- University of Oxford, Department of Oncology, Oxford, United Kingdom
- Zuidwest Radiotherapeutic Institute, Vlissingen, Zeeland, TheNetherlands
| | - Anna Vella
- University of Oxford, Department of Oncology, Oxford, United Kingdom
- Oxford University Hospitals, Department of Hæmatology & Oncology, Oxford, United Kingdom
| | - Francesca Fiorini
- University of Oxford, Department of Oncology, Oxford, United Kingdom
- Rutherford Cancer Centre Thames Valley, Reading, United Kingdom
| | - Mark Brooke
- University of Oxford, Department of Oncology, Oxford, United Kingdom
| | - Mark A Hill
- University of Oxford, Department of Oncology, Oxford, United Kingdom
| | - Tim Maughan
- University of Oxford, Department of Oncology, Oxford, United Kingdom
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Nickson CM, Fabbrizi MR, Carter RJ, Hughes JR, Kacperek A, Hill MA, Parsons JL. USP9X Is Required to Maintain Cell Survival in Response to High-LET Radiation. Front Oncol 2021; 11:671431. [PMID: 34277417 PMCID: PMC8281306 DOI: 10.3389/fonc.2021.671431] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 06/15/2021] [Indexed: 12/26/2022] Open
Abstract
Ionizing radiation (IR) principally acts through induction of DNA damage that promotes cell death, although the biological effects of IR are more broad ranging. In fact, the impact of IR of higher-linear energy transfer (LET) on cell biology is generally not well understood. Critically, therefore, the cellular enzymes and mechanisms responsible for enhancing cell survival following high-LET IR are unclear. To this effect, we have recently performed siRNA screening to identify deubiquitylating enzymes that control cell survival specifically in response to high-LET α-particles and protons, in comparison to low-LET X-rays and protons. From this screening, we have now thoroughly validated that depletion of the ubiquitin-specific protease 9X (USP9X) in HeLa and oropharyngeal squamous cell carcinoma (UMSCC74A) cells using small interfering RNA (siRNA), leads to significantly decreased survival of cells after high-LET radiation. We consequently investigated the mechanism through which this occurs, and demonstrate that an absence of USP9X has no impact on DNA damage repair post-irradiation nor on apoptosis, autophagy, or senescence. We discovered that USP9X is required to stabilize key proteins (CEP55 and CEP131) involved in centrosome and cilia formation and plays an important role in controlling pericentrin-rich foci, particularly in response to high-LET protons. This was also confirmed directly by demonstrating that depletion of CEP55/CEP131 led to both enhanced radiosensitivity of cells to high-LET protons and amplification of pericentrin-rich foci. Our evidence supports the importance of USP9X in maintaining centrosome function and biogenesis and which is crucial particularly in the cellular response to high-LET radiation.
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Affiliation(s)
- Catherine M. Nickson
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Maria Rita Fabbrizi
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Rachel J. Carter
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Jonathan R. Hughes
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Andrzej Kacperek
- Clatterbridge Cancer Centre NHS Foundation Trust, Bebington, United Kingdom
| | - Mark A. Hill
- Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, Oxford, United Kingdom
| | - Jason L. Parsons
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, United Kingdom
- Clatterbridge Cancer Centre NHS Foundation Trust, Bebington, United Kingdom
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Sahu S, Sridhar D, Abnave P, Kosaka N, Dattani A, Thompson JM, Hill MA, Aboobaker A. Ongoing repair of migration-coupled DNA damage allows planarian adult stem cells to reach wound sites. eLife 2021; 10:e63779. [PMID: 33890575 PMCID: PMC8104965 DOI: 10.7554/elife.63779] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 04/22/2021] [Indexed: 12/21/2022] Open
Abstract
Mechanical stress during cell migration may be a previously unappreciated source of genome instability, but the extent to which this happens in any animal in vivo remains unknown. We consider an in vivo system where the adult stem cells of planarian flatworms are required to migrate to a distal wound site. We observe a relationship between adult stem cell migration and ongoing DNA damage and repair during tissue regeneration. Migrating planarian stem cells undergo changes in nuclear shape and exhibit increased levels of DNA damage. Increased DNA damage levels reduce once stem cells reach the wound site. Stem cells in which DNA damage is induced prior to wounding take longer to initiate migration and migrating stem cell populations are more sensitive to further DNA damage than stationary stem cells. RNAi-mediated knockdown of DNA repair pathway components blocks normal stem cell migration, confirming that active DNA repair pathways are required to allow successful migration to a distal wound site. Together these findings provide evidence that levels of migration-coupled-DNA-damage are significant in adult stem cells and that ongoing migration requires DNA repair mechanisms. Our findings reveal that migration of normal stem cells in vivo represents an unappreciated source of damage, which could be a significant source of mutations in animals during development or during long-term tissue homeostasis.
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Affiliation(s)
- Sounak Sahu
- Department of Zoology, University of OxfordOxfordUnited Kingdom
| | - Divya Sridhar
- Department of Zoology, University of OxfordOxfordUnited Kingdom
| | - Prasad Abnave
- Department of Zoology, University of OxfordOxfordUnited Kingdom
| | | | - Anish Dattani
- Department of Zoology, University of OxfordOxfordUnited Kingdom
| | - James M Thompson
- CRUK/MRC Oxford Institute for Radiation Oncology, ORCRB Roosevelt Drive, University of OxfordOxfordUnited Kingdom
| | - Mark A Hill
- CRUK/MRC Oxford Institute for Radiation Oncology, ORCRB Roosevelt Drive, University of OxfordOxfordUnited Kingdom
| | - Aziz Aboobaker
- Department of Zoology, University of OxfordOxfordUnited Kingdom
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Jiang Y, Martin J, Alkadhimi M, Shigemori K, Kinchesh P, Gilchrist S, Kersemans V, Smart S, Thompson JM, Hill MA, O'Connor MJ, Davies BR, Ryan AJ. Olaparib increases the therapeutic index of hemithoracic irradiation compared with hemithoracic irradiation alone in a mouse lung cancer model. Br J Cancer 2021; 124:1809-1819. [PMID: 33742147 PMCID: PMC8144220 DOI: 10.1038/s41416-021-01296-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 12/27/2020] [Accepted: 01/27/2021] [Indexed: 12/15/2022] Open
Abstract
Background The radiosensitising effect of the poly(ADP-ribose) polymerase inhibitor olaparib on tumours has been reported. However, its effect on normal tissues in combination with radiation has not been well studied. Herein, we investigated the therapeutic index of olaparib combined with hemithoracic radiation in a urethane-induced mouse lung cancer model. Methods To assess tolerability, A/J mice were treated with olaparib plus whole thorax radiation (13 Gy), body weight changes were monitored and normal tissue effects were assessed by histology. In anti-tumour (intervention) studies, A/J mice were injected with urethane to induce lung tumours, and were then treated with olaparib alone, left thorax radiation alone or the combination of olaparib plus left thorax radiation at 8 weeks (early intervention) or 18 weeks (late intervention) after urethane injection. Anti-tumour efficacy and normal tissue effects were assessed by visual inspection, magnetic resonance imaging and histology. Results Enhanced body weight loss and oesophageal toxicity were observed when olaparib was combined with whole thorax but not hemithorax radiation. In both the early and late intervention studies, olaparib increased the anti-tumour effects of hemithoracic irradiation without increasing lung toxicity. Conclusions The addition of olaparib increased the therapeutic index of hemithoracic radiation in a mouse model of lung cancer.
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Affiliation(s)
- Yanyan Jiang
- CRUK & MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Jennifer Martin
- CRUK & MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Maryam Alkadhimi
- CRUK & MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Kay Shigemori
- CRUK & MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Paul Kinchesh
- CRUK & MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Stuart Gilchrist
- CRUK & MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Veerle Kersemans
- CRUK & MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Sean Smart
- CRUK & MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - James M Thompson
- CRUK & MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Mark A Hill
- CRUK & MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | | | | | - Anderson J Ryan
- CRUK & MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK.
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Elbakrawy EM, Mayah A, Hill MA, Kadhim M. Induction of Genomic Instability in a Primary Human Fibroblast Cell Line Following Low-Dose Alpha-Particle Exposure and the Potential Role of Exosomes. Biology (Basel) 2020; 10:biology10010011. [PMID: 33379152 PMCID: PMC7824692 DOI: 10.3390/biology10010011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 12/18/2020] [Indexed: 02/07/2023]
Abstract
PURPOSE To study the induction of genomic instability (GI) in the progeny of cell populations irradiated with low doses of alpha-particles and the potential role of exosome-encapsulated bystander signalling. METHODS The induction of GI in HF19 normal fibroblast cells was assessed by determining the formation of micronuclei (MN) in binucleate cells along with using the alkaline comet assay to assess DNA damage. RESULTS Low dose alpha-particle exposure (0.0001-1 Gy) was observed to produce a significant induction of micronuclei and DNA damage shortly after irradiation (assays performed at 5 and 1 h post exposure, respectively). This damage was not only still evident and statistically significant in all irradiated groups after 10 population doublings, but similar trends were observed after 20 population doublings. Exosomes from irradiated cells were also observed to enhance the level of DNA damage in non-irradiated bystander cells at early times. CONCLUSION very low doses of alpha-particles are capable of inducing GI in the progeny of irradiated cells even at doses where <1% of the cells are traversed, where the level of response was similar to that observed at doses where 100% of the cells were traversed. This may have important implications with respect to the evaluation of cancer risk associated with very low-dose alpha-particle exposure and deviation from a linear dose response.
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Affiliation(s)
- Eman Mohammed Elbakrawy
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK; (E.M.E.); (A.M.)
- Department of Radiation Physics, National Center for Radiation Research and Technology, Atomic Energy Authority, 3 Ahmed El-Zomor Al Manteqah Ath Thamenah, Nasr City, Cairo 11787, Egypt
| | - Ammar Mayah
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK; (E.M.E.); (A.M.)
| | - Mark A. Hill
- Gray Laboratories, MRC Oxford Institute for Radiation Oncology, University of Oxford, ORCRB Roosevelt Drive, Oxford OX3 7DQ, UK;
| | - Munira Kadhim
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK; (E.M.E.); (A.M.)
- Correspondence: ; Tel.: +44-0-1865-483954
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Wan X, Wu X, Hill MA, Ebner DV. ReN VM spheroids in matrix: A neural progenitor three-dimensional in vitro model reveals DYRK1A inhibitors as potential regulators of radio-sensitivity. Biochem Biophys Res Commun 2020; 531:535-542. [PMID: 32807492 DOI: 10.1016/j.bbrc.2020.07.130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 07/28/2020] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Pre-clinical testing of small molecules for therapeutic development across many pathologies relies on the use of in-vitro and in-vivo models. When designed and implemented well, these models serve to predict the clinical outcome as well as the toxicity of the evaluated therapies. The two-dimensional (2D) reductionist approach where cells are incubated in a mono-layer on hard plastic microtiter plates is relatively inexpensive but not physiologically relevant. In contrast, well developed and applied three dimensional (3D) in vitro models could be employed to bridge the gap between 2D in vitro primary screening and expensive in vivo rodent models by incorporating key features of the tissue microenvironment to explore differentiation, cortical development, cancers and various neuronal dysfunctions. These features include an extracellular matrix, co-culture, tension and perfusion and could replace several hundred rodents in the drug screening validation cascade. METHODS Human neural progenitor cells from middle brain (ReN VM, Merck Millipore, UK) were expanded as instructed by the supplier (Merck Millipore, UK), and then seeded in 96-well low-attachment plates (Corning, UK) to form multicellular spheroids followed by adding a Matrigel layer to mimic extracellular matrix around neural stem cell niche. ReN VM cells were then differentiated via EGF and bFGF deprivation for 7 days and were imaged at day 7. Radiotherapy was mimicked via gamma-radiation at 2Gy in the absence and presence of selected DYRK1A inhibitors Harmine, INDY and Leucettine 41 (L41). Cell viability was measured by AlamarBlue assay. Immunofluorescence staining was used to assess cell pluripotency marker SOX2 and differentiation marker GFAP. RESULTS After 7 days of differentiation, neuron early differentiation marker (GFAP, red) started to be expressed among the cells expressing neural stem cell marker SOX2 (green). Radiation treatment caused significant morphology change including the reduced viability of the spheroids. These spheroids also revealed sensitizing potential of DYRK1A inhibitors tested in this study, including Harmine, INDY and L41. DISCUSSION & CONCLUSIONS Combined with the benefit of greatly reducing the issues associated with in vivo rodent models, including reducing numbers of animals used in a drug screening cascade, cost, ethics, and potential animal welfare burden, we feel the well-developed and applied 3D neural spheroid model presented in this study will provide a crucial tool to evaluate combinatorial therapies, optimal drug concentrations and treatment dosages.
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Affiliation(s)
- Xiao Wan
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, OX3 7FZ, Oxford, England, UK
| | - Xiaoning Wu
- Oxford Institute for Radiation Oncology, University of Oxford, OX3 7DQ, Oxford, England, UK
| | - Mark A Hill
- Oxford Institute for Radiation Oncology, University of Oxford, OX3 7DQ, Oxford, England, UK
| | - Daniel V Ebner
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, OX3 7FZ, Oxford, England, UK.
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Georgiou G, Kumar S, Würfel JU, Underwood TSA, Thompson JM, Hill MA, Rowbottom CG, Fenwick JD. Density compensated diodes for small field dosimetry: comprehensive testing and implications for design. Phys Med Biol 2020; 65:155011. [PMID: 32392539 DOI: 10.1088/1361-6560/ab91d9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE In small megavoltage photon fields, the accuracies of an unmodified PTW 60017-type diode dosimeter and six diodes modified by adding airgaps of thickness 0.6-1.6 mm and diameter 3.6 mm have been comprehensively characterized experimentally and computationally. The optimally thick airgap for density compensation was determined, and detectors were micro-CT imaged to investigate differences between experimentally measured radiation responses and those predicted computationally. METHODS Detectors were tested on- and off-axis, at 5 and 15 cm depths in 6 and 15 MV fields ≥ 0.5 × 0.5 cm2. Computational studies were carried out using the EGSnrc/BEAMnrc Monte Carlo radiation transport code. Experimentally, radiation was delivered using a Varian TrueBeam linac and doses absorbed by water were measured using Gafchromic EBT3 film and ionization chambers, and compared with diode readings. Detector response was characterized via the [Formula: see text] formalism, choosing a 4 × 4 cm2 reference field. RESULTS For the unmodified 60017 diode, the maximum error in small field doses obtained from diode readings uncorrected by [Formula: see text] factors was determined as 11.9% computationally at +0.25 mm off-axis and 5 cm depth in a 15 MV 0.5 × 0.5 cm2 field, and 11.7% experimentally at -0.30 mm off-axis and 5 cm depth in the same field. A detector modified to include a 1.6 mm thick airgap performed best, with maximum computationally and experimentally determined errors of 2.2% and 4.1%. The 1.6 mm airgap deepened the modified dosimeter's effective point of measurement by 0.5 mm. For some detectors significant differences existed between responses in small fields determined computationally and experimentally, micro-CT imaging indicating that these differences were due to within-tolerance variations in the thickness of an epoxy resin layer. CONCLUSIONS The dosimetric performance of a 60017 diode detector was comprehensively improved throughout 6 and 15 MV small photon fields via density compensation. For this approach to work well with good detector-to-detector reproducibility, tolerances on dense component dimensions should be reduced to limit associated variations of response in small fields, or these components should be modified to have more water-like densities.
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Affiliation(s)
- Georgios Georgiou
- Department of Molecular and Clinical Cancer Medicine, Institute of Translational Medicine, University of Liverpool, The Sherrington Building, Ashton Street, Liverpool L69 3BX, United Kingdom. Department of Physics, Clatterbridge Cancer Centre, Clatterbridge Road, Wirral CH63 4JY, United Kingdom. Department of Physics, University of Liverpool, Oliver Lodge Laboratory, Oxford Street, Liverpool L69 7ZE, United Kingdom
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Jones B, Hill MA. The physical separation between the LET associated with the ultimate relative biological effect (RBE) and the maximum LET in a proton or ion beam. Biomed Phys Eng Express 2020; 6:055001. [DOI: 10.1088/2057-1976/ab9e13] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Hill MA. Radiation Track Structure: How the Spatial Distribution of Energy Deposition Drives Biological Response. Clin Oncol (R Coll Radiol) 2020; 32:75-83. [PMID: 31511190 DOI: 10.1016/j.clon.2019.08.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/04/2019] [Accepted: 07/08/2019] [Indexed: 12/22/2022]
Abstract
Ionising radiation is incredibly effective at causing biological effects. This is due to the unique way energy is deposited along highly structured tracks of ionisation and excitation events, which results in correlation with sites of DNA damage from the nanometre to the micrometre scale. Correlation of these events along the track on the nanometre scale results in clustered damage, which not only results in the formation of DNA double-strand breaks (DSB), but also more difficult to repair complex DSB, which include additional damage within a few base pairs. The track structure varies significantly with radiation quality and the increase in relative biological effectiveness observed with increasing linear energy transfer in part corresponds to an increase in the probability and complexity of clustered DNA damage produced. Likewise, correlation over larger scales, associated with packing of DNA and associated chromosomes within the cell nucleus, can also have a major impact on the biological response. The proximity of the correlated damage along the track increases the probability of miss-repair through pairwise interactions resulting in an increase in probability and complexity of DNA fragments/deletions, mutations and chromosomal rearrangements. Understanding the mechanisms underlying the biological effectiveness of ionising radiation can provide an important insight into ways of increasing the efficacy of radiotherapy, as well as the risks associated with exposure. This requires a multi-scale approach for modelling, not only considering the physics of the track structure from the millimetre scale down to the nanometre scale, but also the structural packing of the DNA within the nucleus, the resulting chemistry in the context of the highly reactive environment of the nucleus, together with the subsequent biological response.
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Affiliation(s)
- M A Hill
- MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, Oxford, UK.
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Lu VM, Crawshay-Williams F, White B, Elliot A, Hill MA, Townley HE. Cytotoxicity, dose-enhancement and radiosensitization of glioblastoma cells with rare earth nanoparticles. Artif Cells Nanomed Biotechnol 2019; 47:132-143. [PMID: 30663430 DOI: 10.1080/21691401.2018.1544564] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 10/17/2018] [Accepted: 10/23/2018] [Indexed: 10/27/2022]
Abstract
Glioblastoma is a heterogeneous disease with multiple genotypic origins. Despite treatment protocols such as surgery, radiotherapy and chemotherapy, the prognosis for patients remains poor. This study investigates the cytotoxic and radiation dose-enhancing and radiosensitizing ability of five rare earth oxide nanoparticles, in two different immortalized mammalian cell lines; U-87 MG and Mo59K. Significant cytotoxicity was observed in U-87 MG cells when exposed to Nd2O3 and La2O3. Autophagy was also detected in cells after incubation with Nd2O3. Radiosensitization was observed in U-87 MG when incubated with Gd2O3, CeO2-Gd and Nd2O3:Si. Importantly, these elements did not cause any intrinsic toxicity in the absence of irradiation and so could be considered biocompatible. The Gd2O3 and CeO2-Gd nanoparticles were also seen to generate ROS in U-87 MG cells after irradiation. Furthermore, the Mo59K and U-87 MG cells responded very differently to exposure to the rare earth nanoparticles. This may indicate the importance of the genotype of cells in the successful use of rare earth oxides for treatment.
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Affiliation(s)
- Victor M Lu
- a Nuffield department of Women's and Reproductive Health , Women's Centre, John Radcliffe Hospital, University of Oxford , Oxford , UK
| | - Felicity Crawshay-Williams
- a Nuffield department of Women's and Reproductive Health , Women's Centre, John Radcliffe Hospital, University of Oxford , Oxford , UK
| | - Benjamin White
- a Nuffield department of Women's and Reproductive Health , Women's Centre, John Radcliffe Hospital, University of Oxford , Oxford , UK
| | - Amy Elliot
- b Gray Laboratories, CRUK/MRC Oxford Institute for Radiation Oncology , University of Oxford , Oxford , UK
| | - Mark A Hill
- b Gray Laboratories, CRUK/MRC Oxford Institute for Radiation Oncology , University of Oxford , Oxford , UK
| | - Helen E Townley
- a Nuffield department of Women's and Reproductive Health , Women's Centre, John Radcliffe Hospital, University of Oxford , Oxford , UK
- c Department of Engineering Science , University of Oxford , Oxford , UK
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Jones B, Hill MA. Physical characteristics at the turnover-points of relative biological effect (RBE) with linear energy transfer (LET). Phys Med Biol 2019; 64:225010. [PMID: 31665711 DOI: 10.1088/1361-6560/ab52a5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
This paper considers the kinematic physical characteristics of ionic beams for maximum relative bio-effectiveness (RBE). RBE studies, based on heterogenous cell survival studies at different laboratories and linear energy transfer (LET) conditions for proton, helium, carbon, neon and argon ions, have been further analysed to determine the LETU values where RBE is maximal and the LET-RBE relationship has a turnover point. The SRIM stopping power software and other classical equations are used to determine the particle velocities, kinetic energies and their effective ionic charges at LETU. The estimated mean LETU values increase with atomic number (Z). Each LETU has a unique relativistic velocity, β = v/c, the velocity v expressed as a fraction of the speed of light, (c), and which is non-linearly proportional to Z. For ions helium and heavier ions, these velocities indicate that the effective charge Z * is around 0.99 of the full Z value at each LETU, with remarkably stable velocities of 3-4 nm · fs-1 per nucleon, or around 6-8 nm · fs-1 per unit Z. For Z = 1, (protons and deuterium) some values fall outside these ranges but the result depends on the mix of proton and deuterium used in experiments. An alternative index of βA/Z 2 (A is the atomic mass number), suggests an average velocity of around 15 nm · fs-1 for each particle at LETU. These distances, traversed in the time of the radiochemical process initiation, are all within the dimensions of the nucleosome. Curve fitting of the data set provides a predictive equation for LETU for any ion, as LETU = 30.4 + [Formula: see text] (1 - Exp[-0.61 √ (Z - 1)]) when normalised to protons. These data can be extended to heavier ions such as silicon and iron and give values that are consistent with experimental data. Each ion probably has a unique LETU value. Kinematic studies show maximum bio-effectiveness occurs at particle velocities where electron stripping remains at around 99% and where the velocity per nucleon is around 3-4 nm · fs-1. This study enhances the limited prior knowledge about the physical conditions of particle beams that provide maximum bio-effectiveness, with applications in particle radiotherapy, radiation protection and space travel.
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Affiliation(s)
- Bleddyn Jones
- Gray Laboratory, Oxford Institute for Radiation Oncology and Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DG, United Kingdom. Author to whom any correspondence should be addressed
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Abstract
Nontargeted effects include radiation-induced genomic instability (RIGI) which is observed in the progeny of cells exposed to ionizing radiation and can be manifested in different ways, including chromosomal instability and micronucleus (MN) formation. Since genomic instability is commonly observed in tumors and has a role in tumor progression, RIGI has the potential of being an important mechanism for radiation-induced cancer. The work presented explores the role of dose and dose rate on RIGI, determined using a MN assay, in normal primary human fibroblast (HF19) cells exposed to either 0.1 Gy or 1 Gy of X-rays delivered either as an acute (0.42 Gy/min) or protracted (0.0031 Gy/min) exposure. While the expected increase in MN was observed following the first mitosis of the irradiated cells compared to unirradiated controls, the results also demonstrate a significant increase in MN yields in the progeny of these cells at 10 and 20 population doublings following irradiation. Minimal difference was observed between the two doses used (0.1 and 1 Gy) and the dose rates (acute and protracted). Therefore, these nontargeted effects have the potential to be important for the low-dose and dose-rate exposure. The results also show an enhancement of the cellular levels of reactive oxygen species after 20 population doublings, which suggests that ionising radiation (IR) could potentially perturb the homeostasis of oxidative stress and so modify the background rate of endogenous DNA damage induction. In conclusion, the investigations have demonstrated that normal primary human fibroblast (HF19) cells are susceptible to the induction of early DNA damage and RIGI, not only after a high dose and high dose rate exposure to low linear energy transfer, but also following low dose, low dose rate exposures. The results suggest that the mechanism of radiation induced RIGI in HF19 cells can be correlated with the induction of reactive oxygen species levels following exposure to 0.1 and 1 Gy low-dose rate and high-dose rate x-ray irradiation.
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Affiliation(s)
- Eman Mohammed Elbakrawy
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, England, UK.,Department of Radiation Physics, National Center for Radiation Research and Technology, Atomic Energy Authority, Nasr City, Cairo, Egypt
| | - Mark A Hill
- Department of Oncology, Gray Laboratories, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England, UK
| | - Munira A Kadhim
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, England, UK
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22
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Krewski D, Bird M, Al-Zoughool M, Birkett N, Billard M, Milton B, Rice JM, Grosse Y, Cogliano VJ, Hill MA, Baan RA, Little J, Zielinski JM. Key characteristics of 86 agents known to cause cancer in humans. J Toxicol Environ Health B Crit Rev 2019; 22:244-263. [PMID: 31637961 DOI: 10.1080/10937404.2019.1643536] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Since the inception of the International Agency for Research on Cancer (IARC) in the early 1970s, the IARC Monographs Programme has evaluated more than 1000 agents with respect to carcinogenic hazard; of these, up to and including Volume 119 of the IARC Monographs, 120 agents met the criteria for classification as carcinogenic to humans (Group 1). Volume 100 of the IARC Monographs provided a review and update of Group 1 carcinogens. These agents were divided into six broad categories: (I) pharmaceuticals; (II) biological agents; (III) arsenic, metals, fibers, and dusts; (IV) radiation; (V) personal habits and indoor combustions; and (VI) chemical agents and related occupations. Data on biological mechanisms of action (MOA) were extracted from the Monographs to assemble a database on the basis of ten key characteristics attributed to human carcinogens. After some grouping of similar agents, the characteristic profiles were examined for 86 Group 1 agents for which mechanistic information was available in the IARC Monographs up to and including Volume 106, based upon data derived from human in vivo, human in vitro, animal in vivo, and animal in vitro studies. The most prevalent key characteristic was "is genotoxic", followed by "alters cell proliferation, cell death, or nutrient supply" and "induces oxidative stress". Most agents exhibited several of the ten key characteristics, with an average of four characteristics per agent, a finding consistent with the notion that cancer development in humans involves multiple pathways. Information on the key characteristics was often available from multiple sources, with many agents demonstrating concordance between human and animal sources, particularly with respect to genotoxicity. Although a detailed comparison of the characteristics of different types of agents was not attempted here, the overall characteristic profiles for pharmaceutical agents and for chemical agents and related occupations appeared similar. Further in-depth analyses of this rich database of characteristics of human carcinogens are expected to provide additional insights into the MOA of human cancer development.
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Affiliation(s)
- Daniel Krewski
- McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- Risk Sciences International, Ottawa, Canada
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
| | - Michael Bird
- McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Mustafa Al-Zoughool
- McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- Department of Community and Environmental Health, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Nicholas Birkett
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
| | - Mélissa Billard
- McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Jerry M Rice
- Department of Oncology, Georgetown University Medical Center, Georgetown University, Washington, DC, USA
| | - Yann Grosse
- IARC Monographs Programme, International Agency for Research on Cancer, Lyon, France
| | - Vincent J Cogliano
- National Center for Environmental Assessment, U.S. Environmental Protection Agency, Washington, DC, USA
| | - Mark A Hill
- Department of Oncology, University of Oxford, Oxford, UK
| | - Robert A Baan
- International Agency for Research on Cancer (retired), Lyon, France
| | - Julian Little
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
| | - Jan M Zielinski
- McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
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23
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Fouad S, Wells OS, Hill MA, D'Angiolella V. Cullin Ring Ubiquitin Ligases (CRLs) in Cancer: Responses to Ionizing Radiation (IR) Treatment. Front Physiol 2019; 10:1144. [PMID: 31632280 PMCID: PMC6781834 DOI: 10.3389/fphys.2019.01144] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 08/22/2019] [Indexed: 12/19/2022] Open
Abstract
Treatment with ionizing radiation (IR) remains the cornerstone of therapy for multiple cancer types, including disseminated and aggressive diseases in the palliative setting. Radiotherapy efficacy could be improved in combination with drugs that regulate the ubiquitin-proteasome system (UPS), many of which are currently being tested in clinical trials. The UPS operates through the covalent attachment of ATP-activated ubiquitin molecules onto substrates following the transfer of ubiquitin from an E1, to an E2, and then to the substrate via an E3 enzyme. The specificity of ubiquitin ligation is dictated by E3 ligases, which select substrates to be ubiquitylated. Among the E3s, cullin ring ubiquitin ligases (CRLs) represent prototypical multi-subunit E3s, which use the cullin subunit as a central assembling scaffold. CRLs have crucial roles in controlling the cell cycle, hypoxia signaling, reactive oxygen species clearance and DNA repair; pivotal factors regulating the cancer and normal tissue response to IR. Here, we summarize the findings on the involvement of CRLs in the response of cancer cells to IR, and we discuss the therapeutic approaches to target the CRLs which could be exploited in the clinic.
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Affiliation(s)
- Shahd Fouad
- Medical Research Council Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Owen S Wells
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Mark A Hill
- Medical Research Council Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Vincenzo D'Angiolella
- Medical Research Council Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
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24
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Lee BQ, Abbott EM, Able S, Thompson JM, Hill MA, Kartsonaki C, Vallis KA, Falzone N. Radiosensitivity of colorectal cancer to 90Y and the radiobiological implications for radioembolisation therapy. Phys Med Biol 2019; 64:135018. [PMID: 31117062 PMCID: PMC6611228 DOI: 10.1088/1361-6560/ab23c4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Approximately 50% of all colorectal cancer (CRC) patients will develop metastasis to the liver. 90Y selective internal radiation therapy (SIRT) is an established treatment for metastatic CRC. There is still a fundamental lack of understanding regarding the radiobiology underlying the dose response. This study was designed to determine the radiosensitivity of two CRC cell lines (DLD-1 and HT-29) to 90Y β− radiation exposure, and thus the relative effectiveness of 90Y SIRT in relation to external beam radiotherapy (EBRT). A 90Y-source dish was sandwiched between culture dishes to irradiate DLD-1 or HT-29 cells for a period of 6 d. Cell survival was determined by clonogenic assay. Dose absorbed per 90Y disintegration was calculated using the PENELOPE Monte Carlo code. PENELOPE simulations were benchmarked against relative dose measurements using EBT3 GAFchromic™ film. Statistical regression based on the linear-quadratic model was used to determine the radiosensitivity parameters and using R. These results were compared to radiosensitivity parameters determined for 6 MV clinical x-rays and 137Cs γ-ray exposure. Equivalent dose of EBRT in 2 Gy () and 10 Gy () fractions were derived for 90Y dose. HT-29 cells were more radioresistant than DLD-1 for all treatment modalities. Radiosensitivity parameters determined for 6 MV x-rays and 137Cs γ-ray were equivalent for both cell lines. The ratio for 90Y β−-particle exposure was over an order of magnitude higher than the other two modalities due to protraction of dose delivery. Consequently, an 90Y SIRT absorbed dose of 60 Gy equates to an of 28.7 and 54.5 Gy and an of 17.6 and 19.3 Gy for DLD-1 and HT-29 cell lines, respectively. We derived radiosensitivity parameters for two CRC cell lines exposed to 90Y β−-particles, 6 MV x-rays, and 137Cs γ-ray irradiation. These radiobiological parameters are critical to understanding the dose response of CRC lesions and ultimately informs the efficacy of 90Y SIRT relative to other radiation therapy modalities.
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Affiliation(s)
- Boon Q Lee
- CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom. Joint first authors. Author to whom any correspondence should be addressed
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25
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Thompson JM, Elliott A, D’Abrantes S, Sawakuchi GO, Hill MA. TRACKING DOWN ALPHA-PARTICLES: THE DESIGN, CHARACTERISATION AND TESTING OF A SHALLOW-ANGLED ALPHA-PARTICLE IRRADIATOR. Radiat Prot Dosimetry 2019; 183:264-269. [PMID: 30726978 PMCID: PMC6525335 DOI: 10.1093/rpd/ncy300] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Indexed: 06/09/2023]
Abstract
Human exposure to α-particles from radon and other radionuclides is associated with carcinogenesis, but if well controlled and targeted to cancer cells, α-particles may be used in radiotherapy. Thus, it is important to understand the biological effects of α-particles to predict cancer risk and optimise radiotherapy. To enable studies of α-particles in cells, we developed and characterised an α-particle automated irradiation rig that allows exposures at a shallow angle (70° to the normal) of cell monolayers in a 30 mm diameter dish to complement standard perpendicular irradiations. The measured incident energy of the α-particles was 3.3 ± 0.5 MeV (LET in water = 120 keV μm-1), with a maximum incident dose rate of 1.28 ± 0.02 Gy min-1, which for a 5 μm cell monolayer corresponds to a mean dose rate of 1.57 ± 0.02 Gy min-1 and a mean LET in water of 154 keV μm-1. The feasibility of resolving radiation-induced DNA double-strand breaks (DSB) foci along the track of α-particles was demonstrated using immunofluorescent labelling with γH2AX and 53BP1 in normal MRC-5 human lung cells.
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Affiliation(s)
- James M Thompson
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Amy Elliott
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Sofia D’Abrantes
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Gabriel O Sawakuchi
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1400 Pressler St., Unit 1420, Houston, TX 77030, USA
| | - Mark A Hill
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB Roosevelt Drive, Oxford OX3 7DQ, UK
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26
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Carter RJ, Nickson CM, Thompson JM, Kacperek A, Hill MA, Parsons JL. Characterisation of Deubiquitylating Enzymes in the Cellular Response to High-LET Ionizing Radiation and Complex DNA Damage. Int J Radiat Oncol Biol Phys 2019; 104:656-665. [PMID: 30851349 PMCID: PMC6542414 DOI: 10.1016/j.ijrobp.2019.02.053] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 01/31/2019] [Accepted: 02/26/2019] [Indexed: 12/11/2022]
Abstract
PURPOSE Ionizing radiation, particular high-linear energy transfer (LET) radiation, can induce complex DNA damage (CDD) wherein 2 or more DNA lesions are induced in close proximity, which contributes significantly to the cell killing effects. However, knowledge of the enzymes and mechanisms involved in coordinating the recognition and processing of CDD in cellular DNA are currently lacking. METHODS AND MATERIALS A small interfering RNA screen of deubiquitylation enzymes was conducted in HeLa cells irradiated with high-LET α-particles or protons, versus low-LET protons and x-rays, and cell survival was monitored by clonogenic assays. Candidates whose depletion led to decreased cell survival specifically in response to high-LET radiation were validated in both HeLa and oropharyngeal squamous cell carcinoma (UMSCC74A) cells, and the association with CDD repair was confirmed using an enzyme modified neutral comet assay. RESULTS Depletion of USP6 decreased cell survival specifically after high-LET α-particles and protons, but not low-LET protons or x-rays. USP6 depletion caused cell cycle arrest and a deficiency in CDD repair mediated through instability of poly(ADP-ribose) polymerase-1 (PARP-1) protein. Increased radiosensitivity of cells to high-LET protons as a consequence of defective CDD repair was furthermore mimicked using the PARP inhibitor olaparib, and through PARP-1 small interfering RNA. CONCLUSIONS USP6 controls cell survival in response to high-LET radiation by stabilizing PARP-1 protein levels, which is essential for CDD repair. We also describe synergy between CDD induced by high-LET protons and PARP inhibition, or PARP-1 depletion, in effective cancer cell killing.
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Affiliation(s)
- Rachel J Carter
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Catherine M Nickson
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, United Kingdom
| | - James M Thompson
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, Oxford, United Kingdom
| | - Andrzej Kacperek
- The National Eye Proton Therapy Centre, The Clatterbridge Cancer Centre NHS Foundation Trust, Bebington, United Kingdom
| | - Mark A Hill
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, Oxford, United Kingdom
| | - Jason L Parsons
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, United Kingdom.
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27
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Hill MA. Two Web Resources Linking Major Human Embryology Collections Worldwide. Cells Tissues Organs 2019; 205:293-302. [PMID: 30673660 DOI: 10.1159/000495619] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 11/20/2018] [Indexed: 11/19/2022] Open
Abstract
Human embryology is a core subject for medicine and current research. While animal models of development now have significant online resources available, the vast majority of human embryonic material is locked up in historic collections. When accessed today, these collections are still contributing to our understanding of human development. This paper describes two online resources for studying human development that are unlocking these invaluable collections and providing related human developmental resources. The first of these is the online Embryology website (http://tiny.cc/Embryo) that links the human developmental timeline to historic and current research findings. Secondly is the Digital Embryology Consortium (https://human-embryology.org), an international research partnership to digitise, preserve, and make the major embryology histological collections available for researchers. By making this histological material more widely available to researchers with new methods of analysis, a better understanding of human development can be reached. This also opens the opportunity for new 3D reconstruction and virtual reality representation of these embryos.
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Affiliation(s)
- Mark A Hill
- Anatomy, School of Medical Sciences, UNSW Sydney, Sydney, New South Wales, Australia,
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28
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Martin S, Prise KM, Hill MA. Pushing the frontiers of radiobiology: A special feature in memory of Sir Oliver Scott and Professor Jack Fowler. Br J Radiol 2019. [DOI: 10.1259/bjr.20189005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Stewart Martin
- Department of Clinical Oncology, Translational & Radiation Biology Research Group, Division of Cancer and Stem Cells, University of Nottingham, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Kevin M Prise
- Centre for Cancer Research and Cell Biology, Queen’s University Belfast, Belfast, UK
| | - Mark A Hill
- Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford, UK
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29
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Hallgren S, Hill MA, Thompson JM, Elliott A, Paddick I, Jones B, Hopewell JW. Effects of variations in overall treatment time on the clonogenic survival of V79-4 cells: Implications for radiosurgery. J Radiosurg SBRT 2019; 6:1-9. [PMID: 30775069 PMCID: PMC6355450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 12/08/2018] [Indexed: 06/09/2023]
Abstract
The importance of effects related to the repair of sublethal radiation damage as treatment duration varies, partly a function of dose-rate, is a current controversy in clinical radiosurgery. Cell survival studies have been performed to verify the importance of this effect in relation to established models. Mammalian V79-4 cells were irradiated in vitro with γ-rays, either as an acute exposure in a few minutes, where the effects of sublethal irradiation damage repair over the period of exposure can be ignored, or as protracted exposures delivered over 15-120 min. Protraction was achieved either by introducing a variable time gap between two doses of 7 Gy, or as a continuous exposure at lower dose rates so that a range of doses were delivered in fixed times of 30, 60 or 120 min. For all doses there was a progressive reduction in efficacy with increasing overall treatment time. This was illustrated by the progressive increase in clonogenic cell survival with a resulting right shift of the survival curves. Cell survival curves for irradiations given either as an acute exposure (6.1 Gy/min), over fixed times (30, 60 and 120 min) or for a fixed low dose-rate (0.2 Gy/min) were well fitted by the Linear Quadratic (LQ) model giving an α/β ratio of 4.0 Gy and a single repair half-time of 31.5 min. The present results are consistent with published data with respect to the response of solid tumors and normal tissues, whose response to both continuous and fractionated irradiation is also well described by the LQ model. This suggests the need for dose compensation in radiosurgical treatments, and other forms of radiotherapy, where dose is delivered over a similar range of protracted overall treatment times, perhaps as a prerequisite to full biological effective dose treatment planning.
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Affiliation(s)
- Steven Hallgren
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Mark A Hill
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - James M Thompson
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Amy Elliott
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Ian Paddick
- Queen Square Radiosurgery Centre, National Hospital for Neurology and Neurosurgery, London, UK
| | - Bleddyn Jones
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB Roosevelt Drive, Oxford, OX3 7DQ, UK
- Green Temple College, University of Oxford, Oxford UK
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30
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Hill MA. Track to the future: historical perspective on the importance of radiation track structure and DNA as a radiobiological target. Int J Radiat Biol 2018; 94:759-768. [PMID: 29219655 PMCID: PMC6113897 DOI: 10.1080/09553002.2017.1387304] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 09/22/2017] [Accepted: 09/27/2017] [Indexed: 12/04/2022]
Abstract
PURPOSE Understanding the mechanisms behind induced biological response following exposure to ionizing radiation is not only important in assessing the risk associated with human exposure, but potentially can help identify ways of improving the efficacy of radiotherapy. Over the decades, there has been much discussion on what is the key biological target for radiation action and its associated size. It was already known in the 1930s that microscopic features of radiation significantly influenced biological outcomes. This resulted in the development of classic target theory, leading to field of microdosimetry and subsequently nanodosimetry, studying the inhomogeneity and stochastics of interactions, along with the identification of DNA as a key target. CONCLUSIONS Ultimately, the biological response has been found to be dependent on the radiation track structure (spatial and temporal distribution of ionization and excitation events). Clustering of energy deposition on the nanometer scale has been shown to play a critical role in determining biological response, producing not just simple isolated DNA lesions but also complex clustered lesions that are more difficult to repair. The frequency and complexity of these clustered damage sites are typically found to increase with increasing LET. However in order to fully understand the consequences, it is important to look at the relative distribution of these lesions over larger dimensions along the radiation track, up to the micrometer scale. Correlation of energy deposition events and resulting sites of DNA damage can ultimately result in complex gene mutations and complex chromosome rearrangements following repair, with the frequency and spectrum of the resulting rearrangements critically dependent on the spatial and temporal distribution of these sites and therefore the radiation track. Due to limitations in the techniques used to identify these rearrangements it is likely that the full complexity of the genetic rearrangements that occur has yet to be revealed. This paper discusses these issues from a historical perspective, with many of these historical studies still having relevance today. These can not only cast light on current studies but guide future studies, especially with the increasing range of biological techniques available. So, let us build on past knowledge to effectively explore the future.
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Affiliation(s)
- Mark A. Hill
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB Roosevelt Drive, Oxford, UK
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31
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Cole JM, Symes DR, Lopes NC, Wood JC, Poder K, Alatabi S, Botchway SW, Foster PS, Gratton S, Johnson S, Kamperidis C, Kononenko O, De Lazzari M, Palmer CAJ, Rusby D, Sanderson J, Sandholzer M, Sarri G, Szoke-Kovacs Z, Teboul L, Thompson JM, Warwick JR, Westerberg H, Hill MA, Norris DP, Mangles SPD, Najmudin Z. High-resolution μCT of a mouse embryo using a compact laser-driven X-ray betatron source. Proc Natl Acad Sci U S A 2018; 115:6335-6340. [PMID: 29871946 PMCID: PMC6016801 DOI: 10.1073/pnas.1802314115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the field of X-ray microcomputed tomography (μCT) there is a growing need to reduce acquisition times at high spatial resolution (approximate micrometers) to facilitate in vivo and high-throughput operations. The state of the art represented by synchrotron light sources is not practical for certain applications, and therefore the development of high-brightness laboratory-scale sources is crucial. We present here imaging of a fixed embryonic mouse sample using a compact laser-plasma-based X-ray light source and compare the results to images obtained using a commercial X-ray μCT scanner. The radiation is generated by the betatron motion of electrons inside a dilute and transient plasma, which circumvents the flux limitations imposed by the solid or liquid anodes used in conventional electron-impact X-ray tubes. This X-ray source is pulsed (duration <30 fs), bright (>1010 photons per pulse), small (diameter <1 μm), and has a critical energy >15 keV. Stable X-ray performance enabled tomographic imaging of equivalent quality to that of the μCT scanner, an important confirmation of the suitability of the laser-driven source for applications. The X-ray flux achievable with this approach scales with the laser repetition rate without compromising the source size, which will allow the recording of high-resolution μCT scans in minutes.
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Affiliation(s)
- Jason M Cole
- The John Adams Institute for Accelerator Science, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - Daniel R Symes
- Central Laser Facility, Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom;
| | - Nelson C Lopes
- The John Adams Institute for Accelerator Science, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
- Group of Lasers and Plasmas (GoLP)/Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, University of Lisbon, Lisboa 1049-001, Portugal
| | - Jonathan C Wood
- The John Adams Institute for Accelerator Science, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - Kristjan Poder
- The John Adams Institute for Accelerator Science, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - Saleh Alatabi
- The John Adams Institute for Accelerator Science, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - Stanley W Botchway
- Central Laser Facility, Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - Peta S Foster
- Central Laser Facility, Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - Sarah Gratton
- Central Laser Facility, Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - Sara Johnson
- The Mary Lyon Centre, MRC Harwell Institute, Harwell OX11 0RD, United Kingdom
| | - Christos Kamperidis
- The John Adams Institute for Accelerator Science, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
- Extreme Light Infrastructure Attosecond Light Pulse Source (ELI-ALPS), ELI-HU Non-profit Ltd., H-6720 Szeged, Hungary
| | - Olena Kononenko
- Linear Accelerator Technologies, Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg, Germany
| | - Michael De Lazzari
- Cancer Research UK/Medical Research Council (CRUK/MRC) Oxford Institute for Radiation Research, Gray Laboratories, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Charlotte A J Palmer
- Linear Accelerator Technologies, Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg, Germany
| | - Dean Rusby
- Central Laser Facility, Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - Jeremy Sanderson
- Medical Research Council (MRC) Harwell Institute, Harwell OX11 0RD, United Kingdom
| | - Michael Sandholzer
- Medical Research Council (MRC) Harwell Institute, Harwell OX11 0RD, United Kingdom
| | - Gianluca Sarri
- School of Mathematics and Physics, Queen's University, Belfast BT7 1NN, United Kingdom
| | | | - Lydia Teboul
- The Mary Lyon Centre, MRC Harwell Institute, Harwell OX11 0RD, United Kingdom
| | - James M Thompson
- Cancer Research UK/Medical Research Council (CRUK/MRC) Oxford Institute for Radiation Research, Gray Laboratories, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Jonathan R Warwick
- School of Mathematics and Physics, Queen's University, Belfast BT7 1NN, United Kingdom
| | - Henrik Westerberg
- Medical Research Council (MRC) Harwell Institute, Harwell OX11 0RD, United Kingdom
| | - Mark A Hill
- Cancer Research UK/Medical Research Council (CRUK/MRC) Oxford Institute for Radiation Research, Gray Laboratories, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Dominic P Norris
- Medical Research Council (MRC) Harwell Institute, Harwell OX11 0RD, United Kingdom
| | - Stuart P D Mangles
- The John Adams Institute for Accelerator Science, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - Zulfikar Najmudin
- The John Adams Institute for Accelerator Science, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
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Verhaegen F, Dubois L, Gianolini S, Hill MA, Karger CP, Lauber K, Prise KM, Sarrut D, Thorwarth D, Vanhove C, Vojnovic B, Weersink R, Wilkens JJ, Georg D. ESTRO ACROP: Technology for precision small animal radiotherapy research: Optimal use and challenges. Radiother Oncol 2018; 126:471-478. [PMID: 29269093 DOI: 10.1016/j.radonc.2017.11.016] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 11/21/2017] [Indexed: 11/30/2022]
Abstract
Many radiotherapy research centers have recently installed novel research platforms enabling the investigation of the radiation response of tumors and normal tissues in small animal models, possibly in combination with other treatment modalities. Many more research institutes are expected to follow in the coming years. These novel platforms are capable of mimicking human radiotherapy more closely than older technology. To facilitate the optimal use of these novel integrated precision irradiators and various small animal imaging devices, and to maximize the impact of the associated research, the ESTRO committee on coordinating guidelines ACROP (Advisory Committee in Radiation Oncology Practice) has commissioned a report to review the state of the art of the technology used in this new field of research, and to issue recommendations. This report discusses the combination of precision irradiation systems, small animal imaging (CT, MRI, PET, SPECT, bioluminescence) systems, image registration, treatment planning, and data processing. It also provides guidelines for reporting on studies.
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Affiliation(s)
- Frank Verhaegen
- Department of Radiation Oncology (MAASTRO), GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands
| | - Ludwig Dubois
- Department of Radiation Oncology (MAASTRO), GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands
| | | | - Mark A Hill
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, UK
| | - Christian P Karger
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg, Germany; National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - Kirsten Lauber
- Department of Radiation Oncology, University Hospital, Ludwig-Maximilians-University of Munich, Germany
| | - Kevin M Prise
- Centre for Cancer Research & Cell Biology, Queen's University Belfast, UK
| | - David Sarrut
- Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, Centre Léon Bérard, France
| | - Daniela Thorwarth
- Section for Biomedical Physics, Department of Radiation Oncology, University Hospital Tübingen, Germany
| | - Christian Vanhove
- Institute Biomedical Technology (IBiTech), Medical Imaging and Signal Processing (MEDISIP), Ghent University, Belgium
| | - Boris Vojnovic
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, UK
| | - Robert Weersink
- Department of Radiation Oncology, University of Toronto, Department of Radiation Medicine, Princess Margaret Hospital, Canada
| | - Jan J Wilkens
- Department of Radiation Oncology, Technical University of Munich, Klinikum rechts der Isar, Germany
| | - Dietmar Georg
- Division of Medical Radiation Physics, Department of Radiation Oncology and Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Austria
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Affiliation(s)
- Mark A Hill
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB Roosevelt Drive, Oxford, UK
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Carter RJ, Nickson CM, Thompson JM, Kacperek A, Hill MA, Parsons JL. Complex DNA Damage Induced by High Linear Energy Transfer Alpha-Particles and Protons Triggers a Specific Cellular DNA Damage Response. Int J Radiat Oncol Biol Phys 2017; 100:776-784. [PMID: 29413288 PMCID: PMC5796827 DOI: 10.1016/j.ijrobp.2017.11.012] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 10/27/2017] [Accepted: 11/07/2017] [Indexed: 12/31/2022]
Abstract
Purpose To investigate the precise mechanism of recognition and processing of ionizing radiation (IR)-induced complex DNA damage (CDD), where two or more DNA lesions are in close proximity, in cellular DNA which is packaged with histones to form chromatin. Methods and Materials HeLa and oropharyngeal squamous cell carcinoma (UMSCC74A and UMSCC6) cells were irradiated with high linear energy transfer (LET) α-particles or protons, versus low-LET protons and X rays. At various time points after irradiation, site-specific histone post-translational modifications were analyzed by quantitative Western blotting; DNA damage and repair were measured by different versions of the comet assay; and cell survival was determined using clonogenic assays. Results Site-specific histone post-translational modifications after low- and high-LET radiation, particularly proton irradiation, were screened, aiming to identify those responsive to CDD. We demonstrate that histone H2B ubiquitylated on lysine 120 (H2Bub) is specifically induced several hours after irradiation in response to high-LET α-particles and protons but not by low-LET protons or X rays/γ-radiation. This is associated with increased levels of CDD, which contributes to decreased cell survival. We further discovered that modulation of H2Bub is under the control of two E3 ubiquitin ligases, MSL2 and RNF20/RNF40 complex, whose depletion leads to defective processing and further persistence of CDD, and to additional decreased cell survival after irradiation. Conclusion This study demonstrates that the signaling and repair of CDD, particularly induced by high-LET IR is co-ordinated through the specific induction of H2Bub catalyzed by MSL2 and RNF20/40, a mechanism that contributes significantly to cell survival after irradiation.
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Affiliation(s)
- Rachel J Carter
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, United Kingdom
| | - Catherine M Nickson
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, United Kingdom
| | - James M Thompson
- Gray Laboratories, Cancer Research UK/Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - Andrzej Kacperek
- The National Eye Proton Therapy Centre, The Clatterbridge Cancer Centre NHS Foundation Trust, Bebington, United Kingdom
| | - Mark A Hill
- Gray Laboratories, Cancer Research UK/Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - Jason L Parsons
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, United Kingdom.
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Abnave P, Aboukhatwa E, Kosaka N, Thompson J, Hill MA, Aboobaker AA. Epithelial-mesenchymal transition transcription factors control pluripotent adult stem cell migration in vivo in planarians. Development 2017; 144:3440-3453. [PMID: 28893948 PMCID: PMC5665486 DOI: 10.1242/dev.154971] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 08/14/2017] [Indexed: 01/23/2023]
Abstract
Migration of stem cells underpins the physiology of metazoan animals. For tissues to be maintained, stem cells and their progeny must migrate and differentiate in the correct positions. This need is even more acute after tissue damage by wounding or pathogenic infection. Inappropriate migration also underpins metastasis. Despite this, few mechanistic studies address stem cell migration during repair or homeostasis in adult tissues. Here, we present a shielded X-ray irradiation assay that allows us to follow stem cell migration in planarians. We demonstrate the use of this system to study the molecular control of stem cell migration and show that snail-1, snail-2 and zeb-1 EMT transcription factor homologs are necessary for cell migration to wound sites and for the establishment of migratory cell morphology. We also observed that stem cells undergo homeostatic migration to anterior regions that lack local stem cells, in the absence of injury, maintaining tissue homeostasis. This requires the polarity determinant notum Our work establishes planarians as a suitable model for further in-depth study of the processes controlling stem cell migration in vivo.
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Affiliation(s)
- Prasad Abnave
- Department of Zoology, Tinbergen Building, South Parks Road, University of Oxford, Oxford OX1 3PS, UK
| | - Ellen Aboukhatwa
- Department of Zoology, Tinbergen Building, South Parks Road, University of Oxford, Oxford OX1 3PS, UK
| | - Nobuyoshi Kosaka
- Department of Zoology, Tinbergen Building, South Parks Road, University of Oxford, Oxford OX1 3PS, UK
| | - James Thompson
- CRUK/MRC Oxford Institute for Radiation Oncology, ORCRB Roosevelt Drive, University of Oxford, Oxford OX3 7DQ, UK
| | - Mark A Hill
- CRUK/MRC Oxford Institute for Radiation Oncology, ORCRB Roosevelt Drive, University of Oxford, Oxford OX3 7DQ, UK
| | - A Aziz Aboobaker
- Department of Zoology, Tinbergen Building, South Parks Road, University of Oxford, Oxford OX1 3PS, UK
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Corroyer-Dulmont A, Falzone N, Kersemans V, Thompson J, Allen DP, Able S, Kartsonaki C, Malcolm J, Kinchesh P, Hill MA, Vojnovic B, Smart SC, Gaze MN, Vallis KA. Improved outcome of 131I-mIBG treatment through combination with external beam radiotherapy in the SK-N-SH mouse model of neuroblastoma. Radiother Oncol 2017; 124:488-495. [PMID: 28595752 PMCID: PMC5636618 DOI: 10.1016/j.radonc.2017.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 05/03/2017] [Accepted: 05/04/2017] [Indexed: 12/03/2022]
Abstract
PURPOSE To assess the efficacy of different schedules for combining external beam radiotherapy (EBRT) with molecular radiotherapy (MRT) using 131I-mIBG in the management of neuroblastoma. MATERIALS AND METHODS BALB/c nu/nu mice bearing SK-N-SH neuroblastoma xenografts were assigned to five treatment groups: 131I-mIBG 24h after EBRT, EBRT 6days after 131I-mIBG, EBRT alone, 131I-mIBG alone and control (untreated). A total of 56 mice were assigned to 3 studies. Study 1: Vessel permeability was evaluated using dynamic contrast-enhanced (DCE)-MRI (n=3). Study 2: Tumour uptake of 131I-mIBG in excised lesions was evaluated by γ-counting and autoradiography (n=28). Study 3: Tumour volume was assessed by longitudinal MR imaging and survival was analysed (n=25). Tumour dosimetry was performed using Monte Carlo simulations of absorbed fractions with the radiation transport code PENELOPE. RESULTS Given alone, both 131I-mIBG and EBRT resulted in a seven-day delay in tumour regrowth. Following EBRT, vessel permeability was evaluated by DCE-MRI and showed an increase at 24h post irradiation that correlated with an increase in 131I-mIBG tumour uptake, absorbed dose and overall survival in the case of combined treatment. Similarly, EBRT administered seven days after MRT to coincide with tumour regrowth, significantly decreased the tumour volume and increased overall survival. CONCLUSIONS This study demonstrates that combining EBRT and MRT has an enhanced therapeutic effect and emphasizes the importance of treatment scheduling according to pathophysiological criteria such as tumour vessel permeability and tumour growth kinetics.
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Affiliation(s)
| | - Nadia Falzone
- CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, Oxford University, UK
| | - Veerle Kersemans
- CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, Oxford University, UK
| | - James Thompson
- CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, Oxford University, UK
| | - Danny P Allen
- CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, Oxford University, UK
| | - Sarah Able
- CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, Oxford University, UK
| | | | - Javian Malcolm
- CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, Oxford University, UK
| | - Paul Kinchesh
- CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, Oxford University, UK
| | - Mark A Hill
- CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, Oxford University, UK
| | - Boris Vojnovic
- CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, Oxford University, UK
| | - Sean C Smart
- CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, Oxford University, UK
| | - Mark N Gaze
- University College London Hospitals NHS Foundation Trust, London, UK
| | - Katherine A Vallis
- CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, Oxford University, UK.
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Hill MA, Thompson JM, Kavanagh A, Tullis IDC, Newman RG, Prentice J, Beech J, Gilchrist S, Smart S, Fokas E, Vojnovic B. The Development of Technology for Effective Respiratory-Gated Irradiation Using an Image-Guided Small Animal Irradiator. Radiat Res 2017; 188:247-263. [PMID: 28715250 DOI: 10.1667/rr14753.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The development of image-guided small animal irradiators represents a significant improvement over standard irradiators by enabling preclinical studies to mimic radiotherapy in humans. The ability to deliver tightly collimated targeted beams, in conjunction with gantry or animal couch rotation, has the potential to maximize tumor dose while sparing normal tissues. However, the current commercial platforms do not incorporate respiratory gating, which is required for accurate and precise targeting in organs subject to respiration related motions that may be up to the order of 5 mm in mice. Therefore, a new treatment head assembly for the Xstrahl Small Animal Radiation Research Platform (SARRP) has been designed. This includes a fast X-ray shutter subsystem, a motorized beam hardening filter assembly, an integrated transmission ionization chamber to monitor beam delivery, a kinematically positioned removable beam collimator and a targeting laser exiting the center of the beam collimator. The X-ray shutter not only minimizes timing errors but also allows beam gating during imaging and treatment, with irradiation only taking place during the breathing cycle when tissue movement is minimal. The breathing related movement is monitored by measuring, using a synchronous detector/lock-in amplifier that processes diffuse reflectance light from a modulated light source. After thresholding of the resulting signal, delays are added around the inhalation/exhalation phases, enabling the "no movement" period to be isolated and to open the X-ray shutter. Irradiation can either be performed for a predetermined time of X-ray exposure, or through integration of a current from the transmission monitor ionization chamber (corrected locally for air density variations). The ability to successfully deliver respiratory-gated X-ray irradiations has been demonstrated by comparing movies obtained using planar X-ray imaging with and without respiratory gating, in addition to comparing dose profiles observed from a collimated beam on EBT3 radiochromic film mounted on the animal's chest. Altogether, the development of respiratory-gated irradiation facilitates improved dose delivery during animal movement and constitutes an important new tool for preclinical radiation studies. This approach is particularly well suited for irradiation of orthotopic tumors or other targets within the chest and abdomen where breathing related movement is significant.
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Affiliation(s)
- M A Hill
- Cancer Research UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, Oxford OX3 7DQ, United Kingdom
| | - J M Thompson
- Cancer Research UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, Oxford OX3 7DQ, United Kingdom
| | - A Kavanagh
- Cancer Research UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, Oxford OX3 7DQ, United Kingdom
| | - I D C Tullis
- Cancer Research UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, Oxford OX3 7DQ, United Kingdom
| | - R G Newman
- Cancer Research UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, Oxford OX3 7DQ, United Kingdom
| | - J Prentice
- Cancer Research UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, Oxford OX3 7DQ, United Kingdom
| | - J Beech
- Cancer Research UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, Oxford OX3 7DQ, United Kingdom
| | - S Gilchrist
- Cancer Research UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, Oxford OX3 7DQ, United Kingdom
| | - S Smart
- Cancer Research UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, Oxford OX3 7DQ, United Kingdom
| | - E Fokas
- Cancer Research UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, Oxford OX3 7DQ, United Kingdom
| | - B Vojnovic
- Cancer Research UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, Oxford OX3 7DQ, United Kingdom
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Caplan GA, Tai JI, Mohd Hanizan F, McVeigh CL, Hill MA, Poljak A. Cerebrospinal Fluid Apolipoprotein E Levels in Delirium. Dement Geriatr Cogn Dis Extra 2017; 7:240-248. [PMID: 28868067 PMCID: PMC5567000 DOI: 10.1159/000477847] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 05/29/2017] [Indexed: 12/23/2022] Open
Abstract
Background/Aims Delirium and the apolipoprotein E ε4 allele are risk factors for late-onset Alzheimer disease (LOAD), but the connection is unclear. We looked for an association. Methods Inpatients with delirium (n = 18) were compared with LOAD outpatients (n = 19), assaying blood and cerebrospinal fluid (CSF) using multiplex ELISA. Results The patients with delirium had a higher Confusion Assessment Method (CAM) score (5.6 ± 1.2 vs. 0.0 ± 0.0; p < 0.001) and Delirium Index (13.1 ± 4.0 vs. 2.9 ± 1.2; p = 0.001) but a lower Mini-Mental State Examination (MMSE) score (14.3 ± 6.8 vs. 20.8 ± 4.6; p = 0.003). There was a reduction in absolute CSF apolipoprotein E level during delirium (median [interquartile range]: 9.55 μg/mL [5.65–15.05] vs. 16.86 μg/mL [14.82–20.88]; p = 0.016) but no differences in apolipoprotein A1, B, C3, H, and J. There were no differences in blood apolipoprotein levels, and no correlations between blood and CSF apolipoprotein levels. CSF apolipoprotein E correlated negatively with the CAM score (r = −0.354; p = 0.034) and Delirium Index (r = −0.341; p = 0.042) but not with the Acute Physiology and Chronic Health Evaluation (APACHE) index, or the MMSE or Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE). Conclusion Reduced CSF apolipoprotein E levels during delirium may be a mechanistic link between two important risk factors for LOAD.
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Affiliation(s)
- Gideon A Caplan
- Department of Geriatric Medicine, Prince of Wales Hospital, Sydney, New South Wales, Australia.,Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales, Australia
| | - JIan Tai
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Fazrul Mohd Hanizan
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Catherine L McVeigh
- Department of Geriatric Medicine, Prince of Wales Hospital, Sydney, New South Wales, Australia.,Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales, Australia
| | - Mark A Hill
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Anne Poljak
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.,Bioanalytical Mass Spectrometry Facility, University of New South Wales, Sydney, New South Wales, Australia.,Centre for Healthy Brain Ageing, University of New South Wales, Sydney, New South Wales, Australia
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Morrison RA, Rybak-Smith MJ, Thompson JM, Thiebaut B, Hill MA, Townley HE. Efficacy of radiosensitizing doped titania nanoparticles under hypoxia and preparation of an embolic microparticle. Int J Nanomedicine 2017; 12:3851-3863. [PMID: 28572729 PMCID: PMC5441663 DOI: 10.2147/ijn.s127341] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The aim of this study was to develop a manufacturing protocol for large-scale production of doped titania radiosensitizing nanoparticles (NPs) to establish their activity under hypoxia and to produce a multimodal radiosensitizing embolic particle for cancer treatment. We have previously shown that radiosensitizing NPs can be synthesized from titania doped with rare earth elements, especially gadolinium. To translate this technology to the clinic, a crucial step is to find a suitable, scalable, high-throughput method. Herein, we have described the use of flame spray pyrolysis (FSP) to generate NPs from titanium and gadolinium precursors to produce titania NPs doped with 5 at% gadolinium. The NPs were fully characterized, and their capacity to act as radiosensitizers was confirmed by clonogenic assays. The integrity of the NPs in vitro was also ascertained due to the potentially adverse effects of free gadolinium in the body. The activity of the NPs was then studied under hypoxia since this is often a barrier to effective radiotherapy. In vitro radiosensitization experiments were performed with both the hypoxia mimetics deferoxamine and cobalt chloride and also under true hypoxia (oxygen concentration of 0.2%). It was shown that the radiosensitizing NPs were able to cause a significant increase in cell death even after irradiation under hypoxic conditions such as those found in tumors. Subsequently, the synthesized NPs were used to modify polystyrene embolization microparticles. The NPs were sintered to the surface of the microparticles by heating at 230°C for 15 minutes. This resulted in a good coverage of the surface and to generate embolization particles that were shown to be radiosensitizing. Such multimodal particles could therefore result in occlusion of the tumor blood vessels in conjunction with localized reactive oxygen species generation, even under hypoxic conditions such as those found in the center of tumors.
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Affiliation(s)
| | | | - James M Thompson
- Gray Laboratories, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford
| | | | - Mark A Hill
- Gray Laboratories, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford
| | - Helen E Townley
- Department of Engineering Science.,Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital, University of Oxford, Oxford, UK
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Kersemans V, Beech JS, Gilchrist S, Kinchesh P, Allen PD, Thompson J, Gomes AL, D’Costa Z, Bird L, Tullis IDC, Newman RG, Corroyer-Dulmont A, Falzone N, Azad A, Vallis KA, Sansom OJ, Muschel RJ, Vojnovic B, Hill MA, Fokas E, Smart SC. An efficient and robust MRI-guided radiotherapy planning approach for targeting abdominal organs and tumours in the mouse. PLoS One 2017; 12:e0176693. [PMID: 28453537 PMCID: PMC5409175 DOI: 10.1371/journal.pone.0176693] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 04/16/2017] [Indexed: 12/20/2022] Open
Abstract
INTRODUCTION Preclinical CT-guided radiotherapy platforms are increasingly used but the CT images are characterized by poor soft tissue contrast. The aim of this study was to develop a robust and accurate method of MRI-guided radiotherapy (MR-IGRT) delivery to abdominal targets in the mouse. METHODS A multimodality cradle was developed for providing subject immobilisation and its performance was evaluated. Whilst CT was still used for dose calculations, target identification was based on MRI. Each step of the radiotherapy planning procedure was validated initially in vitro using BANG gel dosimeters. Subsequently, MR-IGRT of normal adrenal glands with a size-matched collimated beam was performed. Additionally, the SK-N-SH neuroblastoma xenograft model and the transgenic KPC model of pancreatic ductal adenocarcinoma were used to demonstrate the applicability of our methods for the accurate delivery of radiation to CT-invisible abdominal tumours. RESULTS The BANG gel phantoms demonstrated a targeting efficiency error of 0.56 ± 0.18 mm. The in vivo stability tests of body motion during MR-IGRT and the associated cradle transfer showed that the residual body movements are within this MR-IGRT targeting error. Accurate MR-IGRT of the normal adrenal glands with a size-matched collimated beam was confirmed by γH2AX staining. Regression in tumour volume was observed almost immediately post MR-IGRT in the neuroblastoma model, further demonstrating accuracy of x-ray delivery. Finally, MR-IGRT in the KPC model facilitated precise contouring and comparison of different treatment plans and radiotherapy dose distributions not only to the intra-abdominal tumour but also to the organs at risk. CONCLUSION This is, to our knowledge, the first study to demonstrate preclinical MR-IGRT in intra-abdominal organs. The proposed MR-IGRT method presents a state-of-the-art solution to enabling robust, accurate and efficient targeting of extracranial organs in the mouse and can operate with a sufficiently high throughput to allow fractionated treatments to be given.
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MESH Headings
- Abdomen/diagnostic imaging
- Abdomen/radiation effects
- Abdominal Neoplasms/diagnostic imaging
- Abdominal Neoplasms/radiotherapy
- Adrenal Glands/diagnostic imaging
- Adrenal Glands/radiation effects
- Animals
- Cell Line, Tumor
- Humans
- Magnetic Resonance Imaging/instrumentation
- Magnetic Resonance Imaging/methods
- Mice, Inbred BALB C
- Mice, Inbred CBA
- Mice, Inbred NOD
- Mice, Nude
- Mice, Transgenic
- Motion
- Multimodal Imaging/instrumentation
- Neoplasm Transplantation
- Phantoms, Imaging
- Radiometry/instrumentation
- Radiotherapy Dosage
- Radiotherapy Planning, Computer-Assisted/instrumentation
- Radiotherapy Planning, Computer-Assisted/methods
- Radiotherapy, Image-Guided/instrumentation
- Radiotherapy, Image-Guided/methods
- Tomography, X-Ray Computed/instrumentation
- Tomography, X-Ray Computed/methods
- Tumor Burden
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Affiliation(s)
- Veerle Kersemans
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - John S. Beech
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Stuart Gilchrist
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Paul Kinchesh
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Philip D. Allen
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - James Thompson
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Ana L. Gomes
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Zenobia D’Costa
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Luke Bird
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Iain D. C. Tullis
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Robert G. Newman
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Aurelien Corroyer-Dulmont
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Nadia Falzone
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Abul Azad
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Katherine A. Vallis
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Owen J. Sansom
- Cancer Research UK Beatson Institute, Glasgow, United Kingdom
| | - Ruth J. Muschel
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Borivoj Vojnovic
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Mark A. Hill
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Emmanouil Fokas
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
- Department of Radiotherapy and Oncology, Goethe University Frankfurt, Frankfurt, German
- German Cancer Research Center (DKFZ), Heidelberg, Germany, German Cancer Consortium (DKTK) (Partner Site), Frankfurt, Germany
| | - Sean C. Smart
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
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Hill MA, Vojnovic B. Implications of respiratory motion for small animal image-guided radiotherapy. Br J Radiol 2017; 90:20160482. [PMID: 27384471 PMCID: PMC5605024 DOI: 10.1259/bjr.20160482] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 06/24/2016] [Accepted: 06/28/2016] [Indexed: 11/06/2022] Open
Abstract
Image-guided small animal irradiators have the potential to make a significant impact on facilitating the translation of radiobiological research into the clinic. To fully exploit the improved precision in dose delivery to the target/tumour while minimizing dose to surrounding tissues, minimal positional error in the target is required. However, for many sites within the thorax and abdomen, respiratory motion may be a critical factor in limiting the accuracy of beam delivery and until now, very little attention has been paid to the impact and management of this motion. We report on the implications of respiratory motion with respect to the negative impact of delivered dose distributions and their assessment, ways being developed to effectively manage this motion, so that beam delivery only occurs during the stationary resting phase of the breathing cycle, and comment on the need to effectively integrate these developments into the software used to plan and control beam delivery. Altogether, the implementation of respiratory-gated imaging and beam delivery will lead to significant improvements in the precision in dose delivery and constitutes an important development for preclinical radiotherapy studies.
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Affiliation(s)
- Mark A Hill
- Cancer Research UK/Medical Research Council Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Borivoj Vojnovic
- Cancer Research UK/Medical Research Council Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
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Hill MA, O'Neill P, McKenna WG. Comments on potential health effects of MRI-induced DNA lesions: quality is more important to consider than quantity. Eur Heart J Cardiovasc Imaging 2016; 17:1230-1238. [PMID: 27550664 PMCID: PMC5081138 DOI: 10.1093/ehjci/jew163] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 07/13/2016] [Indexed: 01/01/2023] Open
Abstract
Magnetic resonance imaging (MRI) is increasingly being used in cardiology to detect heart disease and guide therapy. It is mooted to be a safer alternative to imaging techniques, such as computed tomography (CT) or coronary angiographic imaging. However, there has recently been an increased interest in the potential long-term health risks of MRI, especially in the light of the controversy resulting from a small number of research studies reporting an increase in DNA damage following exposure, with calls to limit its use and avoid unnecessary examination, according to the precautionary principle. Overall the published data are somewhat limited and inconsistent; the ability of MRI to produce DNA lesions has yet to be robustly demonstrated and future experiments should be carefully designed to optimize sensitivity and benchmarked to validate and assess reproducibility. The majority of the current studies have focussed on the initial induction of DNA damage, and this has led to comparisons between the reported induction of γH2AX and implied double-strand break (DSB) yields produced following MRI with induction by imaging techniques using ionizing radiation. However, γH2AX is not only a marker of classical double-ended DSB, but also a marker of stalled replication forks and in certain circumstances stalled DNA transcription. Additionally, ionizing radiation is efficient at producing complex DNA damage, unique to ionizing radiation, with an associated reduction in repairability. Even if the fields associated with MRI are capable of producing DNA damage, the lesions produced will in general be simple, similar to those produced by endogenous processes. It is therefore inappropriate to try and infer cancer risk by simply comparing the yields of γH2AX foci or DNA lesions potentially produced by MRI to those produced by a given exposure of ionizing radiation, which will generally be more biologically effective and have a greater probability of leading to long-term health effects. As a result, it is important to concentrate on more relevant downstream end points (e.g. chromosome aberration production), along with potential mechanisms by which MRI may lead to DNA lesions. This could potentially involve a perturbation in homeostasis of oxidative stress, modifying the background rate of endogenous DNA damage induction. In summary, what the field needs at the moment is more research and less fear mongering.
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Affiliation(s)
- M A Hill
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB Roosevelt Drive, Oxford OX3 7DQ, UK
| | - P O'Neill
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB Roosevelt Drive, Oxford OX3 7DQ, UK
| | - W G McKenna
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, ORCRB Roosevelt Drive, Oxford OX3 7DQ, UK
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Abdelrazzak AB, Pottgießer SJ, Hill MA, O'Neill P, Bauer G. Enhancement of Peroxidase Release from Non-Malignant and Malignant Cells through Low-Dose Irradiation with Different Radiation Quality. Radiat Res 2016; 185:199-213. [PMID: 26849404 DOI: 10.1667/rr14245.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The release of peroxidase by nontransformed or transformed fibroblasts or epithelial cells (effector cells) triggers apoptosis induction selectively in transformed fibroblasts or transformed epithelial cells (target cells) through intercellular apoptosis-inducing signaling. The release of peroxidase can be induced either by treatment with transforming growth factor beta 1 or by low doses of alpha particles, gamma rays or ultrasoft X rays. In addiation, data indicates that radiation quality does not determine the overall efficiency of peroxidase release and the effects among a wide range of radiation doses are indistinguishable. These findings suggested that peroxidase release might be being triggered through intercellular bystander signaling. We show here that maximal peroxidase release does indeed occur after coculture of a small number of irradiated cells with an excess of unirradiated cells and demonstrate an enhanced effector function of nontransformed cells after the addition of a small number of irradiated cells. These data strongly indicate that peroxidase release is indeed triggered through bystander signaling mechanisms in mammalian cells.
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Affiliation(s)
- Abdelrazek B Abdelrazzak
- a CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford OX3 7DQ, United Kingdom; and
| | - Stefanie J Pottgießer
- b Institute of Virology, Department of Medical Microbiology and Hygiene, University Medical Center, Freiburg, Germany
| | - Mark A Hill
- a CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford OX3 7DQ, United Kingdom; and
| | - Peter O'Neill
- a CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford OX3 7DQ, United Kingdom; and
| | - Georg Bauer
- b Institute of Virology, Department of Medical Microbiology and Hygiene, University Medical Center, Freiburg, Germany
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Seo SJ, Han SM, Cho JH, Hyodo K, Zaboronok A, You H, Peach K, Hill MA, Kim JK. Enhanced production of reactive oxygen species by gadolinium oxide nanoparticles under core-inner-shell excitation by proton or monochromatic X-ray irradiation: implication of the contribution from the interatomic de-excitation-mediated nanoradiator effect to dose enhancement. Radiat Environ Biophys 2015; 54:423-431. [PMID: 26242374 DOI: 10.1007/s00411-015-0612-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 07/26/2015] [Indexed: 06/04/2023]
Abstract
Core-inner-valence ionization of high-Z nanoparticle atomic clusters can de-excite electrons through various interatomic de-excitation processes, thereby leading to the ionization of both directly exposed atoms and adjacent neutral atoms within the nanoparticles, and to an enhancement in photon-electron emission, which is termed the nanoradiator effect. To investigate the nanoradiator-mediated dose enhancement in the radio-sensitizing of high-Z nanoparticles, the production of reactive oxygen species (ROS) was measured in a gadolinium oxide nanoparticle (Gd-oxide NP) solution under core-inner-valence excitation of Gd with either 50 keV monochromatic synchrotron X-rays or 45 MeV protons. This measurement was compared with either a radiation-only control or a gadolinium-chelate magnetic resonance imaging contrast agent solution containing equal amounts of gadolinium as the separate atomic species in which Gd-Gd interatomic de-excitations are absent. Ionization excitations followed by ROS measurements were performed on nanoparticle-loaded cells or aqueous solutions. Both photoexcitation and proton impact produced a dose-dependent enhancement in the production of ROS by a range of factors from 1.6 to 1.94 compared with the radiation-only control. Enhanced production of ROS, by a factor of 1.83, was observed from Gd-oxide NP atomic clusters compared with the Gd-chelate molecule, with a Gd concentration of 48 μg/mL in the core-level photon excitation, or by a factor of 1.82 under a Gd concentration of 12 μg/mL for the proton impact at 10 Gy (p < 0.02). The enhanced production of ROS in the irradiated nanoparticles suggests the potential for additional therapeutic dose enhancements in radiation treatment via the potent Gd-Gd interatomic de-excitation-driven nanoradiator effect.
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Affiliation(s)
- Seung-Jun Seo
- Biomedical Engineering and Radiology, School of Medicine, Catholic University of Daegu, Daegu, Korea
| | - Sung-Mi Han
- Anatomy, School of Medicine, Catholic University of Daegu, Daegu, Korea
| | - Jae-Hoon Cho
- Neurosurgery, School of Medicine, Catholic University of Daegu, Daegu, Korea
| | - Kazuyuki Hyodo
- High Energy Accelerator Research Organization (KEK), Photon Factory, Tsukuba, Japan
| | | | - He You
- Shanghai Synchrotron Radiation Facility, Shanghai, China
| | - Ken Peach
- Particle Therapy Cancer Research Institute, University of Oxford, Oxford, UK
| | - Mark A Hill
- Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford, UK
| | - Jong-Ki Kim
- Biomedical Engineering and Radiology, School of Medicine, Catholic University of Daegu, Daegu, Korea.
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Mariotti LG, Abdelrazzak AB, Ottolenghi A, O'Neill P, Hill MA. Stimulation of intercellular induction of apoptosis in transformed cells at very low doses of ionising radiation: spatial and temporal features. Radiat Prot Dosimetry 2015; 166:161-164. [PMID: 25883313 DOI: 10.1093/rpd/ncv176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The ultimate response of a cell or tissue to radiation is dependent in part on intercellular signalling. This becomes increasingly important at low doses, or at low dose rates, associated with typical human exposures. In order to help characterise the underlying mechanism of intercellular signalling, and how they are perturbed following exposure to ionising radiation, a previously well-defined model system of intercellular induction of apoptosis (IIA) (Portess et al. 2007, Cancer Res. 67, 1246-1253) was adopted. The aim of the present work is to evaluate the signalling mechanisms underpinning this process through exploring the variables that can affect the IIA, i.e. dose, time and space.
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Affiliation(s)
- L G Mariotti
- Dipartimento di Fisica, Universit Degli Studi di Pavia, via Bassi 6, Pavia I-27100, Italy Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Pavia, via Bassi 6, Pavia I-27100, Italy CRUK/MRC Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford OX3 7DQ, UK
| | - A B Abdelrazzak
- CRUK/MRC Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford OX3 7DQ, UK Physics Research Division, National Research Centre, Giza, Egypt
| | - A Ottolenghi
- Dipartimento di Fisica, Universit Degli Studi di Pavia, via Bassi 6, Pavia I-27100, Italy Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Pavia, via Bassi 6, Pavia I-27100, Italy
| | - P O'Neill
- CRUK/MRC Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford OX3 7DQ, UK
| | - M A Hill
- CRUK/MRC Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford OX3 7DQ, UK
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Abstract
The target theory of radiation-induced effects has been challenged by numerous studies, which indicate that in addition to biological effects resulting from direct DNA damage within the cell, a variety of non-DNA targeted effects (NTE) may make important contributions to the overall outcome. Ionising radiation induces complex, global cellular responses, such as genomic instability (GI) in both irradiated and never-irradiated 'bystander' cells that receive molecular signals produced by irradiated cells. GI is a well-known feature of many cancers, increasing the probability of cells to acquire the 'hallmarks of cancer' during the development of tumours. Although epidemiological data include contributions of both direct and NTE, they lack (i) statistical power at low dose where differences in dose response for NTE and direct effects are likely to be more important and (ii) heterogeneity of non-targeted responses due to genetic variability between individuals. In this article, NTE focussing on GI and bystander effects were critically examined, the specific principles of NTE were discussed and the potential influence on human health risk assessment from low-dose radiation was considered.
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Affiliation(s)
- M A Kadhim
- Genomic Instability Group, Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK
| | - M A Hill
- CRUK/MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, ORCRB Roosevelt Drive, Oxford OX3 7DQ, UK
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Abstract
The yield of chromosome aberrations is not only dependent on dose but also on radiation quality, with high linear energy transfer (LET) typically having a greater biological effectiveness per unit dose than those of low-LET radiation. Differences in radiation track structure and cell morphology can also lead to quantitative differences in the spectra of the resulting chromosomal rearrangements, especially at low doses associated with typical human exposures. The development of combinatorial fluorescent labelling techniques (such as mFISH and mBAND) has helped to reveal the complexity of rearrangements, showing increasing complexity of observed rearrangements with increasing LET but has a resolution limited to ∼10 MBp. High-LET particles have not only been shown to produce clustered sites of DNA damage but also produce multiple correlated breaks along its path resulting in DNA fragments smaller than the resolution of these techniques. Additionally, studies have shown that the vast majority of radiation-induced HPRT mutations were also not detectable using fluorescent in situ hybridisation (FISH) techniques, with correlation of breaks along the track being reflected in the complexity of mutations, with intra- and inter-chromosomal insertions, and inversions occurring at the sites of some of the deletions. Therefore, the analysis of visible chromosomal rearrangements observed using current FISH techniques is likely to represent just the tip of the iceberg, considerably underestimating the extent and complexity of radiation induced rearrangements.
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Affiliation(s)
- M A Hill
- CRUK/MRC Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, ORCRB Roosevelt Drive, Oxford OX3 7DQ, UK
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Morrison R, Thompson J, Bird L, Hill MA, Townley H. Synthesis and characterization of polystyrene embolization particles doped with tantalum oxide nanoparticles for X-ray contrast. J Mater Sci Mater Med 2015; 26:218. [PMID: 26223792 DOI: 10.1007/s10856-015-5549-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 07/03/2015] [Indexed: 11/08/2023]
Abstract
Radiopaque and fluorescent embolic particles have been synthesized and characterised to match the size of vasculature found in tumours to ensure effective occlusion of the vessels. A literature search showed that the majority of vessels surrounding a tumour were less than 50 µm and therefore polydispersed polystyrene particles with a peak size of 50 µm have been synthesised. The embolic particles contain 5-8 nm amorphous tantalum oxide nanoparticles which provide X-ray contrast. Embolic particles containing up to 9.4 wt% tantalum oxide were prepared and showed significant contrast compared to the undoped polystyrene particles. The X-ray contrast of the embolic particles was shown to be linear (R(2) = 0.9) with respect to the concentration of incorporated tantalum nanoparticles. A model was developed which showed that seventy-five 50 µm embolic particles containing 10% tantalum oxide could provide the same contrast as 5 cm of bone. Therefore, the synthesized particles would provide sufficient X-ray contrast to enable visualisation within a tumour.
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Affiliation(s)
- Rachel Morrison
- Department of Engineering Science, Oxford University, Parks Road, Oxford, OX1 3PJ, UK
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Tracy BL, Stevens DL, Goodhead DT, Hill MA. Variation in RBE for Survival of V79-4 Cells as a Function of Alpha-Particle (Helium Ion) Energy. Radiat Res 2015; 184:33-45. [PMID: 26121227 DOI: 10.1667/rr13835.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
High linear energy transfer (LET) α particles are important with respect to the carcinogenic risk associated with human exposure to ionizing radiation, most notably to radon and its progeny. Additionally, the potential use of alpha-particle-emitting radionuclides in radiotherapy is increasingly being explored. Within the body the emitted alpha particles slow down, traversing a number of cells with a range of energies and therefore with varying efficiencies at inducing biological response. The LET of the particle typically rises from between ~70-90 keV μm(-1) at the start of the track (depending on initial energy) to a peak of ~237 keV μm(-1) towards the end of the track, before falling again at the very end of its range. To investigate the variation in biological response with incident energy, a plutonium-238 alpha-particle irradiator was calibrated to enable studies with incident energies ranging from 4.0 MeV down to 1.1 MeV. The variation in clonogenic survival of V79-4 cells was determined as a function of incident energy, along with the relative variation in the initial yields of DNA double-strand breaks (DSB) measured using the FAR assay. The clonogenic survival data also extends previously published data obtained at the Medical Research Council (MRC), Harwell using the same cells irradiated with helium ions, with energies ranging from 34.9 MeV to 5.85 MeV. These studies were performed in conjunction with cell morphology measurements on live cells enabling the determination of absorbed dose and calculation of the average LET in the cell. The results show an increase in relative biological effectiveness (RBE) for cell inactivation with decreasing helium ion energy (increasing LET), reaching a maximum for incident energies of ~3.2 MeV and corresponding average LET of 131 keV μm(-1), above which the RBE is observed to fall at lower energies (higher LETs). The effectiveness of single alpha-particle traversals (relevant to low-dose exposure) at inducing cell inactivation was observed to increase with decreasing energy to a peak of ~68% survival probability for incident energies of ~1.8 MeV (average LET of 190 keV μm(-1)) producing ~0.39 lethal lesions per track. However, the efficiency of a single traversal will also vary significantly with cell morphology and angle of incidence, as well as cell type.
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Affiliation(s)
- Bliss L Tracy
- a Medical Research Council, Harwell, Oxfordshire OX11 0RD, United Kingdom;,b Radiation Protection Bureau, Health Canada 6302D1, Ottawa, Ontario K1A 1C1, Canada; and
| | - David L Stevens
- a Medical Research Council, Harwell, Oxfordshire OX11 0RD, United Kingdom;,c Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Dudley T Goodhead
- a Medical Research Council, Harwell, Oxfordshire OX11 0RD, United Kingdom
| | - Mark A Hill
- a Medical Research Council, Harwell, Oxfordshire OX11 0RD, United Kingdom;,c Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford OX3 7DQ, United Kingdom
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Abstract
Dose distributions for proton therapy treatments are almost exclusively calculated using pencil beam algorithms. An essential input to these algorithms is the patient model, derived from x-ray computed tomography (CT), which is used to estimate proton stopping power along the pencil beam paths. This study highlights a potential inaccuracy in the mapping between mass density and proton stopping power used by a clinical pencil beam algorithm in materials less dense than water. It proposes an alternative physically-motivated function (the mass average, or MA, formula) for use in this region. Comparisons are made between dose-depth curves calculated by the pencil beam method and those calculated by the Monte Carlo particle transport code MCNPX in a one-dimensional lung model. Proton range differences of up to 3% are observed between the methods, reduced to <1% when using the MA function. The impact of these range errors on clinical dose distributions is demonstrated using treatment plans for a non-small cell lung cancer patient. The change in stopping power calculation methodology results in relatively minor differences in dose when plans use three fields, but differences are observed at the 2%-2 mm level when a single field uniform dose technique is adopted. It is therefore suggested that the MA formula is adopted by users of the pencil beam algorithm for optimal dose calculation in lung, and that a similar approach is considered when beams traverse other low density regions such as the paranasal sinuses and mastoid process.
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Affiliation(s)
- Daniel R Warren
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK. Particle Therapy Cancer Research Institute, University of Oxford, Oxfordshire, OX1 3RH, UK
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