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Tsuchiya H, Shimada M, Tsukada K, Meng Q, Kobayashi J, Matsumoto Y. THE ROLE OF DNA DOUBLE-STRAND BREAK REPAIR THROUGH NON-HOMOLOGOUS END JOINING IN THE DOSE-RATE EFFECT IN TERMS OF CLONOGENIC ABILITY. RADIATION PROTECTION DOSIMETRY 2022; 198:990-997. [PMID: 36083749 DOI: 10.1093/rpd/ncac030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 02/01/2022] [Accepted: 02/08/2022] [Indexed: 06/15/2023]
Abstract
It is generally and widely accepted that the biological effects of a given dose of ionizing radiation, especially those of low linear energy transfer radiations like X-ray and gamma ray, become smaller as the dose rate becomes lower. This phenomenon, known as 'dose-rate effect (DRE),' is considered due to the repair of sublethal damage during irradiation but the precise mechanisms for DRE have remained to be clarified. We recently showed that DRE in terms of clonogenic cell survival is diminished or even inversed in rodent cells lacking Ku, which is one of the essential factors in the repair of DNA double-strand breaks (DSBs) through non-homologous end joining (NHEJ). Here we review and discuss the involvement of NHEJ in DRE, which has potential implications in radiological protection and cancer therapeutics.
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Affiliation(s)
- Hisayo Tsuchiya
- Laboratory for Zero-Carbon Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Mikio Shimada
- Laboratory for Zero-Carbon Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Kaima Tsukada
- Laboratory for Zero-Carbon Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Qingmei Meng
- Department of Interdisciplinary Environment, Graduate School of Human and Environmental Sciences, Kyoto University, Yoshidanihonmatsucho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Junya Kobayashi
- Department of Radiological Sciences, School of Health Science at Narita, International University of Health and Welfare, 4-3 Kozunomori, Narita, Chiba 286-8686, Japan
| | - Yoshihisa Matsumoto
- Laboratory for Zero-Carbon Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
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Anbalagan S, Ström C, Downs JA, Jeggo PA, McBay D, Wilkins A, Rothkamm K, Harrington KJ, Yarnold JR, Somaiah N. TP53 modulates radiotherapy fraction size sensitivity in normal and malignant cells. Sci Rep 2021; 11:7119. [PMID: 33782505 PMCID: PMC8007815 DOI: 10.1038/s41598-021-86681-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/18/2021] [Indexed: 01/01/2023] Open
Abstract
Recent clinical trials in breast and prostate cancer have established that fewer, larger daily doses (fractions) of radiotherapy are safe and effective, but these do not represent personalised dosing on a patient-by-patient basis. Understanding cell and molecular mechanisms determining fraction size sensitivity is essential to fully exploit this therapeutic variable for patient benefit. The hypothesis under test in this study is that fraction size sensitivity is dependent on the presence of wild-type (WT) p53 and intact non-homologous end-joining (NHEJ). Using single or split-doses of radiation in a range of normal and malignant cells, split-dose recovery was determined using colony-survival assays. Both normal and tumour cells with WT p53 demonstrated significant split-dose recovery, whereas Li-Fraumeni fibroblasts and tumour cells with defective G1/S checkpoint had a large S/G2 component and lost the sparing effect of smaller fractions. There was lack of split-dose recovery in NHEJ-deficient cells and DNA-PKcs inhibitor increased sensitivity to split-doses in glioma cells. Furthermore, siRNA knockdown of p53 in fibroblasts reduced split-dose recovery. In summary, cells defective in p53 are less sensitive to radiotherapy fraction size and lack of split-dose recovery in DNA ligase IV and DNA-PKcs mutant cells suggests the dependence of fraction size sensitivity on intact NHEJ.
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Affiliation(s)
| | | | | | - Penny A Jeggo
- The Institute of Cancer Research, London, UK
- Genome Damage and Stability Centre, University of Sussex, Sussex, UK
| | - David McBay
- The Institute of Cancer Research, London, UK
| | - Anna Wilkins
- The Institute of Cancer Research, London, UK
- The Royal Marsden NHS Foundation Trust, London, UK
| | - Kai Rothkamm
- University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Kevin J Harrington
- The Institute of Cancer Research, London, UK
- The Royal Marsden NHS Foundation Trust, London, UK
| | - John R Yarnold
- The Institute of Cancer Research, London, UK
- The Royal Marsden NHS Foundation Trust, London, UK
| | - Navita Somaiah
- The Institute of Cancer Research, London, UK.
- The Royal Marsden NHS Foundation Trust, London, UK.
- The Royal Marsden, Downs Road, Sutton, SM2 5PT, UK.
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Tsuchiya H, Shimada M, Tsukada K, Meng Q, Kobayashi J, Matsumoto Y. Diminished or inversed dose-rate effect on clonogenic ability in Ku-deficient rodent cells. JOURNAL OF RADIATION RESEARCH 2021; 62:198-205. [PMID: 33372229 PMCID: PMC7948855 DOI: 10.1093/jrr/rraa128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 11/09/2020] [Indexed: 06/12/2023]
Abstract
The biological effects of ionizing radiation, especially those of sparsely ionizing radiations like X-ray and γ-ray, are generally reduced as the dose rate is reduced. This phenomenon is known as 'the dose-rate effect'. The dose-rate effect is considered to be due to the repair of DNA damage during irradiation but the precise mechanisms for the dose-rate effect remain to be clarified. Ku70, Ku86 and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) are thought to comprise the sensor for DNA double-strand break (DSB) repair through non-homologous end joining (NHEJ). In this study, we measured the clonogenic ability of Ku70-, Ku86- or DNA-PKcs-deficient rodent cells, in parallel with respective control cells, in response to high dose-rate (HDR) and low dose-rate (LDR) γ-ray radiation (~0.9 and ~1 mGy/min, respectively). Control cells and murine embryonic fibroblasts (MEF) from a severe combined immunodeficiency (scid) mouse, which is DNA-PKcs-deficient, showed higher cell survival after LDR irradiation than after HDR irradiation at the same dose. On the other hand, MEF from Ku70-/- mice exhibited lower clonogenic cell survival after LDR irradiation than after HDR irradiation. XR-V15B and xrs-5 cells, which are Ku86-deficient, exhibited mostly identical clonogenic cell survival after LDR and HDR irradiation. Thus, the dose-rate effect in terms of clonogenic cell survival is diminished or even inversed in Ku-deficient rodent cells. These observations indicate the involvement of Ku in the dose-rate effect.
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Affiliation(s)
- Hisayo Tsuchiya
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 Japan
| | - Mikio Shimada
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 Japan
| | - Kaima Tsukada
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 Japan
| | - Qingmei Meng
- Department of Interdisciplinary Environment, Graduate School of Human and Environmental Sciences, Kyoto University, Yoshidanihonmatsucho, Sakyo-ku, Kyoto 606-8501 Japan
| | - Junya Kobayashi
- Radiation Biology Center, Graduate School of Biostudies, Kyoto University, Yoshida-Konoecho, Sakyo-ku, Kyoto 606-8501 Japan
| | - Yoshihisa Matsumoto
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 Japan
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Li S, Miyamoto C, Wang B, Giaddui T, Micaily B, Hollander A, Weiss SE, Weaver M. A unified multi-activation (UMA) model of cell survival curves over the entire dose range for calculating equivalent doses in stereotactic body radiation therapy (SBRT), high dose rate brachytherapy (HDRB), and stereotactic radiosurgery (SRS). Med Phys 2021; 48:2038-2049. [PMID: 33590493 PMCID: PMC8248130 DOI: 10.1002/mp.14690] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 12/16/2020] [Accepted: 12/18/2020] [Indexed: 12/25/2022] Open
Abstract
PURPOSE Application of linear-quadratic (LQ) model to large fractional dose treatments is inconsistent with observed cell survival curves having a straight portion at high doses. We have proposed a unified multi-activation (UMA) model to fit cell survival curves over the entire dose range that allows us to calculate EQD2 for hypofractionated SBRT, SRT, SRS, and HDRB. METHODS A unified formula of cell survival S = n / e D D o + n - 1 using only the extrapolation number of n and the dose slope of Do was derived. Coefficient of determination, R2 , relative residuals, r, and relative experimental errors, e, normalized to survival fraction at each dose point, were calculated to quantify the goodness in modeling of a survival curve. Analytical solutions for α and β, the coefficients respectively describe the linear and quadratic parts of the survival curve, as well as the α/β ratio for the LQ model and EQD2 at any fractional doses were derived for tumor cells undertaking any fractionated radiation therapy. RESULTS Our proposed model fits survival curves of in-vivo and in-vitro tumor cells with R2 > 0.97 and r < e. The predicted α, β, and α/β ratio are significantly different from their values in the LQ model. Average EQD2 of 20-Gy SRS of glioblastomas and melanomas metastatic to the brain, 10-Gy × 5 SBRT of the lung cancer, and 7-Gy × 5 HDRB of endometrial and cervical carcinomas are 36.7 (24.3-48.5), 114.1 (86.6-173.1),, and 45.5 (35-52.6) Gy, different from the LQ model estimates of 50.0, 90.0, and 49.6 Gy, respectively. CONCLUSION Our UMA model validated through many tumor cell lines can fit cell survival curves over the entire dose range within their experimental errors. The unified formula theoretically indicates a common mechanism of cell inactivation and can estimate EQD2 at all dose levels.
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Affiliation(s)
- Shidong Li
- Department of Radiation Oncology, Temple University Hospital, Philadelphia, PA, USA
| | - Curtis Miyamoto
- Department of Radiation Oncology, Temple University Hospital, Philadelphia, PA, USA
| | - Bin Wang
- Department of Radiation Oncology, Temple University Hospital, Philadelphia, PA, USA
| | - Tawfik Giaddui
- Department of Radiation Oncology, Temple University Hospital, Philadelphia, PA, USA
| | - Bizhan Micaily
- Department of Radiation Oncology, Temple University Hospital, Philadelphia, PA, USA
| | - Andrew Hollander
- Department of Radiation Oncology, Temple University Hospital, Philadelphia, PA, USA
| | - Stephanie E Weiss
- Department of Radiation Oncology, Fox Chase Cancer Center, Temple University Health System, Philadelphia, PA, USA
| | - Michael Weaver
- Department of Neurosurgery, Temple University Health System, Philadelphia, PA, USA
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Willers H, Keane FK, Kamran SC. Toward a New Framework for Clinical Radiation Biology. Hematol Oncol Clin North Am 2019; 33:929-945. [PMID: 31668212 DOI: 10.1016/j.hoc.2019.07.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Radiation biology has entered the era of precision oncology, and this article reviews time-tested factors that determine the effects of fractionated radiation therapy in a wide variety of tumor types and normal tissues: the association of tumor control with radiation dose, the importance of fractionation and overall treatment time, and the role of tumor hypoxia. Therapeutic gain can only be achieved if the increased tumor toxicity produced by biological treatment modifications is balanced against injury to early-responding and late-responding normal tissues. Developments in precision oncology and immuno-oncology will allow an emphasis on treatment individualization and predictive biomarker development.
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Affiliation(s)
- Henning Willers
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA.
| | - Florence K Keane
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA. https://twitter.com/KatieKeaneMD
| | - Sophia C Kamran
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA. https://twitter.com/sophia_kamran
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Matsumoto Y, Ando K, Kato TA, Sekino Y, Ishikawa H, Sakae T, Tsuboi K, Sakurai H. DIFFERENCE IN DEGREE OF SUB-LETHAL DAMAGE RECOVERY BETWEEN CLINICAL PROTON BEAMS AND X-RAYS. RADIATION PROTECTION DOSIMETRY 2019; 183:93-97. [PMID: 30576477 DOI: 10.1093/rpd/ncy270] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Indexed: 06/09/2023]
Abstract
Fractionated proton beam radiotherapy is spreading worldwide these days. However, biological data of sub-lethal damage recovery (SLDR) after proton irradiation is not known yet. We here conducted split-dose experiments (20-360 min intervals) to clarify SLDR kinetics, and also compared the kinetics between cells with different repairability of DNA double-strand breaks. CHO and 51D1 cell lines but not V3 cell line showed significant SLDR, which reached plateau in 4-6 h. The recovery rates and recovery halftime of SLDR after X-rays were significantly higher and shorter than proton beams for CHO and 51D1 cells, respectively. Additionally, the frequency of remaining gamma-H2AX foci after two fractions was remarkably higher for X-rays than proton beams. These data suggest that there is a difference between proton beam and X-rays in SLDR and the retained DNA double-strand breaks after split-dose irradiation.
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Affiliation(s)
- Yoshitaka Matsumoto
- Radiation Oncology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan
- Radiation Biology, Proton Medical Research Center, University of Tsukuba Hospital, 2-1-1 Amakubo, Tsukuba, Ibaraki, Japan
| | - Koichi Ando
- Medicine & Biology Division, Heavy Ion Medical Center, Gunma University, 3-39-22 Showa-machi, Maebashi, Gunma, Japan
| | - Takamitsu A Kato
- Radiation Cancer Biology and Oncology, Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - Yuta Sekino
- Radiation Oncology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan
- Radiation Biology, Proton Medical Research Center, University of Tsukuba Hospital, 2-1-1 Amakubo, Tsukuba, Ibaraki, Japan
| | - Hitoshi Ishikawa
- Radiation Oncology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan
- Radiation Biology, Proton Medical Research Center, University of Tsukuba Hospital, 2-1-1 Amakubo, Tsukuba, Ibaraki, Japan
| | - Takeji Sakae
- Radiation Oncology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan
- Radiation Biology, Proton Medical Research Center, University of Tsukuba Hospital, 2-1-1 Amakubo, Tsukuba, Ibaraki, Japan
| | - Koji Tsuboi
- Radiation Oncology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan
- Radiation Biology, Proton Medical Research Center, University of Tsukuba Hospital, 2-1-1 Amakubo, Tsukuba, Ibaraki, Japan
| | - Hideyuki Sakurai
- Radiation Oncology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan
- Radiation Biology, Proton Medical Research Center, University of Tsukuba Hospital, 2-1-1 Amakubo, Tsukuba, Ibaraki, Japan
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Herskind C, Liu Q, Liu X, Zhang Y, Ma L, Angelie E, Ma HH, Liu J, Giordano FA, Wenz F, Veldwijk MR. A HYPOTHESIS OF RADIORESISTANCE AND CELL-SURVIVAL CURVE SHAPE BASED ON CELL-CYCLE PROGRESSION AND DAMAGE TOLERANCE. RADIATION PROTECTION DOSIMETRY 2019; 183:107-110. [PMID: 30535312 DOI: 10.1093/rpd/ncy247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Exponential survival curves of early-passage human fibroblasts challenge classic biophysical models of cell inactivation. Thus, X-ray doses of 2-4 Gy inactivate normal, human skin fibroblasts in spite of negligible residual double-strand breaks. By contrast, radioresistant p53-mutant U251 glioblastoma cells proliferate in spite of residual damage. Similarly, p53 wildtype TK6 lymphoblastoid cells show exponential survival curves while the related p53-mutant WTK1 cell line continued to proliferate and showed a shouldered survival curve. Here, we propose a model in which the radioresistant shoulder region is due to tolerance to certain types or amounts of residual damage that would otherwise inactivate normal cells. Thus, the steeper initial slope and absence of a shoulder in the survival curve of normal cells may not imply a higher number of residual lesions but rather non-tolerance to these lesions.
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Affiliation(s)
- Carsten Herskind
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
- Cellular and Molecular Radiation Oncology Laboratory, Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
| | - Qi Liu
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
| | - Xiaolei Liu
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
| | - Yingying Zhang
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
- Cellular and Molecular Radiation Oncology Laboratory, Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
| | - Lin Ma
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
| | - Elsa Angelie
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
| | - Hui Hui Ma
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
| | - Junqi Liu
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
| | - Frank A Giordano
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
- Translation Radiation Oncology, Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
| | - Frederik Wenz
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
| | - Marlon R Veldwijk
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
- Cellular and Molecular Radiation Oncology Laboratory, Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
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Recovery from sublethal damage and potentially lethal damage : Proton beam irradiation vs. X‑ray irradiation. Strahlenther Onkol 2017; 194:343-351. [PMID: 29038831 DOI: 10.1007/s00066-017-1223-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 09/26/2017] [Indexed: 01/06/2023]
Abstract
PURPOSE In order to clarify the biological response of tumor cells to proton beam irradiation, sublethal damage recovery (SLDR) and potentially lethal damage recovery (PLDR) induced after proton beam irradiation at the center of a 10 cm spread-out Bragg peak (SOBP) were compared with those seen after X‑ray irradiation. METHODS Cell survival was determined by a colony assay using EMT6 and human salivary gland tumor (HSG) cells. First, two doses of 4 Gy/GyE (Gray equivalents, GyE) were given at an interfraction interval of 0-6 h. Second, five fractions of 1.6 Gy/GyE were administered at interfraction intervals of 0-5 min. Third, a delayed-plating assay involving cells in plateau-phase cultures was conducted. The cells were plated in plastic dishes immediately or 2-24 h after being irradiated with 8 Gy/GyE of X‑rays or proton beams. Furthermore, we investigated the degree of protection from the effects of X‑rays or proton beams afforded by the radical scavenger dimethyl sulfoxide to estimate the contribution of the indirect effect of radiation. RESULTS In both the first and second experiments, SLDR was more suppressed after proton beam irradiation than after X‑ray irradiation. In the third experiment, there was no difference in PLDR between the proton beam and X‑ray irradiation conditions. The degree of protection tended to be higher after X‑ray irradiation than after proton beam irradiation. CONCLUSION Compared with that seen after X‑ray irradiation, SLDR might take place to a lesser extent after proton beam irradiation at the center of a 10 cm SOBP, while the extent of PLDR does not differ significantly between these two conditions.
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Herskind C, Ma L, Liu Q, Zhang B, Schneider F, Veldwijk MR, Wenz F. Biology of high single doses of IORT: RBE, 5 R's, and other biological aspects. Radiat Oncol 2017; 12:24. [PMID: 28107823 PMCID: PMC5251326 DOI: 10.1186/s13014-016-0750-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 12/21/2016] [Indexed: 01/14/2023] Open
Abstract
Intraoperative radiotherapy differs from conventional, fractionated radiotherapy in several aspects that may influence its biological effect. The radiation quality influences the relative biologic effectiveness (RBE), and the role of the five R’s of radiotherapy (reassortment, repair, reoxygenation, repopulation, radiosensitivity) is different. Furthermore, putative special biological effects and the small volume receiving a high single dose may be important. The present review focuses on RBE, repair, and repopulation, and gives an overview of the other factors that potentially contribute to the efficacy. The increased RBE should be taken into account for low-energy X-rays while evidence of RBE < 1 for high-energy electrons at higher doses is presented. Various evidence supports a hypothesis that saturation of the primary DNA double-strand break (DSB) repair mechanisms leads to increasing use of an error-prone backup repair system leading to genomic instability that may contribute to inactivate tumour cells at high single doses. Furthermore, the elimination of repopulation of residual tumour cells in the tumour bed implies that some patients are likely to have very few residual tumour cells which may be cured even by low doses to the tumour bed. The highly localised dose distribution of IORT has the potential to inactivate tumour cells while sparing normal tissue by minimising the volume exposed to high doses. Whether special effects of high single doses also contribute to the efficacy will require further experimental and clinical studies.
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Affiliation(s)
- Carsten Herskind
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
| | - Lin Ma
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.,Present Address: Department of Radiation Oncology, University of California, San Francisco, CA, USA
| | - Qi Liu
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.,Present Address: Department of Radiation Oncology, University of California, San Francisco, CA, USA
| | - Bo Zhang
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.,Present Address: Department of Oncology at No. 2 Hospital Anhui Medical University, and School of Life Sciences, Anhui Medical University, Hefei, Anhui, China
| | - Frank Schneider
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany
| | - Marlon R Veldwijk
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany
| | - Frederik Wenz
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany
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10
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Liu M, Wang H, Lee S, Liu B, Dong L, Wang Y. DNA repair pathway choice at various conditions immediately post irradiation. Int J Radiat Biol 2016; 92:819-822. [PMID: 27622834 DOI: 10.1080/09553002.2016.1230243] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PURPOSE To clarify which DNA double-strand break repair pathway, non-homologous end-joining (NHEJ), homologous recombination repair (HRR) or both, plays a key role in potentially lethal damage repair (PLDR). METHODS AND MATERIALS Combining published data and our new potentially lethal damage repair (PLDR) data, we explain whether similar to sublethal damage repair (SLDR), PLDR also mainly depends on NHEJ versus HRR. The PLDR data used the same cell lines: wild type, HRR or NHEJ-deficient fibroblast cells, as those SLDR data published by our laboratory previously. The PLDR condition that we used was as commonly described by many other groups: the cells were collected immediately or overnight post ionizing radiation for colony formation after cultured to a plateau phase with a low concentration of serum medium. RESULTS Enough data from other groups and our lab showed that wild type or HRR-deficient cells had efficient PLDR, but NHEJ deficient cells did not. CONCLUSION NHEJ contributes more to PLDR than HRR in mammalian cells, which is similar to SLDR. Since both SLDR and PLDR are relevant to clinical tumor status while undergoing radiotherapy, such clarification may benefit radiotherapy in the near future.
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Affiliation(s)
- Min Liu
- a Department of Radiation Oncology , the First Hospital, Jilin University , Changchun , China.,b Department of Radiation Oncology , School of Medicine and the Winship Cancer Institute, Emory University , Atlanta , Georgia , USA
| | - Hongyan Wang
- b Department of Radiation Oncology , School of Medicine and the Winship Cancer Institute, Emory University , Atlanta , Georgia , USA
| | - Solah Lee
- b Department of Radiation Oncology , School of Medicine and the Winship Cancer Institute, Emory University , Atlanta , Georgia , USA
| | - Bailong Liu
- a Department of Radiation Oncology , the First Hospital, Jilin University , Changchun , China.,b Department of Radiation Oncology , School of Medicine and the Winship Cancer Institute, Emory University , Atlanta , Georgia , USA
| | - Lihua Dong
- a Department of Radiation Oncology , the First Hospital, Jilin University , Changchun , China
| | - Ya Wang
- b Department of Radiation Oncology , School of Medicine and the Winship Cancer Institute, Emory University , Atlanta , Georgia , USA
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