1
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Marinescu IM, Rogg M, Spohn S, von Büren M, Kamps M, Jilg CA, Fountzila E, Papadopoulou K, Ceci L, Bettermann A, Ruf J, Benndorf M, Adebahr S, Zips D, Grosu AL, Schell C, Zamboglou C. Ex vivo γH2AX assay for tumor radiosensitivity in primary prostate cancer patients and correlation with clinical parameters. Radiat Oncol 2022; 17:163. [PMID: 36199143 PMCID: PMC9533509 DOI: 10.1186/s13014-022-02131-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 09/13/2022] [Indexed: 11/15/2022] Open
Abstract
Backround Accurate surrogate parameters for radio resistance are warranted for individualized radiotherapy (RT) concepts in prostate cancer (PCa). The purpose of this study was to assess intertumoral heterogeneity in terms of radio resistance using an ex-vivo γH2AX assay after irradiation of prostate biopsy cores and to investigate its correlation with clinical features of respective patients as well as imaging and genomic features of tumor areas.
Methods Twenty one patients with histologically-proven PCa and pre-therapeutic multiparametric resonance imaging and prostate-specific membrane antigen positron emission tomography were included in the study. Biopsy cores were collected from 26 PCa foci. Residual γH2AX foci were counted 24 h after ex-vivo irradiation (with 0 and 4 Gy) of biopsy specimen and served as a surrogate for radio resistance. Clinical, genomic (next generation sequencing) and imaging features were collected and their association with the radio resistance was studied. Results In total 18 PCa lesions from 16 patients were included in the final analysis. The median γH2AX foci value per PCa lesion was 3.12. According to this, the patients were divided into two groups (radio sensitive vs. radio resistant) with significant differences in foci number (p < 0.0001). The patients in the radio sensitive group had significantly higher prostate specific antigen serum concentration (p = 0.015), tumor areas in the radio sensitive group had higher SUV (standardized uptake values in PSMA PET)-max and -mean values (p = 0.0037, p = 0.028) and lower ADC (apparent diffusion coefficient-mean values, p = 0.049). All later parameters had significant (p < 0.05) correlations in Pearson’s test. One patient in the radio sensitive group displayed a previously not reported loss of function frameshift mutation in the NBN gene (c.654_658delAAAAC) that introduces a premature termination codon and results in a truncated protein. Conclusion In this pilot study, significant differences in intertumoral radio resistance were observed and clinical as well as imaging parameters may be applied for their prediction. After further prospective validation in larger patient cohorts these finding may lead to individual RT dose prescription for PCa patients in the future.
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Affiliation(s)
- Ioana M Marinescu
- Department of Radiation Oncology, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany. .,German Cancer Consortium (DKTK), Partner Site, Freiburg, Germany.
| | - Manuel Rogg
- Institute for Surgical Pathology, Medical Center - University of Freiburg, Freiburg, Germany
| | - Simon Spohn
- Department of Radiation Oncology, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany.,German Cancer Consortium (DKTK), Partner Site, Freiburg, Germany
| | - Moritz von Büren
- Department of Urology, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Marius Kamps
- Department of Urology, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Cordula A Jilg
- Department of Urology, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Elena Fountzila
- Second Department of Medical Oncology, Euromedica General Clinic of Thessaloniki, Thessaloniki, Greece.,Greece and European University Cyprus, Engomi, Cyprus
| | - Kyriaki Papadopoulou
- Laboratory of Molecular Oncology, Hellenic Foundation for Cancer Research, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Lara Ceci
- Department of Radiation Oncology, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany.,German Cancer Consortium (DKTK), Partner Site, Freiburg, Germany
| | - Alisa Bettermann
- Department of Radiation Oncology, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany.,German Cancer Consortium (DKTK), Partner Site, Freiburg, Germany
| | - Juri Ruf
- Department of Nuclear Medicine, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Matthias Benndorf
- Department of Radiology, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Sonja Adebahr
- Department of Radiation Oncology, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany.,German Cancer Consortium (DKTK), Partner Site, Freiburg, Germany
| | - Daniel Zips
- Medical Faculty and University Hospital, Radiation Oncology, Eberhard Karls University Tübingen, Tübingen, Germany.,German Cancer Consortium (DKTK), Partner Site Tübingen, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Anca L Grosu
- Department of Radiation Oncology, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany.,German Cancer Consortium (DKTK), Partner Site, Freiburg, Germany
| | - Christoph Schell
- Institute for Surgical Pathology, Medical Center - University of Freiburg, Freiburg, Germany
| | - Constantinos Zamboglou
- Department of Radiation Oncology, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany.,German Cancer Consortium (DKTK), Partner Site, Freiburg, Germany.,Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Tumorbank Comprehensive Cancer Center Freiburg, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, University of Freiburg, Freiburg, Germany.,German Oncology Center, European University Cyprus, Limassol, Cyprus
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2
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Rashid AM, Dhakal R, Moussa H. Estimating Absorbed Dose to Breast Adipose Tissue from Mammograms. J Med Phys 2021; 46:171-180. [PMID: 34703101 PMCID: PMC8491318 DOI: 10.4103/jmp.jmp_27_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/11/2021] [Accepted: 06/11/2021] [Indexed: 11/18/2022] Open
Abstract
Purpose Breast cancer usually originates in the glandular tissue of the breast. However, inflamed adipose tissue surrounding glandular tissue may expedite the local growth of cancerous cells. Exposing adipose tissue to radiation during mammography might cause inflammation in adipose tissue. This inflammation depends on the dose, and thus on the energy deposited from the X-ray mammography. Therefore, estimating the absorbed dose to adipose tissue during mammography is essential in breast cancer research. Materials and Methods Absorbed dose to adipose tissue in the breast is determined using a new geometrical (semi-elliptical) model and Monte Carlo N-Particle transport code (MCNP6). X-ray mammogram images of patient breasts were taken as the basis of the new compressed breast geometry. The source probability density used in the MCNP6 code was generated from a published X-ray spectrum corresponding to tube voltage and air kerma. The relationship between various mammogram parameters such as peak tube voltage, compressed breast thickness, and adipose tissue weight fraction versus estimated absorbed dose is established for analysis. Results Significant influences of adipose tissue weight fraction on absorbed dose were observed. Conclusion Estimating the absorbed dose to breast adipose tissue during mammography and patients' degree of obesity are important factors in breast cancer research.
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Affiliation(s)
- Al Maqsudur Rashid
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, USA
| | - Rabin Dhakal
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, USA
| | - Hanna Moussa
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, USA
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3
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Koo BY, Lee KS. Reduction of scattered radiation dose by X-ray shielding during mammography. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2020.109111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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4
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Yang DW, Wang TM, Zhang JB, Li XZ, He YQ, Xiao R, Xue WQ, Zheng XH, Zhang PF, Zhang SD, Hu YZ, Shen GP, Chen M, Sun Y, Jia WH. Genome-wide association study identifies genetic susceptibility loci and pathways of radiation-induced acute oral mucositis. J Transl Med 2020; 18:224. [PMID: 32503578 PMCID: PMC7275566 DOI: 10.1186/s12967-020-02390-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 05/28/2020] [Indexed: 12/17/2022] Open
Abstract
Background Radiation-induced oral mucositis (OM) is one of the most common acute complications for head and neck cancer. Severe OM is associated with radiation treatment breaks, which harms successful tumor management. Radiogenomics studies have indicated that genetic variants are associated with adverse effects of radiotherapy. Methods A large-scale genome-wide scan was performed in 1467 nasopharyngeal carcinoma patients, including 753 treated with 2D-CRT from Genetic Architecture of the Radiotherapy Toxicity and Prognosis (GARTP) cohort and 714 treated with IMRT (192 from the GARTP and 522 newly recruited). Subgroup analysis by radiotherapy technique was further performed in the top associations. We also performed physical and regulatory mapping of the risk loci and gene set enrichment analysis of the candidate target genes. Results We identified 50 associated genomic loci and 64 genes via positional mapping, expression quantitative trait locus (eQTL) mapping, chromatin interaction mapping and gene-based analysis, and 36 of these loci were replicated in subgroup analysis. Interestingly, one of the top loci located in TNKS, a gene relevant to radiation toxicity, was associated with increased OM risk with OR = 3.72 of the lead SNP rs117157809 (95% CI 2.10–6.57; P = 6.33 × 10−6). Gene set analyses showed that the 64 candidate target genes were enriched in the biological processes of regulating telomere capping and maintenance and telomerase activity (Top P = 7.73 × 10−7). Conclusions These results enhance the biological understanding of radiotherapy toxicity. The association signals enriched in telomere function regulation implicate the potential underlying mechanism and warrant further functional investigation and potential individual radiotherapy applications.
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Affiliation(s)
- Da-Wei Yang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.,School of Public Health, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Tong-Min Wang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China
| | - Jiang-Bo Zhang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China
| | - Xi-Zhao Li
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China
| | - Yong-Qiao He
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China
| | - Ruowen Xiao
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China
| | - Wen-Qiong Xue
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China
| | - Xiao-Hui Zheng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China
| | - Pei-Fen Zhang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China
| | - Shao-Dan Zhang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China
| | - Ye-Zhu Hu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China
| | - Guo-Ping Shen
- Department of Radiation Oncology, Sun Yat-sen University First Affiliated Hospital, Guangzhou, People's Republic of China
| | - Mingyuan Chen
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.,Department of Nasopharyngeal Carcinoma, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China
| | - Ying Sun
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.,Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China
| | - Wei-Hua Jia
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China. .,School of Public Health, Sun Yat-sen University, Guangzhou, People's Republic of China. .,Department of Radiation Oncology, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, People's Republic of China.
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5
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Helm JS, Rudel RA. Adverse outcome pathways for ionizing radiation and breast cancer involve direct and indirect DNA damage, oxidative stress, inflammation, genomic instability, and interaction with hormonal regulation of the breast. Arch Toxicol 2020. [PMID: 32399610 DOI: 10.1007/s00204-020-02752-z)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Abstract
Knowledge about established breast carcinogens can support improved and modernized toxicological testing methods by identifying key mechanistic events. Ionizing radiation (IR) increases the risk of breast cancer, especially for women and for exposure at younger ages, and evidence overall supports a linear dose-response relationship. We used the Adverse Outcome Pathway (AOP) framework to outline and evaluate the evidence linking ionizing radiation with breast cancer from molecular initiating events to the adverse outcome through intermediate key events, creating a qualitative AOP. We identified key events based on review articles, searched PubMed for recent literature on key events and IR, and identified additional papers using references. We manually curated publications and evaluated data quality. Ionizing radiation directly and indirectly causes DNA damage and increases production of reactive oxygen and nitrogen species (RONS). RONS lead to DNA damage and epigenetic changes leading to mutations and genomic instability (GI). Proliferation amplifies the effects of DNA damage and mutations leading to the AO of breast cancer. Separately, RONS and DNA damage also increase inflammation. Inflammation contributes to direct and indirect effects (effects in cells not directly reached by IR) via positive feedback to RONS and DNA damage, and separately increases proliferation and breast cancer through pro-carcinogenic effects on cells and tissue. For example, gene expression changes alter inflammatory mediators, resulting in improved survival and growth of cancer cells and a more hospitable tissue environment. All of these events overlap at multiple points with events characteristic of "background" induction of breast carcinogenesis, including hormone-responsive proliferation, oxidative activity, and DNA damage. These overlaps make the breast particularly susceptible to ionizing radiation and reinforce that these biological activities are important characteristics of carcinogens. Agents that increase these biological processes should be considered potential breast carcinogens, and predictive methods are needed to identify chemicals that increase these processes. Techniques are available to measure RONS, DNA damage and mutation, cell proliferation, and some inflammatory proteins or processes. Improved assays are needed to measure GI and chronic inflammation, as well as the interaction with hormonally driven development and proliferation. Several methods measure diverse epigenetic changes, but it is not clear which changes are relevant to breast cancer. In addition, most toxicological assays are not conducted in mammary tissue, and so it is a priority to evaluate if results from other tissues are generalizable to breast, or to conduct assays in breast tissue. Developing and applying these assays to identify exposures of concern will facilitate efforts to reduce subsequent breast cancer risk.
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Affiliation(s)
- Jessica S Helm
- Silent Spring Institute, 320 Nevada Street, Suite 302, Newton, MA, 02460, USA
| | - Ruthann A Rudel
- Silent Spring Institute, 320 Nevada Street, Suite 302, Newton, MA, 02460, USA.
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6
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Helm JS, Rudel RA. Adverse outcome pathways for ionizing radiation and breast cancer involve direct and indirect DNA damage, oxidative stress, inflammation, genomic instability, and interaction with hormonal regulation of the breast. Arch Toxicol 2020; 94:1511-1549. [PMID: 32399610 PMCID: PMC7261741 DOI: 10.1007/s00204-020-02752-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 04/16/2020] [Indexed: 12/15/2022]
Abstract
Knowledge about established breast carcinogens can support improved and modernized toxicological testing methods by identifying key mechanistic events. Ionizing radiation (IR) increases the risk of breast cancer, especially for women and for exposure at younger ages, and evidence overall supports a linear dose-response relationship. We used the Adverse Outcome Pathway (AOP) framework to outline and evaluate the evidence linking ionizing radiation with breast cancer from molecular initiating events to the adverse outcome through intermediate key events, creating a qualitative AOP. We identified key events based on review articles, searched PubMed for recent literature on key events and IR, and identified additional papers using references. We manually curated publications and evaluated data quality. Ionizing radiation directly and indirectly causes DNA damage and increases production of reactive oxygen and nitrogen species (RONS). RONS lead to DNA damage and epigenetic changes leading to mutations and genomic instability (GI). Proliferation amplifies the effects of DNA damage and mutations leading to the AO of breast cancer. Separately, RONS and DNA damage also increase inflammation. Inflammation contributes to direct and indirect effects (effects in cells not directly reached by IR) via positive feedback to RONS and DNA damage, and separately increases proliferation and breast cancer through pro-carcinogenic effects on cells and tissue. For example, gene expression changes alter inflammatory mediators, resulting in improved survival and growth of cancer cells and a more hospitable tissue environment. All of these events overlap at multiple points with events characteristic of "background" induction of breast carcinogenesis, including hormone-responsive proliferation, oxidative activity, and DNA damage. These overlaps make the breast particularly susceptible to ionizing radiation and reinforce that these biological activities are important characteristics of carcinogens. Agents that increase these biological processes should be considered potential breast carcinogens, and predictive methods are needed to identify chemicals that increase these processes. Techniques are available to measure RONS, DNA damage and mutation, cell proliferation, and some inflammatory proteins or processes. Improved assays are needed to measure GI and chronic inflammation, as well as the interaction with hormonally driven development and proliferation. Several methods measure diverse epigenetic changes, but it is not clear which changes are relevant to breast cancer. In addition, most toxicological assays are not conducted in mammary tissue, and so it is a priority to evaluate if results from other tissues are generalizable to breast, or to conduct assays in breast tissue. Developing and applying these assays to identify exposures of concern will facilitate efforts to reduce subsequent breast cancer risk.
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Affiliation(s)
- Jessica S Helm
- Silent Spring Institute, 320 Nevada Street, Suite 302, Newton, MA, 02460, USA
| | - Ruthann A Rudel
- Silent Spring Institute, 320 Nevada Street, Suite 302, Newton, MA, 02460, USA.
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7
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Maqsudur Rashid A, Ramalingam L, Al-Jawadi A, Moustaid-Moussa N, Moussa H. Low dose radiation, inflammation, cancer and chemoprevention. Int J Radiat Biol 2018; 95:506-515. [DOI: 10.1080/09553002.2018.1484194] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Al Maqsudur Rashid
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, USA
| | - Latha Ramalingam
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX, USA
- Obesity Research Cluster, Texas Tech University, Lubbock, TX, USA
| | - Arwa Al-Jawadi
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX, USA
- Obesity Research Cluster, Texas Tech University, Lubbock, TX, USA
| | - Naima Moustaid-Moussa
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX, USA
- Obesity Research Cluster, Texas Tech University, Lubbock, TX, USA
| | - Hanna Moussa
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, USA
- Obesity Research Cluster, Texas Tech University, Lubbock, TX, USA
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8
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Gray JM, Rasanayagam S, Engel C, Rizzo J. State of the evidence 2017: an update on the connection between breast cancer and the environment. Environ Health 2017; 16:94. [PMID: 28865460 PMCID: PMC5581466 DOI: 10.1186/s12940-017-0287-4] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 07/17/2017] [Indexed: 05/23/2023]
Abstract
BACKGROUND In this review, we examine the continually expanding and increasingly compelling data linking radiation and various chemicals in our environment to the current high incidence of breast cancer. Singly and in combination, these toxicants may have contributed significantly to the increasing rates of breast cancer observed over the past several decades. Exposures early in development from gestation through adolescence and early adulthood are particularly of concern as they re-shape the program of genetic, epigenetic and physiological processes in the developing mammary system, leading to an increased risk for developing breast cancer. In the 8 years since we last published a comprehensive review of the relevant literature, hundreds of new papers have appeared supporting this link, and in this update, the evidence on this topic is more extensive and of better quality than that previously available. CONCLUSION Increasing evidence from epidemiological studies, as well as a better understanding of mechanisms linking toxicants with development of breast cancer, all reinforce the conclusion that exposures to these substances - many of which are found in common, everyday products and byproducts - may lead to increased risk of developing breast cancer. Moving forward, attention to methodological limitations, especially in relevant epidemiological and animal models, will need to be addressed to allow clearer and more direct connections to be evaluated.
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Affiliation(s)
- Janet M. Gray
- Department of Psychology and Program in Science, Technology, and Society, Vassar College, 124 Raymond Avenue, Poughkeepsie, NY 12604-0246 USA
| | - Sharima Rasanayagam
- Breast Cancer Prevention Partners, 1388 Sutter St., Suite 400, San Francisco, CA 94109-5400 USA
| | - Connie Engel
- Breast Cancer Prevention Partners, 1388 Sutter St., Suite 400, San Francisco, CA 94109-5400 USA
| | - Jeanne Rizzo
- Breast Cancer Prevention Partners, 1388 Sutter St., Suite 400, San Francisco, CA 94109-5400 USA
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9
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Frenzel M, Ricoul M, Benadjaoud MA, Bellamy M, Lenain A, Haddy N, Diallo I, Mateus C, de Vathaire F, Sabatier L. Retrospective cohort study and biobanking of patients treated for hemangioma in childhood – telomeres as biomarker of aging and radiation exposure. Int J Radiat Biol 2017. [DOI: 10.1080/09553002.2017.1337278] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Monika Frenzel
- PROCyTOX (Radiation Oncology, Cytogenetics, and Toxicology Platform), DRF Commissariat à l’Energie Atomique et aux Energies Alternatives CEA, Paris, Saclay, France
| | - Michelle Ricoul
- PROCyTOX (Radiation Oncology, Cytogenetics, and Toxicology Platform), DRF Commissariat à l’Energie Atomique et aux Energies Alternatives CEA, Paris, Saclay, France
| | | | - Marion Bellamy
- PROCyTOX (Radiation Oncology, Cytogenetics, and Toxicology Platform), DRF Commissariat à l’Energie Atomique et aux Energies Alternatives CEA, Paris, Saclay, France
- Radiation Epidemiology Group, INSERM U1018, Villejuif, Université Paris, Saclay, France
| | - Aude Lenain
- PROCyTOX (Radiation Oncology, Cytogenetics, and Toxicology Platform), DRF Commissariat à l’Energie Atomique et aux Energies Alternatives CEA, Paris, Saclay, France
| | - Nadia Haddy
- Radiation Epidemiology Group, INSERM U1018, Villejuif, Université Paris, Saclay, France
| | - Ibrahima Diallo
- Radiation Epidemiology Group, INSERM U1018, Villejuif, Université Paris, Saclay, France
| | - Christine Mateus
- Service de dermatologie, Gustave Roussy, Université Paris-Saclay, Département de Médecine Oncologique, Villejuif, France
| | - Florent de Vathaire
- Radiation Epidemiology Group, INSERM U1018, Villejuif, Université Paris, Saclay, France
| | - Laure Sabatier
- PROCyTOX (Radiation Oncology, Cytogenetics, and Toxicology Platform), DRF Commissariat à l’Energie Atomique et aux Energies Alternatives CEA, Paris, Saclay, France
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10
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Berardinelli F, Coluzzi E, Sgura A, Antoccia A. Targeting telomerase and telomeres to enhance ionizing radiation effects in in vitro and in vivo cancer models. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 773:204-219. [PMID: 28927529 DOI: 10.1016/j.mrrev.2017.02.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 02/13/2017] [Accepted: 02/14/2017] [Indexed: 01/05/2023]
Abstract
One of the hallmarks of cancer consists in the ability of tumor cells to divide indefinitely, and to maintain stable telomere lengths throughout the activation of specific telomere maintenance mechanisms (TMM). Therefore in the last fifteen years, researchers proposed to target telomerase or telomeric structure in order to block limitless replicative potential of cancer cells providing a fascinating strategy for a broad-spectrum cancer therapy. In the present review, we report in vitro and in vivo evidence regarding the use of chemical agents targeting both telomerase or telomere structure and showing promising antitumor effects when used in combination with ionizing radiation (IR). RNA interference, antisense oligonucleotides (e.g., GRN163L), non-nucleoside inhibitors (e.g., BIBR1532) and nucleoside analogs (e.g., AZT) represent some of the most potent strategies to inhibit telomerase activity used in combination with IR. Furthermore, radiosensitizing effects were demonstrated also for agents acting directly on the telomeric structure such as G4-ligands (e.g., RHPS4 and Telomestatin) or telomeric-oligos (T-oligos). To date, some of these compounds are under clinical evaluation (e.g., GRN163L and KML001). Advantages of Telomere/Telomerase Targeting Compounds (T/TTCs) coupled with radiotherapy may be relevant in the treatment of radioresistant tumors and in the development of new optimized treatment plans with reduced dose adsorbed by patients and consequent attenuation of short- end long-term side effects. Pros and cons of possible future applications in cancer therapy based on the combination of T/TCCs and radiation treatment are discussed.
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Affiliation(s)
- F Berardinelli
- Dipartimento di Scienze, Università Roma Tre, Rome Italy; Istituto Nazionale di Fisica Nucleare, INFN, Sezione di Roma Tre, Rome, Italy.
| | - E Coluzzi
- Dipartimento di Scienze, Università Roma Tre, Rome Italy
| | - A Sgura
- Dipartimento di Scienze, Università Roma Tre, Rome Italy; Istituto Nazionale di Fisica Nucleare, INFN, Sezione di Roma Tre, Rome, Italy
| | - A Antoccia
- Dipartimento di Scienze, Università Roma Tre, Rome Italy; Istituto Nazionale di Fisica Nucleare, INFN, Sezione di Roma Tre, Rome, Italy
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11
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Daughtry BL, Chavez SL. Chromosomal instability in mammalian pre-implantation embryos: potential causes, detection methods, and clinical consequences. Cell Tissue Res 2016; 363:201-225. [PMID: 26590822 PMCID: PMC5621482 DOI: 10.1007/s00441-015-2305-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 09/24/2015] [Indexed: 01/08/2023]
Abstract
Formation of a totipotent blastocyst capable of implantation is one of the first major milestones in early mammalian embryogenesis, but less than half of in vitro fertilized embryos from most mammals will progress to this stage of development. Whole chromosomal abnormalities, or aneuploidy, are key determinants of whether human embryos will arrest or reach the blastocyst stage. Depending on the type of chromosomal abnormality, however, certain embryos still form blastocysts and may be morphologically indistinguishable from chromosomally normal embryos. Despite the implementation of pre-implantation genetic screening and other advanced in vitro fertilization (IVF) techniques, the identification of aneuploid embryos remains complicated by high rates of mosaicism, atypical cell division, cellular fragmentation, sub-chromosomal instability, and micro-/multi-nucleation. Moreover, several of these processes occur in vivo following natural human conception, suggesting that they are not simply a consequence of culture conditions. Recent technological achievements in genetic, epigenetic, chromosomal, and non-invasive imaging have provided additional embryo assessment approaches, particularly at the single-cell level, and clinical trials investigating their efficacy are continuing to emerge. In this review, we summarize the potential mechanisms by which aneuploidy may arise, the various detection methods, and the technical advances (such as time-lapse imaging, "-omic" profiling, and next-generation sequencing) that have assisted in obtaining this data. We also discuss the possibility of aneuploidy resolution in embryos via various corrective mechanisms, including multi-polar divisions, fragment resorption, endoreduplication, and blastomere exclusion, and conclude by examining the potential implications of these findings for IVF success and human fecundity.
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Affiliation(s)
- Brittany L Daughtry
- Department of Cell, Developmental & Cancer Biology, Graduate Program in Molecular & Cellular Biosciences, Oregon Health & Science University School of Medicine, Portland, Ore., USA
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, 505 NW 185th Avenue, Beaverton, OR 97006, USA
| | - Shawn L Chavez
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, 505 NW 185th Avenue, Beaverton, OR 97006, USA.
- Physiology & Pharmacology, Oregon Health & Science University School of Medicine, Portland, Ore., USA.
- Department of Obstetrics & Gynecology, Oregon Health & Science University School of Medicine, Portland, Ore., USA.
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12
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Pauwels EK, Foray N, Bourguignon MH. Breast Cancer Induced by X-Ray Mammography Screening? A Review Based on Recent Understanding of Low-Dose Radiobiology. Med Princ Pract 2016; 25:101-9. [PMID: 26571215 PMCID: PMC5588356 DOI: 10.1159/000442442] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 11/15/2015] [Indexed: 12/28/2022] Open
Abstract
Screening mammography offers the possibility of discovering malignant diseases at an early stage, which is consequently treated early, thereby reducing the mortality rate. However, ionizing radiation as used in low-dose X-ray mammography may be associated with a risk of radiation-induced carcinogenesis. In the context of the harmful effects of ionizing radiation, this article reviewed novel radiobiological data and provided a simulation of the relative incidence of radiation-induced breast cancer due to screening against a background baseline incidence in a population of 100,000 individuals. The use of modern digital mammographic technology was assumed, giving rise to a glandular dose of 2.5 mGy from a 2-view per breast image. Assuming no latency time, this led to a ratio of induced incidence rate over baseline incidence rate of about 1.6‰ for biennial screening in women aged 50-74 years, although it cannot be excluded that the dose and dose rate effectiveness factor values relying on new radiobiological insights may lower this number to about 0.7‰. This carcinogenic risk is considered small in relation to the potential beneficial effects of screening, especially as latency time was not taken into consideration. However, individuals who are known to be carriers of risk-increasing genetic variations and/or have an inherited disposition of breast cancer should avoid ionizing radiation as much as possible and should be referred to ultrasound or magnetic resonance imaging. In addition, a significant, but difficult to quantify, risk of cancer is present for individuals who suffer from hypersusceptibility to ionizing radiation.
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Affiliation(s)
- Ernest K.J. Pauwels
- Department of Radiology, University Medical Center Leiden, Leiden
- Department of Nuclear Medicine, University Medical School Pisa, Pisa, Italy
- *Prof. emer. Dr. E.K.J. Pauwels, Department of Radiology and Nuclear Medicine, Via di San Gennaro 79B, IT—55010 Capannori (Italy), E-Mail
| | - Nicolas Foray
- Department of Radiobiology INSERM, UMR1052, Cancer Research Centre of Lyon, Lyon
| | - Michel H. Bourguignon
- Department of Biophysics, University of Versailles, Paris, France
- Institut de Radioprotection et de Sureté Nucléaire, Fontenay-aux-Roses, France
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13
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Berardinelli F, Siteni S, Tanzarella C, Stevens MF, Sgura A, Antoccia A. The G-quadruplex-stabilising agent RHPS4 induces telomeric dysfunction and enhances radiosensitivity in glioblastoma cells. DNA Repair (Amst) 2014; 25:104-15. [PMID: 25467559 DOI: 10.1016/j.dnarep.2014.10.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 10/21/2014] [Accepted: 10/24/2014] [Indexed: 10/24/2022]
Abstract
G-quadruplex (G4) interacting agents are a class of ligands that can bind to and stabilise secondary structures located in genomic G-rich regions such as telomeres. Stabilisation of G4 leads to telomere architecture disruption with a consequent detrimental effect on cell proliferation, which makes these agents good candidates for chemotherapeutic purposes. RHPS4 is one of the most effective and well-studied G4 ligands with a very high specificity for telomeric G4. In this work, we tested the in vitro efficacy of RHPS4 in astrocytoma cell lines, and we evaluated whether RHPS4 can act as a radiosensitising agent by destabilising telomeres. In the first part of the study, the response to RHPS4 was investigated in four human astrocytoma cell lines (U251MG, U87MG, T67 and T70) and in two normal primary fibroblast strains (AG01522 and MRC5). Cell growth reduction, histone H2AX phosphorylation and telomere-induced dysfunctional foci (TIF) formation were markedly higher in astrocytoma cells than in normal fibroblasts, despite the absence of telomere shortening. In the second part of the study, the combined effect of submicromolar concentrations of RHPS4 and X-rays was assessed in the U251MG glioblastoma radioresistant cell line. Long-term growth curves, cell cycle analysis and cell survival experiments, clearly showed the synergistic effect of the combined treatment. Interestingly the effect was greater in cells bearing a higher number of dysfunctional telomeres. DNA double-strand breaks rejoining after irradiation revealed delayed repair kinetics in cells pre-treated with the drug and a synergistic increase in chromosome-type exchanges and telomeric fusions. These findings provide the first evidence that exposure to RHPS4 radiosensitizes astrocytoma cells, suggesting the potential for future therapeutic applications.
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Affiliation(s)
- F Berardinelli
- Department of Science, Università "Roma Tre", Rome, Italy; INFN Roma Tre, Rome, Italy.
| | - S Siteni
- Department of Science, Università "Roma Tre", Rome, Italy; Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy
| | - C Tanzarella
- Department of Science, Università "Roma Tre", Rome, Italy
| | - M F Stevens
- Centre for Biomolecular Sciences, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom
| | - A Sgura
- Department of Science, Università "Roma Tre", Rome, Italy; INFN Roma Tre, Rome, Italy
| | - A Antoccia
- Department of Science, Università "Roma Tre", Rome, Italy; INFN Roma Tre, Rome, Italy
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Bakhmutsky MV, Joiner MC, Jones TB, Tucker JD. Differences in cytogenetic sensitivity to ionizing radiation in newborns and adults. Radiat Res 2014; 181:605-16. [PMID: 24828110 DOI: 10.1667/rr13598.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Radiation exposure causes DNA breaks leading to structural chromosome aberrations that can be carcinogenic. Lifetime cancer risks are elevated in irradiated children compared to similarly exposed adults. To determine the extent to which age influences the frequency and types of chromosome damage in response to ionizing radiation, peripheral blood samples were collected from 20 adults (aged 22-78 years) and from the umbilical cords of 10 newborns and acutely exposed to 0 (control), 1, 2, 3 or 4 Gy of cobalt-60 gamma rays. Cells were cultured in the presence of the mitogen phytohemagglutinin, harvested at 48 h and then evaluated for structural chromosome aberrations by fluorescence in situ hybridization whole chromosome painting. Regression analyses were used to evaluate radiation-induced translocated chromosomes, dicentrics, acentric fragments, color junctions and aberrant cells to determine whether the frequencies of these events was dependent upon age. Peripheral blood lymphocytes from newborns showed statistically significant increases in the induced frequencies of translocated chromosomes, dicentrics, acentric fragments, color junctions and abnormal cells at several radiation doses when compared to blood from adults. No significant changes in sensitivity with age were observed when adults were evaluated separately. We conclude that peripheral lymphocytes from newborns are significantly more prone to radiation-induced chromosome aberrations than peripheral lymphocytes from adults. The increased sensitivity of newborns in this study relative to adults was found to be 37(±9)%, 18(±4)%, 12(±2)% and 4(±5)% at doses of 1, 2, 3 and 4 Gy, respectively. These data may be relevant when making radiation exposure risk assessments.
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15
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Suppression of telomere-binding protein TPP1 resulted in telomere dysfunction and enhanced radiation sensitivity in telomerase-negative osteosarcoma cell line. Biochem Biophys Res Commun 2014; 445:363-8. [PMID: 24513288 DOI: 10.1016/j.bbrc.2014.02.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 02/01/2014] [Indexed: 02/04/2023]
Abstract
Mammalian telomeres are protected by the shelterin complex that contains the six core proteins POT1, TPP1, TIN2, TRF1, TRF2 and RAP1. TPP1, formerly known as TINT1, PTOP, and PIP1, is a key factor that regulates telomerase recruitment and activity. In addition to this, TPP1 is required to mediate the shelterin assembly and stabilize telomere. Previous work has found that TPP1 expression was elevated in radioresistant cells and that overexpression of TPP1 led to radioresistance and telomere lengthening in telomerase-positive cells. However, the exact effects and mechanism of TPP1 on radiosensitivity are yet to be precisely defined in the ALT cells. Here we report on the phenotypes of the conditional deletion of TPP1 from the human osteosarcoma U2OS cells using ALT pathway to extend the telomeres.TPP1 deletion resulted in telomere shortening, increased apoptosis and radiation sensitivity enhancement. Together, our findings show that TPP1 plays a vital role in telomere maintenance and protection and establish an intimate relationship between TPP1, telomere and cellular response to ionizing radiation, but likely has the specific mechanism yet to be defined.
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Shim G, Ricoul M, Hempel WM, Azzam EI, Sabatier L. Crosstalk between telomere maintenance and radiation effects: A key player in the process of radiation-induced carcinogenesis. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2014; 760:S1383-5742(14)00002-7. [PMID: 24486376 PMCID: PMC4119099 DOI: 10.1016/j.mrrev.2014.01.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 01/14/2014] [Accepted: 01/22/2014] [Indexed: 02/06/2023]
Abstract
It is well established that ionizing radiation induces chromosomal damage, both following direct radiation exposure and via non-targeted (bystander) effects, activating DNA damage repair pathways, of which the proteins are closely linked to telomeric proteins and telomere maintenance. Long-term propagation of this radiation-induced chromosomal damage during cell proliferation results in chromosomal instability. Many studies have shown the link between radiation exposure and radiation-induced changes in oxidative stress and DNA damage repair in both targeted and non-targeted cells. However, the effect of these factors on telomeres, long established as guardians of the genome, still remains to be clarified. In this review, we will focus on what is known about how telomeres are affected by exposure to low- and high-LET ionizing radiation and during proliferation, and will discuss how telomeres may be a key player in the process of radiation-induced carcinogenesis.
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17
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Increased mammogram-induced DNA damage in mammary epithelial cells aged in vitro. PLoS One 2013; 8:e63052. [PMID: 23667571 PMCID: PMC3646886 DOI: 10.1371/journal.pone.0063052] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 03/27/2013] [Indexed: 12/11/2022] Open
Abstract
Concerned about the risks of mammography screening in the adult population, we analyzed the ability of human mammary epithelial cells to cope with mammogram-induced DNA damage. Our study shows that an X-ray dose of 20 mGy, which is the standard dose received by the breast surface per two-view mammogram X-ray exploration, induces increased frequencies of DNA double-strand breaks to in vitro aged–but not to young–human mammary epithelial cells. We provide evidence that aged epithelial breast cells are more radiosensitive than younger ones. Our studies point to an inefficient damage response of aged cells to low-dose radiation, this being due to both delayed and incomplete mobilization of repair proteins to DNA strand breaks. This inefficient damage response is translated into an important delay in double-strand break disappearance and consequent accumulation of unrepaired DNA breaks. The result of this is a significant increase in micronuclei frequency in the in vitro aged mammary epithelial cells exposed to doses equivalent to a single mammogram X-ray exploration. Since our experiments were carried out in primary epithelial cell cultures in which cells age at the same time as they undergo replication-dependent telomere shortening, we needed to determine the contribution of these two factors to their phenotype. In this paper, we report that the exogenous expression of human telomerase retrotranscriptase in late population doubling epithelial cells does not rescue its delayed repair phenotype. Therefore, retarded DNA break repair is a direct consequence of cellular aging itself, rather than a consequence of the presence of dysfunctional telomeres. Our findings of long-lasting double strand breaks and incomplete DNA break repair in the in vitro aged epithelial cells are in line with the increased carcinogenic risks of radiation exposures at older ages revealed by epidemiologic studies.
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18
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Jacobs JJL. Loss of telomere protection: consequences and opportunities. Front Oncol 2013; 3:88. [PMID: 23596571 PMCID: PMC3625723 DOI: 10.3389/fonc.2013.00088] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 04/02/2013] [Indexed: 01/22/2023] Open
Abstract
Telomeres are repetitive sequences at the natural ends of linear eukaryotic chromosomes that protect these from recognition as chromosome breaks. Their ability to do so critically depends on the binding of sufficient quantities of functional shelterin, a six-unit protein complex with specific and crucial roles in telomere maintenance and function. Insufficient telomere length, leading to insufficient concentration of shelterin at chromosome ends, or otherwise crippled shelterin function, causes telomere deprotection. While contributing to aging-related pathologies, loss of telomere protection can act as a barrier to tumorigenesis, as dysfunctional telomeres activate DNA-damage-like checkpoint responses that halt cell proliferation or trigger cell death. In addition, dysfunctional telomeres affect cancer development and progression by being a source of genomic instability. Reviewed here are the different approaches that are being undertaken to investigate the mammalian cellular response to telomere dysfunction and its consequences for cancer. Furthermore, it is discussed how current and future knowledge about the mechanisms underlying telomere damage responses might be applied for diagnostic purposes or therapeutic intervention.
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Affiliation(s)
- Jacqueline J L Jacobs
- Division of Molecular Oncology, The Netherlands Cancer Institute Amsterdam, Netherlands
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19
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Novel connections between DNA replication, telomere homeostasis, and the DNA damage response revealed by a genome-wide screen for TEL1/ATM interactions in Saccharomyces cerevisiae. Genetics 2013; 193:1117-33. [PMID: 23378069 DOI: 10.1534/genetics.113.149849] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tel1 is the budding yeast ortholog of the mammalian tumor suppressor and DNA damage response (DDR) kinase ATM. However, tel1-Δ cells, unlike ATM-deficient cells, do not exhibit sensitivity to DNA-damaging agents, but do display shortened (but stably maintained) telomere lengths. Neither the extent to which Tel1p functions in the DDR nor the mechanism by which Tel1 contributes to telomere metabolism is well understood. To address the first question, we present the results from a comprehensive genome-wide screen for genetic interactions with tel1-Δ that cause sensitivity to methyl methanesulfonate (MMS) and/or ionizing radiation, along with follow-up characterizations of the 13 interactions yielded by this screen. Surprisingly, many of the tel1-Δ interactions that confer DNA damage sensitivity also exacerbate the short telomere phenotype, suggesting a connection between these two phenomena. Restoration of normal telomere length in the tel1-Δ xxx-Δ mutants results in only minor suppression of the DNA damage sensitivity, demonstrating that the sensitivity of these mutants must also involve mechanisms independent of telomere length. In support of a model for increased replication stress in the tel1-Δ xxx-Δ mutants, we show that depletion of dNTP pools through pretreatment with hydroxyurea renders tel1-Δ cells (but not wild type) MMS-sensitive, demonstrating that, under certain conditions, Tel1p does indeed play a critical role in the DDR.
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20
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Berardinelli F, Nieri D, Sgura A, Tanzarella C, Antoccia A. Telomere loss, not average telomere length, confers radiosensitivity to TK6-irradiated cells. Mutat Res 2012; 740:13-20. [PMID: 23220250 DOI: 10.1016/j.mrfmmm.2012.11.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 11/20/2012] [Accepted: 11/22/2012] [Indexed: 06/01/2023]
Abstract
Many and varied are the proposed mechanisms that lead to resistance to ionizing radiation treatment. Among them, an inverse relationship between telomere length and radioresistance has been recently advanced. Investigating such a relationship in TK6 lymphoblasts, we found that clones originating from cells survived to 4Gy of X-rays showed a significantly higher telomere length when compared with clones grown from untreated cells. The lengthening observed was not attributable to a radiation-induced increase in telomerase activity, as demonstrated by TRAP assay performed in the dose range of 1-10Gy. Given the evidence that TK6 whole population was characterized by heterogeneity in cellular mean telomere length and telomere loss, we tested the hypothesis that a process of selection may favour cells with longer telomeres (more radioresistant cells) following exposure to irradiation. In order to do this 15 independent TK6 clones were selected and characterized for telomere length and loss on the basis of q-FISH and flow-FISH analysis. Among the screened clones four characterized by long telomeres and four characterized by short telomeres were tested for their radiosensitivity by means of clonogenic assay. The results obtained showed that, in our experimental conditions (cellular model, radiation doses) no significant correlation was observed between radiosensitivity and mean telomere lengths, whereas a positive correlation was observed with respect to telomere loss. Overall, these results indicate that telomere loss and not mean telomere length plays a critical role in the phenomenon of radiosensitivity/radioresistance.
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21
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Ferrandon S, Saultier P, Carras J, Battiston-Montagne P, Alphonse G, Beuve M, Malleval C, Honnorat J, Slatter T, Hung N, Royds J, Rodriguez-Lafrasse C, Poncet D. Telomere profiling: toward glioblastoma personalized medicine. Mol Neurobiol 2012; 47:64-76. [PMID: 23065374 DOI: 10.1007/s12035-012-8363-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 10/01/2012] [Indexed: 02/03/2023]
Abstract
Despite a standard of care combining surgery, radiotherapy (RT), and temozolomide chemotherapy, the average overall survival (OS) of glioblastoma patients is only 15 months, and even far lower when the patient cannot benefit from this combination. Therefore, there is a strong need for new treatments, such as new irradiation techniques. Against this background, carbon ion hadrontherapy, a new kind of irradiation, leads to a greater biological response of the tumor, while minimizing adverse effects on healthy tissues in comparison with RT. As carbon ion hadrontherapy is restricted to RT-resistant patients, photon irradiation resistance biomarkers are needed. Long telomeres and high telomerase activity have been widely associated with photon radioresistance in other cancers. Moreover, telomere protection, telomere function, and telomere length (TL) also depend on the shelterin protein complex (TRF1, TRF2, TPP1, POT1, TIN2, and hRAP1). We thus decided to evaluate an enlarged telomeric status (TL, telomerase catalytic subunit, and the shelterin component expression level) as a potential radioresistance biomarker in vitro using cellular models and ex vivo using patient tumor biopsies. In addition, nothing was known about the role of telomeres in carbon ion response. We thus evaluated telomeric status after both types of irradiation. We report here a significant correlation between TL and the basal POT1 expression level and photon radioresistance, in vitro, and a significant increase in the OS of patients with long telomeres or a high POT1 level, in vivo. POT1 expression was predictive of patient response irrespective of the TL. Strikingly, these correlations were lost, in vitro, when considering carbon irradiation. We thus propose (1) a model of the implications of telomeric damage in the cell response to both types of irradiation and (2) assessment of the POT1 expression level and TL using patient tumor biopsies to identify radioresistant patients who could benefit from carbon hadrontherapy.
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Affiliation(s)
- Sylvain Ferrandon
- EMR3738, Cellular and Molecular Radiobiology Laboratory, Medicine Faculty, Lyon 1 University, 69921, Oullins Cedex 12, France
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Park HR, Jo SK. Lasting effects of an impairment of Th1-like immune response in γ-irradiated mice: A resemblance between irradiated mice and aged mice. Cell Immunol 2010; 267:1-8. [PMID: 21092942 DOI: 10.1016/j.cellimm.2010.10.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Revised: 10/11/2010] [Accepted: 10/15/2010] [Indexed: 11/30/2022]
Abstract
Although one of the several chronic effects of ionizing radiation is aging, there are no experimental data on radiation-induced immunological aging. The most interesting change in aging was a helper T (Th) 1/Th2 imbalance. We investigated chronic effect on immune responses after ionizing radiation and its effects in irradiated mice were compared with those of aged mice. The 2-month-old mice received a whole-body irradiation of 5Gy. At 6months after irradiation, we compared the immune functions of the irradiated mice with those of normal mice of the same age and with those of older. Interferon (IFN)-γ and antigen-specific immunoglobulin (Ig)G2a level were lower in the irradiated mice than in normal mice of same age, showing similar levels to those of old normal mice. In contrast, interleukin (IL)-4 and IL-5 and antigen-specific IgG1 level were increased in irradiated mice when compared with the same aged-normal mice. Next, we investigated the low expression of IL-12p70, IL-12 receptors and IL-18 receptors in irradiated and old mice. Also, the decrease of natural killer cell activity was intensified in the irradiated mice, showing lower than values to those of old mice. Interestingly, in irradiated mice, the absolute numbers and the percentages of natural killer (NK) cells was extremely decreased. But the absolute numbers of Th cells and cytotoxic T (Tc) cells in old mice were significantly decreased. In conclusion, an immunological imbalance by the whole-body irradiation of 5Gy induces to persist in the long term, resulting in the similar results with aging. Our results suggest that the downregulation of the Th1-like immune response shown in old mice rapidly occurred through exposure of ionizing radiation.
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Affiliation(s)
- Hae-Ran Park
- Radiation Biotechnology Research Division, Advanced Radiation Technology Institute, Jeongeup Campus of Korea Atomic Energy Research Institute (KAERI), 1266 Sinjeong-dong, Jeongeup-si Jeonbuk 580-185, Republic of Korea
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