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Cherednichenko O, Pilyugina A, Nuraliev S, Azizbekova D. Persons chronically exposed to low doses of ionizing radiation: A cytogenetic dosimetry study. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2024; 894:503728. [PMID: 38432778 DOI: 10.1016/j.mrgentox.2024.503728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/10/2024] [Accepted: 01/13/2024] [Indexed: 03/05/2024]
Abstract
The dosimetry and control of exposure for individuals chronically exposed to ionizing radiation are important and complex issues. Assessment may be optimized by evaluating individual adaptation and radiosensitivity, but it is not possible for a single model to account for all relevant parameters. Our goal was to develop approaches for the calculation of doses for persons chronically exposed to ionizing radiation, taking their radiosensitivities into consideration. On the basis of ex vivo radiation of blood samples, dose-effect models were constructed for dose ranges 0.01-2.0 and 0.01-0.4 Gy, using different cytogenetic criteria. The frequencies of "dicentric chromosomes and rings" at low doses are too low to have predictive value. The different responses of subjects to radiation made it possible to categorize them according to their radiosensitivities and to generate separate dose-effect curves for radiosensitive, average, and radioresistant individuals, reducing the amount of error in retrospective dosimetry.
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Affiliation(s)
- Oksana Cherednichenko
- Laboratory of Genetic Monitoring, Institute of Genetics and Physiology, Almaty 050060, Kazakhstan.
| | - Anastassiya Pilyugina
- Laboratory of Genetic Monitoring, Institute of Genetics and Physiology, Almaty 050060, Kazakhstan
| | - Serikbai Nuraliev
- Laboratory of Genetic Monitoring, Institute of Genetics and Physiology, Almaty 050060, Kazakhstan
| | - Dinara Azizbekova
- Laboratory of Genetic Monitoring, Institute of Genetics and Physiology, Almaty 050060, Kazakhstan
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Averbeck D. Low-Dose Non-Targeted Effects and Mitochondrial Control. Int J Mol Sci 2023; 24:11460. [PMID: 37511215 PMCID: PMC10380638 DOI: 10.3390/ijms241411460] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 06/26/2023] [Accepted: 06/29/2023] [Indexed: 07/30/2023] Open
Abstract
Non-targeted effects (NTE) have been generally regarded as a low-dose ionizing radiation (IR) phenomenon. Recently, regarding long distant abscopal effects have also been observed at high doses of IR) relevant to antitumor radiation therapy. IR is inducing NTE involving intracellular and extracellular signaling, which may lead to short-ranging bystander effects and distant long-ranging extracellular signaling abscopal effects. Internal and "spontaneous" cellular stress is mostly due to metabolic oxidative stress involving mitochondrial energy production (ATP) through oxidative phosphorylation and/or anaerobic pathways accompanied by the leakage of O2- and other radicals from mitochondria during normal or increased cellular energy requirements or to mitochondrial dysfunction. Among external stressors, ionizing radiation (IR) has been shown to very rapidly perturb mitochondrial functions, leading to increased energy supply demands and to ROS/NOS production. Depending on the dose, this affects all types of cell constituents, including DNA, RNA, amino acids, proteins, and membranes, perturbing normal inner cell organization and function, and forcing cells to reorganize the intracellular metabolism and the network of organelles. The reorganization implies intracellular cytoplasmic-nuclear shuttling of important proteins, activation of autophagy, and mitophagy, as well as induction of cell cycle arrest, DNA repair, apoptosis, and senescence. It also includes reprogramming of mitochondrial metabolism as well as genetic and epigenetic control of the expression of genes and proteins in order to ensure cell and tissue survival. At low doses of IR, directly irradiated cells may already exert non-targeted effects (NTE) involving the release of molecular mediators, such as radicals, cytokines, DNA fragments, small RNAs, and proteins (sometimes in the form of extracellular vehicles or exosomes), which can induce damage of unirradiated neighboring bystander or distant (abscopal) cells as well as immune responses. Such non-targeted effects (NTE) are contributing to low-dose phenomena, such as hormesis, adaptive responses, low-dose hypersensitivity, and genomic instability, and they are also promoting suppression and/or activation of immune cells. All of these are parts of the main defense systems of cells and tissues, including IR-induced innate and adaptive immune responses. The present review is focused on the prominent role of mitochondria in these processes, which are determinants of cell survival and anti-tumor RT.
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Affiliation(s)
- Dietrich Averbeck
- Laboratory of Cellular and Molecular Radiobiology, PRISME, UMR CNRS 5822/IN2P3, IP2I, Lyon-Sud Medical School, University Lyon 1, 69921 Oullins, France
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Bennett PV, Johnson AM, Ackerman SE, Chaudhary P, Keszenman DJ, Wilson PF. Dose-Rate Effects of Protons and Light Ions for DNA Damage Induction, Survival and Transformation in Apparently Normal Primary Human Fibroblasts. Radiat Res 2021; 197:298-313. [PMID: 34910217 DOI: 10.1667/rade-21-00138.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 11/09/2021] [Indexed: 11/03/2022]
Abstract
We report on effects of low-dose exposures of accelerated protons delivered at high-dose rate (HDR) or a simulated solar-particle event (SPE) like low-dose rate (LDR) on immediate DNA damage induction and processing, survival and in vitro transformation of low passage NFF28 apparently normal primary human fibroblasts. Cultures were exposed to 50, 100 and 1,000 MeV monoenergetic protons in the Bragg entrance/plateau region and cesium-137 γ rays at 20 Gy/h (HDR) or 1 Gy/h (LDR). DNA double-strand breaks (DSB) and clustered DNA damages (containing oxypurines and abasic sites) were measured using transverse alternating gel electrophoresis (TAFE) and immunocytochemical detection/scoring of colocalized γ-H2AX pS139/53BP1 foci, with their induction being linear energy transfer (LET) dependent and dose-rate sparing observed for the different damage classes. Relative biological effectiveness (RBE) values for cell survival after proton irradiation at both dose-rates ranged from 0.61-0.73. Transformation RBE values were dose-rate dependent, ranging from ∼1.8-3.1 and ∼0.6-1.0 at low doses (≤30 cGy) for HDR and LDR irradiations, respectively. However peak transformation frequencies were significantly higher (1.3-7.3-fold) for higher doses of 0.5-1 Gy delivered at SPE-like LDR. Cell survival and transformation frequencies measured after low-dose 500 MeV/n He-4, 290 MeV/n C-12 and 600 MeV/n Si-28 ion irradiations also showed an inverse dose-rate effect for transformation at SPE-like LDR. This work demonstrates the existence of inverse dose-rate effects for proton and light-ion-induced postirradiation cell survival and in vitro transformation for space mission-relevant doses and dose rates.
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Affiliation(s)
- Paula V Bennett
- Biology Department, Brookhaven National Laboratory, Upton, New York
| | - Alicia M Johnson
- Biology Department, Brookhaven National Laboratory, Upton, New York
| | - Sarah E Ackerman
- Biology Department, Brookhaven National Laboratory, Upton, New York
| | - Pankaj Chaudhary
- Biology Department, Brookhaven National Laboratory, Upton, New York
| | | | - Paul F Wilson
- Biology Department, Brookhaven National Laboratory, Upton, New York
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Averbeck D, Rodriguez-Lafrasse C. Role of Mitochondria in Radiation Responses: Epigenetic, Metabolic, and Signaling Impacts. Int J Mol Sci 2021; 22:ijms222011047. [PMID: 34681703 PMCID: PMC8541263 DOI: 10.3390/ijms222011047] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/24/2021] [Accepted: 10/08/2021] [Indexed: 12/15/2022] Open
Abstract
Until recently, radiation effects have been considered to be mainly due to nuclear DNA damage and their management by repair mechanisms. However, molecular biology studies reveal that the outcomes of exposures to ionizing radiation (IR) highly depend on activation and regulation through other molecular components of organelles that determine cell survival and proliferation capacities. As typical epigenetic-regulated organelles and central power stations of cells, mitochondria play an important pivotal role in those responses. They direct cellular metabolism, energy supply and homeostasis as well as radiation-induced signaling, cell death, and immunological responses. This review is focused on how energy, dose and quality of IR affect mitochondria-dependent epigenetic and functional control at the cellular and tissue level. Low-dose radiation effects on mitochondria appear to be associated with epigenetic and non-targeted effects involved in genomic instability and adaptive responses, whereas high-dose radiation effects (>1 Gy) concern therapeutic effects of radiation and long-term outcomes involving mitochondria-mediated innate and adaptive immune responses. Both effects depend on radiation quality. For example, the increased efficacy of high linear energy transfer particle radiotherapy, e.g., C-ion radiotherapy, relies on the reduction of anastasis, enhanced mitochondria-mediated apoptosis and immunogenic (antitumor) responses.
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Affiliation(s)
- Dietrich Averbeck
- Laboratory of Cellular and Molecular Radiobiology, PRISME, UMR CNRS 5822/IN2P3, IP2I, Lyon-Sud Medical School, University Lyon 1, 69921 Oullins, France;
- Correspondence:
| | - Claire Rodriguez-Lafrasse
- Laboratory of Cellular and Molecular Radiobiology, PRISME, UMR CNRS 5822/IN2P3, IP2I, Lyon-Sud Medical School, University Lyon 1, 69921 Oullins, France;
- Department of Biochemistry and Molecular Biology, Lyon-Sud Hospital, Hospices Civils de Lyon, 69310 Pierre-Bénite, France
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Tanaka Y, Furuta M. Biological effects of low-dose γ-ray irradiation on chromosomes and DNA of Drosophila melanogaster. JOURNAL OF RADIATION RESEARCH 2021; 62:1-11. [PMID: 33290547 PMCID: PMC7779362 DOI: 10.1093/jrr/rraa108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/27/2020] [Indexed: 06/12/2023]
Abstract
While the damage to chromosomes and genes induced by high-dose radiation (HDR) has been well researched in many organisms, the effects of low-dose radiation (LDR), defined as a radiation dose of ≤100 mSv, are still being debated. Recent research has suggested that the biological effects of LDR differ from those observed in HDR. To detect the effect of LDR on genes, we selected a gene of Drosophila melanogaster, known as the multiple wing hair (mwh) gene. The hatched heterozygous larvae with genotype mwh/+ were irradiated by γ-rays of a 60Co source. After eclosion, the wing hairs of the heterozygous flies were observed. The area of only one or two mwh cells (small spot) and that of more than three mwh cells (large spot) were counted. The ratio of the two kinds of spots were compared between groups irradiated by different doses including a non-irradiated control group. For the small spot in females, the eruption frequency increased in the groups irradiated with 20-75 mGy, indicating hypersensitivity (HRS) to LDR, while in the groups irradiated with 200 and 300 mGy, the frequency decreased, indicating induced radioresistance (IRR), while in males, 50 and 100 mGy conferred HRS and 75 and 200 mGy conferred IRR. For the large spot in females, 75 mGy conferred HRS and 100-800 mGy conferred IRR. In conclusion, HRS and IRR to LDR was found in Drosophila wing cells by delimiting the dose of γ-rays finely, except in the male large spot.
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Affiliation(s)
- Yoshiharu Tanaka
- Corresponding author. Radiation Biology and Molecular Genetics, Division of Quantum Radiation, Faculty of Technology and Biology and Cultural Sciences, Faculty of Liberal Arts and Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan. Tel: 81-72-254-9750;
| | - Masakazu Furuta
- Radiation Biology and Molecular Genetics, Division of Quantum Radiation, Faculty of Technology and Department of Radiation Research Center, Osaka Prefecture University, 1-2 Gakuencho, Naka-ku, Sakai 591-8531, Japan
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Yang G, Yu D, Li W, Zhao Y, Wen X, Liang X, Zhang X, Zhou L, Hu J, Niu C, Tian H, Han F, Chen X, Dong L, Cai L, Cui J. Distinct biological effects of low-dose radiation on normal and cancerous human lung cells are mediated by ATM signaling. Oncotarget 2018; 7:71856-71872. [PMID: 27708248 PMCID: PMC5342128 DOI: 10.18632/oncotarget.12379] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 09/25/2016] [Indexed: 11/30/2022] Open
Abstract
Low-dose radiation (LDR) induces hormesis and adaptive response in normal cells but not in cancer cells, suggesting its potential protection of normal tissue against damage induced by conventional radiotherapy. However, the underlying mechanisms are not well established. We addressed this in the present study by examining the role of the ataxia telangiectasia mutated (ATM) signaling pathway in response to LDR using A549 human lung adenocarcinoma cells and HBE135-E6E7 (HBE) normal lung epithelial cells. We found that LDR-activated ATM was the initiating event in hormesis and adaptive response to LDR in HBE cells. ATM activation increased the expression of CDK4/CDK6/cyclin D1 by activating the AKT/glycogen synthase kinase (GSK)-3β signaling pathway, which stimulated HBE cell proliferation. Activation of ATM/AKT/GSK-3β signaling also increased nuclear accumulation of nuclear factor erythroid 2-related factor 2, leading to increased expression of antioxidants, which mitigated cellular damage from excessive reactive oxygen species production induced by high-dose radiation. However, these effects were not observed in A549 cells. Thus, the failure to activate these pathways in A549 cells likely explains the difference between normal and cancer cells in terms of hormesis and adaptive response to LDR.
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Affiliation(s)
- Guozi Yang
- Cancer Center, The First Hospital of Jilin University, Changchun 130021, China.,Department of Radiation-Oncology, The First Hospital of Jilin University, Changchun 130021, China
| | - Dehai Yu
- Cancer Center, The First Hospital of Jilin University, Changchun 130021, China
| | - Wei Li
- Cancer Center, The First Hospital of Jilin University, Changchun 130021, China
| | - Yuguang Zhao
- Cancer Center, The First Hospital of Jilin University, Changchun 130021, China
| | - Xue Wen
- Cancer Center, The First Hospital of Jilin University, Changchun 130021, China
| | - Xinyue Liang
- Cancer Center, The First Hospital of Jilin University, Changchun 130021, China
| | - Xiaoying Zhang
- Cancer Center, The First Hospital of Jilin University, Changchun 130021, China
| | - Lei Zhou
- Cancer Center, The First Hospital of Jilin University, Changchun 130021, China
| | - Jifan Hu
- Cancer Center, The First Hospital of Jilin University, Changchun 130021, China
| | - Chao Niu
- Cancer Center, The First Hospital of Jilin University, Changchun 130021, China
| | - Huimin Tian
- Cancer Center, The First Hospital of Jilin University, Changchun 130021, China
| | - Fujun Han
- Cancer Center, The First Hospital of Jilin University, Changchun 130021, China
| | - Xiao Chen
- Cancer Center, The First Hospital of Jilin University, Changchun 130021, China
| | - Lihua Dong
- Department of Radiation-Oncology, The First Hospital of Jilin University, Changchun 130021, China
| | - Lu Cai
- Cancer Center, The First Hospital of Jilin University, Changchun 130021, China.,Kosair Children's Hospital Research Institute, Departments of Pediatrics, Radiation Oncology, Pharmacology and Toxicology, University of Louisville, Louisville, KY 40292, USA
| | - Jiuwei Cui
- Cancer Center, The First Hospital of Jilin University, Changchun 130021, China
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Dionet C, Müller-Barthélémy M, Marceau G, Denis JM, Averbeck D, Gueulette J, Sapin V, Pereira B, Tchirkov A, Chautard E, Verrelle P. Different dose rate-dependent responses of human melanoma cells and fibroblasts to low dose fast neutrons. Int J Radiat Biol 2016; 92:527-35. [PMID: 27258624 DOI: 10.1080/09553002.2016.1186300] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
PURPOSE To analyze the dose rate influence in hyper-radiosensitivity (HRS) of human melanoma cells to very low doses of fast neutrons and to compare to the behaviour of normal human skin fibroblasts. MATERIALS AND METHODS We explored different neutron dose rates as well as possible implication of DNA double-strand breaks (DSB), apoptosis, and energy-provider adenosine-triphosphate (ATP) levels during HRS. RESULTS HRS in melanoma cells appears only at a very low dose rate (VLDR), while a high dose rate (HDR) induces an initial cell-radioresistance (ICRR). HRS does not seem to be due either to DSB or to apoptosis. Both phenomena (HRS and ICRR) appear to be related to ATP availability for triggering cell repair. Fibroblast survival after neutron irradiation is also dose rate-dependent but without HRS. CONCLUSIONS Melanoma cells or fibroblasts exert their own survival behaviour at very low doses of neutrons, suggesting that in some cases there is a differential between cancer and normal cells radiation responses. Only the survival of fibroblasts at HDR fits the linear no-threshold model. This new insight into human cell responses to very low doses of neutrons, concerns natural radiations, surroundings of accelerators, proton-therapy devices, flights at high altitude. Furthermore, ATP inhibitors could increase HRS during high-linear energy transfer (high-LET) irradiation.
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Affiliation(s)
- Claude Dionet
- a Centre Jean Perrin , Laboratoire de Radio-Oncologie Expérimentale , Clermont-Ferrand , France
| | - Melanie Müller-Barthélémy
- a Centre Jean Perrin , Laboratoire de Radio-Oncologie Expérimentale , Clermont-Ferrand , France ;,b Clermont Université, Université d'Auvergne, EA7283 CREaT , Clermont-Ferrand , France
| | - Geoffroy Marceau
- c Biochimie et Biologie Moléculaire , CHU Clermont-Ferrand, Centre de Biologie , Clermont-Ferrand , France
| | - Jean-Marc Denis
- d Radiotherapy Department , Cliniques Universitaires Saint Luc-UCL , Bruxelles , Belgique ;,f Université Catholique de Louvain (UCL-IREC-MIRO) , Bruxelles , Belgique
| | - Dietrich Averbeck
- e Institut Curie-Recherche, UMR3348 CNRS/IC, Centre Universitaire, Orsay , France
| | - John Gueulette
- f Université Catholique de Louvain (UCL-IREC-MIRO) , Bruxelles , Belgique
| | - Vincent Sapin
- c Biochimie et Biologie Moléculaire , CHU Clermont-Ferrand, Centre de Biologie , Clermont-Ferrand , France
| | - Bruno Pereira
- g CHU Clermont-Ferrand, Biostatistics unit (DRCI) , Clermont-Ferrand , France
| | - Andrei Tchirkov
- h Cytogénétique médicale, CHU Estaing , Clermont-Ferrand , France
| | - Emmanuel Chautard
- a Centre Jean Perrin , Laboratoire de Radio-Oncologie Expérimentale , Clermont-Ferrand , France ;,b Clermont Université, Université d'Auvergne, EA7283 CREaT , Clermont-Ferrand , France
| | - Pierre Verrelle
- a Centre Jean Perrin , Laboratoire de Radio-Oncologie Expérimentale , Clermont-Ferrand , France ;,b Clermont Université, Université d'Auvergne, EA7283 CREaT , Clermont-Ferrand , France
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Ye F, Ning J, Liu X, Jin X, Wang T, Li Q. The influence of non-DNA-targeted effects on carbon ion-induced low-dose hyper-radiosensitivity in MRC-5 cells. JOURNAL OF RADIATION RESEARCH 2016; 57:103-109. [PMID: 26559335 PMCID: PMC4795944 DOI: 10.1093/jrr/rrv072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 09/28/2015] [Accepted: 10/04/2015] [Indexed: 06/05/2023]
Abstract
Low-dose hyper-radiosensitivity (LDHRS) is a hot topic in normal tissue radiation protection. However, the primary causes for LDHRS still remain unclear. In this study, the impact of non-DNA-targeted effects (NTEs) on high-LET radiation-induced LDHRS was investigated. Human normal lung fibroblast MRC-5 cells were irradiated with high-LET carbon ions, and low-dose biological effects (in terms of various bio-endpoints, including colony formation, DNA damage and micronuclei formation) were detected under conditions with and without gap junctional intercellular communication (GJIC) inhibition. LDHRS was observed when the radiation dose was <0.2 Gy for all bio-endpoints under investigation, but vanished when the GJIC was suppressed. Based on the probability of cells being hit and micro-dose per cell calculation, we deduced that the LDHRS phenomenon came from the combined action of direct hits and NTEs. We concluded that GJIC definitely plays an important role in cytotoxic substance spreading in high-LET carbon ion-induced LDHRS.
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Affiliation(s)
- Fei Ye
- Medical Physics Division, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China Department of Modern Physics, Lanzhou University, Lanzhou 730000, China University of Chinese Academy of Sciences, Beijing 100049, China Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China
| | - Jing Ning
- Gansu Provincial People's Hospital, Lanzhou 730000, China
| | - Xinguo Liu
- Medical Physics Division, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China
| | - Xiaodong Jin
- Medical Physics Division, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China
| | - Tieshan Wang
- Department of Modern Physics, Lanzhou University, Lanzhou 730000, China
| | - Qiang Li
- Medical Physics Division, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China
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Xue L, Furusawa Y, Yu D. ATR signaling cooperates with ATM in the mechanism of low dose hypersensitivity induced by carbon ion beam. DNA Repair (Amst) 2015; 34:1-8. [PMID: 26246317 DOI: 10.1016/j.dnarep.2015.07.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 07/04/2015] [Accepted: 07/14/2015] [Indexed: 02/04/2023]
Abstract
Little work has been done on the mechanism of low dose hyper-radiosensitivity (HRS) and later appeared radioresistance (termed induced radioresistance (IRR)) after irradiation with medium and high linear energy transfer (LET) particles. The aim of this study was to find out whether ATR pathway is involved in the mechanism of HRS induced by high LET radiation. GM0639 cells and two ATM deficient/mutant cells, AT5BIVA and AT2KY were irradiated by carbon ion beam. Thymidine block technique was developed to enrich the G2-phase population. Radiation induced early G2/M checkpoint was quantitatively assess with dual-parameter flow cytometry by detecting the cells positive for phospho-histone H3. The involvement of ATR pathway in HRS/IRR response was detected with pretreatment of specific inhibitors prior to carbon ion beam. The link between the early G2/M checkpoint and HRS/IRR under carbon ion beam was first confirmed in GM0639 cells, through the enrichment of cell population in G2-phase or with Aurora kinase inhibitor that attenuates the transition from G2 to M phase. Interestingly, the early G2/M arrest could still be observed in ATM deficient/mutant cells with an effect of ATR signaling, which was discovered to function in an LET-dependent manner, even as low as 0.2Gy for carbon ion radiation. The involvement of ATR pathway in heavy particles induced HRS/IRR was determined with the specific ATR inhibitor in GM0639 cells, which affected the HRS/IRR occurrence similarly as ATM inhibitor. These data demonstrate that ATR pathway may cooperate with ATM in the mechanism of low dose hypersensitivity induced by carbon ion beam.
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Affiliation(s)
- Lian Xue
- School of Public Health, Medical College of Soochow University, Suzhou, China; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, School of Public Health, Soochow University, Suzhou, China
| | - Yoshiya Furusawa
- Microbeam Development Office, Research/Development/Support Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Dong Yu
- School of Radiological Medicine and Protection, Medical College of Soochow University, Suzhou, China.
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