1
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Zhang Y, Wang H, Du Y, Zhang L, Li X, Guo H, Liu J, Zhou L, Xu X, Li J. Biological responses of an elite centipedegrass [ Eremochloa ophiuroides (Munro) Hack.] cultivar (Ganbei) to carbon ion beam irradiation. FRONTIERS IN PLANT SCIENCE 2024; 15:1433121. [PMID: 39359635 PMCID: PMC11445083 DOI: 10.3389/fpls.2024.1433121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Accepted: 09/02/2024] [Indexed: 10/04/2024]
Abstract
Carbon ion beam irradiation (CIBI) is a highly efficient mutagenesis for generating mutations that can be used to expand germplasm resources and create superior new germplasm. The study investigated the effects of different doses of CIBI (50 Gy, 100 Gy, 150 Gy, 200 Gy and 300 Gy) on seed germination and seedling survival, seedling morphological and physiological traits of an elite centipedegrass cultivar Ganbei. The results showed that irradiation greater than 50 Gy cause inhibition of seed germination, and the semi-lethal dose (LD50) is around 90 Gy for CIBI treated seeds of Ganbei. A carbon ion beam-mutagenized centipedegrass population was generated from Ganbei, with irradiation dosages from 50 Gy to 200 Gy. More than ten types of phenotypic variations and novel mutants with heritable tendencies mainly including putative mutants of stolon number, length and diameter, of internode length, of leaf length and width, of leaf chlorophyll content, of stolon growth rate, of aboveground tissue dry weight, of sward height were identified. While the total sugar content of the plants from irradiated seeds showed no obvious change in all treatments as compared to the control, the crude protein content displayed significant reduction at a high-dose treatment of 200 Gy. Genetic polymorphism was detected in mutagenized centipedegrass population using SSR-PCR analysis, suggesting that CIBI caused alteration of larger fragments of the DNA sequence. As a result, a preliminary batch of mutants was screened in this study. In summary, carbon ion beam mutagenesis is an effective way for developing centipedegrass germplasm with wider variation, and treating seeds with CIBI at a dosage of ~100 Gy could be effective in centipedegrass mutation breeding.
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Affiliation(s)
- Yuan Zhang
- The National Forestry and Grassland Administration Engineering Research Center for Germplasm Innovation and Utilization of Warm-season Turfgrasses/Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing Botanical Garden, Mem. Sun Yat-Sen, Nanjing, Jiangsu, China
| | - Haoran Wang
- The National Forestry and Grassland Administration Engineering Research Center for Germplasm Innovation and Utilization of Warm-season Turfgrasses/Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing Botanical Garden, Mem. Sun Yat-Sen, Nanjing, Jiangsu, China
| | - Yan Du
- Biophysics Group, Biomedical Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China
| | - Ling Zhang
- The National Forestry and Grassland Administration Engineering Research Center for Germplasm Innovation and Utilization of Warm-season Turfgrasses/Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing Botanical Garden, Mem. Sun Yat-Sen, Nanjing, Jiangsu, China
| | - Xiaohui Li
- The National Forestry and Grassland Administration Engineering Research Center for Germplasm Innovation and Utilization of Warm-season Turfgrasses/Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing Botanical Garden, Mem. Sun Yat-Sen, Nanjing, Jiangsu, China
| | - Hailin Guo
- The National Forestry and Grassland Administration Engineering Research Center for Germplasm Innovation and Utilization of Warm-season Turfgrasses/Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing Botanical Garden, Mem. Sun Yat-Sen, Nanjing, Jiangsu, China
| | - Jianxiu Liu
- The National Forestry and Grassland Administration Engineering Research Center for Germplasm Innovation and Utilization of Warm-season Turfgrasses/Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing Botanical Garden, Mem. Sun Yat-Sen, Nanjing, Jiangsu, China
| | - Libin Zhou
- Biophysics Group, Biomedical Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China
| | - Xin Xu
- The National Forestry and Grassland Administration Engineering Research Center for Germplasm Innovation and Utilization of Warm-season Turfgrasses/Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing Botanical Garden, Mem. Sun Yat-Sen, Nanjing, Jiangsu, China
| | - Jianjian Li
- The National Forestry and Grassland Administration Engineering Research Center for Germplasm Innovation and Utilization of Warm-season Turfgrasses/Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing Botanical Garden, Mem. Sun Yat-Sen, Nanjing, Jiangsu, China
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2
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Chaudhary P, Milluzzo G, McIlvenny A, Ahmed H, McMurray A, Maiorino C, Polin K, Romagnani L, Doria D, McMahon SJ, Botchway SW, Rajeev PP, Prise KM, Borghesi M. Cellular irradiations with laser-driven carbon ions at ultra-high dose rates. Phys Med Biol 2023; 68. [PMID: 36625355 DOI: 10.1088/1361-6560/aca387] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 11/16/2022] [Indexed: 01/11/2023]
Abstract
Objective.Carbon is an ion species of significant radiobiological interest, particularly in view of its use in cancer radiotherapy, where its large Relative Biological Efficiency is often exploited to overcome radio resistance. A growing interest in highly pulsed carbon delivery has arisen in the context of the development of the FLASH radiotherapy approach, with recent studies carried out at dose rates of 40 Gy s-1. Laser acceleration methods, producing ultrashort ion bursts, can now enable the delivery of Gy-level doses of carbon ions at ultra-high dose rates (UHDRs), exceeding 109Gy s-1. While studies at such extreme dose rate have been carried out so far using low LET particles such as electrons and protons, the radiobiology of high-LET, UHDR ions has not yet been explored. Here, we report the first application of laser-accelerated carbon ions generated by focussing 1020W cm-2intense lasers on 10-25 nm carbon targets, to irradiate radioresistant patient-derived Glioblastoma stem like cells (GSCs).Approach.We exposed GSCs to 1 Gy of 9.5 ± 0.5 MeV/n carbon ions delivered in a single ultra-short (∼400-picosecond) pulse, at a dose rate of 2 × 109Gy s-1, generated using the ASTRA GEMINI laser of the Central Laser Facility at the Rutherford Appleton Laboratory, Didcot, Oxfordshire, UK. We quantified carbon ion-induced DNA double strand break (DSB) damage using the 53BP1 foci formation assay and used 225 kVp x-rays as a reference radiation.Main Results.Laser-accelerated carbon ions induced complex DNA DSB damage, as seen through persistent 53BP1 foci (11.5 ± 0.4 foci/cell/Gy) at 24 h and significantly larger foci (1.69 ± 0.07μm2) than x-rays induced ones (0.63 ± 0.02μm2). The relative foci induction value for laser-driven carbon ions relative to conventional x-rays was 3.2 ± 0.3 at 24 h post-irradiation also confirming the complex nature of the induced damage.Significance.Our study demonstrates the feasibility of radiobiology investigations at unprecedented dose rates using laser-accelerated high-LET carbon ions in clinically relevant models.
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Affiliation(s)
- Pankaj Chaudhary
- The Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Lisburn Road, Belfast, BT9 7AE, Northern Ireland, United Kingdom.,Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom
| | - Giuliana Milluzzo
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom.,Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare,, via S Sofia 62, I-95123 Catania, Sicily, Italy
| | - Aodhan McIlvenny
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom
| | - Hamad Ahmed
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom.,Experimental Science Group, Central Laser Facility, Rutherford Appleton Laboratory, Didcot, Oxford, OX11 0QX, England, United Kingdom
| | - Aaron McMurray
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom
| | - Carla Maiorino
- The Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Lisburn Road, Belfast, BT9 7AE, Northern Ireland, United Kingdom.,Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare,, via S Sofia 62, I-95123 Catania, Sicily, Italy.,Extreme Light Infrastructure (ELI-NP) and Horia Hulubei National Institute for R & D in Physics and Nuclear Engineering (IFIN-HH), Str. Reactorului No. 30, 077125 Bucharest, Magurele, Romania.,University College Cork, College of Medicine and Health, Discipline of Diagnostic Radiography and Radiation Therapy, Brookfield Health Sciences Complex, Brookfield College Road, T12AK54, Cork, United Kingdom
| | - Kathryn Polin
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom
| | - Lorenzo Romagnani
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom.,Laboratoire LULI, École Polytechnique, Route de Saclay, F-91128 Palaiseau, Paris, France
| | - Domenico Doria
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom.,Extreme Light Infrastructure (ELI-NP) and Horia Hulubei National Institute for R & D in Physics and Nuclear Engineering (IFIN-HH), Str. Reactorului No. 30, 077125 Bucharest, Magurele, Romania
| | - Stephen J McMahon
- The Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Lisburn Road, Belfast, BT9 7AE, Northern Ireland, United Kingdom
| | - Stanley W Botchway
- Research Complex at Harwell & Central Laser facility, Rutherford Appleton Laboratory, Didcot, Oxford, OX11 0QX, England, United Kingdom
| | - Pattathil P Rajeev
- Experimental Science Group, Central Laser Facility, Rutherford Appleton Laboratory, Didcot, Oxford, OX11 0QX, England, United Kingdom
| | - Kevin M Prise
- The Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Lisburn Road, Belfast, BT9 7AE, Northern Ireland, United Kingdom
| | - Marco Borghesi
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom
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Belchior A, Canhoto JF, Giesen U, Langner F, Rabus H, Schulte R. Repair Kinetics of DSB-Foci Induced by Proton and α-Particle Microbeams of Different Energies. Life (Basel) 2022; 12:2040. [PMID: 36556405 PMCID: PMC9785158 DOI: 10.3390/life12122040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/30/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022] Open
Abstract
In this work, the induction and repair of radiation-induced 53BP1 foci were studied in human umbilical vein endothelial cells irradiated at the PTB microbeam with protons and α-particles of different energies. The data were analyzed in terms of the mean number of 53BP1 foci induced by the different ion beams. The number of 53BP1 foci found at different times post-irradiation suggests that the disappearance of foci follows first order kinetics. The mean number of initially produced foci shows the expected increase with LET. The most interesting finding of this work is that the absolute number of persistent foci increases with LET but not their fraction. Furthermore, protons seem to produce more persistent foci as compared to α-particles of even higher LET. This may be seen as experimental evidence that protons may be more effective in producing severe DNA lesions, as was already shown in other work, and that LET may not be the best suited parameter to characterize radiation quality.
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Affiliation(s)
- Ana Belchior
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal
| | - João F. Canhoto
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal
- Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Ulrich Giesen
- Physikalisch-Technische Bundesanstalt (PTB), 38116 Braunschweig, Germany
| | - Frank Langner
- Physikalisch-Technische Bundesanstalt (PTB), 38116 Braunschweig, Germany
| | - Hans Rabus
- Physikalisch-Technische Bundesanstalt (PTB), 10587 Berlin, Germany
| | - Reinhard Schulte
- Division of Biomedical Engineering Sciences, Loma Linda University, Loma Linda, CA 92350, USA
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4
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Ma L, Kong F, Sun K, Wang T, Guo T. From Classical Radiation to Modern Radiation: Past, Present, and Future of Radiation Mutation Breeding. Front Public Health 2022; 9:768071. [PMID: 34993169 PMCID: PMC8725632 DOI: 10.3389/fpubh.2021.768071] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 11/15/2021] [Indexed: 12/12/2022] Open
Abstract
Radiation mutation breeding has been used for nearly 100 years and has successfully improved crops by increasing genetic variation. Global food production is facing a series of challenges, such as rapid population growth, environmental pollution and climate change. How to feed the world's enormous human population poses great challenges to breeders. Although advanced technologies, such as gene editing, have provided effective ways to breed varieties, by editing a single or multiple specific target genes, enhancing germplasm diversity through mutation is still indispensable in modern and classical radiation breeding because it is more likely to produce random mutations in the whole genome. In this short review, the current status of classical radiation, accelerated particle and space radiation mutation breeding is discussed, and the molecular mechanisms of radiation-induced mutation are demonstrated. This review also looks into the future development of radiation mutation breeding, hoping to deepen our understanding and provide new vitality for the further development of radiation mutation breeding.
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Affiliation(s)
- Liqiu Ma
- Department of Nuclear Physics, China Institute of Atomic Energy, Beijing, China.,National Innovation Center of Radiation Application, Beijing, China
| | - Fuquan Kong
- Department of Nuclear Physics, China Institute of Atomic Energy, Beijing, China.,National Innovation Center of Radiation Application, Beijing, China
| | - Kai Sun
- National Engineering Research Center of Plant Space Breeding, South China Agricultural University, Guangdong, China
| | - Ting Wang
- Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Tao Guo
- National Engineering Research Center of Plant Space Breeding, South China Agricultural University, Guangdong, China
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5
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Tatin X, Muggiolu G, Sauvaigo S, Breton J. Evaluation of DNA double-strand break repair capacity in human cells: Critical overview of current functional methods. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2021; 788:108388. [PMID: 34893153 DOI: 10.1016/j.mrrev.2021.108388] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 06/17/2021] [Accepted: 06/23/2021] [Indexed: 02/05/2023]
Abstract
DNA double-strand breaks (DSBs) are highly deleterious lesions, responsible for mutagenesis, chromosomal translocation or cell death. DSB repair (DSBR) is therefore a critical part of the DNA damage response (DDR) to restore molecular and genomic integrity. In humans, this process is achieved through different pathways with various outcomes. The balance between DSB repair activities varies depending on cell types, tissues or individuals. Over the years, several methods have been developed to study variations in DSBR capacity. Here, we mainly focus on functional techniques, which provide dynamic information regarding global DSB repair proficiency or the activity of specific pathways. These methods rely on two kinds of approaches. Indirect techniques, such as pulse field gel electrophoresis (PFGE), the comet assay and immunofluorescence (IF), measure DSB repair capacity by quantifying the time-dependent decrease in DSB levels after exposure to a DNA-damaging agent. On the other hand, cell-free assays and reporter-based methods directly track the repair of an artificial DNA substrate. Each approach has intrinsic advantages and limitations and despite considerable efforts, there is currently no ideal method to quantify DSBR capacity. All techniques provide different information and can be regarded as complementary, but some studies report conflicting results. Parameters such as the type of biological material, the required equipment or the cost of analysis may also limit available options. Improving currently available methods measuring DSBR capacity would be a major step forward and we present direct applications in mechanistic studies, drug development, human biomonitoring and personalized medicine, where DSBR analysis may improve the identification of patients eligible for chemo- and radiotherapy.
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Affiliation(s)
- Xavier Tatin
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, SyMMES, 38000 Grenoble, France; LXRepair, 5 Avenue du Grand Sablon, 38700 La Tronche, France
| | | | - Sylvie Sauvaigo
- LXRepair, 5 Avenue du Grand Sablon, 38700 La Tronche, France
| | - Jean Breton
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, SyMMES, 38000 Grenoble, France.
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6
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Zhou Q, Howard ME, Tu X, Zhu Q, Denbeigh JM, Remmes NB, Herman MG, Beltran CJ, Yuan J, Greipp PT, Boughey JC, Wang L, Johnson N, Goetz MP, Sarkaria JN, Lou Z, Mutter RW. Inhibition of ATM Induces Hypersensitivity to Proton Irradiation by Upregulating Toxic End Joining. Cancer Res 2021; 81:3333-3346. [PMID: 33597272 PMCID: PMC8260463 DOI: 10.1158/0008-5472.can-20-2960] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 12/30/2020] [Accepted: 02/11/2021] [Indexed: 12/15/2022]
Abstract
Proton Bragg peak irradiation has a higher ionizing density than conventional photon irradiation or the entrance of the proton beam profile. Whether targeting the DNA damage response (DDR) could enhance vulnerability to the distinct pattern of damage induced by proton Bragg peak irradiation is currently unknown. Here, we performed genetic or pharmacologic manipulation of key DDR elements and evaluated DNA damage signaling, DNA repair, and tumor control in cell lines and xenografts treated with the same physical dose across a radiotherapy linear energy transfer spectrum. Radiotherapy consisted of 6 MV photons and the entrance beam or Bragg peak of a 76.8 MeV spot scanning proton beam. More complex DNA double-strand breaks (DSB) induced by Bragg peak proton irradiation preferentially underwent resection and engaged homologous recombination (HR) machinery. Unexpectedly, the ataxia-telangiectasia mutated (ATM) inhibitor, AZD0156, but not an inhibitor of ATM and Rad3-related, rendered cells hypersensitive to more densely ionizing proton Bragg peak irradiation. ATM inhibition blocked resection and shunted more DSBs to processing by toxic ligation through nonhomologous end-joining, whereas loss of DNA ligation via XRCC4 or Lig4 knockdown rescued resection and abolished the enhanced Bragg peak cell killing. Proton Bragg peak monotherapy selectively sensitized cell lines and tumor xenografts with inherent HR defects, and the repair defect induced by ATM inhibitor coadministration showed enhanced efficacy in HR-proficient models. In summary, inherent defects in HR or administration of an ATM inhibitor in HR-proficient tumors selectively enhances the relative biological effectiveness of proton Bragg peak irradiation. SIGNIFICANCE: Coadministration of an ATM inhibitor rewires DNA repair machinery to render cancer cells uniquely hypersensitive to DNA damage induced by the proton Bragg peak, which is characterized by higher density ionization.See related commentary by Nickoloff, p. 3156.
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Affiliation(s)
- Qin Zhou
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | | | - Xinyi Tu
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Qian Zhu
- Department of Oncology, Mayo Clinic, Rochester, Minnesota
| | - Janet M Denbeigh
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | | | - Michael G Herman
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Chris J Beltran
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Jian Yuan
- Department of Oncology, Mayo Clinic, Rochester, Minnesota
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | - Patricia T Greipp
- Division of Laboratory Genetics and Genomics, Mayo Clinic, Rochester, Minnesota
| | - Judy C Boughey
- Department of Surgery, Mayo Clinic, Rochester, Minnesota
| | - Liewei Wang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | - Neil Johnson
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Matthew P Goetz
- Division of Medical Oncology, Mayo Clinic, Rochester, Minnesota
| | - Jann N Sarkaria
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Zhenkun Lou
- Department of Oncology, Mayo Clinic, Rochester, Minnesota.
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | - Robert W Mutter
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota.
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7
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Clinical Progress in Proton Radiotherapy: Biological Unknowns. Cancers (Basel) 2021; 13:cancers13040604. [PMID: 33546432 PMCID: PMC7913745 DOI: 10.3390/cancers13040604] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/27/2021] [Accepted: 02/01/2021] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Proton radiation therapy is a more recent type of radiotherapy that uses proton beams instead of classical photon or X-rays beams. The clinical benefit of proton therapy is that it allows to treat tumors more precisely. As a result, proton radiotherapy induces less toxicity to healthy tissue near the tumor site. Despite the experience in the clinical use of protons, the response of cells to proton radiation, the radiobiology, is less understood. In this review, we describe the current knowledge about proton radiobiology. Abstract Clinical use of proton radiation has massively increased over the past years. The main reason for this is the beneficial depth-dose distribution of protons that allows to reduce toxicity to normal tissues surrounding the tumor. Despite the experience in the clinical use of protons, the radiobiology after proton irradiation compared to photon irradiation remains to be completely elucidated. Proton radiation may lead to differential damages and activation of biological processes. Here, we will review the current knowledge of proton radiobiology in terms of induction of reactive oxygen species, hypoxia, DNA damage response, as well as cell death after proton irradiation and radioresistance.
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8
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Cornforth MN. Occam's broom and the dirty DSB: cytogenetic perspectives on cellular response to changes in track structure and ionization density. Int J Radiat Biol 2020; 97:1099-1108. [PMID: 31971454 DOI: 10.1080/09553002.2019.1704302] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 10/30/2019] [Accepted: 11/11/2019] [Indexed: 12/19/2022]
Abstract
Given equal doses, it is well-known that densely ionizing radiations are more potent in causing a number of biological effects compared to sparsely ionizing radiations, such as x- or gamma rays. According to classical models of radiation action, this results from differences in the spatial distribution of lesions along charged particle tracks. In recent years investigators have been barraged with the alternative narrative that this is instead due to 'qualitative' differences in the types of molecular lesions that each type of radiation produces. The present review discusses, mainly from a cytogenetic perspective, the merits and shortcomings of these seemingly contradictory viewpoints. There may be a kernel of truth to the idea that qualitative differences in the types of molecular lesions produced at the nanometer level affect RBE/LET relationships, but to ignore the fact that such differences result from longer-range spatial distributions of lesions produced along charged particle tracks is an unjustifiably narrow stance tantamount to employing Occam's Broom. Not only are such spatial considerations indispensable in explaining the impact of ionization density upon higher-order biological endpoints, particularly chromosome aberrations, the explanations they provide render arguments based principally on the quality of IR damage largely superfluous.
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Affiliation(s)
- Michael N Cornforth
- Department of Radiation Oncology, University of Texas Medical Branch, Galveston, TX, USA
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9
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Ferreira S, Dutreix M. DNA repair inhibitors to enhance radiotherapy: Progresses and limitations. Cancer Radiother 2019; 23:883-890. [PMID: 31615730 DOI: 10.1016/j.canrad.2019.08.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 08/29/2019] [Accepted: 08/31/2019] [Indexed: 02/08/2023]
Abstract
Radiotherapy is one of the most common form of treatment in oncology care. Indeed, radiotherapy proved to be very effective in treating a wide range of malignancies. Nevertheless, certain tumours are intrinsically radioresistant or may evolve to become radioresistant. Resistance to radiotherapy is often associated with dysregulated DNA damage response and repair. Recently, a number of strategies have been developed to improve radiotherapy efficacy by targeting the DNA damage response and repair pathways. Ongoing clinical trials showed the potential of some of these approaches in enhancing radiotherapy, but also highlighted the possible limitations. Here, we will describe (i) the main mechanisms involved in double-strand break repair; (ii) available strategies that target these DNA repair processes to improve radiotherapy and (iii) the clinical outcomes and challenges that have emerged so far.
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Affiliation(s)
- S Ferreira
- Centre universitaire, institut Curie, UMR « Etic », bâtiment 110, 91405 Orsay cedex, France; Université PSL, 91405 Orsay, France; CNRS, UMR 3347, 91405 Orsay, France; Inserm, UMR 3347, 91405 Orsay, France; Université Paris-Sud université Paris-Saclay, 91405 Orsay, France
| | - M Dutreix
- Centre universitaire, institut Curie, UMR « Etic », bâtiment 110, 91405 Orsay cedex, France; Université PSL, 91405 Orsay, France; CNRS, UMR 3347, 91405 Orsay, France; Inserm, UMR 3347, 91405 Orsay, France; Université Paris-Sud université Paris-Saclay, 91405 Orsay, France.
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10
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Haas-Kogan D, Indelicato D, Paganetti H, Esiashvili N, Mahajan A, Yock T, Flampouri S, MacDonald S, Fouladi M, Stephen K, Kalapurakal J, Terezakis S, Kooy H, Grosshans D, Makrigiorgos M, Mishra K, Poussaint TY, Cohen K, Fitzgerald T, Gondi V, Liu A, Michalski J, Mirkovic D, Mohan R, Perkins S, Wong K, Vikram B, Buchsbaum J, Kun L. National Cancer Institute Workshop on Proton Therapy for Children: Considerations Regarding Brainstem Injury. Int J Radiat Oncol Biol Phys 2019; 101:152-168. [PMID: 29619963 DOI: 10.1016/j.ijrobp.2018.01.013] [Citation(s) in RCA: 115] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/21/2017] [Accepted: 01/01/2018] [Indexed: 01/08/2023]
Abstract
PURPOSE Proton therapy can allow for superior avoidance of normal tissues. A widespread consensus has been reached that proton therapy should be used for patients with curable pediatric brain tumor to avoid critical central nervous system structures. Brainstem necrosis is a potentially devastating, but rare, complication of radiation. Recent reports of brainstem necrosis after proton therapy have raised concerns over the potential biological differences among radiation modalities. We have summarized findings from the National Cancer Institute Workshop on Proton Therapy for Children convened in May 2016 to examine brainstem injury. METHODS AND MATERIALS Twenty-seven physicians, physicists, and researchers from 17 institutions with expertise met to discuss this issue. The definition of brainstem injury, imaging of this entity, clinical experience with photons and photons, and potential biological differences among these radiation modalities were thoroughly discussed and reviewed. The 3 largest US pediatric proton therapy centers collectively summarized the incidence of symptomatic brainstem injury and physics details (planning, dosimetry, delivery) for 671 children with focal posterior fossa tumors treated with protons from 2006 to 2016. RESULTS The average rate of symptomatic brainstem toxicity from the 3 largest US pediatric proton centers was 2.38%. The actuarial rate of grade ≥2 brainstem toxicity was successfully reduced from 12.7% to 0% at 1 center after adopting modified radiation guidelines. Guidelines for treatment planning and current consensus brainstem constraints for proton therapy are presented. The current knowledge regarding linear energy transfer (LET) and its relationship to relative biological effectiveness (RBE) are defined. We review the current state of LET-based planning. CONCLUSIONS Brainstem injury is a rare complication of radiation therapy for both photons and protons. Substantial dosimetric data have been collected for brainstem injury after proton therapy, and established guidelines to allow for safe delivery of proton radiation have been defined. Increased capability exists to incorporate LET optimization; however, further research is needed to fully explore the capabilities of LET- and RBE-based planning.
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Affiliation(s)
- Daphne Haas-Kogan
- Department of Radiation Oncology, Harvard Medical School and Brigham and Women's Hospital, Dana-Farber Cancer Institute, Boston Children's Hospital, Boston, Massachusetts
| | - Daniel Indelicato
- Department of Radiation Oncology, University of Florida, Jacksonville, Florida
| | - Harald Paganetti
- Department of Radiation Oncology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts
| | - Natia Esiashvili
- Department of Radiation Oncology, Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Anita Mahajan
- Department of Radiation Oncology, MD Anderson Cancer Center, Houston, Texas; Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Torunn Yock
- Department of Radiation Oncology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts
| | - Stella Flampouri
- Department of Radiation Oncology, University of Florida, Jacksonville, Florida
| | - Shannon MacDonald
- Department of Radiation Oncology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts
| | - Maryam Fouladi
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Kry Stephen
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas
| | - John Kalapurakal
- Department of Radiation Oncology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Stephanie Terezakis
- Department of Radiation Oncology, Johns Hopkins Medical Institute, Baltimore, Maryland
| | - Hanne Kooy
- Department of Radiation Oncology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts
| | - David Grosshans
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Mike Makrigiorgos
- Department of Radiation Oncology, Harvard Medical School and Dana-Farber Cancer Institute, Boston, Massachusetts
| | - Kavita Mishra
- Department of Radiation Oncology, University of California, San Francisco, San Francisco, California
| | - Tina Young Poussaint
- Department of Radiology, Harvard Medical School and Dana-Farber Cancer Institute, Boston Children's Hospital, Boston, Massachusetts
| | - Kenneth Cohen
- Department of Pediatrics, Johns Hopkins Medical Institute, Baltimore, Maryland
| | - Thomas Fitzgerald
- Department of Radiation Oncology, UMass Memorial Medical Center, Worcester, Massachusetts
| | - Vinai Gondi
- Northwestern Medicine Chicago Proton Center, Chicago, Illinois
| | - Arthur Liu
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
| | - Jeff Michalski
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri
| | - Dragan Mirkovic
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Radhe Mohan
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Stephanie Perkins
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri
| | - Kenneth Wong
- Children's Hospital of Angeles and University of Southern California Keck School of Medicine, Los Angles, California
| | - Bhadrasain Vikram
- Radiation Research Program, National Cancer Institute, National Institutes of Health, Rockville, Maryland
| | - Jeff Buchsbaum
- Radiation Research Program, National Cancer Institute, National Institutes of Health, Rockville, Maryland
| | - Larry Kun
- Department of Radiation Oncology, University of Texas Southwestern Medical School, Dallas, Texas.
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11
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Paganetti H. Proton Relative Biological Effectiveness - Uncertainties and Opportunities. Int J Part Ther 2018; 5:2-14. [PMID: 30370315 DOI: 10.14338/ijpt-18-00011.1] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Proton therapy treatments are prescribed using a biological effectiveness relative to photon therapy of 1.1, that is, proton beams are considered to be 10% more biologically effective. Debate is ongoing as to whether this practice needs to be revised. This short review summarizes current knowledge on relative biological effectiveness variations and uncertainties in vitro and in vivo. Clinical relevance is discussed and strategies toward biologically guided treatment planning are presented.
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Affiliation(s)
- Harald Paganetti
- Department of Radiation Oncology, Massachusetts General Hospital, and Harvard Medical School, Boston, MA, USA
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12
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Toward A variable RBE for proton beam therapy. Radiother Oncol 2018; 128:68-75. [PMID: 29910006 DOI: 10.1016/j.radonc.2018.05.019] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 05/09/2018] [Accepted: 05/17/2018] [Indexed: 12/19/2022]
Abstract
In the clinic, proton beam therapy (PBT) is based on the use of a generic relative biological effectiveness (RBE) of 1.1 compared to photons in human cancers and normal tissues. However, the experimental basis for this RBE lacks any significant number of representative tumor models and clinically relevant endpoints for dose-limiting organs at risk. It is now increasingly appreciated that much of the variations of treatment responses in cancers are due to inter-tumoral genomic heterogeneity. Indeed, recently it has been shown that defects in certain DNA repair pathways, which are found in subsets of many cancers, are associated with a RBE increase in vitro. However, there currently exist little in vivo or clinical data that confirm the existence of similarly increased RBE values in human cancers. Furthermore, evidence for variable RBE values for normal tissue toxicity has been sparse and conflicting to date. If we could predict variable RBE values in patients, we would be able to optimally use and personalize PBT. For example, predictive tumor biomarkers may facilitate selection of patients with proton-sensitive cancers previously ineligible for PBT. Dose de-escalation may be possible to reduce normal tissue toxicity, especially in pediatric patients. Knowledge of increased tumor RBE may allow us to develop biologically optimized therapies to enhance local control while RBE biomarkers for normal tissues could lead to a better understanding and prevention of unusual PBT-associated toxicity. Here, we will review experimental data on the repair of proton damage to DNA that impact both RBE values and biophysical modeling to predict RBE variations. Experimental approaches for studying proton sensitivity in vitro and in vivo will be reviewed as well and recent clinical findings discussed. Ultimately, therapeutically exploiting the understudied biological advantages of protons and developing approaches to limit treatment toxicity should fundamentally impact the clinical use of PBT.
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13
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Sage E, Shikazono N. Radiation-induced clustered DNA lesions: Repair and mutagenesis. Free Radic Biol Med 2017; 107:125-135. [PMID: 27939934 DOI: 10.1016/j.freeradbiomed.2016.12.008] [Citation(s) in RCA: 152] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 12/05/2016] [Accepted: 12/07/2016] [Indexed: 12/18/2022]
Abstract
Clustered DNA lesions, also called Multiply Damaged Sites, is the hallmark of ionizing radiation. It is defined as the combination of two or more lesions, comprising strand breaks, oxidatively generated base damage, abasic sites within one or two DNA helix turns, created by the passage of a single radiation track. DSB clustered lesions associate DSB and several base damage and abasic sites in close vicinity, and are assimilated to complex DSB. Non-DSB clustered lesions comprise single strand break, base damage and abasic sites. At radiation with low Linear Energy Transfer (LET), such as X-rays or γ-rays clustered DNA lesions are 3-4 times more abundant than DSB. Their proportion and their complexity increase with increasing LET; they may represent a large part of the damage to DNA. Studies in vitro using engineered clustered DNA lesions of increasing complexity have greatly enhanced our understanding on how non-DSB clustered lesions are processed. Base excision repair is compromised, the observed hierarchy in the processing of the lesions within a cluster leads to the formation of SSB or DSB as repair intermediates and increases the lifetime of the lesions. As a consequence, the chances of mutation drastically increase. Complex DSB, either formed directly by irradiation or by the processing of non-DSB clustered lesions, are repaired by slow kinetics or left unrepaired and cause cell death or pass mitosis. In surviving cells, large deletions, translocations, and chromosomal aberrations are observed. This review details the most recent data on the processing of non-DSB clustered lesions and complex DSB and tends to demonstrate the high significance of these specific DNA damage in terms of genomic instability induction.
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Affiliation(s)
- Evelyne Sage
- Institut Curie, PSL Research University, CNRS, UMR3347, F-91405 Orsay, France.
| | - Naoya Shikazono
- Quantum Beam Science Research Directorate, National Institutes of Quantum and Radiological Science and Technology, Kansai Photon Science Institute, 8-1-7 Umemidai, Kizugawa-Shi, Kyoto 619-0215, Japan.
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14
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Liang Y, Fu Q, Wang X, Liu F, Yang G, Luo C, Ouyang Q, Wang Y. Relative biological effectiveness for photons: implication of complex DNA double-strand breaks as critical lesions. Phys Med Biol 2017; 62:2153-2175. [DOI: 10.1088/1361-6560/aa56ed] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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15
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Ishii K, Kazama Y, Morita R, Hirano T, Ikeda T, Usuda S, Hayashi Y, Ohbu S, Motoyama R, Nagamura Y, Abe T. Linear Energy Transfer-Dependent Change in Rice Gene Expression Profile after Heavy-Ion Beam Irradiation. PLoS One 2016; 11:e0160061. [PMID: 27462908 PMCID: PMC4962992 DOI: 10.1371/journal.pone.0160061] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 07/13/2016] [Indexed: 12/14/2022] Open
Abstract
A heavy-ion beam has been recognized as an effective mutagen for plant breeding and applied to the many kinds of crops including rice. In contrast with X-ray or γ-ray, the heavy-ion beam is characterized by a high linear energy transfer (LET). LET is an important factor affecting several aspects of the irradiation effect, e.g. cell survival and mutation frequency, making the heavy-ion beam an effective mutagen. To study the mechanisms behind LET-dependent effects, expression profiling was performed after heavy-ion beam irradiation of imbibed rice seeds. Array-based experiments at three time points (0.5, 1, 2 h after the irradiation) revealed that the number of up- or down-regulated genes was highest 2 h after irradiation. Array-based experiments with four different LETs at 2 h after irradiation identified LET-independent regulated genes that were up/down-regulated regardless of the value of LET; LET-dependent regulated genes, whose expression level increased with the rise of LET value, were also identified. Gene ontology (GO) analysis of LET-independent up-regulated genes showed that some GO terms were commonly enriched, both 2 hours and 3 weeks after irradiation. GO terms enriched in LET-dependent regulated genes implied that some factor regulates genes that have kinase activity or DNA-binding activity in cooperation with the ATM gene. Of the LET-dependent up-regulated genes, OsPARP3 and OsPCNA were identified, which are involved in DNA repair pathways. This indicates that the Ku-independent alternative non-homologous end-joining pathway may contribute to repairing complex DNA legions induced by high-LET irradiation. These findings may clarify various LET-dependent responses in rice.
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Affiliation(s)
| | | | | | - Tomonari Hirano
- RIKEN Nishina Center, Wako, Saitama, Japan
- Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan
| | | | | | | | - Sumie Ohbu
- RIKEN Nishina Center, Wako, Saitama, Japan
| | - Ritsuko Motoyama
- Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan
| | - Yoshiaki Nagamura
- Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan
| | - Tomoko Abe
- RIKEN Nishina Center, Wako, Saitama, Japan
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16
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Gavande NS, VanderVere-Carozza PS, Hinshaw HD, Jalal SI, Sears CR, Pawelczak KS, Turchi JJ. DNA repair targeted therapy: The past or future of cancer treatment? Pharmacol Ther 2016; 160:65-83. [PMID: 26896565 DOI: 10.1016/j.pharmthera.2016.02.003] [Citation(s) in RCA: 266] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The repair of DNA damage is a complex process that relies on particular pathways to remedy specific types of damage to DNA. The range of insults to DNA includes small, modest changes in structure including mismatched bases and simple methylation events to oxidized bases, intra- and interstrand DNA crosslinks, DNA double strand breaks and protein-DNA adducts. Pathways required for the repair of these lesions include mismatch repair, base excision repair, nucleotide excision repair, and the homology directed repair/Fanconi anemia pathway. Each of these pathways contributes to genetic stability, and mutations in genes encoding proteins involved in these pathways have been demonstrated to promote genetic instability and cancer. In fact, it has been suggested that all cancers display defects in DNA repair. It has also been demonstrated that the ability of cancer cells to repair therapeutically induced DNA damage impacts therapeutic efficacy. This has led to targeting DNA repair pathways and proteins to develop anti-cancer agents that will increase sensitivity to traditional chemotherapeutics. While initial studies languished and were plagued by a lack of specificity and a defined mechanism of action, more recent approaches to exploit synthetic lethal interaction and develop high affinity chemical inhibitors have proven considerably more effective. In this review we will highlight recent advances and discuss previous failures in targeting DNA repair to pave the way for future DNA repair targeted agents and their use in cancer therapy.
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Affiliation(s)
- Navnath S Gavande
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | | | - Hilary D Hinshaw
- Department of Obstetrics and Gynecology, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Shadia I Jalal
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Catherine R Sears
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | | | - John J Turchi
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, United States; NERx Biosciences, Indianapolis, IN 46202, United States; Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, United States.
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17
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Stewart RD, Streitmatter SW, Argento DC, Kirkby C, Goorley JT, Moffitt G, Jevremovic T, Sandison GA. Rapid MCNP simulation of DNA double strand break (DSB) relative biological effectiveness (RBE) for photons, neutrons, and light ions. Phys Med Biol 2015; 60:8249-74. [PMID: 26449929 DOI: 10.1088/0031-9155/60/21/8249] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
To account for particle interactions in the extracellular (physical) environment, information from the cell-level Monte Carlo damage simulation (MCDS) for DNA double strand break (DSB) induction has been integrated into the general purpose Monte Carlo N-particle (MCNP) radiation transport code system. The effort to integrate these models is motivated by the need for a computationally efficient model to accurately predict particle relative biological effectiveness (RBE) in cell cultures and in vivo. To illustrate the approach and highlight the impact of the larger scale physical environment (e.g. establishing charged particle equilibrium), we examined the RBE for DSB induction (RBEDSB) of x-rays, (137)Cs γ-rays, neutrons and light ions relative to γ-rays from (60)Co in monolayer cell cultures at various depths in water. Under normoxic conditions, we found that (137)Cs γ-rays are about 1.7% more effective at creating DSB than γ-rays from (60)Co (RBEDSB = 1.017) whereas 60-250 kV x-rays are 1.1 to 1.25 times more efficient at creating DSB than (60)Co. Under anoxic conditions, kV x-rays may have an RBEDSB up to 1.51 times as large as (60)Co γ-rays. Fission neutrons passing through monolayer cell cultures have an RBEDSB that ranges from 2.6 to 3.0 in normoxic cells, but may be as large as 9.93 for anoxic cells. For proton pencil beams, Monte Carlo simulations suggest an RBEDSB of about 1.2 at the tip of the Bragg peak and up to 1.6 a few mm beyond the Bragg peak. Bragg peak RBEDSB increases with decreasing oxygen concentration, which may create opportunities to apply proton dose painting to help address tumor hypoxia. Modeling of the particle RBE for DSB induction across multiple physical and biological scales has the potential to aid in the interpretation of laboratory experiments and provide useful information to advance the safety and effectiveness of hadron therapy in the treatment of cancer.
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Affiliation(s)
- Robert D Stewart
- Department of Radiation Oncology, University of Washington School of Medicine, School of Medicine, 1959 NE Pacific Street, Box 356043, Seattle, WA 98195, USA
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18
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Tsai JY, Chen FH, Hsieh TY, Hsiao YY. Effects of indirect actions and oxygen on relative biological effectiveness: estimate of DSB induction and conversion induced by gamma rays and helium ions. JOURNAL OF RADIATION RESEARCH 2015; 56:691-699. [PMID: 25902742 PMCID: PMC4497398 DOI: 10.1093/jrr/rrv025] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 03/17/2015] [Accepted: 03/21/2015] [Indexed: 06/04/2023]
Abstract
Clustered DNA damage other than double-strand breaks (DSBs) can be detrimental to cells and can lead to mutagenesis or cell death. In addition to DSBs induced by ionizing radiation, misrepair of non-DSB clustered damage contributes extra DSBs converted from DNA misrepair via pathways for base excision repair and nucleotide excision repair. This study aimed to quantify the relative biological effectiveness (RBE) when DSB induction and conversion from non-DSB clustered damage misrepair were used as biological endpoints. The results showed that both linear energy transfer (LET) and indirect action had a strong impact on the yields for DSB induction and conversion. RBE values for DSB induction and maximum DSB conversion of helium ions (LET = 120 keV/μm) to (60)Co gamma rays were 3.0 and 3.2, respectively. These RBE values increased to 5.8 and 5.6 in the absence of interference of indirect action initiated by addition of 2-M dimethylsulfoxide. DSB conversion was ∼1-4% of the total non-DSB damage due to gamma rays, which was lower than the 10% estimate by experimental measurement. Five to twenty percent of total non-DSB damage due to helium ions was converted into DSBs. Hence, it may be possible to increase the yields of DSBs in cancerous cells through DNA repair pathways, ultimately enhancing cell killing.
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Affiliation(s)
- Ju-Ying Tsai
- Institute of Biotechnology and Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
| | - Fang-Hsin Chen
- Department of Medical Imaging and Radiological Sciences, Chang Gung University, Kweishan, Taiwan, Republic of China Radiation Biology Research Center, Institute for Radiological Research, Chang Gung University/Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan, Republic of China
| | - Tsung-Yu Hsieh
- Department of Medical Imaging and Radiological Sciences, Chung Shan Medical University, No. 110, Section 1, Chien-Kuo N Road, Taichung, 402, Taiwan, Republic of China
| | - Ya-Yun Hsiao
- Department of Medical Imaging and Radiological Sciences, Chung Shan Medical University, No. 110, Section 1, Chien-Kuo N Road, Taichung, 402, Taiwan, Republic of China
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19
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Hirano T, Kazama Y, Ishii K, Ohbu S, Shirakawa Y, Abe T. Comprehensive identification of mutations induced by heavy-ion beam irradiation in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:93-104. [PMID: 25690092 DOI: 10.1111/tpj.12793] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 01/25/2015] [Accepted: 02/05/2015] [Indexed: 05/06/2023]
Abstract
Heavy-ion beams are widely used for mutation breeding and molecular biology. Although the mutagenic effects of heavy-ion beam irradiation have been characterized by sequence analysis of some restricted chromosomal regions or loci, there have been no evaluations at the whole-genome level or of the detailed genomic rearrangements in the mutant genomes. In this study, using array comparative genomic hybridization (array-CGH) and resequencing, we comprehensively characterized the mutations in Arabidopsis thaliana genomes irradiated with Ar or Fe ions. We subsequently used this information to investigate the mutagenic effects of the heavy-ion beams. Array-CGH demonstrated that the average number of deleted areas per genome were 1.9 and 3.7 following Ar-ion and Fe-ion irradiation, respectively, with deletion sizes ranging from 149 to 602,180 bp; 81% of the deletions were accompanied by genomic rearrangements. To provide a further detailed analysis, the genomes of the mutants induced by Ar-ion beam irradiation were resequenced, and total mutations, including base substitutions, duplications, in/dels, inversions, and translocations, were detected using three algorithms. All three resequenced mutants had genomic rearrangements. Of the 22 DNA fragments that contributed to the rearrangements, 19 fragments were responsible for the intrachromosomal rearrangements, and multiple rearrangements were formed in the localized regions of the chromosomes. The interchromosomal rearrangements were detected in the multiply rearranged regions. These results indicate that the heavy-ion beams led to clustered DNA damage in the chromosome, and that they have great potential to induce complicated intrachromosomal rearrangements. Heavy-ion beams will prove useful as unique mutagens for plant breeding and the establishment of mutant lines.
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Affiliation(s)
- Tomonari Hirano
- Innovation Center, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan; Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
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20
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Joshi N, Grant SG. Pulsed-field gel electrophoresis analysis of multicellular DNA double-strand break damage and repair. Methods Mol Biol 2014; 1105:193-202. [PMID: 24623230 DOI: 10.1007/978-1-62703-739-6_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
This assay quantifies the extent of double-strand break (DSB) DNA damage in cell populations embedded in agarose and analyzed for migratory DNA using pulsed-field gel electrophoresis with ethidium bromide staining. The assay can measure preexisting damage as well as induction of DSB by chemical (e.g., bleomycin), physical (e.g., X-irradiation), or biological (e.g., restriction enzymes) agents. By incubating the cells under physiological conditions prior to processing, the cells can be allowed to repair DSB, primarily via the process of nonhomologous end joining. The amount of repair, corresponding to the repair capacity of the treated cells, is then quantified by determining the ratio of the fractions of activity released in the lanes in comparison to the total amount of DNA fragmentation following determination of an optimal exposure for maximum initial fragmentation. Repair kinetics can also be analyzed through a time-course regimen.
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Affiliation(s)
- Nina Joshi
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, USA
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21
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Paganetti H. Relative biological effectiveness (RBE) values for proton beam therapy. Variations as a function of biological endpoint, dose, and linear energy transfer. Phys Med Biol 2014; 59:R419-72. [PMID: 25361443 DOI: 10.1088/0031-9155/59/22/r419] [Citation(s) in RCA: 616] [Impact Index Per Article: 61.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Proton therapy treatments are based on a proton RBE (relative biological effectiveness) relative to high-energy photons of 1.1. The use of this generic, spatially invariant RBE within tumors and normal tissues disregards the evidence that proton RBE varies with linear energy transfer (LET), physiological and biological factors, and clinical endpoint. Based on the available experimental data from published literature, this review analyzes relationships of RBE with dose, biological endpoint and physical properties of proton beams. The review distinguishes between endpoints relevant for tumor control probability and those potentially relevant for normal tissue complication. Numerous endpoints and experiments on sub-cellular damage and repair effects are discussed. Despite the large amount of data, considerable uncertainties in proton RBE values remain. As an average RBE for cell survival in the center of a typical spread-out Bragg peak (SOBP), the data support a value of ~1.15 at 2 Gy/fraction. The proton RBE increases with increasing LETd and thus with depth in an SOBP from ~1.1 in the entrance region, to ~1.15 in the center, ~1.35 at the distal edge and ~1.7 in the distal fall-off (when averaged over all cell lines, which may not be clinically representative). For small modulation widths the values could be increased. Furthermore, there is a trend of an increase in RBE as (α/β)x decreases. In most cases the RBE also increases with decreasing dose, specifically for systems with low (α/β)x. Data on RBE for endpoints other than clonogenic cell survival are too diverse to allow general statements other than that the RBE is, on average, in line with a value of ~1.1. This review can serve as a source for defining input parameters for applying or refining biophysical models and to identify endpoints where additional radiobiological data are needed in order to reduce the uncertainties to clinically acceptable levels.
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Affiliation(s)
- Harald Paganetti
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, 30 Fruit Street, Boston, MA 02114, USA
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22
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Vadhavkar N, Pham C, Georgescu W, Deschamps T, Heuskin AC, Tang J, Costes SV. Combinatorial DNA Damage Pairing Model Based on X-Ray-Induced Foci Predicts the Dose and LET Dependence of Cell Death in Human Breast Cells. Radiat Res 2014; 182:273-81. [DOI: 10.1667/rr13792.1] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Vandersickel V, Beukes P, Van Bockstaele B, Depuydt J, Vral A, Slabbert J. Induction and disappearance of γH2AX foci and formation of micronuclei after exposure of human lymphocytes to ⁶⁰Co γ-rays and p(66)+ Be(40) neutrons. Int J Radiat Biol 2014; 90:149-58. [PMID: 24168313 DOI: 10.3109/09553002.2014.860252] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To investigate both the formation of micronuclei (MN) and the induction and subsequent loss of phosphorylated histone H2AX foci (γH2AX foci) after in vitro exposure of human lymphocytes to either (60)Co γ-rays or p(66)+ Be(40) neutrons. MATERIALS AND METHODS MN dose response (DR) curves were obtained by exposing isolated lymphocytes of 10 different donors to doses ranging from 0-4 Gy γ-rays or 0-2 Gy neutrons. Also, γH2AX foci DR curves were obtained following exposure to doses ranging from 0-0.5 Gy of either γ-rays or neutrons. Foci kinetics for lymphocytes for a single donor exposed to 0.5 Gy γ-rays or neutrons were studied up to 24 hours post-irradiation. RESULTS Micronuclei yields following neutron exposure were consistently higher compared to that from (60)Co γ-rays. All MN yields were over-dispersed compared to a Poisson distribution. Over-dispersion was higher after neutron irradiation for all doses > 0.1 Gy. Up to 4 hours post-irradiation lower yields of neutron-induced γH2AX foci were observed. Between 4 and 24 hours the numbers of foci from neutrons were consistently higher than that from γ-rays. The half-live of foci disappearance is only marginally longer for neutrons compared to that from γ-rays. Foci formations were more likely to be over-dispersed for neutron irradiations. CONCLUSION Although neutrons are more effective to induce MN, the absolute number of induced γH2AX foci are less at first compared to γ-rays. With time neutron-induced foci are more persistent. These findings are helpful for using γH2AX foci in biodosimetry and to understand the repair of neutron-induced cellular damage.
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Affiliation(s)
- Veerle Vandersickel
- NRF iThemba LABS (Laboratory for Accelerated Based Sciences), Somerset West, South Africa and Department of Medical Imaging and Clinical Oncology, University of Stellenbosch , South Africa
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Kazama Y, Hirano T, Nishihara K, Ohbu S, Shirakawa Y, Abe T. Effect of high-LET Fe-ion beam irradiation on mutation induction in Arabidopsis thaliana. Genes Genet Syst 2014; 88:189-97. [PMID: 24025247 DOI: 10.1266/ggs.88.189] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Heavy-ion beams are powerful mutagens. They cause a broad spectrum of mutation phenotypes with high efficiency even at low irradiation doses and short irradiation times. These mutagenic effects are due to dense ionisation in a localised region along the ion particle path. Linear energy transfer (LET; keV·μm(-1)), which represents the degree of locally deposited energy, is an important parameter in heavy-ion mutagenesis. For high LET radiation above 290 keV∙μm(-1), however, neither the mutation frequency nor the molecular nature of the mutations has been fully characterised. In this study, we investigated the effect of Fe-ion beams with an LET of 640 keV∙μm(-1) on both the mutation frequency and the molecular nature of the mutations. Screening of well-characterised mutants (hy and gl) revealed that the mutation frequency was lower than any other ion species with low LET. We investigated the resulting mutations in the 4 identified mutants. Three mutants were examined by employing PCR-based methods, one of which had 2-bp deletion, another had 178 bp of tandemly duplication, and other one had complicated chromosomal rearrangements with variable deletions in size at breakpoints. We also detected large deletions in the other mutant by using array comparative genomic hybridisation. From the results of the analysis of the breakpoints and junctions of the detected deletions, it was revealed that the mutants harboured chromosomal rearrangements in their genomes. These results indicate that Fe-ion irradiation tends to cause complex mutations with low efficiency. We conclude that Fe-ion irradiation could be useful for inducing chromosomal rearrangements or large deletions.
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Cartwright IM, Genet MD, Fujimori A, Kato TA. Role of LET and chromatin structure on chromosomal inversion in CHO10B2 cells. Genome Integr 2014; 5:1. [PMID: 24467838 PMCID: PMC3917374 DOI: 10.1186/2041-9414-5-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 01/21/2014] [Indexed: 11/25/2022] Open
Abstract
Background In this study we evaluated the effect of linear energy transfer (LET) and chromatin structure on the induction of chromosomal inversion. High LET radiation causes more complex DNA damage than low LET radiation; this “dirty” damage is more difficult to repair and may result in an increase in inversion formation. CHO10B2 cells synchronized in either G1 or M phase were exposed 0, 1, or 2 Gy of 5 mm Al and Cu filters at 200 kVp and 20 mA X-rays or 500 MeV/nucleon of initial energy and 200 keV/μ m Fe ion radiation. In order to increase the sensitivity of prior techniques used to study inversions, we modified the more traditional Giemsa plus fluorescence technique so that cells were only allowed to incorporate BrdU for a single cycle verses 2 cycles. The BrdU incorporated DNA strand was labeled using a BrdU antibody and an Alexa Fluor 488 probe. This modified technique allowed us to observe inversions smaller than 0.6 megabases (Mb). Results In this study we have shown that high LET radiation induces significantly more inversions in G1 cells than in M phase cells. Additionally, we have shown that the sizes of the induced inversions not only differ between Fe ion and X-rays, but also between G1 and M phase cells exposed to Fe ions. Conclusion We have effectively shown that both radiation quality and chromosome structure interact to alter not only the number of inversions induced, but also the size of the inversions.
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Affiliation(s)
| | | | | | - Takamitsu A Kato
- Department of Environmental and Radiological Health Sciences, Colorado State University, 1618 Campus Delivery, Fort Collins 80523, USA.
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Xiao Y, Chen J, Liao Q, Wu Y, Peng C, Chen X. Lytic infection of Kaposi's sarcoma-associated herpesvirus induces DNA double-strand breaks and impairs non-homologous end joining. J Gen Virol 2013; 94:1870-1875. [PMID: 23677788 DOI: 10.1099/vir.0.053033-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) has been associated with the development of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease. Cytogenetic studies have revealed chromosome abnormalities in KS tissues, including recurring copy number changes in chromosomes and the loss of chromosomes. Unfaithful DNA repair may contribute to the genomic instability that is one of the most common hallmarks of tumours. We found that lytic infection of KSHV can cause severe DNA double-strand breaks (DSBs) and impair non-homologous end joining (NHEJ) in host cells. Processivity factor 8 (PF-8) of KSHV was identified as interacting with Ku70 and Ku86, and the interaction was dependent on DSBs and DNA. Overexpression of PF-8 in HeLa cells impaired NHEJ by blocking the interaction between the Ku complex and the DNA-dependent protein kinase catalytic subunit. These results suggest that KSHV lytic replication may contribute to tumorigenesis by causing DNA DSBs and interfering with the repair of DSBs.
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Affiliation(s)
- Yi Xiao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Jungang Chen
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Qingjiao Liao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Yang Wu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Can Peng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Xulin Chen
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
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Loucas BD, Cornforth MN. The LET dependence of unrepaired chromosome damage in human cells: a break too far? Radiat Res 2013; 179:393-405. [PMID: 23578187 PMCID: PMC6058738 DOI: 10.1667/rr3159.2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cytogenetic damage is among the few radiobiological end points that allow a precise distinction to be made between misrepaired damage, represented by exchange-type aberrations such as dicentrics and translocations, and unrepaired damage that leads to "open breaks". This latter category includes both terminal deletions and incomplete exchanges, whose different mechanisms of formation can be recognized by multicolor fluorescence in situ hybridization (mFISH). mFISH was used to examine the yields of chromosome aberrations at the first postirradiation mitosis in human fibroblasts and lymphocytes irradiated with ¹³⁷Cs γ rays, a radiation of low-linear energy transfer (LET), and two sources of high-LET radiation: α particles from ²³⁸Pu and 1 GeV/amu ⁵⁶Fe ions. In agreement with previous studies, our results show that irrespective of radiation quality, the overall level of misrepaired damage exceeds that of unrepaired damage by a large margin. The unrepaired component of damage produced by γ rays and α particles was remarkably similar, about 5%. On that basis it is difficult to justify the popular notion that the strong LET-dependence for aberration formation is due to unrepaired DNA double-strand breaks (DSBs) that, by virtue of their complexity at the nanometer scale, are qualitatively different in nature. In marked contrast, this unrejoined component rose to about 14% after exposure to Fe ions. A closer look at the unrepaired component revealed that most of this roughly threefold difference was derived from incomplete exchanges. Despite vast differences in LET, unrejoined breaks from incomplete exchanges were far more likely to occur among exchanges that involved more than two breakpoints. We attempted to reconcile these observations in the form of a hypothesis that predicts that exchanges, irrespective of LET, should exhibit an increasing tendency for incompleteness as the number of initial breaks destined to take part in the exchange increases. This effect, we argue is not caused by the number of initial breaks per se, but instead reflects the maximum distance over which proximate breaks can interact. This adds a spatial aspect to multi-break interactions that we call "A Break Too Far".
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Affiliation(s)
- Bradford D Loucas
- Department of Radiation Oncology, The University of Texas Medical Branch, Galveston, Texas 77555, USA.
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Girdhani S, Sachs R, Hlatky L. Biological Effects of Proton Radiation: What We Know and Don't Know. Radiat Res 2013; 179:257-72. [DOI: 10.1667/rr2839.1] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Hirano T, Kazama Y, Ohbu S, Shirakawa Y, Liu Y, Kambara T, Fukunishi N, Abe T. Molecular nature of mutations induced by high-LET irradiation with argon and carbon ions in Arabidopsis thaliana. Mutat Res 2012; 735:19-31. [PMID: 22579628 DOI: 10.1016/j.mrfmmm.2012.04.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 04/18/2012] [Accepted: 04/27/2012] [Indexed: 10/28/2022]
Abstract
Linear energy transfer (LET) is an important parameter to be considered in heavy-ion mutagenesis. However, in plants, no quantitative data are available on the molecular nature of the mutations induced with high-LET radiation above 101-124keVμm(-1). In this study, we irradiated dry seeds of Arabidopsis thaliana with Ar and C ions with an LET of 290keVμm(-1). We analyzed the DNA alterations caused by the higher-LET radiation. Mutants were identified from the M(2) pools. In total, 14 and 13 mutated genes, including bin2, egy1, gl1, gl2, hy1, hy3-5, ttg1, and var2, were identified in the plants derived from Ar- and C-ions irradiation, respectively. In the mutants from both irradiations, deletion was the most frequent type of mutation; 13 of the 14 mutated genes from the Ar ion-irradiated plants and 11 of the 13 mutated genes from the C ion-irradiated plants harbored deletions. Analysis of junction regions generated by the 2 types of irradiation suggested that alternative non-homologous end-joining was the predominant pathway of repair of break points. Among the deletions, the proportion of large deletions (>100bp) was about 54% for Ar-ion irradiation and about 64% for C-ion irradiation. Both current results and previously reported data revealed that the proportions of the large deletions induced by 290-keVμm(-1) radiations were higher than those of the large deletions induced by lower-LET radiations (6% for 22.5-30.0keVμm(-1) and 27% for 101-124keVμm(-1)). Therefore, the 290keVμm(-1) heavy-ion beams can effectively induce large deletions and will prove useful as novel mutagens for plant breeding and analysis of gene functions, particularly tandemly arrayed genes.
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Affiliation(s)
- Tomonari Hirano
- Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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Ho B, Baker PM, Singh S, Shih SJ, Vaughan AT. Localized DNA cleavage secondary to genotoxic exposure adjacent to an Alu inverted repeat. Genes Chromosomes Cancer 2012; 51:501-9. [PMID: 22334386 DOI: 10.1002/gcc.21938] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 01/05/2012] [Indexed: 01/12/2023] Open
Abstract
Radiation is a potent inducer of DNA damage leading to both random DNA loss and mutation. As part of a study focused on the mechanism whereby cells undergo loss of heterozygosity (LOH), a region of common LOH telomeric termination at 11q24 was observed in clones of H292 mucoepidermoid cells established after irradiation (IR). A 10-kbp region including the telomeric extent of LOH termination was analyzed after IR using six sets of ligation-mediated polymerase chain reaction (PCR) primers to detect the presence of DNA breaks. A cluster of DNA breaks was detected that closely mapped to the telomeric extent of LOH and which were observed up to 8 hr after IR. Repeating the experiment in the presence of the inhibitor of apoptosis, zVAD.fmk, did not change the location or amount of cleavage. A similar distribution of breaks was also seen in the MCF-10A breast cancer cell line after IR. Further inspection of the involved region showed that 22/32 and 7/7 DNA breaks found in H292 and MCF-10A cells, respectively, were located either in or immediately adjacent to an AluSx1 sequence, itself ≈ 1 kbp 5' to an AluSq2 that was in an inverted orientation to the AluSx1. The region between the inverted Alu repeats was notable for both DNAse hypersensitivity and an open chromatin conformation inferred from histone modification data. These factors may contribute to genomic instability at this location.
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Affiliation(s)
- Bay Ho
- Department of Radiation Oncology, University of California at Davis, Sacramento, CA 95817, USA
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Kazama Y, Hirano T, Saito H, Liu Y, Ohbu S, Hayashi Y, Abe T. Characterization of highly efficient heavy-ion mutagenesis in Arabidopsis thaliana. BMC PLANT BIOLOGY 2011; 11:161. [PMID: 22085561 PMCID: PMC3261129 DOI: 10.1186/1471-2229-11-161] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 11/15/2011] [Indexed: 05/18/2023]
Abstract
BACKGROUND Heavy-ion mutagenesis is recognised as a powerful technology to generate new mutants, especially in higher plants. Heavy-ion beams show high linear energy transfer (LET) and thus more effectively induce DNA double-strand breaks than other mutagenic techniques. Previously, we determined the most effective heavy-ion LET (LETmax: 30.0 keV μm(-1)) for Arabidopsis mutagenesis by analysing the effect of LET on mutation induction. However, the molecular structure of mutated DNA induced by heavy ions with LETmax remains unclear. Knowledge of the structure of mutated DNA will contribute to the effective exploitation of heavy-ion beam mutagenesis. RESULTS Dry Arabidopsis thaliana seeds were irradiated with carbon (C) ions with LETmax at a dose of 400 Gy and with LET of 22.5 keV μm(-1) at doses of 250 Gy or 450 Gy. The effects on mutation frequency and alteration of DNA structure were compared. To characterise the structure of mutated DNA, we screened the well-characterised mutants elongated hypocotyls (hy) and glabrous (gl) and identified mutated DNA among the resulting mutants by high-resolution melting curve, PCR and sequencing analyses. The mutation frequency induced by C ions with LETmax was two-fold higher than that with 22.5 keV μm(-1) and similar to the mutation frequency previously induced by ethyl methane sulfonate. We identified the structure of 22 mutated DNAs. Over 80% of the mutations caused by C ions with both LETs were base substitutions or deletions/insertions of less than 100 bp. The other mutations involved large rearrangements. CONCLUSIONS The C ions with LETmax showed high mutation efficiency and predominantly induced base substitutions or small deletions/insertions, most of which were null mutations. These small alterations can be determined by single-nucleotide polymorphism (SNP) detection systems. Therefore, C ions with LETmax might be useful as a highly efficient reverse genetic system in conjunction with SNP detection systems, and will be beneficial for forward genetics and plant breeding.
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Affiliation(s)
- Yusuke Kazama
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Tomonari Hirano
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- RIKEN Innovation Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hiroyuki Saito
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yang Liu
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Sumie Ohbu
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yoriko Hayashi
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Tomoko Abe
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- RIKEN Innovation Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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Neher TM, Turchi JJ. Current advances in DNA repair: regulation of enzymes and pathways involved in maintaining genomic stability. Antioxid Redox Signal 2011; 14:2461-4. [PMID: 21235357 PMCID: PMC3096511 DOI: 10.1089/ars.2010.3748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Novel discoveries in the DNA repair field have lead to continuous and rapid advancement of our understanding of not only DNA repair but also DNA replication and recombination. Research in the field transcends numerous areas of biology, biochemistry, physiology, and medicine, making significant connections across these broad areas of study. From early studies conducted in bacterial systems to current analyses in eukaryotic systems and human disease, the innovative research into the mechanisms of repair machines and the consequences of ineffective DNA repair has impacted a wide scientific community. This Forum contains a select mix of primary research articles in addition to a number of timely reviews covering a subset of DNA repair pathways where recent advances and novel discoveries are improving our understanding of DNA repair, its regulation, and implications to human disease.
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Affiliation(s)
- Tracy M. Neher
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - John J. Turchi
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
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Konishi T, Takeyasu A, Natsume T, Furusawa Y, Hieda K. Visualization of heavy ion tracks by labeling 3'-OH termini of induced DNA strand breaks. JOURNAL OF RADIATION RESEARCH 2011; 52:433-440. [PMID: 21785232 DOI: 10.1269/jrr.10097] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
African green monkey kidney cells, CV-1, were irradiated with Carbon ions (LET: 735 keV/µm Argon ions (LET: 3,000 keV/µm) to visualize ion tracks through the cell nucleus by labeling the 3'-OH termini result of DNA strand breaks. The 3'-OH termini of DNA were labeled with BrdU-triphosphate catalyzed by TdT. This method of TUNEL (TdT-mediated dUTP Nick End labeling) is based on the specific binding of TdT to 3'-OH termini of DNA. Subsequent immuno-fluorescent staining with the primary monoclonal antibody against BrdU, followed by a secondary antibody of Alexa Fluor 488, was performed to visualize the BrdU labeled DNA termini. Images of the cell nuclei were acquired by confocal laser microscopy. When cell monolayers were irradiated perpendicularly with argon ions, induced DSBs in cell nuclei were identifiable as fluorescent spots. In another irradiation setup, when cells were irradiated at a small angle with incident argon ions, DNA strand breaks were detected as fluorescent stripes across the cell nucleus. These results demonstrate the induction of 3'-OH termini at sites of DNA strand breaks along Argon ion tracks.
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Affiliation(s)
- Teruaki Konishi
- Department of Technical Support and Development, Fundamental Technology Center, National Institute of Radiological Sciences.
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Datta K, Purkayastha S, Neumann RD, Pastwa E, Winters TA. Base damage immediately upstream from double-strand break ends is a more severe impediment to nonhomologous end joining than blocked 3'-termini. Radiat Res 2011; 175:97-112. [PMID: 21175352 PMCID: PMC3518376 DOI: 10.1667/rr2332.1] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Radiation-induced DNA double-strand breaks (DSBs) are critical cytotoxic lesions that are typically repaired by nonhomologous end joining (NHEJ) in human cells. Our previous work indicated that the highly cytotoxic DSBs formed by (125)I decay possess base damage clustered within 8 to 10 bases of the break and 3'-phosphate (P) and 3'-OH ends. This study examined the effect of such structures on NHEJ in in vitro assays employing either (125)I decay-induced DSB linearized plasmid DNA or structurally defined duplex oligonucleotides. Duplex oligonucleotides that possess either a 3'-P or 3'-phosphoglycolate (PG) or a ligatable 3'-OH end with either an AP site or an 8-oxo-dG 1 nucleotide upstream (-1n) from the 3'-terminus have been examined for reparability. Moderate to severe end-joining inhibition was observed for modified DSB ends or 8-oxo-dG upstream from a 3'-OH end. In contrast, abolition of end joining was observed with duplexes possessing an AP site upstream from a ligatable 3'-OH end or for a lesion combination involving 3'-P plus an upstream 8-oxo-dG. In addition, base mismatches at the -1n position were also strong inhibitors of NHEJ in this system, suggesting that destabilization of the DSB terminus as a result of base loss or improper base pairing may play a role in the inhibitory effects of these structures. Furthermore, we provide data indicating that DSB end joining is likely to occur prior to removal or repair of base lesions proximal to the DSB terminus. Our results show that base damage or base loss near a DSB end may be a severe block to NHEJ and that complex combinations of lesions presented in the context of a DSB may be more inhibitory than the individual lesions alone. In contrast, blocked DSB 3'-ends alone are only modestly inhibitory to NHEJ. Finally, DNA ligase activity is implicated as being responsible for these effects.
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Affiliation(s)
- Kamal Datta
- Nuclear Medicine Department, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892
| | - Shubhadeep Purkayastha
- Nuclear Medicine Department, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892
| | - Ronald D. Neumann
- Nuclear Medicine Department, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892
| | - Elzbieta Pastwa
- Department of Medicinal Chemistry, Medical University of Lodz, Lodz, Poland 92-215
| | - Thomas A. Winters
- Nuclear Medicine Department, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892
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Pang D, Winters TA, Jung M, Purkayastha S, Cavalli LR, Chasovkikh S, Haddad BR, Dritschilo A. Radiation-generated short DNA fragments may perturb non-homologous end-joining and induce genomic instability. JOURNAL OF RADIATION RESEARCH 2011; 52:309-19. [PMID: 21628845 PMCID: PMC5469405 DOI: 10.1269/jrr.10147] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Cells exposed to densely ionizing radiation (high-LET) experience more severe biological damage than do cells exposed to sparsely ionizing radiation (low-LET). The prevailing hypothesis is that high-LET radiations induce DNA double strand-breaks (DSB) that are more complex and clustered, and are thereby more challenging to repair. Here, we present experimental data obtained by atomic force microscopy imaging, DNA-dependent protein kinase (DNA-PK) activity determination, DNA ligation assays, and genomic studies to suggest that short DNA fragments are important products of radiation-induced DNA lesions, and that the lengths of DNA fragments may be significant in the cellular responses to ionizing radiation. We propose the presence of a subset of short DNA fragments that may affect cell survival and genetic stability following exposure to ionizing radiation, and that the enhanced biological effects of high-LET radiation may be explained, in part, by the production of increased quantities of short DNA fragments.
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Affiliation(s)
- Dalong Pang
- Department of Radiation Medicine, Georgetown University Medical Center
| | - Thomas A. Winters
- Radiology and Imaging Sciences Department, Warren Grant Magnuson Clinical Center, National Institutes of Health
| | - Mira Jung
- Department of Radiation Medicine, Georgetown University Medical Center
| | - Shubhadeep Purkayastha
- Radiology and Imaging Sciences Department, Warren Grant Magnuson Clinical Center, National Institutes of Health
| | - Luciane R. Cavalli
- Department of Oncology/Lombardi Comprehensive Cancer Center, Georgetown University Medical Center
| | - Sergey Chasovkikh
- Department of Radiation Medicine, Georgetown University Medical Center
| | - Bassem R. Haddad
- Department of Oncology/Lombardi Comprehensive Cancer Center, Georgetown University Medical Center
| | - Anatoly Dritschilo
- Department of Radiation Medicine, Georgetown University Medical Center
- Corresponding author: Anatoly Dritschilo, MD, Department of Radiation Medicine, Georgetown University Medical Center, 3800 Reservoir Road, NW, LL Bles Washington, DC 20007
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Ulsh BA. Checking the foundation: recent radiobiology and the linear no-threshold theory. HEALTH PHYSICS 2010; 99:747-758. [PMID: 21068593 DOI: 10.1097/hp.0b013e3181e32477] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The linear no-threshold (LNT) theory has been adopted as the foundation of radiation protection standards and risk estimation for several decades. The "microdosimetric argument" has been offered in support of the LNT theory. This argument postulates that energy is deposited in critical cellular targets by radiation in a linear fashion across all doses down to zero, and that this in turn implies a linear relationship between dose and biological effect across all doses. This paper examines whether the microdosimetric argument holds at the lowest levels of biological organization following low dose, low dose-rate exposures to ionizing radiation. The assumptions of the microdosimetric argument are evaluated in light of recent radiobiological studies on radiation damage in biological molecules and cellular and tissue level responses to radiation damage. There is strong evidence that radiation initially deposits energy in biological molecules (e.g., DNA) in a linear fashion, and that this energy deposition results in various forms of prompt DNA damage that may be produced in a pattern that is distinct from endogenous (e.g., oxidative) damage. However, a large and rapidly growing body of radiobiological evidence indicates that cell and tissue level responses to this damage, particularly at low doses and/or dose-rates, are nonlinear and may exhibit thresholds. To the extent that responses observed at lower levels of biological organization in vitro are predictive of carcinogenesis observed in vivo, this evidence directly contradicts the assumptions upon which the microdosimetric argument is based.
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Affiliation(s)
- Brant A Ulsh
- National Institute for Occupational Safety and Health, 4676 Columbia Parkway, Mailstop C-46, Cincinnati, OH 45226, USA
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Asaithamby A, Chen DJ. Mechanism of cluster DNA damage repair in response to high-atomic number and energy particles radiation. Mutat Res 2010; 711:87-99. [PMID: 21126526 DOI: 10.1016/j.mrfmmm.2010.11.002] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 10/29/2010] [Accepted: 11/23/2010] [Indexed: 02/07/2023]
Abstract
Low-linear energy transfer (LET) radiation (i.e., γ- and X-rays) induces DNA double-strand breaks (DSBs) that are rapidly repaired (rejoined). In contrast, DNA damage induced by the dense ionizing track of high-atomic number and energy (HZE) particles is slowly repaired or is irreparable. These unrepaired and/or misrepaired DNA lesions may contribute to the observed higher relative biological effectiveness for cell killing, chromosomal aberrations, mutagenesis, and carcinogenesis in HZE particle irradiated cells compared to those treated with low-LET radiation. The types of DNA lesions induced by HZE particles have been characterized in vitro and usually consist of two or more closely spaced strand breaks, abasic sites, or oxidized bases on opposing strands. It is unclear why these lesions are difficult to repair. In this review, we highlight the potential of a new technology allowing direct visualization of different types of DNA lesions in human cells and document the emerging significance of live-cell imaging for elucidation of the spatio-temporal characterization of complex DNA damage. We focus on the recent insights into the molecular pathways that participate in the repair of HZE particle-induced DSBs. We also discuss recent advances in our understanding of how different end-processing nucleases aid in repair of DSBs with complicated ends generated by HZE particles. Understanding the mechanism underlying the repair of DNA damage induced by HZE particles will have important implications for estimating the risks to human health associated with HZE particle exposure.
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Affiliation(s)
- Aroumougame Asaithamby
- Division of Molecular Radiation Biology, Department of Radiation Oncology, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, United States.
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Kortylewicz ZP, Nearman J, Baranowska-Kortylewicz J. Radiolabeled 5-iodo-3'-O-(17beta-succinyl-5alpha-androstan-3-one)-2'-deoxyuridine and its 5'-monophosphate for imaging and therapy of androgen receptor-positive cancers: synthesis and biological evaluation. J Med Chem 2010; 52:5124-43. [PMID: 19653647 DOI: 10.1021/jm9005803] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
High levels of androgen receptor (AR) are often indicative of recurrent, advanced, or metastatic cancers. These conditions are also characterized by a high proliferative fraction. 5-Radioiodo-3'-O-(17beta-succinyl-5alpha-androstan-3-one)-2'-deoxyuridine 8 and 5-radioiodo-3'-O-(17beta-succinyl-5alpha-androstan-3-one)-2'-deoxyuridin-5'-yl monophosphate 13 target AR. They are also degraded intracellularly to 5-radioiodo-2'-deoxyuridine 1 and its monophosphate 20, respectively, which can participate in the DNA synthesis. Both drugs were prepared at the no-carrier-added level. Precursors and methods are readily adaptable to radiolabeling with various radiohalides suitable for SPECT and PET imaging, as well as endoradiotherapy. In vitro and in vivo studies confirm the AR-dependent interactions. Both drugs bind to sex hormone binding globulin. This binding significantly improves their stability in serum. Biodistribution and imaging studies show preferential uptake and retention of 8 and 13 in ip xenografts of human ovarian adenocarcinoma cells NIH:OVCAR-3, which overexpress AR. When these drugs are administered at therapeutic dose levels, a significant tumor growth arrest is observed.
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Affiliation(s)
- Zbigniew P Kortylewicz
- Department of Radiation Oncology, J. Bruce Henriksen Cancer Research Laboratories, University of Nebraska Medical Center, 986850 Nebraska Medical Center, Omaha, Nebraska 68198-6850, USA.
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Poplawski T, Pastwa E, Blasiak J. Non-homologous DNA end joining in normal and cancer cells and its dependence on break structures. Genet Mol Biol 2010; 33:368-73. [PMID: 21637496 PMCID: PMC3036873 DOI: 10.1590/s1415-47572010005000018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Accepted: 10/06/2009] [Indexed: 11/21/2022] Open
Abstract
DNA double-strand breaks (DSBs) are a serious threat to the cell, for if not or miss-repaired, they can lead to chromosomal aberration, mutation and cancer. DSBs in human cells are repaired via non-homologous DNA end joining (NHEJ) and homologous recombination repair pathways. In the former process, the structure of DNA termini plays an important role, as does the genetic constitution of the cells, through being different in normal and pathological cells. In order to investigate the dependence of NHEJ on DSB structure in normal and cancer cells, we used linearized plasmids with various, complementary or non-complementary, single-stranded or blunt DNA termini, as well as whole-cell extract isolated from normal human lymphocytes, chronic myeloid leukemia K562 cells and lung cancer A549 cells. We observed a pronounced variability in the efficacy of NHEJ reaction depending on the type of ends. Plasmids with complementary and blunt termini were more efficiently repaired than the substrate with 3' protruding single-strand ends. The hierarchy of the effectiveness of NHEJ was on average, from the most effective to the least, A549/ normal lymphocytes/ K562. Our results suggest that the genetic constitution of the cells together with the substrate terminal structure may contribute to the efficacy of the NHEJ reaction. This should be taken into account on considering its applicability in cancer chemo- or radiotherapy by pharmacologically modulating NHEJ cellular responses.
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Affiliation(s)
- Tomasz Poplawski
- Department of Molecular Genetics, University of Lodz, Banacha, Lodz Poland
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Abstract
Genomska nestabilnost i test osjetljivosti na bleomicinProcjena individualne osjetljivosti na mutagene često je dio istraživanja u epidemiološkim studijama koje prate pojavnost zloćudnih bolesti u populacijama. Posljedica djelovanja mutagena u genomu izloženih osoba jest nastanak osoba jest nastanak određene, manje ili veće, količine oštećenja, uvjetovane individualnim razlikama u osjetljivosti. Viša razina takve genomske nestabilnosti znači opasnost (rizik) od razvoja zloćudnih bolesti. Interindividualne razlike u odgovoru na mutagene obično se povezuju i s promijenjenom (većinom smanjenom) sposobnosti (kapacitetom) za popravak DNA. Citogenetičke studije su pokazale da je genom tumorskih stanica nestabilniji od normalnih, a time i skloniji akumuliranju oštećenja, bilo da je nestabilnost uzrokovana nasljeđem, izloženošću ili kombinacijom tih dvaju učinaka. U oboljelih ispitanika utvrđena je povećana učestalost kromatidnih i kromosomskih aberacija naspram normalne populacije te sklonost razvoju određenih vrsta neoplazija. U praćenju povezanosti promijenjenog odgovora i pojavnosti tumora služe nam različiti biomarkeri. Kao indirektni pokazatelji uspješnosti popravka DNA često se rabe testovi osjetljivosti na mutagene u kulturama limfocita periferne krvi. Jedan od takvih testova je i bleomicinski test. Radiomimetik i citostatik, a po strukturi glikopeptid, bleomicin se u stanici prevodi u aktivni oblik sposoban cijepati molekulu DNA što uzrokuje brojne jednolančane i dvolančane lomove. Kao jednostavna i jeftina metoda, zasniva se na utvrđivanju ukupnog broja jednolančanih lomova u kromosomima limfocita uzgajanih u staničnoj kulturi koji su u uvjetima in vitro tijekom kasne G2-faze staničnog ciklusa bili izloženi bleomicinu. Ovaj revijalni rad daje pregled utjecaja raznih faktora na rezultate samog testa i pokazuje njegovu široku primjenu u proučavanju genomske nestabilnosti koju najčešće uzrokuje kombinacija raznih faktora.
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Daley JM, Wilson TE, Ramotar D. Genetic interactions between HNT3/Aprataxin and RAD27/FEN1 suggest parallel pathways for 5' end processing during base excision repair. DNA Repair (Amst) 2010; 9:690-9. [PMID: 20399152 DOI: 10.1016/j.dnarep.2010.03.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 02/26/2010] [Accepted: 03/22/2010] [Indexed: 10/19/2022]
Abstract
Mutations in Aprataxin cause the neurodegenerative syndrome ataxia oculomotor apraxia type 1. Aprataxin catalyzes removal of adenosine monophosphate (AMP) from the 5' end of a DNA strand, which results from an aborted attempt to ligate a strand break containing a damaged end. To gain insight into which DNA lesions are substrates for Aprataxin action in vivo, we deleted the Saccharomyces cerevisiae HNT3 gene, which encodes the Aprataxin homolog, in combination with known DNA repair genes. While hnt3Delta single mutants were not sensitive to DNA damaging agents, loss of HNT3 caused synergistic sensitivity to H(2)O(2) in backgrounds that accumulate strand breaks with blocked termini, including apn1Delta apn2Delta tpp1Delta and ntg1Delta ntg2Delta ogg1Delta. Loss of HNT3 in rad27Delta cells, which are deficient in long-patch base excision repair (LP-BER), resulted in synergistic sensitivity to H(2)O(2) and MMS, indicating that Hnt3 and LP-BER provide parallel pathways for processing 5' AMPs. Loss of HNT3 also increased the sister chromatid exchange frequency. Surprisingly, HNT3 deletion partially rescued H(2)O(2) sensitivity in recombination-deficient rad51Delta and rad52Delta cells, suggesting that Hnt3 promotes formation of a repair intermediate that is resolved by recombination.
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Affiliation(s)
- James M Daley
- Centre de Recherche, Hôpital Maisonneuve-Rosemont, Université de Montréal, Montréal, QC H1T 2M4, Canada
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Alloni D, Campa A, Belli M, Esposito G, Facoetti A, Friedland W, Liotta M, Mariotti L, Paretzke HG, Ottolenghi A. A Monte Carlo Study of the Radiation Quality Dependence of DNA Fragmentation Spectra. Radiat Res 2010; 173:263-71. [DOI: 10.1667/rr1957.1] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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The influence of reduced glutathione on chromosome damage induced by X-rays or heavy ion beams of different LETs and on the interaction of DNA lesions induced by radiations and bleomycin. Mutat Res 2010; 696:154-9. [PMID: 20100593 DOI: 10.1016/j.mrgentox.2010.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 01/13/2010] [Accepted: 01/17/2010] [Indexed: 11/20/2022]
Abstract
It is thought that high linear energy transfer (LET) radiation induces more complex DNA damage than low-LET particles, specifically clustered DNA damage that causes cells to repair DNA double strand breaks (DSB) more slowly and leads to severe biological consequences. The present study aimed to investigate the role of exogenously added glutathione (GSH) on (12)C-beam (287keV/mum) and (7)Li-beam (60keV/mum) induced chromosome aberration (CA) formation, particularly on exchange aberration formation. In order to characterize the role of GSH in the joining of DNA DSBs, we induced DNA lesions with bleomycin (Blem) in conjunction with either high- or low-LET radiation (X-rays) since the chemistry of the free DNA ends created by Blem and X-rays is similar. CHO cells were exposed to reduced GSH at a concentration of 2mM for 3h before radiation. Treatment with Blem (20mug/ml) was carried out for 2h before the cells were exposed to radiation. Our results show that the frequency of chromosomal aberration increases with increased LET. Heavy ion exposed cells show a higher frequency of CA over time than do X-irradiated cells. An analysis of the first post-irradiation mitosis of exposed CHO cells shows that high-LET radiation induces more breaks than exchange-type aberrations and exogenous GSH has no influence on high-LET radiation-induced DNA damage. The DNA lesions induced by low-LET radiation interact relatively strongly with Blem-induced lesions whereas interaction between Blem and high-LET radiations was poor. This could be attributed to differences in repair kinetics and qualitative differences in the DNA lesions induced by Blem and high-LET radiation.
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Zafar F, Seidler SB, Kronenberg A, Schild D, Wiese C. Homologous recombination contributes to the repair of DNA double-strand breaks induced by high-energy iron ions. Radiat Res 2010; 173:27-39. [PMID: 20041757 DOI: 10.1667/rr1910.1] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
To test the contribution of homologous recombinational repair (HRR) in repairing DNA damage sites induced by high-energy iron ions, we used (1) HRR-deficient rodent cells carrying a deletion in the RAD51D gene and (2) syngeneic human cells impaired for HRR by RAD51D or RAD51 knockdown using RNA interference. We found that in response to exposure to iron ions, HRR contributed to cell survival in rodent cells and that HRR deficiency abrogated RAD51 focus formation. Complementation of the HRR defect by human RAD51D rescues both enhanced cytotoxicity and RAD51 focus formation. For human cells irradiated with iron ions, cell survival was decreased, and in p53 mutant cells, the levels of mutagenesis were increased when HRR was impaired. Human cells synchronized in S phase exhibited a more pronounced resistance to iron ions compared with cells in G(1) phase, and this increase in radioresistance was diminished by RAD51 knockdown. These results indicate a role for RAD51-mediated DNA repair (i.e. HRR) in removing a fraction of clustered lesions induced by charged-particle radiation. Our results are the first to directly show the requirement for an intact HRR pathway in human cells in ensuring DNA repair and cell survival after exposure to high-energy high-LET radiation.
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Affiliation(s)
- Faria Zafar
- Lawrence Berkeley National Laboratory, Life Sciences Division, Berkeley, California 94720, USA
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Zhou L, Li W, Yu L, Li P, Li Q, Ma S, Dong X, Zhou G, Leloup C. Linear energy transfer dependence of the effects of carbon ion beams on adventitious shoot regeneration fromin vitroleaf explants ofSaintpaulia ionahta. Int J Radiat Biol 2009; 82:473-81. [PMID: 16882619 DOI: 10.1080/09553000600863080] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To determine the effects of carbon ion beams with five different linear energy transfer (LET) values on adventitious shoots from in vitro leaf explants of Saintpaulia ionahta Mauve cultivar with regard to tissue increase, shoots differentiation and morphology changes in the shoots. MATERIALS AND METHODS In vitro leaf explant samples were irradiated with carbon ion beams with LET values in the range of 31 approximately 151 keV/microm or 8 MeV of X-rays (LET = 0.2 keV/microm) at different doses. Fresh weight increase, surviving fraction and percentage of the explants with regenerated malformed shoots in all the irradiated leaf explants were statistically analysed. RESULTS The fresh weight increase (FWI) and surviving fraction (SF) decreased dramatically with increasing LET at the same doses. In addition, malformed shoots, including curliness, carnification, nicks and chlorophyll deficiency, occurred in both carbon ion beam and X-ray irradiations. The induction frequency with the former, however, was far more than that with the X-rays. CONCLUSIONS This work demonstrated the LET dependence of the relative biological effectiveness (RBE) of tissue culture of Saintpaulia ionahta according to 50% FWI and 50% SF. After irradiating leaf explants with 5 Gy of a 221 MeV carbon ion beam having a LET value of 96 keV/microm throughout the sample, a chlorophyll-deficient (CD) mutant, which could transmit the character of chlorophyll deficiency to its progeny through three continuous tissue culture cycles, and plantlets with other malformations were obtained.
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Affiliation(s)
- Libin Zhou
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, PR China.
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Agrawala PK, Eschenbrenner A, du Penhoat MAH, Boissiere A, Politis MF, Touati A, Sage E, Chetioui A. Induction and repairability of DNA damage caused by ultrasoft X-rays: Role of core events. Int J Radiat Biol 2009; 84:1093-103. [DOI: 10.1080/09553000802478083] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Mladenov E, Kalev P, Anachkova B. The complexity of double-strand break ends is a factor in the repair pathway choice. Radiat Res 2009; 171:397-404. [PMID: 19397440 DOI: 10.1667/rr1487.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The repair of double-strand breaks in mammalian cells is carried out by two pathways: homologous recombination and nonhomologous end joining. The factors that regulate the mechanism through which a specific repair pathway is activated are still not clearly defined. To study whether the complexity of the double-strand break ends is a factor that determines the choice of the repair pathway, we examined the involvement of homologous recombination by the formation of Rad51 foci in human HeLa cells treated with bleomycin and ionizing radiation. The quantity of double-strand breaks was determined by gel electrophoresis and the formation of gamma-H2AX foci. Two hours after treatment with low doses of the agents that induced similar quantities of double-strand breaks that could be repaired effectively by the cells, Rad51 foci were observed only in the irradiated cells. Rad51 foci appeared in bleomycin-treated cells after prolonged exposure to the drug when the cells were arrested in the G2 phase of the cell cycle. Since bleomycin produces double-strand breaks that are less complex than the breaks induced by ionizing radiation, these results indicate that the complexity of the break ends is a factor in the choice of repair pathway and that homologous recombination is recruited in the repair of breaks with more complex multiply damaged ends during the late S and G2 phases of the cell cycle.
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Affiliation(s)
- Emil Mladenov
- Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
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Pastwa E, Somiari RI, Malinowski M, Somiari SB, Winters TA. In vitro non-homologous DNA end joining assays--the 20th anniversary. Int J Biochem Cell Biol 2008; 41:1254-60. [PMID: 19110069 DOI: 10.1016/j.biocel.2008.11.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 11/20/2008] [Accepted: 11/28/2008] [Indexed: 11/16/2022]
Abstract
DNA double-strand breaks (DSBs) are the most serious forms of DNA damage in cells. Unrepaired or misrepaired DSBs account for some of the genetic instabilities that lead to mutations or cell death, and consequently, to cancer predisposition. In human cells non-homologous DNA end joining (NHEJ) is the main repair mechanism of these breaks. Systems for DNA end joining study have been developing during the last 20 years. New assays have some advantages over earlier in vitro DSBs repair assays because they are less time-consuming, allow the use of clinical material and examination of the joining DNA ends produced physiologically in mammalian cells. Proteins involved in NHEJ repair pathway can serve as biomarkers or molecular targets for anticancer drugs. Results of studies on NHEJ in cancer could help to select potent repair inhibitors that may selectively sensitize tumor cells to ionizing radiation (IR) and chemotherapy. Here, we review the principles and practice of in vitro NHEJ assays and provide some insights into the future prospects of this assay in cancer diagnosis and treatment.
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Affiliation(s)
- Elzbieta Pastwa
- Department of Molecular Genetics, Medical University of Lodz, Mazowiecka 6/8, 92-215 Lodz, Poland.
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Tseng SF, Gabriel A, Teng SC. Proofreading activity of DNA polymerase Pol2 mediates 3'-end processing during nonhomologous end joining in yeast. PLoS Genet 2008; 4:e1000060. [PMID: 18437220 PMCID: PMC2312331 DOI: 10.1371/journal.pgen.1000060] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Accepted: 03/26/2008] [Indexed: 02/02/2023] Open
Abstract
Genotoxic agents that cause double-strand breaks (DSBs) often generate damage at the break termini. Processing enzymes, including nucleases and polymerases, must remove damaged bases and/or add new bases before completion of repair. Artemis is a nuclease involved in mammalian nonhomologous end joining (NHEJ), but in Saccharomyces cerevisiae the nucleases and polymerases involved in NHEJ pathways are poorly understood. Only Pol4 has been shown to fill the gap that may form by imprecise pairing of overhanging 3' DNA ends. We previously developed a chromosomal DSB assay in yeast to study factors involved in NHEJ. Here, we use this system to examine DNA polymerases required for NHEJ in yeast. We demonstrate that Pol2 is another major DNA polymerase involved in imprecise end joining. Pol1 modulates both imprecise end joining and more complex chromosomal rearrangements, and Pol3 is primarily involved in NHEJ-mediated chromosomal rearrangements. While Pol4 is the major polymerase to fill the gap that may form by imprecise pairing of overhanging 3' DNA ends, Pol2 is important for the recession of 3' flaps that can form during imprecise pairing. Indeed, a mutation in the 3'-5' exonuclease domain of Pol2 dramatically reduces the frequency of end joins formed with initial 3' flaps. Thus, Pol2 performs a key 3' end-processing step in NHEJ.
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Affiliation(s)
- Shun-Fu Tseng
- Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Abram Gabriel
- Department of Biochemistry and Molecular Biology, Rutgers University, Piscataway, New Jersey, United States of America
| | - Shu-Chun Teng
- Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Institute of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- * E-mail:
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High LET heavy ion radiation induces lower numbers of initial chromosome breaks with minimal repair than low LET radiation in normal human cells. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2008; 652:95-101. [DOI: 10.1016/j.mrgentox.2008.01.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Revised: 12/19/2007] [Accepted: 01/19/2008] [Indexed: 01/21/2023]
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