1
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Zhang FL, Ma HH, Dong PY, Yan YMC, Chen Y, Yang GM, Shen W, Zhang XF. Bacillus licheniformis ameliorates Aflatoxin B1-induced testicular damage by improving the gut-metabolism-testis axis. JOURNAL OF HAZARDOUS MATERIALS 2024; 468:133836. [PMID: 38394902 DOI: 10.1016/j.jhazmat.2024.133836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 02/03/2024] [Accepted: 02/17/2024] [Indexed: 02/25/2024]
Abstract
Global aflatoxin B1 (AFB1) contamination is inevitable, and it can significantly damage testicular development. However, the current mechanism is confusing. Here, by integrating the transcriptome, microbiome, and serum metabolome, we comprehensively explain the impact of AFB1 on testis from the gut-metabolism-testis axis. Transcriptome analysis suggested that AFB1 exposure directly causes abnormalities in testicular inflammation-related signalling, such as tumor necrosis factor (TNF) pathway, and proliferation-related signalling pathways, such as phosphatidylinositide 3-kinases-protein kinase B (PI3K-AKT) pathway, which was verified by immunofluorescence. On the other hand, we found that upregulated inflammatory factors in the intestine after AFB1 exposure were associated with intestinal microbial dysbiosis, especially the enrichment of Bacilli, and enrichment analysis showed that this may be related to NLR family pyrin domain containing 3 (NLRP3)-mediated NOD-like receptor signalling. Also, AFB1 exposure caused blood metabolic disturbances, manifested as decreased hormone levels and increased oxidative stress. Significantly, B. licheniformis has remarkable AFB1 degradation efficiency (> 90%). B. licheniformis treatment is effective in attenuating gut-testis axis damage caused by AFB1 exposure through the above-mentioned signalling pathways. In conclusion, our findings indicate that AFB1 exposure disrupts testicular development through the gut-metabolism-testis axis, and B. licheniformis can effectively degrade AFB1.
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Affiliation(s)
- Fa-Li Zhang
- College of Veterinary medicine, Qingdao Agricultural University, Qingdao 266100, China; College of Life Sciences, Key Laboratory of Animal Reproduction and Biotechnology in Universities of Shandong, Qingdao Agricultural University, Qingdao 266109, China
| | - Hao-Hai Ma
- College of Veterinary medicine, Qingdao Agricultural University, Qingdao 266100, China
| | - Pei-Yu Dong
- College of Veterinary medicine, Qingdao Agricultural University, Qingdao 266100, China
| | - Yu-Mei Chen Yan
- College of Veterinary medicine, Qingdao Agricultural University, Qingdao 266100, China
| | - Yu Chen
- College of Veterinary medicine, Qingdao Agricultural University, Qingdao 266100, China
| | - Guo-Ming Yang
- College of Veterinary medicine, Qingdao Agricultural University, Qingdao 266100, China
| | - Wei Shen
- College of Life Sciences, Key Laboratory of Animal Reproduction and Biotechnology in Universities of Shandong, Qingdao Agricultural University, Qingdao 266109, China
| | - Xi-Feng Zhang
- College of Veterinary medicine, Qingdao Agricultural University, Qingdao 266100, China.
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2
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Qin N, Geng A, Xue R. Activated or Impaired: An Overview of DNA Repair in Neurodegenerative Diseases. Aging Dis 2022; 13:987-1004. [PMID: 35855336 PMCID: PMC9286913 DOI: 10.14336/ad.2021.1212] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 12/08/2021] [Indexed: 11/06/2022] Open
Abstract
As the population ages, age-related neurodegenerative diseases have become a major challenge in health science. Currently, the pathology of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and Huntington's disease, is still not fully understood. Remarkably, emerging evidence indicates a role of genomic DNA damage and repair in various neurodegenerative disorders. Here, we summarized the current understanding of the function of DNA damage repair, especially base excision repair and double strand break repair pathways, in a variety of neurodegenerative diseases. We concluded that exacerbation of DNA lesions is found in almost all types of neurodegenerative diseases, whereas the activities of different DNA repair pathways demonstrate distinct trends, depending on disease type and even brain region. Specifically, key enzymes involved in base excision repair are likely impaired in Alzheimer's disease and amyotrophic lateral sclerosis but activated in Parkinson's disease, while nonhomologous end joining is likely downregulated in most types of neurodegenerative diseases. Hence, impairment of nonhomologous end joining is likely a common etiology for most neurodegenerative diseases, while defects in base excision repair are likely involved in the pathology of Alzheimer's disease and amyotrophic lateral sclerosis but are Parkinson's disease, based on current findings. Although there are still discrepancies and further studies are required to completely elucidate the exact roles of DNA repair in neurodegeneration, the current studies summarized here provide crucial insights into the pathology of neurodegenerative diseases and may reveal novel drug targets for corresponding neurodegenerative diseases.
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Affiliation(s)
- Nan Qin
- Shanghai Key Laboratory of Maternal Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Anke Geng
- Shanghai Key Laboratory of Maternal Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Renhao Xue
- Shanghai Key Laboratory of Maternal Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
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3
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Zelensky AN, Schoonakker M, Brandsma I, Tijsterman M, van Gent DC, Essers J, Kanaar R. Low dose ionizing radiation strongly stimulates insertional mutagenesis in a γH2AX dependent manner. PLoS Genet 2020; 16:e1008550. [PMID: 31945059 PMCID: PMC6964834 DOI: 10.1371/journal.pgen.1008550] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 12/02/2019] [Indexed: 11/21/2022] Open
Abstract
Extrachromosomal DNA can integrate into the genome with no sequence specificity producing an insertional mutation. This process, which is referred to as random integration (RI), requires a double stranded break (DSB) in the genome. Inducing DSBs by various means, including ionizing radiation, increases the frequency of integration. Here we report that non-lethal physiologically relevant doses of ionizing radiation (10-100 mGy), within the range produced by medical imaging equipment, stimulate RI of transfected and viral episomal DNA in human and mouse cells with an extremely high efficiency. Genetic analysis of the stimulated RI (S-RI) revealed that it is distinct from the background RI, requires histone H2AX S139 phosphorylation (γH2AX) and is not reduced by DNA polymerase θ (Polq) inactivation. S-RI efficiency was unaffected by the main DSB repair pathway (homologous recombination and non-homologous end joining) disruptions, but double deficiency in MDC1 and 53BP1 phenocopies γH2AX inactivation. The robust responsiveness of S-RI to physiological amounts of DSBs can be exploited for extremely sensitive, macroscopic and direct detection of DSB-induced mutations, and warrants further exploration in vivo to determine if the phenomenon has implications for radiation risk assessment.
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Affiliation(s)
- Alex N. Zelensky
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
- Oncode Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Mascha Schoonakker
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Inger Brandsma
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Marcel Tijsterman
- Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Dik C. van Gent
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
- Oncode Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Jeroen Essers
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Radiation Oncology, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Roland Kanaar
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
- Oncode Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
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4
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Ma N, Mochel NRD, Pham PD, Yoo TY, Cho KWY, Digman MA. Label-free assessment of pre-implantation embryo quality by the Fluorescence Lifetime Imaging Microscopy (FLIM)-phasor approach. Sci Rep 2019; 9:13206. [PMID: 31519916 PMCID: PMC6744410 DOI: 10.1038/s41598-019-48107-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 06/28/2019] [Indexed: 01/28/2023] Open
Abstract
Development of quantitative, safe and rapid techniques for assessing embryo quality provides significant advances in Assisted Reproductive Technologies (ART). Instead of assessing the embryo quality by the standard morphologic evaluation, we apply the phasor-FLIM (Fluorescence Lifetime Imaging Microscopy) method to capture endogenous fluorescent biomarkers of pre-implantation embryos as a non-morphological caliber for embryo quality. Here, we identify, under hypoxic and non-hypoxic conditions, the unique spectroscopic trajectories at different stages of mouse pre-implantation development, which is referred to as the developmental, or “D-trajectory”, that consists of fluorescence lifetime from different stages of mouse pre-implantation embryos. The D-trajectory correlates with intrinsic fluorescent species from a distinctive energy metabolism and oxidized lipids, as seen with Third Harmonic Generation (THG) that changes over time. In addition, we have defined a non-morphological Embryo Viability Index (EVI) to distinguish pre-implantation embryo quality using the Distance Analysis (DA), a machine learning algorithm to process the fluorescence lifetime distribution patterns. We show, under our experimental conditions, that the phasor-FLIM approach provides a much-needed non-invasive quantitative technology for identifying healthy embryos at the early compaction stage with 86% accuracy. The DA and phasor-FLIM method may provide the opportunity to improve implantation success rates for in vitro fertilization clinics.
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Affiliation(s)
- Ning Ma
- Department of Biomedical Engineering, University of California, Irvine, CA, USA.,Laboratory of Fluorescence Dynamics (LFD), University of California, Irvine, CA, USA
| | - Nabora Reyes de Mochel
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA.,University of California San Francisco, School of Medicine, San Francisco, USA
| | - Paula Duyen Pham
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA
| | - Tae Yeon Yoo
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA
| | - Ken W Y Cho
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA.
| | - Michelle A Digman
- Department of Biomedical Engineering, University of California, Irvine, CA, USA. .,Laboratory of Fluorescence Dynamics (LFD), University of California, Irvine, CA, USA. .,Department of Developmental and Cell Biology, University of California, Irvine, CA, USA.
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5
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Testa E, Nardozi D, Antinozzi C, Faieta M, Di Cecca S, Caggiano C, Fukuda T, Bonanno E, Zhenkun L, Maldonado A, Roig I, Di Giacomo M, Barchi M. H2AFX and MDC1 promote maintenance of genomic integrity in male germ cells. J Cell Sci 2018; 131:jcs.214411. [PMID: 29437857 DOI: 10.1242/jcs.214411] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 01/31/2018] [Indexed: 12/18/2022] Open
Abstract
In somatic cells, H2afx and Mdc1 are close functional partners in DNA repair and damage response. However, it is not known whether they are also involved in the maintenance of genome integrity in meiosis. By analyzing chromosome dynamics in H2afx-/- spermatocytes, we found that the synapsis of autosomes and X-Y chromosomes was impaired in a fraction of cells. Such defects correlated with an abnormal recombination profile. Conversely, Mdc1 was dispensable for the synapsis of the autosomes and played only a minor role in X-Y synapsis, compared with the action of H2afx This suggested that those genes have non-overlapping functions in chromosome synapsis. However, we observed that both genes play a similar role in the assembly of MLH3 onto chromosomes, a key step in crossover formation. Moreover, we show that H2afx and Mdc1 cooperate in promoting the activation of the recombination-dependent checkpoint, a mechanism that restrains the differentiation of cells with unrepaired DSBs. This occurs by a mechanism that involves P53. Overall, our data show that, in male germ cells, H2afx and Mdc1 promote the maintenance of genome integrity.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Erika Testa
- Department of Biomedicine and Prevention, Section of Anatomy, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Daniela Nardozi
- Department of Biomedicine and Prevention, Section of Anatomy, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Cristina Antinozzi
- Department of Biomedicine and Prevention, Section of Anatomy, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Monica Faieta
- Department of Biomedicine and Prevention, Section of Anatomy, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Stefano Di Cecca
- Department of Biomedicine and Prevention, Section of Anatomy, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Cinzia Caggiano
- Department of Biomedicine and Prevention, Section of Anatomy, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Tomoyuki Fukuda
- Department of Cellular Physiology, Niigata University Graduate School of Medical and Dental Sciences, 951-8510 Niigata, Japan.,Graduate School of Biological Sciences, Nara Institute of Science and Technology, 630-0192 Nara, Japan
| | - Elena Bonanno
- Department of Experimental Medicine and Surgery, Section of Pathological Anatomy, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Lou Zhenkun
- Division of Oncology Research, Department of Oncology, Mayo Clinic, Rochester, MN 55905 USA
| | - Andros Maldonado
- Genome Integrity and Instability Group, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain.,Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain
| | - Ignasi Roig
- Genome Integrity and Instability Group, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain.,Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain
| | | | - Marco Barchi
- Department of Biomedicine and Prevention, Section of Anatomy, University of Rome Tor Vergata, 00133 Rome, Italy
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6
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Leung JWC, Makharashvili N, Agarwal P, Chiu LY, Pourpre R, Cammarata MB, Cannon JR, Sherker A, Durocher D, Brodbelt JS, Paull TT, Miller KM. ZMYM3 regulates BRCA1 localization at damaged chromatin to promote DNA repair. Genes Dev 2017; 31:260-274. [PMID: 28242625 PMCID: PMC5358723 DOI: 10.1101/gad.292516.116] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 01/30/2017] [Indexed: 12/02/2022]
Abstract
In this study, Leung et al. identified ZMYM3 (zinc finger, myeloproliferative, and mental retardation-type 3) as a chromatin-interacting protein that promotes DNA repair by homologous recombination. This work identifies a critical chromatin-binding DNA damage response factor, ZMYM3, which modulates BRCA1 functions within chromatin to ensure the maintenance of genome integrity. Chromatin connects DNA damage response factors to sites of damaged DNA to promote the signaling and repair of DNA lesions. The histone H2A variants H2AX, H2AZ, and macroH2A represent key chromatin constituents that facilitate DNA repair. Through proteomic screening of these variants, we identified ZMYM3 (zinc finger, myeloproliferative, and mental retardation-type 3) as a chromatin-interacting protein that promotes DNA repair by homologous recombination (HR). ZMYM3 is recruited to DNA double-strand breaks through bivalent interactions with both histone and DNA components of the nucleosome. We show that ZMYM3 links the HR factor BRCA1 to damaged chromatin through specific interactions with components of the BRCA1-A subcomplex, including ABRA1 and RAP80. By regulating ABRA1 recruitment to damaged chromatin, ZMYM3 facilitates the fine-tuning of BRCA1 interactions with DNA damage sites and chromatin. Consistent with a role in regulating BRCA1 function, ZMYM3 deficiency results in impaired HR repair and genome instability. Thus, our work identifies a critical chromatin-binding DNA damage response factor, ZMYM3, which modulates BRCA1 functions within chromatin to ensure the maintenance of genome integrity.
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Affiliation(s)
- Justin W C Leung
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA; Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Nodar Makharashvili
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA; Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA.,The Howard Hughes Medical Institute, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Poonam Agarwal
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA; Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Li-Ya Chiu
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA; Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Renaud Pourpre
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA; Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Michael B Cammarata
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Joe R Cannon
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Alana Sherker
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G1X5, Canada
| | - Daniel Durocher
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G1X5, Canada
| | - Jennifer S Brodbelt
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Tanya T Paull
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA; Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA.,The Howard Hughes Medical Institute, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Kyle M Miller
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA; Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA
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7
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Tsai RYL. Balancing self-renewal against genome preservation in stem cells: How do they manage to have the cake and eat it too? Cell Mol Life Sci 2016; 73:1803-23. [PMID: 26886024 PMCID: PMC5040593 DOI: 10.1007/s00018-016-2152-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 01/18/2016] [Accepted: 01/28/2016] [Indexed: 01/22/2023]
Abstract
Stem cells are endowed with the awesome power of self-renewal and multi-lineage differentiation that allows them to be major contributors to tissue homeostasis. Owing to their longevity and self-renewal capacity, they are also faced with a higher risk of genomic damage compared to differentiated cells. Damage on the genome, if not prevented or repaired properly, will threaten the survival of stem cells and culminate in organ failure, premature aging, or cancer formation. It is therefore of paramount importance that stem cells remain genomically stable throughout life. Given their unique biological and functional requirement, stem cells are thought to manage genotoxic stress somewhat differently from non-stem cells. The focus of this article is to review the current knowledge on how stem cells escape the barrage of oxidative and replicative DNA damage to stay in self-renewal. A clear statement on this subject should help us better understand tissue regeneration, aging, and cancer.
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Affiliation(s)
- Robert Y L Tsai
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University Health Science Center, 2121 W. Holcombe Blvd, Houston, TX, 77030, USA.
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, College Station, TX, 77843, USA.
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8
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Pratz KW, Koh BD, Patel AG, Flatten KS, Poh W, Herman JG, Dilley R, Harrell MI, Smith BD, Karp JE, Swisher EM, McDevitt MA, Kaufmann SH. Poly (ADP-Ribose) Polymerase Inhibitor Hypersensitivity in Aggressive Myeloproliferative Neoplasms. Clin Cancer Res 2016; 22:3894-902. [PMID: 26979391 DOI: 10.1158/1078-0432.ccr-15-2351] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 02/29/2016] [Indexed: 01/31/2023]
Abstract
PURPOSE DNA repair defects have been previously reported in myeloproliferative neoplasms (MPN). Inhibitors of PARP have shown activity in solid tumors with defects in homologous recombination (HR). This study was performed to assess MPN sensitivity to PARP inhibitors ex vivo EXPERIMENTAL DESIGN HR pathway integrity in circulating myeloid cells was evaluated by assessing the formation of RAD51 foci after treatment with ionizing radiation or PARP inhibitors. Sensitivity of MPN erythroid and myeloid progenitors to PARP inhibitors was evaluated using colony formation assays. RESULTS Six of 14 MPN primary samples had reduced formation of RAD51 foci after exposure to ionizing radiation, suggesting impaired HR. This phenotype was not associated with a specific MPN subtype, JAK2 mutation status, or karyotype. MPN samples showed increased sensitivity to the PARP inhibitors veliparib and olaparib compared with normal myeloid progenitors. This hypersensitivity, which was most pronounced in samples deficient in DNA damage-induced RAD51 foci, was observed predominantly in samples from patients with diagnoses of chronic myelogenous leukemia, chronic myelomonocytic leukemia, or unspecified myelodysplastic/MPN overlap syndromes. CONCLUSIONS Like other neoplasms with HR defects, MPNs exhibit PARP inhibitor hypersensitivity compared with normal marrow. These results suggest that further preclinical and possibly clinical study of PARP inhibitors in MPNs is warranted. Clin Cancer Res; 22(15); 3894-902. ©2016 AACR.
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Affiliation(s)
- Keith W Pratz
- Department of Oncology and the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University, Baltimore, Maryland.
| | - Brian D Koh
- Department of Oncology, Mayo Clinic, Rochester, Minnesota
| | - Anand G Patel
- Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | | | - Weijie Poh
- Department of Oncology and the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University, Baltimore, Maryland
| | - James G Herman
- Division of Hematology/Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania
| | - Robert Dilley
- Department of Oncology and the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University, Baltimore, Maryland
| | - Maria I Harrell
- Department of Obstetrics & Gynecology, University of Washington School of Medicine, Seattle, Washington
| | - B Douglas Smith
- Department of Oncology and the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University, Baltimore, Maryland
| | - Judith E Karp
- Department of Oncology and the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University, Baltimore, Maryland
| | - Elizabeth M Swisher
- Department of Obstetrics & Gynecology, University of Washington School of Medicine, Seattle, Washington
| | - Michael A McDevitt
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Scott H Kaufmann
- Department of Oncology, Mayo Clinic, Rochester, Minnesota. Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
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9
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ATM and SIRT6/SNF2H Mediate Transient H2AX Stabilization When DSBs Form by Blocking HUWE1 to Allow Efficient γH2AX Foci Formation. Cell Rep 2015; 13:2728-40. [DOI: 10.1016/j.celrep.2015.11.054] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 11/03/2015] [Accepted: 11/17/2015] [Indexed: 01/07/2023] Open
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10
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Caron P, Choudjaye J, Clouaire T, Bugler B, Daburon V, Aguirrebengoa M, Mangeat T, Iacovoni JS, Álvarez-Quilón A, Cortés-Ledesma F, Legube G. Non-redundant Functions of ATM and DNA-PKcs in Response to DNA Double-Strand Breaks. Cell Rep 2015; 13:1598-609. [PMID: 26586426 PMCID: PMC4670905 DOI: 10.1016/j.celrep.2015.10.024] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 09/04/2015] [Accepted: 10/06/2015] [Indexed: 12/13/2022] Open
Abstract
DNA double-strand breaks (DSBs) elicit the so-called DNA damage response (DDR), largely relying on ataxia telangiectasia mutated (ATM) and DNA-dependent protein kinase (DNA-PKcs), two members of the PI3K-like kinase family, whose respective functions during the sequential steps of the DDR remains controversial. Using the DIvA system (DSB inducible via AsiSI) combined with high-resolution mapping and advanced microscopy, we uncovered that both ATM and DNA-PKcs spread in cis on a confined region surrounding DSBs, independently of the pathway used for repair. However, once recruited, these kinases exhibit non-overlapping functions on end joining and γH2AX domain establishment. More specifically, we found that ATM is required to ensure the association of multiple DSBs within "repair foci." Our results suggest that ATM acts not only on chromatin marks but also on higher-order chromatin organization to ensure repair accuracy and survival.
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Affiliation(s)
- Pierre Caron
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Jonathan Choudjaye
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Thomas Clouaire
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Béatrix Bugler
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Virginie Daburon
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Marion Aguirrebengoa
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Thomas Mangeat
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Jason S Iacovoni
- Bioinformatic Plateau I2MC, INSERM and University of Toulouse, 1 Avenue Jean Poulhes, BP 84225, 31432 Toulouse Cedex 4, France
| | - Alejandro Álvarez-Quilón
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), CSIC-Universidad de Sevilla, Sevilla 41092, Spain
| | - Felipe Cortés-Ledesma
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), CSIC-Universidad de Sevilla, Sevilla 41092, Spain
| | - Gaëlle Legube
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France.
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11
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Tada K, Kobayashi M, Takiuchi Y, Iwai F, Sakamoto T, Nagata K, Shinohara M, Io K, Shirakawa K, Hishizawa M, Shindo K, Kadowaki N, Hirota K, Yamamoto J, Iwai S, Sasanuma H, Takeda S, Takaori-Kondo A. Abacavir, an anti-HIV-1 drug, targets TDP1-deficient adult T cell leukemia. SCIENCE ADVANCES 2015; 1:e1400203. [PMID: 26601161 PMCID: PMC4640626 DOI: 10.1126/sciadv.1400203] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 03/29/2015] [Indexed: 05/07/2023]
Abstract
Adult T cell leukemia (ATL) is an aggressive T cell malignancy caused by human T cell leukemia virus type 1 (HTLV-1) and has a poor prognosis. We analyzed the cytotoxic effects of various nucleoside analog reverse transcriptase inhibitors (NRTIs) for HIV-1 on ATL cells and found that abacavir potently and selectively kills ATL cells. Although NRTIs have minimal genotoxicities on host cells, the therapeutic concentration of abacavir induced numerous DNA double-strand breaks (DSBs) in the chromosomal DNA of ATL cells. DSBs persisted over time in ATL cells but not in other cell lines, suggesting impaired DNA repair. We found that the reduced expression of tyrosyl-DNA phosphodiesterase 1 (TDP1), a repair enzyme, is attributable to the cytotoxic effect of abacavir on ATL cells. We also showed that TDP1 removes abacavir from DNA ends in vitro. These results suggest a model in which ATL cells with reduced TDP1 expression are unable to excise abacavir incorporated into genomic DNA, leading to irreparable DSBs. On the basis of the above mechanism, we propose abacavir as a promising chemotherapeutic agent for ATL.
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Affiliation(s)
- Kohei Tada
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Masayuki Kobayashi
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
- Corresponding author: E-mail: (M.K.); (A.T.-K.)
| | - Yoko Takiuchi
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Fumie Iwai
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Takashi Sakamoto
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Kayoko Nagata
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Masanobu Shinohara
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Katsuhiro Io
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Kotaro Shirakawa
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Masakatsu Hishizawa
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Keisuke Shindo
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Norimitsu Kadowaki
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Kouji Hirota
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0397, Japan
| | - Junpei Yamamoto
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Shigenori Iwai
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Hiroyuki Sasanuma
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Shunichi Takeda
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Akifumi Takaori-Kondo
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
- Corresponding author: E-mail: (M.K.); (A.T.-K.)
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12
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Bose P, Dai Y, Grant S. Histone deacetylase inhibitor (HDACI) mechanisms of action: emerging insights. Pharmacol Ther 2014; 143:323-36. [PMID: 24769080 PMCID: PMC4117710 DOI: 10.1016/j.pharmthera.2014.04.004] [Citation(s) in RCA: 206] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 04/10/2014] [Indexed: 02/05/2023]
Abstract
Initially regarded as "epigenetic modifiers" acting predominantly through chromatin remodeling via histone acetylation, HDACIs, alternatively referred to as lysine deacetylase or simply deacetylase inhibitors, have since been recognized to exert multiple cytotoxic actions in cancer cells, often through acetylation of non-histone proteins. Some well-recognized mechanisms of HDACI lethality include, in addition to relaxation of DNA and de-repression of gene transcription, interference with chaperone protein function, free radical generation, induction of DNA damage, up-regulation of endogenous inhibitors of cell cycle progression, e.g., p21, and promotion of apoptosis. Intriguingly, this class of agents is relatively selective for transformed cells, at least in pre-clinical studies. In recent years, additional mechanisms of action of these agents have been uncovered. For example, HDACIs interfere with multiple DNA repair processes, as well as disrupt cell cycle checkpoints, critical to the maintenance of genomic integrity in the face of diverse genotoxic insults. Despite their pre-clinical potential, the clinical use of HDACIs remains restricted to certain subsets of T-cell lymphoma. Currently, it appears likely that the ultimate role of these agents will lie in rational combinations, only a few of which have been pursued in the clinic to date. This review focuses on relatively recently identified mechanisms of action of HDACIs, with particular emphasis on those that relate to the DNA damage response (DDR), and discusses synergistic strategies combining HDACIs with several novel targeted agents that disrupt the DDR or antagonize anti-apoptotic proteins that could have implications for the future use of HDACIs in patients with cancer.
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Affiliation(s)
- Prithviraj Bose
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA; Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Yun Dai
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA; Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Steven Grant
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA; Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA; Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA; Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, USA; Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA, USA; Institute of Molecular Medicine, Virginia Commonwealth University, Richmond, VA, USA.
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13
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Abstract
Solar ultraviolet (UV) radiation, mainly UV-B (280-315 nm), is one of the most potent genotoxic agents that adversely affects living organisms by altering their genomic stability. DNA through its nucleobases has absorption maxima in the UV region and is therefore the main target of the deleterious radiation. The main biological relevance of UV radiation lies in the formation of several cytotoxic and mutagenic DNA lesions such as cyclobutane pyrimidine dimers (CPDs), 6-4 photoproducts (6-4PPs), and their Dewar valence isomers (DEWs), as well as DNA strand breaks. However, to counteract these DNA lesions, organisms have developed a number of highly conserved repair mechanisms such as photoreactivation, excision repair, and mismatch repair (MMR). Photoreactivation involving the enzyme photolyase is the most frequently used repair mechanism in a number of organisms. Excision repair can be classified as base excision repair (BER) and nucleotide excision repair (NER) involving a number of glycosylases and polymerases, respectively. In addition to this, double-strand break repair, SOS response, cell-cycle checkpoints, and programmed cell death (apoptosis) are also operative in various organisms to ensure genomic stability. This review concentrates on the UV-induced DNA damage and the associated repair mechanisms as well as various damage detection methods.
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Affiliation(s)
- Richa
- Laboratory of Photobiology and Molecular Microbiology, Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, 221005, India
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14
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Li Z, Sun B, Clewell RA, Adeleye Y, Andersen ME, Zhang Q. Dose-Response Modeling of Etoposide-Induced DNA Damage Response. Toxicol Sci 2013; 137:371-84. [DOI: 10.1093/toxsci/kft259] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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15
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Kuroda K, Hibi D, Ishii Y, Takasu S, Kijima A, Matsushita K, Masumura KI, Watanabe M, Sugita-Konishi Y, Sakai H, Yanai T, Nohmi T, Ogawa K, Umemura T. Ochratoxin A induces DNA double-strand breaks and large deletion mutations in the carcinogenic target site of gpt delta rats. Mutagenesis 2013; 29:27-36. [DOI: 10.1093/mutage/get054] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Girard PM, Graindorge D, Smirnova V, Rigolet P, Francesconi S, Scanlon S, Sage E. Oxidative stress in mammalian cells impinges on the cysteines redox state of human XRCC3 protein and on its cellular localization. PLoS One 2013; 8:e75751. [PMID: 24116071 PMCID: PMC3793007 DOI: 10.1371/journal.pone.0075751] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 08/19/2013] [Indexed: 11/23/2022] Open
Abstract
In vertebrates, XRCC3 is one of the five Rad51 paralogs that plays a central role in homologous recombination (HR), a key pathway for maintaining genomic stability. While investigating the potential role of human XRCC3 (hXRCC3) in the inhibition of DNA replication induced by UVA radiation, we discovered that hXRCC3 cysteine residues are oxidized following photosensitization by UVA. Our in silico prediction of the hXRCC3 structure suggests that 6 out of 8 cysteines are potentially accessible to the solvent and therefore potentially exposed to ROS attack. By non-reducing SDS-PAGE we show that many different oxidants induce hXRCC3 oxidation that is monitored in Chinese hamster ovarian (CHO) cells by increased electrophoretic mobility of the protein and in human cells by a slight decrease of its immunodetection. In both cell types, hXRCC3 oxidation was reversed in few minutes by cellular reducing systems. Depletion of intracellular glutathione prevents hXRCC3 oxidation only after UVA exposure though depending on the type of photosensitizer. In addition, we show that hXRCC3 expressed in CHO cells localizes both in the cytoplasm and in the nucleus. Mutating all hXRCC3 cysteines to serines (XR3/S protein) does not affect the subcellular localization of the protein even after exposure to camptothecin (CPT), which typically induces DNA damages that require HR to be repaired. However, cells expressing mutated XR3/S protein are sensitive to CPT, thus highlighting a defect of the mutant protein in HR. In marked contrast to CPT treatment, oxidative stress induces relocalization at the chromatin fraction of both wild-type and mutated protein, even though survival is not affected. Collectively, our results demonstrate that the DNA repair protein hXRCC3 is a target of ROS induced by environmental factors and raise the possibility that the redox environment might participate in regulating the HR pathway.
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Affiliation(s)
- Pierre-Marie Girard
- Institut Curie, Centre de Recherche, Orsay, France ; CNRS, UMR3348, Orsay, France
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17
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Lee S, Liu X, Takeda S, Choi K. Genotoxic potentials and related mechanisms of bisphenol A and other bisphenol compounds: a comparison study employing chicken DT40 cells. CHEMOSPHERE 2013; 93:434-440. [PMID: 23791112 DOI: 10.1016/j.chemosphere.2013.05.029] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 04/30/2013] [Accepted: 05/05/2013] [Indexed: 06/02/2023]
Abstract
Bisphenol A (BPA) has been found in plastic food containers, paper currencies and toys. BPA has been reported for various adverse health concerns including reproduction, development and carcinogenesis. These potential health implications have led to increasing use of alternative bisphenols such as bisphenol F and bisphenol S among many. However, little is known about the toxicity of alternative bisphenols and most of the toxicological information is limited to endocrine disrupting potentials. In this study, we evaluated cytotoxicity and the genotoxic potentials of several bisphenol compounds, and identified the mechanism of genotoxicity using a panel of mutant chicken DT40 cell lines deficient in DNA repair pathways. Several bisphenols including bisphenol AP, bisphenol M, or bisphenol P exerted genotoxic potentials that are greater than that of BPA. Generally RAD54(-/-) mutant cells were the most sensitive to all bisphenols except for bisphenol F, suggesting the induction of DNA double-strand breaks that could be rescued by homologous recombination. Genotoxic potential of bisphenols was confirmed by chromosomal aberration assay and γ-H2AX foci forming assay between wild-type and RAD54(-/-) mutant. Among the tested bisphenols, BPP at 12.5μM showed the greatest genotoxic potency, inducing chromosomal aberration and γ-H2AX foci in RAD54(-/-) mutant by 2.6 and 4.8 folds greater than those in wild-type, respectively. Our results clearly show several alternative bisphenols can cause genotoxicity that could be rescued by homologous recombination pathway, and some bisphenols induced even greater genotoxic potentials than that of BPA.
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Affiliation(s)
- Sangwoo Lee
- School of Public Health, Seoul National University, Seoul 151-742, Republic of Korea
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18
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Scully R, Xie A. Double strand break repair functions of histone H2AX. Mutat Res 2013; 750:5-14. [PMID: 23916969 DOI: 10.1016/j.mrfmmm.2013.07.007] [Citation(s) in RCA: 169] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 07/15/2013] [Accepted: 07/19/2013] [Indexed: 12/12/2022]
Abstract
Chromosomal double strand breaks provoke an extensive reaction in neighboring chromatin, characterized by phosphorylation of histone H2AX on serine 139 of its C-terminal tail (to form "γH2AX"). The γH2AX response contributes to the repair of double strand breaks encountered in a variety of different contexts, including those induced by ionizing radiation, physiologically programmed breaks that characterize normal immune cell development and the pathological exposure of DNA ends triggered by telomere dysfunction. γH2AX also participates in the evolutionarily conserved process of sister chromatid recombination, a homologous recombination pathway involved in the suppression of genomic instability during DNA replication and directly implicated in tumor suppression. At a biochemical level, the γH2AX response provides a compelling example of how the "histone code" is adapted to the regulation of double strand break repair. Here, we review progress in research aimed at understanding how γH2AX contributes to double strand break repair in mammalian cells.
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Affiliation(s)
- Ralph Scully
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, United States.
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19
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Ranjan A, Kaur N, Tiwari V, Singh Y, Chaturvedi MM, Tandon V. 3,4-Dimethoxyphenyl Bis-benzimidazole Derivative, Mitigates Radiation-Induced DNA Damage. Radiat Res 2013; 179:647-62. [DOI: 10.1667/rr3246.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Atul Ranjan
- Department of Chemistry, University of Delhi, Delhi, India
| | - Navrinder Kaur
- Department of Chemistry, University of Delhi, Delhi, India
| | - Vinod Tiwari
- Department of Chemistry, University of Delhi, Delhi, India
| | - Yogendra Singh
- Institute of Genomics and Integrative Biology, Delhi, India
| | | | - Vibha Tandon
- Department of Chemistry, University of Delhi, Delhi, India
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20
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Abstract
Histone deacetylase inhibitors (HDACis) increase gene expression through induction of histone acetylation. However, it remains unclear whether specific gene expression changes determine the apoptotic response following HDACis administration. Herein, we discuss evidence that HDACis trigger in cancer and leukemia cells not only widespread histone acetylation but also actual increases in reactive oxygen species (ROS) and DNA damage that are further increased following treatment with DNA-damaging chemotherapies. While the origins of ROS production are not completely understood, mechanisms, including inflammation and altered antioxidant signaling, have been reported. While the generation of ROS is an explanation, at least in part, for the source of DNA damage observed with HDACi treatment, DNA damage can also be independently induced by changes in the DNA repair activity and chromatin remodeling factors. Recent development of sirtuin inhibitors (SIRTis) has shown that, similar to HDACis, these drugs induce increases in ROS and DNA damage used singly, or in combination with HDACis and other drugs. Thus, induction of apoptosis by HDACis/SIRTis may result through oxidative stress and DNA damage mechanisms in addition to direct activation of apoptosis-inducing genes. Nevertheless, while DNA damage and stress responses could be of interest as markers for clinical responses, they have yet to be validated as markers for responses to HDACi treatment in clinical trials, alone, and in combination.
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Affiliation(s)
- Carine Robert
- Department of Radiation Oncology and Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
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21
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Brown JAL, Eykelenboom JK, Lowndes NF. Co-mutation of histone H2AX S139A with Y142A rescues Y142A-induced ionising radiation sensitivity. FEBS Open Bio 2012; 2:313-7. [PMID: 23772364 PMCID: PMC3678120 DOI: 10.1016/j.fob.2012.09.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 09/26/2012] [Indexed: 12/22/2022] Open
Abstract
Under normal conditions histone H2AX is constitutively phosphorylated on tyrosine (Y) 142 by Williams-Beuren syndrome transcription factor kinase (WSTF). Following DNA double strand breaks (DSB), Y142 is de-phosphorylated and serine (S) 139 is phosphorylated. Here we explored DSB-dependent cross talk between H2AX residues S139 and Y142. H2axY142A mutation resulted in increased sensitivity to ionising radiation (IR), compared to H2axS139A. Interestingly, co-mutation of S139A and Y142A rescued IR sensitivity. The DSB response proteins 53Bp1 and Rad51 were recruited to IR-induced foci (IRIF) in H2axS139A, H2axY142A and H2axS139A/Y142A cells. Our results suggest that H2axY142A IR sensitivity is dependent upon the C-terminal residue, S139.
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Key Words
- 53BP1
- A, alanine
- DSB
- DSB, DNA double strand break
- F, phenylalanine
- Fig, Figure
- H2AX
- H2AX/H2ax, MDC1/Mdc1, RAD51/Rad51 and 53BP1/53Bp1, indicate human or mouse/chicken proteins respectively
- IR
- IR, ionising radiation
- IRIF, ionising radiation induced foci
- RT-PCR, reverse transcription polymerase chain reaction
- S139
- W, tryptophan
- WSTF, Williams–Beuren syndrome transcription factor kinase
- WT, Wild type
- Y, tyrosine
- Y142
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Affiliation(s)
- James A L Brown
- Genome Stability Laboratory, Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland, Galway, Galway, Ireland
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22
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Tomicic MT, Kaina B. Topoisomerase degradation, DSB repair, p53 and IAPs in cancer cell resistance to camptothecin-like topoisomerase I inhibitors. Biochim Biophys Acta Rev Cancer 2012; 1835:11-27. [PMID: 23006513 DOI: 10.1016/j.bbcan.2012.09.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 09/13/2012] [Accepted: 09/15/2012] [Indexed: 12/11/2022]
Abstract
Topoisomerase I (TOP1) inhibitors applied in cancer therapy such as topotecan and irinotecan are derivatives of the natural alkaloid camptothecin (CPT). The mechanism of CPT poisoning of TOP1 rests on inhibition of the re-ligation function of the enzyme resulting in the stabilization of the TOP1-cleavable complex. In the presence of CPTs this enzyme-DNA complex impairs transcription and DNA replication, resulting in fork stalling and the formation of DNA double-strand breaks (DSB) in proliferating cells. As with most chemotherapeutics, intrinsic and acquired drug resistance represents a hurdle that limits the success of CPT therapy. Preclinical data indicate that resistance to CPT-based drugs might be caused by factors such as (a) poor drug accumulation in the tumor, (b) high rate of drug efflux, (c) mutations in TOP1 leading to failure in CPT docking, or (d) altered signaling triggered by the drug-TOP1-DNA complex, (e) expression of DNA repair proteins, and (f) failure to activate cell death pathways. This review will focus on the issues (d-f). We discuss degradation of TOP1 as part of the repair pathway in the processing of TOP1 associated DNA damage, give a summary of proteins involved in repair of CPT-induced replication mediated DSB, and highlight the role of p53 and inhibitors of apoptosis proteins (IAPs), particularly XIAP and survivin, in cancer cell resistance to CPT-like chemotherapeutics.
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Affiliation(s)
- Maja T Tomicic
- Department of Toxicology, University Medical Center Mainz, Germany.
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23
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Nagaria P, Robert C, Rassool FV. DNA double-strand break response in stem cells: mechanisms to maintain genomic integrity. Biochim Biophys Acta Gen Subj 2012; 1830:2345-53. [PMID: 22995214 DOI: 10.1016/j.bbagen.2012.09.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Revised: 08/09/2012] [Accepted: 09/05/2012] [Indexed: 12/19/2022]
Abstract
BACKGROUND Embryonic stem cells (ESCs) represent the point of origin of all cells in a given organism and must protect their genomes from both endogenous and exogenous genotoxic stress. DNA double-strand breaks (DSBs) are one of the most lethal forms of damage, and failure to adequately repair DSBs would not only compromise the ability of SCs to self-renew and differentiate, but will also lead to genomic instability and disease. SCOPE OF REVIEW Herein, we describe the mechanisms by which ESCs respond to DSB-inducing agents such as reactive oxygen species (ROS) and ionizing radiation, compared to somatic cells. We will also discuss whether the DSB response is fully reprogrammed in induced pluripotent stem cells (iPSCs) and the role of the DNA damage response (DDR) in the reprogramming of these cells. MAJOR CONCLUSIONS ESCs have distinct mechanisms to protect themselves against DSBs and oxidative stress compared to somatic cells. The response to damage and stress is crucial for the maintenance of self-renewal and differentiation capacity in SCs. iPSCs appear to reprogram some of the responses to genotoxic stress. However, it remains to be determined if iPSCs also retain some DDR characteristics of the somatic cells of origin. GENERAL SIGNIFICANCE The mechanisms regulating the genomic integrity in ESCs and iPSCs are critical for its safe use in regenerative medicine and may shed light on the pathways and factors that maintain genomic stability, preventing diseases such as cancer. This article is part of a Special Issue entitled Biochemistry of Stem Cells.
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Affiliation(s)
- Pratik Nagaria
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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24
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Thompson LH. Recognition, signaling, and repair of DNA double-strand breaks produced by ionizing radiation in mammalian cells: the molecular choreography. Mutat Res 2012; 751:158-246. [PMID: 22743550 DOI: 10.1016/j.mrrev.2012.06.002] [Citation(s) in RCA: 261] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 06/09/2012] [Accepted: 06/16/2012] [Indexed: 12/15/2022]
Abstract
The faithful maintenance of chromosome continuity in human cells during DNA replication and repair is critical for preventing the conversion of normal diploid cells to an oncogenic state. The evolution of higher eukaryotic cells endowed them with a large genetic investment in the molecular machinery that ensures chromosome stability. In mammalian and other vertebrate cells, the elimination of double-strand breaks with minimal nucleotide sequence change involves the spatiotemporal orchestration of a seemingly endless number of proteins ranging in their action from the nucleotide level to nucleosome organization and chromosome architecture. DNA DSBs trigger a myriad of post-translational modifications that alter catalytic activities and the specificity of protein interactions: phosphorylation, acetylation, methylation, ubiquitylation, and SUMOylation, followed by the reversal of these changes as repair is completed. "Superfluous" protein recruitment to damage sites, functional redundancy, and alternative pathways ensure that DSB repair is extremely efficient, both quantitatively and qualitatively. This review strives to integrate the information about the molecular mechanisms of DSB repair that has emerged over the last two decades with a focus on DSBs produced by the prototype agent ionizing radiation (IR). The exponential growth of molecular studies, heavily driven by RNA knockdown technology, now reveals an outline of how many key protein players in genome stability and cancer biology perform their interwoven tasks, e.g. ATM, ATR, DNA-PK, Chk1, Chk2, PARP1/2/3, 53BP1, BRCA1, BRCA2, BLM, RAD51, and the MRE11-RAD50-NBS1 complex. Thus, the nature of the intricate coordination of repair processes with cell cycle progression is becoming apparent. This review also links molecular abnormalities to cellular pathology as much a possible and provides a framework of temporal relationships.
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Affiliation(s)
- Larry H Thompson
- Biology & Biotechnology Division, L452, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551-0808, United States.
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25
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Liu X, Lee J, Ji K, Takeda S, Choi K. Potentials and mechanisms of genotoxicity of six pharmaceuticals frequently detected in freshwater environment. Toxicol Lett 2012; 211:70-6. [DOI: 10.1016/j.toxlet.2012.03.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 03/07/2012] [Accepted: 03/07/2012] [Indexed: 01/22/2023]
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26
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Ji K, Choi K, Giesy JP, Musarrat J, Takeda S. Genotoxicity of several polybrominated diphenyl ethers (PBDEs) and hydroxylated PBDEs, and their mechanisms of toxicity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:5003-5008. [PMID: 21545137 DOI: 10.1021/es104344e] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) have been extensively utilized as flame retardants, and recently there has been concern about potential adverse effects in humans and wildlife. Their hydroxylated analogs (OH-BDEs) have received increasing attention due to their potential for endocrine and neurological toxicities. However, the potentials and mechanisms of genotoxicity of these brominated compounds have scarcely been investigated. In the present study, genotoxicity of tetra-BDEs, penta BDE, octa-BDE, deca-BDE, and tetra-OH-BDEs were investigated by use of chicken DT40 cell lines including wild-type cells and a panel of mutant cell lines deficient in DNA repair pathways. Tetra-BDEs have greater genotoxic potential than do the other BDEs tested. OH-tetra-BDEs were more genotoxic than tetra-BDEs. DT40 cells, deficient in base excision repair (Polβ(-/-)) and translesion DNA synthesis (REV3(-/-)) pathways, were hypersensitive to the genotoxic effects of tetra-BDEs and OH-tetra-BDEs. The observation of chromosomal aberrations and gamma-H2AX assay confirmed that the studied brominated compounds caused double strand breaks. Pretreatment with N-acetyl-l-cysteine (NAC) significantly rescued the Polβ(-/-) and REV3(-/-) mutants, which is consistent with the hypothesis that PBDEs and OH-BDEs cause DNA damage mediated through reactive oxygen species (ROS). Some tetra-BDEs and OH-tetra-BDEs caused base damage through ROS leading to replication blockage and subsequent chromosomal breaks.
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Affiliation(s)
- Kyunghee Ji
- School of Public Health, Seoul National University, Seoul, 151-742, Korea
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27
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Dual inhibition of the homologous recombinational repair and the nonhomologous end-joining repair pathways in chronic lymphocytic leukemia therapy. Leuk Res 2011; 35:1080-6. [PMID: 21281966 DOI: 10.1016/j.leukres.2011.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 01/07/2011] [Accepted: 01/09/2011] [Indexed: 11/21/2022]
Abstract
Resistance to chlorambucil in chronic lymphocytic leukemia (CLL) has been associated with increased DNA repair. Specifically, inhibition of either c-abl, which modulates Rad51 directed homologous recombination or DNA-PK dependent nonhomologous end joining has been shown to sensitize primary CLL lymphocytes to chlorambucil. Here we report that inhibition of c-abl can result in a compensatory increase in DNA-PK and thus inhibition of both c-abl and DNA-PK optimally sensitizes CLL lymphocytes to chlorambucil. In this paper we report a drug-induced compensatory change between two DNA repair pathways with potential therapeutic implications in CLL therapy.
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28
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Rastogi RP, Richa, Kumar A, Tyagi MB, Sinha RP. Molecular mechanisms of ultraviolet radiation-induced DNA damage and repair. J Nucleic Acids 2010; 2010:592980. [PMID: 21209706 PMCID: PMC3010660 DOI: 10.4061/2010/592980] [Citation(s) in RCA: 603] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 08/15/2010] [Accepted: 09/28/2010] [Indexed: 11/20/2022] Open
Abstract
DNA is one of the prime molecules, and its stability is of utmost importance for proper functioning and existence of all living systems. Genotoxic chemicals and radiations exert adverse effects on genome stability. Ultraviolet radiation (UVR) (mainly UV-B: 280-315 nm) is one of the powerful agents that can alter the normal state of life by inducing a variety of mutagenic and cytotoxic DNA lesions such as cyclobutane-pyrimidine dimers (CPDs), 6-4 photoproducts (6-4PPs), and their Dewar valence isomers as well as DNA strand breaks by interfering the genome integrity. To counteract these lesions, organisms have developed a number of highly conserved repair mechanisms such as photoreactivation, base excision repair (BER), nucleotide excision repair (NER), and mismatch repair (MMR). Additionally, double-strand break repair (by homologous recombination and nonhomologous end joining), SOS response, cell-cycle checkpoints, and programmed cell death (apoptosis) are also operative in various organisms with the expense of specific gene products. This review deals with UV-induced alterations in DNA and its maintenance by various repair mechanisms.
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Affiliation(s)
- Rajesh P Rastogi
- Laboratory of Photobiology and Molecular Microbiology, Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi 221005, India
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29
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Rassool FV, Tomkinson AE. Targeting abnormal DNA double strand break repair in cancer. Cell Mol Life Sci 2010; 67:3699-710. [PMID: 20697770 PMCID: PMC3014093 DOI: 10.1007/s00018-010-0493-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 07/28/2010] [Indexed: 12/19/2022]
Abstract
A major challenge in cancer treatment is the development of therapies that target cancer cells with little or no toxicity to normal tissues and cells. Alterations in DNA double strand break (DSB) repair in cancer cells include both elevated and reduced levels of key repair proteins and changes in the relative contributions of the various DSB repair pathways. These differences can result in increased sensitivity to DSB-inducing agents and increased genomic instability. The development of agents that selectively inhibit the DSB repair pathways that cancer cells are more dependent upon will facilitate the design of therapeutic strategies that exploit the differences in DSB repair between normal and cancer cells. Here, we discuss the pathways of DSB repair, alterations in DSB repair in cancer, inhibitors of DSB repair and future directions for cancer therapies that target DSB repair.
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Affiliation(s)
- Feyruz V. Rassool
- Department of Radiation Oncology, Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, 655 West Baltimore Street, BRB, Rm 7-025, Baltimore, MD 21201 USA
| | - Alan E. Tomkinson
- Department of Radiation Oncology, Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, 655 West Baltimore Street, BRB, Rm 7-025, Baltimore, MD 21201 USA
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30
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Saladino C, Bourke E, Conroy PC, Morrison CG. Centriole separation in DNA damage-induced centrosome amplification. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2009; 50:725-732. [PMID: 19274769 DOI: 10.1002/em.20477] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Altered centrosome numbers are seen in tumor cells in response to DNA damaging treatments and are hypothesised to contribute to cancer development. The mechanism by which the centrosome and chromosome cycles become disconnected after DNA damage is not yet clear. Here, we show that centrosome amplification occurs after ionising radiation (IR) in chicken DT40 cells that lack DNA-PK, Ku70, H2AX, Xpa, and Scc1, demonstrating that these activities are not required for centrosome amplification. We show that inhibition of topoisomerase II induces Chk1-dependent centrosome amplification, a similar response to that seen after IR. In the immortalised, nontransformed hTERT-RPE1 line, we observed centriole splitting, followed by dose-dependent centrosome amplification, after IR. We found that IR results in the formation of single, not multiple, daughter centrioles during centrosome amplification in U2OS osteosarcoma cells. Analysis of BRCA1 and BRCA2 mutant tumor cells showed high levels of centriole splitting in the absence of any treatment. IR caused pronounced levels of centrosome amplification in BRCA1 mutant breast cancer cells. These data show that centrosome amplification occurs after different forms of DNA damage in chicken cells, in nontransformed human cells and in human tumor cell lines, indicating that this is a general response to DNA damaging treatments. Together, our data suggest that centriole splitting is a key step in potentiation of the centrosome amplification that is a general response to DNA damage.
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Affiliation(s)
- Chiara Saladino
- Centre for Chromosome Biology, Department of Biochemistry and NCBES, National University of Ireland-Galway, University Road, Galway, Ireland
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31
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Dodson H, Morrison CG. Increased sister chromatid cohesion and DNA damage response factor localization at an enzyme-induced DNA double-strand break in vertebrate cells. Nucleic Acids Res 2009; 37:6054-63. [PMID: 19700769 PMCID: PMC2764452 DOI: 10.1093/nar/gkp684] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The response to DNA damage in vertebrate cells involves successive recruitment of DNA signalling and repair factors. We used light microscopy to monitor the genetic dependencies of such localization to a single, induced DNA double strand break (DSB) in vertebrate cells. We used an inducible version of the rare-cutting I-SceI endonuclease to cut a chromosomally integrated I-SceI site beside a Tet operator array that was visualized by binding a Tet repressor-GFP fusion. Formation of γ-H2AX foci at a single DSB was independent of ATM or Ku70. ATM-deficient cells showed normal kinetics of 53Bp1 recruitment to DSBs, but Rad51 localization was retarded. 53Bp1 and Rad51 foci formation at a single DSB was greatly reduced in H2AX-null DT40 cells. We also observed decreased inter-sister chromatid distances after DSB induction, suggesting that cohesin loading at DSBs causes elevated sister chromatid cohesion. Loss of ATM reduced DSB-induced cohesion, consistent with cohesin being an ATM target in the DSB response. These data show that the same genetic pathways control how cells respond to single DSBs and to multiple lesions induced by whole-cell DNA damage.
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Affiliation(s)
- Helen Dodson
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, University road, Galway, Ireland
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32
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Sak A, Grehl S, Engelhard M, Wierlemann A, Kaelberlah HP, Erichsen P, Pöttgen C, Groneberg M, Stuschke M. Long-Term In vivo Effects of Cisplatin on γ-H2AX Foci Signaling in Peripheral Lymphocytes of Tumor Patients After Irradiation. Clin Cancer Res 2009; 15:2927-34. [DOI: 10.1158/1078-0432.ccr-08-0650] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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33
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Chanoux RA, Yin B, Urtishak KA, Asare A, Bassing CH, Brown EJ. ATR and H2AX cooperate in maintaining genome stability under replication stress. J Biol Chem 2008; 284:5994-6003. [PMID: 19049966 DOI: 10.1074/jbc.m806739200] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chromosomal abnormalities are frequently caused by problems encountered during DNA replication. Although the ATR-Chk1 pathway has previously been implicated in preventing the collapse of stalled replication forks into double-strand breaks (DSB), the importance of the response to fork collapse in ATR-deficient cells has not been well characterized. Herein, we demonstrate that, upon stalled replication, ATR deficiency leads to the phosphorylation of H2AX by ATM and DNA-PKcs and to the focal accumulation of Rad51, a marker of homologous recombination and fork restart. Because H2AX has been shown to play a facilitative role in homologous recombination, we hypothesized that H2AX participates in Rad51-mediated suppression of DSBs generated in the absence of ATR. Consistent with this model, increased Rad51 focal accumulation in ATR-deficient cells is largely dependent on H2AX, and dual deficiencies in ATR and H2AX lead to synergistic increases in chromatid breaks and translocations. Importantly, the ATM and DNA-PK phosphorylation site on H2AX (Ser(139)) is required for genome stabilization in the absence of ATR; therefore, phosphorylation of H2AX by ATM and DNA-PKcs plays a pivotal role in suppressing DSBs during DNA synthesis in instances of ATR pathway failure. These results imply that ATR-dependent fork stabilization and H2AX/ATM/DNA-PKcs-dependent restart pathways cooperatively suppress double-strand breaks as a layered response network when replication stalls.
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Affiliation(s)
- Rebecca A Chanoux
- Abramson Family Cancer Research Institute and Department of Cancer Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Kinner A, Wu W, Staudt C, Iliakis G. Gamma-H2AX in recognition and signaling of DNA double-strand breaks in the context of chromatin. Nucleic Acids Res 2008; 36:5678-94. [PMID: 18772227 PMCID: PMC2553572 DOI: 10.1093/nar/gkn550] [Citation(s) in RCA: 882] [Impact Index Per Article: 55.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
DNA double-strand breaks (DSBs) are extremely dangerous lesions with severe consequences for cell survival and the maintenance of genomic stability. In higher eukaryotic cells, DSBs in chromatin promptly initiate the phosphorylation of the histone H2A variant, H2AX, at Serine 139 to generate γ-H2AX. This phosphorylation event requires the activation of the phosphatidylinositol-3-OH-kinase-like family of protein kinases, DNA-PKcs, ATM, and ATR, and serves as a landing pad for the accumulation and retention of the central components of the signaling cascade initiated by DNA damage. Regions in chromatin with γ-H2AX are conveniently detected by immunofluorescence microscopy and serve as beacons of DSBs. This has allowed the development of an assay that has proved particularly useful in the molecular analysis of the processing of DSBs. Here, we first review the role of γ-H2AX in DNA damage response in the context of chromatin and discuss subsequently the use of this modification as a surrogate marker for mechanistic studies of DSB induction and processing. We conclude with a critical analysis of the strengths and weaknesses of the approach and present some interesting applications of the resulting methodology.
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Affiliation(s)
- Andrea Kinner
- Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, Hufelandstrasse 55, 45122 Essen, Germany
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35
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Role of homologous recombination in trabectedin-induced DNA damage. Eur J Cancer 2008; 44:609-18. [PMID: 18243687 DOI: 10.1016/j.ejca.2008.01.003] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Accepted: 01/04/2008] [Indexed: 11/22/2022]
Abstract
Trabectedin (ET-743, Yondelis) is a natural marine compound with antitumour activity currently undergoing phase II/III clinical trials. The mechanism of the drug's action is still to be defined, even though it has been clearly demonstrated the key role of Nucleotide Excision Repair (NER). To get further insights into the drug's mode of action, we studied the involvement of the DNA-double strand break repair (DNA-DSB) pathways: homologous and non-homologous recombination, both in budding yeasts and in mammalian cells and the possible cross-talk between NER and these repair pathways. Budding yeasts and mammalian cells deficient in the non-homologous end-joining pathway were moderately sensitive to trabectedin, while systems deficient in the homologous recombination pathway were extremely sensitive to the drug, with a 100-fold decrease in the IC50, suggesting that trabectedin-induced lesions are repaired by this pathway. The induction of Rad51 foci and the appearance of gamma-H2AX were chosen as putative markers for DNA-DSBs and were studied at different time points after trabectedin treatment in NER proficient and deficient systems. Both were clearly detected only in the presence of an active NER, suggesting that the DSBs are not directly caused by the drug, but are formed during the processing/repair of the drug- induced lesions.
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36
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Jeffers LJ, Coull BJ, Stack SJ, Morrison CG. Distinct BRCT domains in Mcph1/Brit1 mediate ionizing radiation-induced focus formation and centrosomal localization. Oncogene 2007; 27:139-44. [PMID: 17599047 DOI: 10.1038/sj.onc.1210595] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Microcephalin (MCPH1/BRIT1) forms ionizing radiation-induced nuclear foci (IRIF) and is required for DNA damage-responsive S and G(2)-M-phase checkpoints. MCPH1 contains three BRCT domains. Here we report the cloning of chicken Mcph1 (cMcph1) and functional analysis of its individual BRCT domains. Full-length cMcph1 localized to centrosomes throughout the cell cycle and formed IRIF that colocalized with gamma-H2AX. The tandem C-terminal BRCT2 and BRCT3 domains of cMcph1 were necessary for IRIF formation, while the N-terminal BRCT1 was required for centrosomal localization in irradiated cells. Centrosomal targeting of cMcph1 was independent of ATM, Brca1 or Chk1. cMcph1 formed IRIF in ATM- and Brca1-deficient cells, but not in H2AX-deficient cells. Inability to form cMcph1 IRIF impaired the cellular response to DNA damage. These results suggest that the role of microcephalin in the vertebrate DNA damage response is controlled by interaction of the C-terminal BRCT domains with gamma-H2AX.
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Affiliation(s)
- L J Jeffers
- Department of Biochemistry and NCBES, National University of Ireland-Galway, Galway, Ireland
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Zhao GY, Sonoda E, Barber LJ, Oka H, Murakawa Y, Yamada K, Ikura T, Wang X, Kobayashi M, Yamamoto K, Boulton SJ, Takeda S. A critical role for the ubiquitin-conjugating enzyme Ubc13 in initiating homologous recombination. Mol Cell 2007; 25:663-75. [PMID: 17349954 DOI: 10.1016/j.molcel.2007.01.029] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2006] [Revised: 10/30/2006] [Accepted: 01/12/2007] [Indexed: 11/30/2022]
Abstract
The ubiquitin (Ub)-conjugating enzyme Ubc13 is implicated in Rad6/Rad18-dependent postreplication repair (PRR) in budding yeast, but its function in vertebrates is not known. We show here that disruption or siRNA depletion of UBC13 in chicken DT40 or human cells confers severe growth defects due to chromosome instability, and hypersensitivity to both UV and ionizing radiation, consistent with a conserved role for Ubc13 in PRR. Remarkably, Ubc13-deficient cells are also compromised for DNA double-strand break (DSB) repair by homologous recombination (HR). Recruitment and activation of the E3 Ub ligase function of BRCA1 and the subsequent formation of the Rad51 nucleoprotein filament at DSBs are abolished in Ubc13-deficient cells. Furthermore, generation of ssDNA/RPA complexes at DSBs is severely attenuated in the absence of Ubc13. These data reveal a critical and unexpected role for vertebrate Ubc13 in the initiation of HR at the level of DSB processing.
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Affiliation(s)
- Guang Yu Zhao
- CREST Laboratory, Department of Radiation Genetics, Kyoto University Graduate School of Medicine, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan
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