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Aghamohammadi A, Akrami SM, Yaghmaie M, Rezaei N, Azizi G, Yaseri M, Nosrati H, Zaki-Dizaji M. Individual Radiosensitivity Assessment of the Families of Ataxia-Telangiectasia Patients by G2-Checkpoint Abrogation. Sultan Qaboos Univ Med J 2019; 18:e440-e446. [PMID: 30988961 DOI: 10.18295/squmj.2018.18.04.003] [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: 04/30/2018] [Revised: 06/17/2018] [Accepted: 08/02/2018] [Indexed: 12/16/2022] Open
Abstract
Objectives Ataxia-telangiectasia (A-T) is an autosomal recessive multisystem disorder characterised by cerebellar degeneration, telangiectasia, radiation sensitivity, immunodeficiency, oxidative stress and cancer susceptibility. Epidemiological research has shown that carriers of the heterozygous ataxia-telangiectasia mutated (ATM) gene mutation are radiosensitive to ionising irradiation and have a higher risk of cancers, type 2 diabetes and atherosclerosis. However, there is currently no fast and reliable laboratory-based method to detect heterozygous ATM carriers for family screening and planning purposes. This study therefore aimed to evaluate the ability of a modified G2-assay to identify heterozygous ATM carriers in the families of A-T patients. Methods This study took place at the Tehran University of Medical Sciences, Tehran, Iran, between February and December 2017 and included 16 A-T patients, their parents (obligate heterozygotes) and 30 healthy controls. All of the subjects underwent individual radiosensitivity (IRS) assessment using a modified caffeine-treated G2-assay with G2-checkpoint abrogation. Results The mean IRS of the obligate ATM heterozygotes was significantly higher than the healthy controls (55.13% ± 5.84% versus 39.03% ± 6.95%; P <0.001), but significantly lower than the A-T patients (55.13% ± 5.84% versus 87.39% ± 8.29%; P = 0.001). A receiver operating characteristic (ROC) curve analysis of the G2-assay values indicated high sensitivity and specificity, with an area under the ROC curve of 0.97 (95% confidence interval: 0.95-1.00). Conclusion The modified G2-assay demonstrated adequate precision and relatively high sensitivity and specificity in detecting heterozygous ATM carriers.
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Affiliation(s)
- Asghar Aghamohammadi
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Seyed M Akrami
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Marjan Yaghmaie
- Research Center for Hematology, Oncology & Stem Cell Transplantation, Tehran University of Medical Sciences, Tehran, Iran
| | - Nima Rezaei
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Gholamreza Azizi
- Non-Communicable Diseases Research Center, Alborz University of Medical Sciences, Karaj, Iran
| | - Mehdi Yaseri
- Department of Epidemiology & Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Hassan Nosrati
- Research Center for Radiation Oncology, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Majid Zaki-Dizaji
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
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Zaki-Dizaji M, Akrami SM, Abolhassani H, Rezaei N, Aghamohammadi A. Ataxia telangiectasia syndrome: moonlighting ATM. Expert Rev Clin Immunol 2017; 13:1155-1172. [PMID: 29034753 DOI: 10.1080/1744666x.2017.1392856] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Ataxia-telangiectasia (A-T) a multisystem disorder primarily characterized by cerebellar degeneration, telangiectasia, immunodeficiency, cancer susceptibility and radiation sensitivity. Identification of the gene defective in this syndrome, ataxia-telangiectasia mutated gene (ATM), and further characterization of the disorder together with a greater insight into the function of the ATM protein have expanded our knowledge about the molecular pathogenesis of this disease. Area covered: In this review, we have attempted to summarize the different roles of ATM signaling that have provided new insights into the diverse clinical phenotypes exhibited by A-T patients. Expert commentary: ATM, in addition to DNA repair response, is involved in many cytoplasmic roles that explain diverse phenotypes of A-T patients. It seems accumulation of DNA damage, persistent DNA damage response signaling, and chronic oxidative stress are the main players in the pathogenesis of this disease.
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Affiliation(s)
- Majid Zaki-Dizaji
- a Department of Medical Genetics, School of Medicine , Tehran University of Medical Sciences , Tehran , Iran.,b Research Center for Immunodeficiencies, Children's Medical Center , Tehran University of Medical Science , Tehran , Iran
| | - Seyed Mohammad Akrami
- a Department of Medical Genetics, School of Medicine , Tehran University of Medical Sciences , Tehran , Iran
| | - Hassan Abolhassani
- b Research Center for Immunodeficiencies, Children's Medical Center , Tehran University of Medical Science , Tehran , Iran.,c Division of Clinical Immunology, Department of Laboratory Medicine , Karolinska Institute at Karolinska University Hospital Huddinge , Stockholm , Sweden.,d Primary Immunodeficiency Diseases Network (PIDNet ), Universal Scientific Education and Research Network (USERN) , Stockholm , Sweden
| | - Nima Rezaei
- b Research Center for Immunodeficiencies, Children's Medical Center , Tehran University of Medical Science , Tehran , Iran.,e Department of Immunology and Biology, School of Medicine , Tehran University of Medical Sciences , Tehran , Iran.,f Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA) , Universal Scientific Education and Research Network (USERN) , Tehran , Iran
| | - Asghar Aghamohammadi
- b Research Center for Immunodeficiencies, Children's Medical Center , Tehran University of Medical Science , Tehran , Iran
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Haddy N, Tartier L, Koscielny S, Adjadj E, Rubino C, Brugières L, Pacquement H, Diallo I, de Vathaire F, Averbeck D, Hall J, Benhamou S. Repair of ionizing radiation-induced DNA damage and risk of second cancer in childhood cancer survivors. Carcinogenesis 2014; 35:1745-9. [PMID: 24670918 DOI: 10.1093/carcin/bgu077] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The study's purpose was to assess whether individuals who developed a second malignant neoplasm (SMN) after treatment for a first malignant neoplasm (FMN) had a lower ability to repair DNA double-strand breaks (DSBs) using a bioassay with γH2AX intensity as a surrogate endpoint. In a case-control study nested in a cohort of childhood cancer survivors, lymphoblastoid cell lines (LCLs) were established from blood samples collected from 94 cases (SMN) and 94 matched controls (FMN). LCLs were irradiated with ionizing radiation (2 and 5 Gy) and γH2AX intensities measured 1, 3, 5 and 24h post-irradiation. Differences in mean γH2AX intensity between cases and controls were compared using Kruskal-Wallis tests. Generalized linear models for repeated measures and conditional logistic regressions for SMN risk estimates were performed. The mean baseline γH2AX intensity measured without irradiation was 9.1 [95% confidence interval (95% CI): 8.5-9.7] in the LCLs from cases and 6.4 (95% CI: 6.0-6.8) from controls (P < 0.001). Markedly higher γH2AX intensity, particularly at 1 h post-irradiation, was also found in the LCLs from the cases compared with the controls for all FMNs and for different types of FMN. Chemotherapy and radiation doses received by bone marrow and thymus for FMN treatment showed a non-significant effect on γH2AX intensity. This case-control study shows that higher baseline and post-irradiation levels of DNA DSBs, as measured by γH2AX intensity, are associated with the risk of SMN in childhood cancer survivors. Further investigations in a prospective setting are warranted to confirm this association.
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Affiliation(s)
| | - Laurence Tartier
- Institut Curie-Recherche, Bats 110-112, 91405 Orsay, France, INSERM U612, Institut Curie, Bats 110-112, 91405 Orsay, France
| | | | | | | | | | | | | | | | | | - Janet Hall
- Institut Curie-Recherche, Bats 110-112, 91405 Orsay, France, INSERM U612, Institut Curie, Bats 110-112, 91405 Orsay, France
| | - Simone Benhamou
- INSERM U946, Fondation Jean Dausset, 75010 Paris, France and CNRS UMR8200, Institut Gustave Roussy, 94805 Villejuif, France
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Valdiglesias V, Giunta S, Fenech M, Neri M, Bonassi S. γH2AX as a marker of DNA double strand breaks and genomic instability in human population studies. Mutat Res 2013; 753:24-40. [PMID: 23416207 DOI: 10.1016/j.mrrev.2013.02.001] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 01/30/2013] [Accepted: 02/04/2013] [Indexed: 10/27/2022]
Abstract
DNA double strand breaks (DSB) are the gravest form of DNA damage in eukaryotic cells. Failure to detect DSB and activate appropriate DNA damage responses can cause genomic instability, leading to tumorigenesis and possibly accelerated aging. Phosphorylated histone H2AX (γH2AX) is used as a biomarker of cellular response to DSB and its potential for monitoring DNA damage and repair in human populations has been explored in this review. A systematic search was conducted in PubMed for articles, in English, on human studies reporting γH2AX as a biomarker of either DNA repair or DNA damage. A total of 68 publications were identified. Thirty-four studies (50.0%) evaluated the effect of medical procedures or treatments on γH2AX levels; 20 (29.4%) monitored γH2AX in specific pathological conditions with a case/control or case/case design; 5 studies (7.4%) evaluated the effect of environmental genotoxic exposures, and 9 (13.2%) were descriptive studies on cancer and aging. Peripheral blood lymphocytes (44.6%) or biopsies/tissue specimens (24.3%) were the most commonly used samples. γH2AX was scored by optical microscopy as immunostained foci (78%), or by flow cytometry (16%). Critical features affecting the reliability of the assay, including protocols heterogeneity, specimen, cell cycle, kinetics, study design, and statistical analysis, are hereby discussed. Because of its sensitivity, efficiency and mechanistic relevance, the γH2AX assay has great potential as a DNA damage biomarker; however, the technical and epidemiological heterogeneity highlighted in this review infer a necessity for experimental standardization of the assay.
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Affiliation(s)
- Vanessa Valdiglesias
- Unit of Clinical and Molecular Epidemiology, IRCCS San Raffaele Pisana, Roma, Italy
| | - Simona Giunta
- CSIRO Preventative Health Flagship, Adelaide 5000, Australia
| | - Michael Fenech
- CSIRO Preventative Health Flagship, Adelaide 5000, Australia
| | - Monica Neri
- Unit of Clinical and Molecular Epidemiology, IRCCS San Raffaele Pisana, Roma, Italy
| | - Stefano Bonassi
- Unit of Clinical and Molecular Epidemiology, IRCCS San Raffaele Pisana, Roma, Italy.
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Redon CE, Weyemi U, Parekh PR, Huang D, Burrell AS, Bonner WM. γ-H2AX and other histone post-translational modifications in the clinic. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1819:743-56. [PMID: 22430255 PMCID: PMC3371125 DOI: 10.1016/j.bbagrm.2012.02.021] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/23/2012] [Accepted: 02/28/2012] [Indexed: 12/27/2022]
Abstract
Chromatin is a dynamic complex of DNA and proteins that regulates the flow of information from genome to end product. The efficient recognition and faithful repair of DNA damage, particularly double-strand damage, is essential for genomic stability and cellular homeostasis. Imperfect repair of DNA double-strand breaks (DSBs) can lead to oncogenesis. The efficient repair of DSBs relies in part on the rapid formation of foci of phosphorylated histone H2AX (γ-H2AX) at each break site, and the subsequent recruitment of repair factors. These foci can be visualized with appropriate antibodies, enabling low levels of DSB damage to be measured in samples obtained from patients. Such measurements are proving useful to optimize treatments involving ionizing radiation, to assay in vivo the efficiency of various drugs to induce DNA damage, and to help diagnose patients with a variety of syndromes involving elevated levels of γ-H2AX. We will survey the state of the art of utilizing γ-H2AX in clinical settings. We will also discuss possibilities with other histone post-translational modifications. The ability to measure in vivo the responses of individual patients to particular drugs and/or radiation may help optimize treatments and improve patient care. This article is part of a Special Issue entitled: Chromatin in time and space.
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Affiliation(s)
- Christophe E. Redon
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Urbain Weyemi
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Palak R. Parekh
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Dejun Huang
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, 9000 Rockville Pike, Bethesda, MD, 20892, USA
- School of Life Sciences, Lanzhou University, China
| | - Allison S. Burrell
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, 9000 Rockville Pike, Bethesda, MD, 20892, USA
- Molecular Medicine Program, Institute of Biomedical Sciences, The George Washington University
| | - William M. Bonner
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, 9000 Rockville Pike, Bethesda, MD, 20892, USA
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Rodemann HP, Wouters BG. Frontiers in molecular radiation biology/oncology. Radiother Oncol 2011; 101:1-6. [DOI: 10.1016/j.radonc.2011.09.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 09/30/2011] [Indexed: 12/15/2022]
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Nagelkerke A, van Kuijk SJA, Sweep FCGJ, Nagtegaal ID, Hoogerbrugge N, Martens JWM, Timmermans MA, van Laarhoven HWM, Bussink J, Span PN. Constitutive expression of γ-H2AX has prognostic relevance in triple negative breast cancer. Radiother Oncol 2011; 101:39-45. [PMID: 21840613 DOI: 10.1016/j.radonc.2011.07.009] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 07/09/2011] [Indexed: 01/02/2023]
Abstract
BACKGROUND AND PURPOSE Constitutive γ-H2AX expression might indicate disruption of the DNA damage repair pathway, genomic instability, or shortened telomeric ends. Here, we quantified expression of endogenous γ-H2AX and its downstream factor 53BP1 in a large number of breast cancer cell lines (n=54) and a node-negative breast cancer cohort that had not received adjuvant systemic treatment (n=122). MATERIALS AND METHODS Formalin fixed paraffin embedded breast cancer cell lines and tumors were immunohistochemically analyzed for γ-H2AX and 53BP1 expression, and related to cell line, patient and tumor characteristics and to disease progression. RESULTS In breast cancer cell lines, γ-H2AX positivity was associated with the triple negative/basal like subgroup (p=0.005), and with BRCA1 (p=0.011) or p53 (p=0.053) mutations. Specifically in triple negative breast cancer patients a high number of γ-H2AX foci indicated a significantly worse prognosis (p=0.006 for triple negative vs. p=0.417 for estrogen receptor (ER), progesterone receptor (PR) or HER2 positive patients). A similar association with disease progression was found for 53BP1. In a multivariate analysis with tumor size, grade, and triple negativity, only the interaction between triple negativity and γ-H2AX remained significant (p=0.002, Hazard Ratio=6.77, 95% CI=2.07-22.2). CONCLUSIONS Constitutive γ-H2AX and 53BP1 staining reveals a subset of patients with triple negative breast tumors that have a significantly poorer prognosis.
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Affiliation(s)
- Anika Nagelkerke
- Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Menegakis A, Eicheler W, Yaromina A, Thames HD, Krause M, Baumann M. Residual DNA double strand breaks in perfused but not in unperfused areas determine different radiosensitivity of tumours. Radiother Oncol 2011; 100:137-44. [DOI: 10.1016/j.radonc.2011.07.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 06/30/2011] [Accepted: 07/02/2011] [Indexed: 12/26/2022]
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Retention of γH2AX foci as an indication of lethal DNA damage. Radiother Oncol 2011; 101:18-23. [PMID: 21704409 DOI: 10.1016/j.radonc.2011.05.055] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 05/26/2011] [Accepted: 05/27/2011] [Indexed: 01/09/2023]
Abstract
The application of biological responses of tumours to predict clinical responses to treatment represents a challenging goal with the potential to inform treatment decisions and improve outcome. If tumour cell death is the result of the inability of a cell to repair complex DNA damage, and if γH2AX foci mark sites of unrepaired double-strand breaks, then it may be possible to use residual γH2AX foci to identify treatment-resistant tumour cells early in the course of therapy. This review will highlight some of the evidence that supports the idea that residual γH2AX foci, within certain limitations, may be useful as an early indicator of tumour response to radiotherapy in situ, either alone or in combination with chemotherapy.
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Beucher A, Deckbar D, Schumann E, Krempler A, Frankenberg-Schwager M, Löbrich M. Elevated radiation-induced γH2AX foci in G2 phase heterozygous BRCA2 fibroblasts. Radiother Oncol 2011; 101:46-50. [PMID: 21665305 DOI: 10.1016/j.radonc.2011.05.043] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 05/18/2011] [Accepted: 05/18/2011] [Indexed: 12/26/2022]
Abstract
BACKGROUND AND PURPOSE About 5-10% of all breast cancer cases are associated with heterozygous germ-line mutations in the genes encoding BRCA1 and BRCA2. Carriers of such mutations are highly predisposed for developing breast or ovarian cancer and, thus, are advised to undergo regular radio-diagnostic examinations. BRCA1 and BRCA2 are involved in multiple cellular processes including the repair of ionizing radiation (IR)-induced DNA double-strand breaks (DSBs) and different studies addressing the DSB repair capacity of BRCA1+/- or BRCA2+/- cells led to contradictory results. MATERIALS AND METHODS Using the sensitive method of γH2AX foci analysis in combination with cell cycle markers, we specifically measured DSB repair in confluent G0 as well as in exponentially growing G1 and G2 phase primary WT, BRCA1+/- and BRCA2+/- fibroblasts. RESULTS Both BRCA1+/- and BRCA2+/- cells displayed normal DSB repair in G0 and in G1. In contrast, in G2, BRCA2+/- but not BRCA1+/- cells exhibited a decreased DSB repair capacity which was in between that of WT and that of a hypomorphic BRCA2-/- cell line. CONCLUSIONS The residual amount of normal BRCA1 seems to be sufficient for efficient DSB repair in all cell cycle phases, while the decreased DSB repair capacity of heterozygous BRCA2 mutations suggests gene dosage effects in G2.
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Affiliation(s)
- Andrea Beucher
- Radiation Biology and DNA Repair, Darmstadt University of Technology, Germany
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11
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Molecular and translational radiation biology/oncology: What’s up? Radiother Oncol 2011; 99:257-61. [DOI: 10.1016/j.radonc.2011.06.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 06/14/2011] [Indexed: 01/02/2023]
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Redon CE, Nakamura AJ, Zhang YW, Ji JJ, Bonner WM, Kinders RJ, Parchment RE, Doroshow JH, Pommier Y. Histone gammaH2AX and poly(ADP-ribose) as clinical pharmacodynamic biomarkers. Clin Cancer Res 2010; 16:4532-42. [PMID: 20823146 DOI: 10.1158/1078-0432.ccr-10-0523] [Citation(s) in RCA: 202] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Tumor cells are often deficient in DNA damage response (DDR) pathways, and anticancer therapies are commonly based on genotoxic treatments using radiation and/or drugs that damage DNA directly or interfere with DNA metabolism, leading to the formation of DNA double-strand breaks (DSB), and ultimately to cell death. Because DSBs induce the phosphorylation of histone H2AX (γH2AX) in the chromatin flanking the break site, an antibody directed against γH2AX can be employed to measure DNA damage levels before and after patient treatment. Poly(ADP-ribose) polymerases (PARP1 and PARP2) are also activated by DNA damage, and PARP inhibitors show promising activity in cancers with defective homologous recombination (HR) pathways for DSB repair. Ongoing clinical trials are testing combinations of PARP inhibitors with DNA damaging agents. Poly(ADP-ribosylation), abbreviated as PAR, can be measured in clinical samples and used to determine the efficiency of PARP inhibitors. This review summarizes the roles of γH2AX and PAR in the DDR, and their use as biomarkers to monitor drug response and guide clinical trials, especially phase 0 clinical trials. We also discuss the choices of relevant samples for γH2AX and PAR analyses.
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Affiliation(s)
- Christophe E Redon
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
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Olive PL, Banuelos CA, Durand RE, Kim JY, Aquino-Parsons C. Endogenous and radiation-induced expression of gammaH2AX in biopsies from patients treated for carcinoma of the uterine cervix. Radiother Oncol 2009; 94:82-9. [PMID: 19903578 DOI: 10.1016/j.radonc.2009.10.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 10/01/2009] [Accepted: 10/14/2009] [Indexed: 01/10/2023]
Abstract
BACKGROUND AND PURPOSE The possibility of using gammaH2AX foci as a marker of DNA damage and as a potential predictor of tumour response to treatment was examined using biopsies from 3 sets of patients with advanced carcinoma of the cervix. The relation between endogenous gammaH2AX expression and hypoxia was also examined. MATERIALS AND METHODS Set 1 consisted of 26 biopsies that included pre-treatment and 24h post-radiation treatment samples. Pre-treatment biopsies from 12 patients in Set 2 were used to develop image analysis software while pre-treatment biopsies from 33 patients in Set 3 were examined for the relation between staining for the hypoxia marker pimonidazole and endogenous gammaH2AX expression. Formalin-fixed paraffin-embedded sections were analyzed after antigen retrieval and fluorescence antibody labeling for the hypoxia markers CAIX or pimonidazole in combination with gammaH2AX staining. RESULTS Before treatment, 24+/-19% of cells contained gammaH2AX foci, with most positive cells containing fewer than 5 foci per nucleus. Twenty-four hours after exposure to the first fraction of 1.8-2.5Gy, 38+/-19% contained foci. CAIX positive cells were 1.4 times more likely to exhibit endogenous gammaH2AX foci, and pimonidazole-positive cells were 2.8 times more likely to contain gammaH2AX foci. For 18 patients for whom both pre-treatment and 24h post-irradiation biopsies were available, local control was unrelated to the fraction of cells that retained gammaH2AX foci. However, 24h after irradiation, tumours that had received 2.5Gy showed a significantly higher fraction of cells with residual gammaH2AX foci than tumours given 1.8Gy. CONCLUSIONS Endogenous gammaH2AX foci are enriched in hypoxic tumour regions. Small differences in delivered dose can produce quantifiable differences in residual DNA damage that can overshadow inter-tumour differences in response.
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Affiliation(s)
- Peggy L Olive
- Medical Biophysics Department, British Columbia Cancer Agency Research Centre, 675 W. 10th Ave., Vancouver, BC V5Z 1L3, Canada.
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Dickey JS, Redon CE, Nakamura AJ, Baird BJ, Sedelnikova OA, Bonner WM. H2AX: functional roles and potential applications. Chromosoma 2009; 118:683-92. [PMID: 19707781 DOI: 10.1007/s00412-009-0234-4] [Citation(s) in RCA: 232] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 07/24/2009] [Accepted: 07/30/2009] [Indexed: 12/28/2022]
Abstract
Upon DNA double-strand break (DSB) induction in mammals, the histone H2A variant, H2AX, becomes rapidly phosphorylated at serine 139. This modified form, termed gamma-H2AX, is easily identified with antibodies and serves as a sensitive indicator of DNA DSB formation. This review focuses on the potential clinical applications of gamma-H2AX detection in cancer and in response to other cellular stresses. In addition, the role of H2AX in homeostasis and disease will be discussed. Recent work indicates that gamma-H2AX detection may become a powerful tool for monitoring genotoxic events associated with cancer development and tumor progression.
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Affiliation(s)
- Jennifer S Dickey
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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