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Standards for Quantitative Measurement of DNA Damage in Mammalian Cells. Int J Mol Sci 2023; 24:ijms24065427. [PMID: 36982502 PMCID: PMC10051712 DOI: 10.3390/ijms24065427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/07/2023] [Accepted: 03/09/2023] [Indexed: 03/18/2023] Open
Abstract
As the potential applications of DNA diagnostics continue to expand, there is a need for improved methods and standards for DNA analysis. This report describes several methods that could be considered for the production of reference materials for the quantitative measurement of DNA damage in mammalian cells. With the focus on DNA strand breaks, potentially useful methods for assessing DNA damage in mammalian cells are reviewed. The advantages and limitations of each method, as well as additional concerns with respect to reference material development, are also discussed. In conclusion, we outline strategies for developing candidate DNA damage reference materials that could be adopted by research laboratories in a wide variety of applications.
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Factors to Consider for the Correct Use of γH2AX in the Evaluation of DNA Double-Strand Breaks Damage Caused by Ionizing Radiation. Cancers (Basel) 2022; 14:cancers14246204. [PMID: 36551689 PMCID: PMC9776434 DOI: 10.3390/cancers14246204] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/07/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
People exposed to ionizing radiation (IR) both for diagnostic and therapeutic purposes is constantly increasing. Since the use of IR involves a risk of harmful effects, such as the DNA DSB induction, an accurate determination of this induced DNA damage and a correct evaluation of the risk-benefit ratio in the clinical field are of key relevance. γH2AX (the phosphorylated form of the histone variant H2AX) is a very early marker of DSBs that can be induced both in physiological conditions, such as in the absence of specific external agents, and by external factors such as smoking, heat, background environmental radiation, and drugs. All these internal and external conditions result in a basal level of γH2AX which must be considered for the correct assessment of the DSBs after IR exposure. In this review we analyze the most common conditions that induce H2AX phosphorylation, including specific exogenous stimuli, cellular states, basic environmental factors, and lifestyles. Moreover, we discuss the most widely used methods for γH2AX determination and describe the principal applications of γH2AX scoring, paying particular attention to clinical studies. This knowledge will help us optimize the use of available methods in order to discern the specific γH2AX following IR-induced DSBs from the basal level of γH2AX in the cells.
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Development of a Reference Method and Materials for Quantitative Measurement of UV-Induced DNA Damage in Mammalian Cells: Comparison of Comet Assay and Cell Viability. J Nucleic Acids 2022; 2022:9188636. [PMID: 36164440 PMCID: PMC9509282 DOI: 10.1155/2022/9188636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/06/2022] [Accepted: 08/27/2022] [Indexed: 11/17/2022] Open
Abstract
Application of DNA damage diagnostic tests is rapidly growing, in particular for ovarian, prostate, and skin cancers; environmental monitoring; chronic and degenerative diseases; and male infertility. Such tests suffer from significant variability among different laboratories due the lack of standardization, experimental validation, and differences in data interpretation. Reference methods and materials for quantitative measurement of UVA-induced DNA damage in mammalian cells are frequently needed. In this study, we examined the use of the single-cell gel electrophoresis (comet) assay to assess the UVA-induced DNA damage in surface-attached Chinese hamster ovary (CHO) cells treated with a photosensitizer as a candidate cellular oxidative damage reference material. We found that the comet images became diffused and the viability of the cells decreased substantially (>20%) as the UVA dose and benzo [a] pyrene (BaP) concentration exceeded 6.3 J/cm2 and 10−6 mol/L BaP. Maintaining the conditions of exposure within this range can improve DNA damage measurement fidelity, particularly if used as a quantitative reference method and to produce materials considered as an in vitro standard for the comet assay.
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Smit E, Souza T, Jennen DGJ, Kleinjans JCS, van den Beucken T. Identification of essential transcription factors for adequate DNA damage response after benzo(a)pyrene and aflatoxin B1 exposure by combining transcriptomics with functional genomics. Toxicology 2017; 390:74-82. [PMID: 28882572 DOI: 10.1016/j.tox.2017.09.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/15/2017] [Accepted: 09/01/2017] [Indexed: 01/09/2023]
Abstract
DNA damage mediates widespread changes in transcription through activation or repression of transcription factors (TFs). However, the consequences of regulating specific TFs for the outcome of the DNA repair process remain incompletely understood. Here, we combined transcriptomics and TF binding prediction with functional genomics to identify TFs essential for adequate DNA repair in HepG2 liver cells after a non-cytotoxic dose of carcinogens benzo(a)pyrene (BaP) (2μM) and aflatoxin B1 (AFB1) (5μM). BaP and AFB1 induced a largely common transcriptional response, mediated by similar TFs. A lentiviral shRNA screen knocking down the top31 identified TFs, was performed to determine their effect on DNA repair by assessing phosphorylation of H2AX (γ-H2AX). In addition to the top candidate p53, we identified several other interesting TFs that modulated γ-H2AX after BaP and AFB1 treatment. Validation studies confirmed the role of p53 in reducing γ-H2AX formation and DNA breaks measured by COMET assay after BaP and AFB1 exposure. Expression of the cell cycle inhibitor p21 was profoundly impaired upon p53 knock-down. In addition, the expression of 2 genes involved in nucleotide exchange repair, DDB2 and XPC was significantly reduced in p53 knock-down cells. Although p63 knock-down affected DNA damage upon BaP treatment this was not associated with altered expression of DDB2 or XPC. Finally, knock-down of ARNT reduced γ-H2AX in response to BaP, which was associated with reduced CYP1A1 expression. Importantly, our results suggest a new role for ARNT and its dimerization partner AHR in the occurrence of H2AX phosphorylation after AFB1 treatment. These data show that modulation of TF activity impacts on the repair of BaP- and AFB1-induced DNA damage. Our study also demonstrates the potential of combining functional genomics with genome-wide expression analysis to identify yet unknown causal relationships, thereby aiding in the interpretation of complex biological systems.
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Affiliation(s)
- Evelyn Smit
- Department of Toxicogenomics, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, P.O. Box 616, 6200 MD, Maastricht, The Netherlands
| | - Terezinha Souza
- Department of Toxicogenomics, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, P.O. Box 616, 6200 MD, Maastricht, The Netherlands
| | - Danyel G J Jennen
- Department of Toxicogenomics, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, P.O. Box 616, 6200 MD, Maastricht, The Netherlands
| | - Jos C S Kleinjans
- Department of Toxicogenomics, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, P.O. Box 616, 6200 MD, Maastricht, The Netherlands
| | - Twan van den Beucken
- Department of Toxicogenomics, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, P.O. Box 616, 6200 MD, Maastricht, The Netherlands.
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Liu Q, Xu C, Ji G, Liu H, Mo Y, Tollerud DJ, Gu A, Zhang Q. Sublethal effects of zinc oxide nanoparticles on male reproductive cells. Toxicol In Vitro 2016; 35:131-8. [DOI: 10.1016/j.tiv.2016.05.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 04/08/2016] [Accepted: 05/27/2016] [Indexed: 10/21/2022]
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6
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Ibuki Y, Toyooka T. Evaluation of chemical phototoxicity, focusing on phosphorylated histone H2AX. JOURNAL OF RADIATION RESEARCH 2015; 56:220-8. [PMID: 25480829 PMCID: PMC4380052 DOI: 10.1093/jrr/rru105] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 10/01/2014] [Accepted: 10/07/2014] [Indexed: 05/27/2023]
Abstract
Histone H2AX is a minor component of nuclear histone H2A. The phosphorylation of histone H2AX at Ser 139, termed γ-H2AX, was originally identified as an early event after the direct formation of DNA double-strand breaks (DSBs) by ionizing radiation. Now, the generation of γ-H2AX is also considered to occur in association with secondarily formed DSBs by cellular processing such as DNA replication and repair at the site of the initial damage, including DNA adducts, crosslinks, and UV-induced photolesions. Therefore, γ-H2AX is currently attracting attention as a new biomarker for detecting various genotoxic insults. We have determined the toxic impact of various environmental stresses such as chemicals, light and/or their coexposure using γ-H2AX, and found that the γ-H2AX assay exhibited high sensitivity and a low false-positive rate as a detection system of genotoxic potential. In this review, we introduced our recent findings concerning the evaluation of chemical phototoxicity, focusing on γ-H2AX.
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Affiliation(s)
- Yuko Ibuki
- Graduate Division of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
| | - Tatsushi Toyooka
- Graduate Division of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
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7
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Rossner P, Rossnerova A, Beskid O, Tabashidze N, Libalova H, Uhlirova K, Topinka J, Sram RJ. Nonhomologous DNA end joining and chromosome aberrations in human embryonic lung fibroblasts treated with environmental pollutants. Mutat Res 2014; 763-764:28-38. [PMID: 24694657 DOI: 10.1016/j.mrfmmm.2014.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Revised: 02/25/2014] [Accepted: 03/07/2014] [Indexed: 06/03/2023]
Abstract
In order to evaluate the ability of a representative polycyclic aromatic hydrocarbon (PAH) and PAH-containing complex mixtures to induce double strand DNA breaks (DSBs) and repair of damaged DNA in human embryonic lung fibroblasts (HEL12469 cells), we investigated the effect of benzo[a]pyrene (B[a]P) and extractable organic matter (EOM) from ambient air particles <2.5μm (PM2.5) on nonhomologous DNA end joining (NHEJ) and induction of stable chromosome aberrations (CAs). PM2.5 was collected in winter and summer 2011 in two Czech cities differing in levels and sources of air pollutants. The cells were treated for 24h with the following concentrations of tested chemicals: B[a]P: 1μM, 10μM, 25μM; EOMs: 1μg/ml, 10μg/ml, 25μg/ml. We tested several endpoints representing key steps leading from DSBs to the formation of CAs including histone H2AX phosphorylation, levels of proteins Ku70, Ku80 and XRCC4 participating in NHEJ, in vitro ligation activity of nuclear extracts of the HEL12469 cells and the frequency of stable CAs assessed by whole chromosome painting of chromosomes 1, 2, 4, 5, 7 and 17 using fluorescence in situ hybridization. Our results show that 25μM of B[a]P and most of the tested doses of EOMs induced DSBs as indicated by H2AX phosphorylation. DNA damage was accompanied by induction of XRCC4 expression and an increased frequency of CAs. Translocations most frequently affected chromosome 7. We observed only a weak induction of Ku70/80 expression as well as ligation activity of nuclear extracts. In summary, our data suggest the induction of DSBs and NHEJ after treatment of human embryonic lung fibroblasts with B[a]P and complex mixtures containing PAHs.
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Affiliation(s)
- Pavel Rossner
- Department of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR, Prague, Czech Republic.
| | - Andrea Rossnerova
- Department of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR, Prague, Czech Republic
| | - Olena Beskid
- Department of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR, Prague, Czech Republic
| | - Nana Tabashidze
- Department of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR, Prague, Czech Republic
| | - Helena Libalova
- Department of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR, Prague, Czech Republic
| | - Katerina Uhlirova
- Department of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR, Prague, Czech Republic
| | - Jan Topinka
- Department of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR, Prague, Czech Republic
| | - Radim J Sram
- Department of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR, Prague, Czech Republic
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Tung EW, Philbrook NA, Belanger CL, Ansari S, Winn LM. Benzo[a]pyrene increases DNA double strand break repair in vitro and in vivo: A possible mechanism for benzo[a]pyrene-induced toxicity. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2014; 760:64-9. [DOI: 10.1016/j.mrgentox.2013.12.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 12/23/2013] [Accepted: 12/24/2013] [Indexed: 01/08/2023]
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9
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Matsuda S, Matsuda R, Matsuda Y, Yanagisawa SY, Ikura M, Ikura T, Matsuda T. An Easy-to-use Genotoxicity Assay Using EGFP-MDC1-expressing Human Cells. Genes Environ 2014. [DOI: 10.3123/jemsge.2014.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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10
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Toyooka T, Kubota T, Ibuki Y. Nonylphenol polyethoxylates induce phosphorylation of histone H2AX. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2012; 741:57-64. [DOI: 10.1016/j.mrgentox.2011.10.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 09/02/2011] [Accepted: 10/09/2011] [Indexed: 10/15/2022]
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Toyooka T, Ishihama M, Ibuki Y. Phosphorylation of histone H2AX is a powerful tool for detecting chemical photogenotoxicity. J Invest Dermatol 2011; 131:1313-21. [PMID: 21368771 DOI: 10.1038/jid.2011.28] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Several light-absorbing chemicals are known to show phototoxic effects involving many kinds of DNA damage, and are suspected of initiating skin cancer. In this study, we clarified that phosphorylated histone H2AX (γ-H2AX) (phosphorylated histone H2AX), which was produced with the induction of DNA double-strand breaks, is a sensitive photogenotoxic marker. The immortal human keratinocyte line HaCaT was treated with a library of 11 chemicals (including known strong and weak phototoxic chemicals, and nonphototoxic chemicals) and/or UVA exposure. γ-H2AX was generated after treatments with all phototoxic chemicals and UVA. The limit of detection using γ-H2AX was 100-1,000 times lower than that using cell viability and DNA gel electrophoresis. γ-H2AX was not generated following treatments with nonphototoxic chemicals and UVA. These results indicated that γ-H2AX is a powerful tool for detecting chemical photogenotoxicity.
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Affiliation(s)
- Tatsushi Toyooka
- Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
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12
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Yan C, Lu J, Zhang G, Gan T, Zeng Q, Shao Z, Duerksen-Hughes PJ, Yang J. Benzo[a]pyrene induces complex H2AX phosphorylation patterns by multiple kinases including ATM, ATR, and DNA-PK. Toxicol In Vitro 2011; 25:91-9. [DOI: 10.1016/j.tiv.2010.09.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2009] [Revised: 09/03/2010] [Accepted: 09/24/2010] [Indexed: 10/19/2022]
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13
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Rizzo JL, Dunn J, Rees A, Rünger TM. No formation of DNA double-strand breaks and no activation of recombination repair with UVA. J Invest Dermatol 2010; 131:1139-48. [PMID: 21150922 DOI: 10.1038/jid.2010.365] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Longwave UVA is an independent class I carcinogen. A complete understanding of UVA-induced DNA damage and how this damage is processed in skin cells is therefore of utmost importance. A particular question that has remained contentious is whether UVA induces DNA double-strand breaks (DSBs), either directly or through processing of other types of DNA damage, such as recombination repair of replication forks stalled at DNA photoproducts. We therefore studied activation of the recombination repair pathway by solar available doses of UVA and assessed formation of DNA DSBs in primary skin fibroblasts. We found that, unlike ionizing radiation or UVB, UVA does not activate the Fanconi anemia/BRCA DNA damage response pathway or the "recombinase" RAD51 in primary skin fibroblasts. The fact that this pathway mediates recombination repair of DNA DSBs suggests that DNA DSBs are not formed by UVA. This is further supported by findings that UVA did not induce DNA DSBs, as assayed by neutral single-cell electrophoresis or by formation of γ-H2AX nuclear foci, considered the most sensitive assay for DNA DSBs. The lack of sufficient evidence for formation of DNA DSBs underlines the pivotal role of UVA-induced DNA photoproducts in UVA mutagenesis and carcinogenesis.
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Affiliation(s)
- Jennifer L Rizzo
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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14
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Ohnuki G, Toyooka T, Ibuki Y. UVB in solar-simulated light causes formation of BaP-photoproducts capable of generating phosphorylated histone H2AX. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2010; 702:70-7. [DOI: 10.1016/j.mrgentox.2010.07.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 05/31/2010] [Accepted: 07/04/2010] [Indexed: 01/20/2023]
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15
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Sigounas G, Hairr JW, Cooke CD, Owen JR, Asch AS, Weidner DA, Wiley JE. Role of benzo[alpha]pyrene in generation of clustered DNA damage in human breast tissue. Free Radic Biol Med 2010; 49:77-87. [PMID: 20347033 DOI: 10.1016/j.freeradbiomed.2010.03.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 03/06/2010] [Accepted: 03/18/2010] [Indexed: 12/23/2022]
Abstract
Complex DNA damage may manifest in double-strand breaks (DSBs) and non-DSB, bistranded, oxidatively induced clustered DNA lesions (OCDLs). Although the carcinogen benzo[alpha]pyrene (B[alpha]P) has been shown to induce chromosomal aberrations and transformation of mammary cells, it is not known whether this compound engenders clustered DNA damage. Normal primary breast tissue-derived cells were treated with B[alpha]P, and the levels of DNA lesions, chromosomal aberrations, total antioxidant capacity (TAC), and reactive oxygen species (ROS) were determined. DNA from cells treated with 2 and 8 microM B[alpha]P exhibited increases of 3- and 4-fold in APE1 (p<0.001), 11- and 19-fold in Endo III (p<0.001), and 8- and 15-fold in hOGG1 (p<0.001) OCDLs, respectively, compared to the 0 microM B[alpha]P-treated (control) group. Mammary cells treated with 8 microM B[alpha]P produced 0.12 aberrations per cell (p<0.05) and there was a strong positive correlation (r=0.91) between the levels of OCDLs and those of chromosomal aberrations. Finally, TAC was decreased by 25% (p<0.02), whereas ROS production increased by 2-fold (p<0.02) in cells treated with 8 microM B[alpha]P compared to the control group. In conclusion, oxidatively induced clustered DNA damage mediated through differential expression of APE1, reduced TAC, and increased ROS may play a significant role in the chemically induced transformation of normal primary mammary cells.
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Affiliation(s)
- George Sigounas
- Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA.
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Botta C, Di Giorgio C, Sabatier AS, De Méo M. Effects of UVA and visible light on the photogenotoxicity of benzo[a]pyrene and pyrene. ENVIRONMENTAL TOXICOLOGY 2009; 24:492-505. [PMID: 19003914 DOI: 10.1002/tox.20455] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
This study investigated the role of UVA/visible light (U, 320-800 nm) and visible light (V, 400-800 nm) in the phototoxicity and photogenotoxicity of two ubiquitous polycyclic aromatic hydrocarbons (PAH): benzo[a]pyrene (BaP) and Pyrene (Pyr). These mechanisms were evaluated by the WST-1 test and the comet assay on normal human keratinocytes (NHK) and by the micronucleus test on CHO cells. The production of reactive oxygen species (ROS) was assessed through the induction of 8-oxodeoxyguanine (8-oxodG) lesions by immunofluorescence staining in NHK. Results of the WST-1 test revealed the phototoxic properties of BaP and Pyr after irradiation with U and V lights. BaP presented the highest phototoxic properties. Results of the comet assay showed that U- and V-irradiated BaP and Pyr induced increasing rates of DNA single-strand breaks in NHK, in a dose dependent manner. The tested PAH could also induce increased levels of micronuclei in CHO cells after U and V irradiations. Increasing 8-oxodG levels were detected after U and V irradiations in BaP- and Pyr-treated keratinocytes and confirmed the involvement of ROS in the photogenotoxicity of PAH. Overall, this study highlighted the existence of an alternative pathway of PAH genotoxicity that is induced by UVA and/or visible light. Visible light is suggested to photoactivate PAH by a mechanism which is mainly based on oxidative reactions.
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Affiliation(s)
- Céline Botta
- Laboratoire de Biogénotoxicologie et Mutagenèse Environnementale (EA 1784, FR 3098 - ECCOREV), Faculté de Pharmacie, Aix-Marseille Université, 27 Bd Jean Moulin, 13385 Marseille Cedex 05, France
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17
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Watters GP, Smart DJ, Harvey JS, Austin CA. H2AX phosphorylation as a genotoxicity endpoint. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2009; 679:50-8. [DOI: 10.1016/j.mrgentox.2009.07.007] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Revised: 06/12/2009] [Accepted: 07/04/2009] [Indexed: 12/21/2022]
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18
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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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Jeong JB, Ju SY, Park JH, Lee JR, Yun KW, Kwon ST, Lim JH, Chung GY, Jeong HJ. Antioxidant activity in essential oils of Cnidium officinale makino and Ligusticum chuanxiong hort and their inhibitory effects on DNA damage and apoptosis induced by ultraviolet B in mammalian cell. Cancer Epidemiol 2009; 33:41-6. [DOI: 10.1016/j.canep.2009.04.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Revised: 11/14/2008] [Accepted: 04/01/2009] [Indexed: 10/20/2022]
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20
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Toyooka T, Ibuki Y. Histone deacetylase inhibitor sodium butyrate enhances the cell killing effect of psoralen plus UVA by attenuating nucleotide excision repair. Cancer Res 2009; 69:3492-500. [PMID: 19351858 DOI: 10.1158/0008-5472.can-08-2546] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The use of histone deacetylase inhibitors (HDACI), a promising new class of antineoplastic agents, in combination with cytotoxic agents, such as ionizing radiation and anticancer drugs, has been attracting attention. In this study, we found that sodium butyrate (SB), a widely studied HDACI, remarkably enhanced the cell killing effect of psoralen plus UVA (PUVA) in several cancer cell lines, including skin melanoma. Although a single treatment with PUVA or SB did not greatly affect cell survival, combined treatment with SB and PUVA induced marked apoptosis within 24 hours. The SB-induced augmentation of the cell killing effect was more dramatic in combination with PUVA than with anticancer drugs. The number of double-strand breaks that formed during the repair of PUVA-induced interstrand cross-links (ICL) in chromosomal DNA was significantly reduced in SB-pretreated cells, suggesting that the ability to repair ICL was attenuated by SB. In addition, the incorporation of bromodeoxyuridine and the formation of repair foci of proliferating cell nuclear antigen after PUVA treatment, associated with nucleotide excision repair (NER) in the removal of ICL, were not observed in SB-pretreated cells. Furthermore, the repair kinetics of UV-induced cyclobutane pyrimidine dimers (well-known photolesions repaired by NER) were much slower in SB-pretreated cells than in untreated cells. These results indicated that the enhanced cell killing effect of PUVA by SB was attributable to an attenuated ability to repair DNA and, especially, dysfunctional NER.
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Affiliation(s)
- Tatsushi Toyooka
- Laboratory of Radiation Biology, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
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21
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Ishihama M, Toyooka T, Ibuki Y. Generation of phosphorylated histone H2AX by benzene metabolites. Toxicol In Vitro 2008; 22:1861-8. [DOI: 10.1016/j.tiv.2008.09.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Revised: 08/25/2008] [Accepted: 09/08/2008] [Indexed: 12/22/2022]
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Douki T, Ksoury Z, Marie C, Favier A, Ravanat JL, Maitre A. Genotoxicity of combined exposure to polycyclic aromatic hydrocarbons and UVA--a mechanistic study. Photochem Photobiol 2008; 84:1133-40. [PMID: 18466204 DOI: 10.1111/j.1751-1097.2008.00361.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Solar UV radiation and benzo[a]pyrene (BaP) are two carcinogenic agents. When combined, their deleterious properties are synergistic. In order to get insights into the underlying processes, we carried out a mechanistic study within isolated DNA photosensitized to UVA radiation by either BaP, its diol epoxide metabolite (BPDE) or the tetraol arising from the hydrolysis of this last molecule. Measurement of the level of the oxidized base 8-oxo-7,8-dihydroguanine revealed that BaP is a poor sensitizer while BPDE and tetraol are more potent ones. None of these compounds was found to photosensitize formation of cyclobutane pyrimidine dimers through triplet energy transfer. On the basis of the distribution of oxidized DNA bases, we could show that photosensitization of DNA by BPDE involves electron abstraction (Type I) while tetraol acts mainly through singlet oxygen production (Type II). Under our experimental conditions, Type I was the major photosensitization process, which shows the lack of involvement of tetraol in the observed photo-oxidation reaction. Finally, we could show that the adducts, resulting from the alkylation of DNA by BPDE, are very potent sensitizers. Indeed, they are located in the close vicinity of the double helix and thus perfectly placed to induce oxidation reactions.
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Affiliation(s)
- Thierry Douki
- Laboratoire "Lésions des Acides Nucléiques," Service de Chimie Inorganique et Biologique UMR-E 3 CEA-UJF, CEA/DSM/INaC, CEA-Grenoble, Grenoble, France.
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Toyooka T, Ohnuki G, Ibuki Y. Solar-simulated light-exposed benzo[a]pyrene induces phosphorylation of histone H2AX. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2008; 650:132-9. [DOI: 10.1016/j.mrgentox.2007.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Revised: 10/22/2007] [Accepted: 11/04/2007] [Indexed: 10/22/2022]
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Malmlöf M, Pääjärvi G, Högberg J, Stenius U. Mdm2 as a sensitive and mechanistically informative marker for genotoxicity induced by benzo[a]pyrene and dibenzo[a,l]pyrene. Toxicol Sci 2007; 102:232-40. [PMID: 18096571 DOI: 10.1093/toxsci/kfm305] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mdm2 is an oncoprotein interacting with p53 and maintaining low p53 levels in unstressed cells. Here we investigated the effect of genotoxic compounds on Mdm2 phosphorylation levels. Employing the Mdm2 2A10 antibody and phosphatase treatment we found that Mdm2 accumulated in HepG2 cells when exposed to low concentrations of genotoxic compounds such as mitomycin C, etoposide, 5-fluorouracil, and benzo[a]pyrene (BP). The low-dose responses were not accompanied by p53 accumulation and the effect of low concentrations of BP on Mdm2 was not affected by small interfering RNA for p53. In human lymphoblasts 10nM BP induced an Mdm2 response. Low concentrations of BP also induced binding of Mdm2 to chromatin in HepG2 cells, but no p53 binding or H2AX phosphorylation. The more mutagenic dibenzo[a,l]pyrene as well as higher BP concentrations instead induced gammaH2AX and p53 Ser15 association with chromatin. Acrolein potentiated the effect of BP on p53 stabilization and chromatin binding. Taken together, these data suggest that (1) Mdm2 is a sensitive biomarker for certain types of genotoxicity, and (2) that polycyclic aromatic hydrocarbons-induced Mdm2 binding to chromatin reflects repairable damage, whereas chromatin binding of p53 Ser15 and gammaH2AX indicates more persistent DNA damage. The analysis of Mdm2 and related endpoints might be useful for evaluating mutagenic potentials of DNA damages. It is suggested that patterns documented here can be used for separating BP doses that induce readily repaired DNA adducts from doses that overwhelm this capacity.
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Affiliation(s)
- Maria Malmlöf
- Institute of Environmental Medicine, Karolinska Institutet, S-17177 Stockholm, Sweden
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Ibuki Y, Toyooka T, Shirahata J, Ohura T, Goto R. Water soluble fraction of solar-simulated light-exposed crude oil generates phosphorylation of histone H2AX in human skin cells under UVA exposure. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2007; 48:430-9. [PMID: 17372987 DOI: 10.1002/em.20292] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Crude oil contains compounds, which have toxic and cancer-causing properties to humans. The oil spilled in environments is usually exposed to sunlight; however, the toxicity of sunlight-exposed oil is poorly understood. In this study, we found that the water soluble fraction (WSF) of crude oil irradiated with solar-simulated light (SSL) generated phosphorylation of histone H2AX (gamma-H2AX) in human skin cells under UVA irradiation, which was due to the formation of DNA double strand breaks (DSBs). Crude oil was exposed to SSL for approximately 7 days. The WSF obtained from unexposed crude oil showed no toxicity, whereas the WSF obtained from crude oil pre-exposed to SSL induced acute cell death on exposure to UVA irradiation (induction of phototoxicity), which was more remarkable in human skin fibroblasts than human skin keratinocytes. gamma-H2AX was detected in both cell lines immediately after treatment with the WSF plus UVA. Interestingly, gamma-H2AX was detectable even at low SSL- and UVA-doses, which induced no cytotoxicity. The WSF of crude oil irradiated with SSL, generated DSBs under UVA irradiation, which were detected by biased sinusoidal field gel electrophoresis. This was confirmed using xrs-5 cells isolated from CHO-K1 cells, which are deficient in a repair enzyme for DSBs; the WSF plus UVA induced a more dramatic decrease in survival in xrs-5 cells than CHO-K1 cells. These findings demonstrate that exposure of crude oil to sunlight makes the WSF phototoxic, generating DSBs accompanying the appearance of gamma-H2AX in human skin cells.
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Affiliation(s)
- Yuko Ibuki
- Laboratory of Radiation Biology, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka-Shi 422-8526, Japan.
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Toyooka T, Ibuki Y. New method for testing phototoxicity of polycyclic aromatic hydrocarbons. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2006; 40:3603-8. [PMID: 16786700 DOI: 10.1021/es060182i] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs), widespread environmental pollutants, were recently reported to show photomutagenesis. As contaminants in the environment are usually exposed to sunlight, a way to evaluate the phototoxic characteristics of pollutants is required. We have previously found that phosphorylation of histone H2AX (gamma-H2AX), which accompanied the induction of DNA double strand breaks (DSBs), was significantly induced by low concentrations of benzo[a]pyrene (10(-9)-10(-7) M) and UVA (0.6 J/cm2) in CHO-K1 cells. Higher concentrations have been required for the detection of DSBs. The aim of the present study is to investigate the applicability of gamma-H2AX in a new phototoxicity assay of PAHs. The human keratinocytes, HaCaT, were treated with four model PAHs (naphthalene, phenanthrene, pyrene, and benzo[a]pyrene, 10(-11)-10(-7) M) and/or UVA (5 J/cm2), and the induction of gamma-H2AX was assessed. Furthermore, DSBs were directly detected using a biased sinusoidal field gel electrophoresis, and the cell viability was examined as a general assay of phototoxicity. The induction of gamma-H2AX was detected in the presence of all the PAHs except naphthalene at concentrations of 10(-9)-10(-7) M, whereas neither DSBs nor cell death could be detected at those concentrations, and higher concentrations were required for the detection. Naphthalene showed no phototoxicity in any of the three different assays. These findings suggest that histone H2AX is a potential moleculartargetfor detecting the phototoxicity of PAHs more sensitively than the detection of cell viability and DSBs.
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Affiliation(s)
- Tatsushi Toyooka
- Laboratory of Radiation Biology, Graduate School of Nutritional and Environmental Sciences, Institute for Environmental Sciences, University of Shizuoka, Shizuoka, Japan
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