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Yusoff NA, Abd Hamid Z, Budin SB, Taib IS. Linking Benzene, in Utero Carcinogenicity and Fetal Hematopoietic Stem Cell Niches: A Mechanistic Review. Int J Mol Sci 2023; 24:ijms24076335. [PMID: 37047305 PMCID: PMC10094243 DOI: 10.3390/ijms24076335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/19/2023] [Accepted: 03/23/2023] [Indexed: 03/30/2023] Open
Abstract
Previous research reported that prolonged benzene exposure during in utero fetal development causes greater fetal abnormalities than in adult-stage exposure. This phenomenon increases the risk for disease development at the fetal stage, particularly carcinogenesis, which is mainly associated with hematological malignancies. Benzene has been reported to potentially act via multiple modes of action that target the hematopoietic stem cell (HSCs) niche, a complex microenvironment in which HSCs and multilineage hematopoietic stem and progenitor cells (HSPCs) reside. Oxidative stress, chromosomal aberration and epigenetic modification are among the known mechanisms mediating benzene-induced genetic and epigenetic modification in fetal stem cells leading to in utero carcinogenesis. Hence, it is crucial to monitor exposure to carcinogenic benzene via environmental, occupational or lifestyle factors among pregnant women. Benzene is a well-known cause of adult leukemia. However, proof of benzene involvement with childhood leukemia remains scarce despite previously reported research linking incidences of hematological disorders and maternal benzene exposure. Furthermore, accumulating evidence has shown that maternal benzene exposure is able to alter the developmental and functional properties of HSPCs, leading to hematological disorders in fetus and children. Since HSPCs are parental blood cells that regulate hematopoiesis during the fetal and adult stages, benzene exposure that targets HSPCs may induce damage to the population and trigger the development of hematological diseases. Therefore, the mechanism of in utero carcinogenicity by benzene in targeting fetal HSPCs is the primary focus of this review.
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Holmes TH, Winn LM. DNA damage, DNA repair gene expression, and topoisomerase IIα activity in CD-1 mice following in utero benzene exposure. Toxicol Lett 2022; 368:47-55. [PMID: 35963423 DOI: 10.1016/j.toxlet.2022.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/16/2022] [Accepted: 08/08/2022] [Indexed: 11/19/2022]
Abstract
Benzene is an environmental toxicant and known human carcinogen. Recent epidemiological studies show a relationship between exposure to benzene in pregnant women and increased incidence of childhood leukemias. Studies in murine models demonstrate a relationship between carcinogenicity and in utero benzene exposure which was sex dependent, thus the cellular mechanisms of benzene toxicity by sex require further studies. A hypothesized mechanism of benzene-induced in utero carcinogenicity is through increased DNA damage and reduced fetal DNA repair capacity. This includes the potential inhibition of topoisomerase IIα (topo IIα), in part, to generate double stranded DNA (dsDNA) breaks and induction of error-prone DNA repair. Using a mouse model of transplacental benzene carcinogenicity, gestational day (GD) 14 fetal livers were harvested 2, 6, and 24 h following maternal exposure to 200 mg/kg benzene and used to assess DNA damage, DNA repair gene expression and topo IIα activity. DNA damage, measured by levels of modified histone H2AX (γH2AX), is significantly increased in benzene exposed pups, with sex-dependent significance seen only in female pups. Comet assay results confirmed that benzene exposure in utero induces dsDNA damage in the GD14 fetal liver. Genes involved in DNA repair were assessed, and DNA repair gene expression changes were observed after 24 h in genes related to nucleotide excision repair, homologous recombination, and non-homologous end-joining. There were no significant differences in topo IIα activity in GD14 fetal livers at any timepoint, or between sexes. Overall, this study shows that 200 mg/kg benzene exposure induces dsDNA damage and alters fetal DNA repair gene expression in utero, without perturbing fetal topo IIα in CD-1 mice.
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Affiliation(s)
- Trent H Holmes
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Louise M Winn
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada; School of Environmental Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada.
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Identification of potential pathways and microRNA-mRNA networks associated with benzene metabolite hydroquinone-induced hematotoxicity in human leukemia K562 cells. BMC PHARMACOLOGY AND TOXICOLOGY 2022; 23:20. [PMID: 35366954 PMCID: PMC8976366 DOI: 10.1186/s40360-022-00556-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 03/10/2022] [Indexed: 11/24/2022]
Abstract
Background Hydroquinone (HQ) is a phenolic metabolite of benzene with a potential risk for hematological disorders and hematotoxicity in humans. In the present study, an integrative analysis of microRNA (miRNA) and mRNA expressions was performed to identify potential pathways and miRNA-mRNA network associated with benzene metabolite hydroquinone-induced hematotoxicity. Methods K562 cells were treated with 40 μM HQ for 72 h, mRNA and miRNA expression changes were examined using transcriptomic profiles and miRNA microarray, and then bioinformatics analysis was performed. Results Out of all the differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) induced by HQ, 1482 DEGs and 10 DEMs were up-regulated, and 1594 DEGs and 42 DEMs were down-regulated. HQ-induced DEGs were involved in oxidative stress, apoptosis, DNA methylation, histone acetylation and cellular response to leukemia inhibitory factor GO terms, as well as metabolic, Wnt/β-catenin, NF-κB, and leukemia-related pathways. The regulatory network of mRNAs and miRNAs includes 23 miRNAs, 1108 target genes, and 2304 potential miRNAs-mRNAs pairs. MiR-1246 and miR-224 had the potential to be major regulators in HQ-exposed K562 cells based on the miRNAs-mRNAs network. Conclusions This study reinforces the use of in vitro model of HQ exposure and bioinformatic approaches to advance our knowledge on molecular mechanisms of benzene hematotoxicity at the RNA level. Supplementary Information The online version contains supplementary material available at 10.1186/s40360-022-00556-8.
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Epigenetic Effects of Benzene in Hematologic Neoplasms: The Altered Gene Expression. Cancers (Basel) 2021; 13:cancers13102392. [PMID: 34069279 PMCID: PMC8156840 DOI: 10.3390/cancers13102392] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/06/2021] [Accepted: 05/11/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary Benzene is produced by diverse petroleum transformation processes and it is widely employed in industry despite its oncogenic effects. In fact, occupational exposure to benzene may cause hematopoietic malignancy. The leukemogenic action of benzene is particularly complex. Possible processes of onset of hematological malignancies have been recognized as a genotoxic action and the provocation of immunosuppression. However, benzene can induce modifications that do not involve alterations in the DNA sequence, the so-called epigenetics changes. Acquired epigenetic modification may also induce leukemogenesis, as benzene may alter nuclear receptors, and cause changes at the protein level, thereby modifying the function of regulatory proteins, including oncoproteins and tumor suppressor proteins. Abstract Benzene carcinogenic ability has been reported, and chronic exposure to benzene can be one of the risk elements for solid cancers and hematological neoplasms. Benzene is acknowledged as a myelotoxin, and it is able to augment the risk for the onset of acute myeloid leukemia, myelodysplastic syndromes, aplastic anemia, and lymphomas. Possible mechanisms of benzene initiation of hematological tumors have been identified, as a genotoxic effect, an action on oxidative stress and inflammation and the provocation of immunosuppression. However, it is becoming evident that genetic alterations and the other causes are insufficient to fully justify several phenomena that influence the onset of hematologic malignancies. Acquired epigenetic alterations may participate with benzene leukemogenesis, as benzene may affect nuclear receptors, and provoke post-translational alterations at the protein level, thereby touching the function of regulatory proteins, comprising oncoproteins and tumor suppressor proteins. DNA hypomethylation correlates with stimulation of oncogenes, while the hypermethylation of CpG islands in promoter regions of specific tumor suppressor genes inhibits their transcription and stimulates the onset of tumors. The discovery of the systems of epigenetic induction of benzene-caused hematological tumors has allowed the possibility to operate with pharmacological interventions able of stopping or overturning the negative effects of benzene.
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Chung FFL, Herceg Z. The Promises and Challenges of Toxico-Epigenomics: Environmental Chemicals and Their Impacts on the Epigenome. ENVIRONMENTAL HEALTH PERSPECTIVES 2020; 128:15001. [PMID: 31950866 PMCID: PMC7015548 DOI: 10.1289/ehp6104] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 12/15/2019] [Accepted: 12/16/2019] [Indexed: 05/02/2023]
Abstract
BACKGROUND It has been estimated that a substantial portion of chronic and noncommunicable diseases can be caused or exacerbated by exposure to environmental chemicals. Multiple lines of evidence indicate that early life exposure to environmental chemicals at relatively low concentrations could have lasting effects on individual and population health. Although the potential adverse effects of environmental chemicals are known to the scientific community, regulatory agencies, and the public, little is known about the mechanistic basis by which these chemicals can induce long-term or transgenerational effects. To address this question, epigenetic mechanisms have emerged as the potential link between genetic and environmental factors of health and disease. OBJECTIVES We present an overview of epigenetic regulation and a summary of reported evidence of environmental toxicants as epigenetic disruptors. We also discuss the advantages and challenges of using epigenetic biomarkers as an indicator of toxicant exposure, using measures that can be taken to improve risk assessment, and our perspectives on the future role of epigenetics in toxicology. DISCUSSION Until recently, efforts to apply epigenomic data in toxicology and risk assessment were restricted by an incomplete understanding of epigenomic variability across tissue types and populations. This is poised to change with the development of new tools and concerted efforts by researchers across disciplines that have led to a better understanding of epigenetic mechanisms and comprehensive maps of epigenomic variation. With the foundations now in place, we foresee that unprecedented advancements will take place in the field in the coming years. https://doi.org/10.1289/EHP6104.
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Affiliation(s)
| | - Zdenko Herceg
- Epigenetics Group, International Agency for Research on Cancer (IARC), Lyon, France
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Reis H, Reis C, Sharip A, Reis W, Zhao Y, Sinclair R, Beeson L. Diesel exhaust exposure, its multi-system effects, and the effect of new technology diesel exhaust. ENVIRONMENT INTERNATIONAL 2018; 114:252-265. [PMID: 29524921 DOI: 10.1016/j.envint.2018.02.042] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 02/24/2018] [Accepted: 02/24/2018] [Indexed: 11/07/2023]
Abstract
Exposure to diesel exhaust (DE) from vehicles and industry is hazardous and affects proper function of organ systems. DE can interfere with normal physiology after acute and chronic exposure to particulate matter (PM). Exposure leads to potential systemic disease processes in the central nervous, visual, hematopoietic, respiratory, cardiovascular, and renal systems. In this review, we give an overview of the epidemiological evidence supporting the harmful effects of diesel exhaust, and the numerous animal studies conducted to investigate the specific pathophysiological mechanisms behind DE exposure. Additionally, this review includes a summary of studies that used biomarkers as an indication of biological plausibility, and also studies evaluating new technology diesel exhaust (NTDE) and its systemic effects. Lastly, this review includes new approaches to improving DE emissions, and emphasizes the importance of ongoing study in this field of environmental health.
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Affiliation(s)
- Haley Reis
- Loma Linda University School of Medicine, 11175 Campus Street, Loma Linda, CA 92350, USA
| | - Cesar Reis
- Department of Preventive Medicine, Loma Linda University Medical Center, 24785 Stewart Street, Suite 204, Loma Linda, CA 92354, USA; Loma Linda University School of Medicine, 11175 Campus Street, Loma Linda, CA 92350, USA.
| | - Akbar Sharip
- Department of Occupational Medicine, Loma Linda University Medical Center, 328 East Commercial Road, Suite 101, San Bernardino, CA 92408, USA
| | - Wenes Reis
- Department of Preventive Medicine, Loma Linda University Medical Center, 24785 Stewart Street, Suite 204, Loma Linda, CA 92354, USA
| | - Yong Zhao
- School of Public Health and Management, Chongqing Medical University, Chongqing, China; Research Center for Medicine and Social Development, Chongqing Medical University, Chongqing, China; The Innovation Center for Social Risk Governance in Health, Chongqing Medical University, Chongqing, China
| | - Ryan Sinclair
- Center for Community Resilience, School of Public Health, Loma Linda University, Loma Linda, CA 92350, USA
| | - Lawrence Beeson
- Center for Nutrition, Healthy Lifestyle, and Disease Prevention, School of Public Health, Loma Linda University, Loma Linda, CA 92350, USA.
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Rota F, Conti A, Campo L, Favero C, Cantone L, Motta V, Polledri E, Mercadante R, Dieci G, Bollati V, Fustinoni S. Epigenetic and Transcriptional Modifications in Repetitive Elements in Petrol Station Workers Exposed to Benzene and MTBE. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:E735. [PMID: 29649143 PMCID: PMC5923777 DOI: 10.3390/ijerph15040735] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 03/30/2018] [Accepted: 04/08/2018] [Indexed: 12/19/2022]
Abstract
Benzene, a known human carcinogen, and methyl tert-butyl ether (MTBE), not classifiable as to its carcinogenicity, are fuel-related pollutants. This study investigated the effect of these chemicals on epigenetic and transcriptional alterations in DNA repetitive elements. In 89 petrol station workers and 90 non-occupationally exposed subjects the transcriptional activity of retrotransposons (LINE-1, Alu), the methylation on repeated-element DNA, and of H3K9 histone, were investigated in peripheral blood lymphocytes. Median work shift exposure to benzene and MTBE was 59 and 408 µg/m³ in petrol station workers, and 4 and 3.5 µg/m³, in controls. Urinary benzene (BEN-U), S-phenylmercapturic acid, and MTBE were significantly higher in workers than in controls, while trans,trans-muconic acid (tt-MA) was comparable between the two groups. Increased BEN-U was associated with increased Alu-Y and Alu-J expression; moreover, increased tt-MA was associated with increased Alu-Y and Alu-J and LINE-1 (L1)-5'UTR expression. Among repetitive element methylation, only L1-Pa5 was hypomethylated in petrol station workers compared to controls. While L1-Ta and Alu-YD6 methylation was not associated with benzene exposure, a negative association with urinary MTBE was observed. The methylation status of histone H3K9 was not associated with either benzene or MTBE exposure. Overall, these findings only partially support previous observations linking benzene exposure with global DNA hypomethylation.
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Affiliation(s)
- Federica Rota
- EPIGET, Epidemiology, Epigenetics and Toxicology Lab, Department of Clinical Sciences and Community Health, Università Degli Studi di Milano, via San Barnaba 8, 20122 Milan, Italy.
| | - Anastasia Conti
- Department of Life Sciences, University of Parma, 43124 Parma, Italy.
- Present address: San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), 20132 Milan, Italy.
| | - Laura Campo
- Occupational Medicine Unit, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, 20122 Milan, Italy.
| | - Chiara Favero
- EPIGET, Epidemiology, Epigenetics and Toxicology Lab, Department of Clinical Sciences and Community Health, Università Degli Studi di Milano, via San Barnaba 8, 20122 Milan, Italy.
| | - Laura Cantone
- EPIGET, Epidemiology, Epigenetics and Toxicology Lab, Department of Clinical Sciences and Community Health, Università Degli Studi di Milano, via San Barnaba 8, 20122 Milan, Italy.
| | - Valeria Motta
- EPIGET, Epidemiology, Epigenetics and Toxicology Lab, Department of Clinical Sciences and Community Health, Università Degli Studi di Milano, via San Barnaba 8, 20122 Milan, Italy.
| | - Elisa Polledri
- Occupational Medicine Unit, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, 20122 Milan, Italy.
| | - Rosa Mercadante
- EPIGET, Epidemiology, Epigenetics and Toxicology Lab, Department of Clinical Sciences and Community Health, Università Degli Studi di Milano, via San Barnaba 8, 20122 Milan, Italy.
| | - Giorgio Dieci
- Department of Life Sciences, University of Parma, 43124 Parma, Italy.
| | - Valentina Bollati
- EPIGET, Epidemiology, Epigenetics and Toxicology Lab, Department of Clinical Sciences and Community Health, Università Degli Studi di Milano, via San Barnaba 8, 20122 Milan, Italy.
- Occupational Medicine Unit, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, 20122 Milan, Italy.
| | - Silvia Fustinoni
- EPIGET, Epidemiology, Epigenetics and Toxicology Lab, Department of Clinical Sciences and Community Health, Università Degli Studi di Milano, via San Barnaba 8, 20122 Milan, Italy.
- Occupational Medicine Unit, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, 20122 Milan, Italy.
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Zhang GH, Lu Y, Ji BQ, Ren JC, Sun P, Ding S, Liao X, Liao K, Liu J, Cao J, Lan Q, Rothman N, Xia ZL. Do mutations in DNMT3A/3B affect global DNA hypomethylation among benzene-exposed workers in Southeast China?: Effects of mutations in DNMT3A/3B on global DNA hypomethylation. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2017; 58:678-687. [PMID: 28945286 DOI: 10.1002/em.22136] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 07/01/2017] [Accepted: 08/15/2017] [Indexed: 02/05/2023]
Abstract
Global DNA hypomethylation is commonly observed in benzene-exposed workers, but the underlying mechanisms remain unclear. We sought to discover the relationships among reduced white blood cell (WBC) counts, micronuclear (MN) frequency, and global DNA methylation to determine whether there were associations with mutations in DNMT3A/3B. Therefore, we recruited 410 shoe factory workers and 102 controls from Wenzhou in Zhenjiang Province. A Methylated DNA Quantification Kit was used to quantify global DNA methylation, and single nucleotide polymorphisms (SNPs) in DNMT3A (rs36012910, rs1550117, and R882) and DNMT3B (rs1569686, rs2424909, and rs2424913) were identified using the restriction fragment length polymorphism method. A multilinear regression analysis demonstrated that the benzene-exposed workers experienced significant global DNA hypomethylation compared with the controls (β = -0.51, 95% CI: -0.69 to -0.32, P < 0.001). The DNMT3A R882 mutant allele (R882H and R882C) (β = -0.25, 95% CI: -0.54 to 0.04, P = 0.094) and the DNMT3B rs2424909 GG allele (β = -0.37, 95% CI: -0.70 to -0.03, P = 0.031) were significantly associated with global DNA hypomethylation compared with the wild-type genotype after adjusting for confounding factors. Furthermore, the MN frequency in the R882 mutant allele (R882H and R882C) (FR = 1.18, 95% CI: 0.99 to 1.40, P = 0.054) was higher than that of the wild-type. The results imply that hypomethylation occurs due to benzene exposure and that mutations in DNMTs are significantly associated with global DNA methylation, which might have influenced the induction of MN following exposure to benzene. Environ. Mol. Mutagen. 58:678-687, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Guang-Hui Zhang
- Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, School of Public Health, Xinxiang Medical University, 601 Jinsui Road, Xinxiang, 453003, China
- Department of Occupational Health and Toxicology, School of Public Health, Fudan University, 138 Yixueyuan Road, Shanghai, 200032, China
| | - Ye Lu
- Department of Occupational Health and Toxicology, School of Public Health, Fudan University, 138 Yixueyuan Road, Shanghai, 200032, China
| | - Bu-Qiang Ji
- Department of Hematology, Linyi People's Hospital, 27 Jifang Road, Linyi, 276003, China
| | - Jing-Chao Ren
- Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, School of Public Health, Xinxiang Medical University, 601 Jinsui Road, Xinxiang, 453003, China
| | - Pin Sun
- Department of Occupational Health and Toxicology, School of Public Health, Fudan University, 138 Yixueyuan Road, Shanghai, 200032, China
| | - Shibin Ding
- Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, School of Public Health, Xinxiang Medical University, 601 Jinsui Road, Xinxiang, 453003, China
| | - Xiaoling Liao
- The Second Affiliated Hospital of Shantou University Medical College, Shantou university, Dongxiabei Road, Shantou, 515021, China
| | - Kaiju Liao
- Health Emergency Center, Chinese Centers for Disease Control and Prevention, 155 Changbai Road, Beijing, 102206, China
| | - Jinyi Liu
- Institute of Toxicology, College of Preventive Medicine, Third Military Medical University, 30 Gao tanyan Chongqing, 400040, China
| | - Jia Cao
- Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, School of Public Health, Xinxiang Medical University, 601 Jinsui Road, Xinxiang, 453003, China
- Institute of Toxicology, College of Preventive Medicine, Third Military Medical University, 30 Gao tanyan Chongqing, 400040, China
| | - Qing Lan
- Department of Health and Human Services (DHHS), National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, Maryland
| | - Nathaniel Rothman
- Department of Health and Human Services (DHHS), National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, Maryland
| | - Zhao-Lin Xia
- Department of Occupational Health and Toxicology, School of Public Health, Fudan University, 138 Yixueyuan Road, Shanghai, 200032, China
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Jiménez-Garza O, Guo L, Byun HM, Carrieri M, Bartolucci GB, Zhong J, Baccarelli AA. Promoter methylation status in genes related with inflammation, nitrosative stress and xenobiotic metabolism in low-level benzene exposure: Searching for biomarkers of oncogenesis. Food Chem Toxicol 2017; 109:669-676. [DOI: 10.1016/j.fct.2017.08.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 08/15/2017] [Indexed: 12/13/2022]
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Khairul WM, Daud AI, Mohd Hanifaah NA, Arshad S, Razak IA, Zuki HM, Erben MF. Structural study of a novel acetylide-thiourea derivative and its evaluation as a detector of benzene. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.03.065] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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In vitro hydroquinone-induced instauration of histone bivalent mark on human retroelements (LINE-1) in HL60 cells. Toxicol In Vitro 2016; 40:1-10. [PMID: 27979589 DOI: 10.1016/j.tiv.2016.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 12/07/2016] [Accepted: 12/11/2016] [Indexed: 12/28/2022]
Abstract
Benzene is extensively used in industry despite its leukemogenic activity, representing a significant occupational hazard. We investigated if long-term treatment with low-doses hydroquinone (HQ), a benzene metabolite, might be sufficient to alter in vitro the epigenetic signature underlining LINE-1 sequences, a poorly explored step in health risks associated with benzene exposure. In HL-60 cell line, exploring the epigenetic events occurring in chromatin, we found the transient instauration of the distinctive signature combining the repressive H3Lys27 tri-methylation mark and the activating H3Lys4 tri-methylation mark (H3K27me3/H3K4me3), indicating a tendency toward a poised chromatin conformation. These alterations are lost in time after short-term treatments, while the long-term setting, performed using a concentration within the levels of total HQ in peripheral blood of benzene-exposed workers, showed a gradual increase in H3K4me3. We observed the absence of statistically significant variations in DNA methylation and expression levels of LINE-1, despite a decrease in protein levels of UHRF1, DNA methyl-transferases and histone methyl-transferases. In conclusion, in vitro treatment with low-dose HQ determined the instauration of a reversible poised state of chromatin in LINE-1 sequences, suggesting that prolonged exposure could cause persistent epigenetic alterations.
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Hepatitis B virus X protein (HBx)-induced abnormalities of nucleic acid metabolism revealed by (1)H-NMR-based metabonomics. Sci Rep 2016; 6:24430. [PMID: 27075403 PMCID: PMC4830998 DOI: 10.1038/srep24430] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 03/30/2016] [Indexed: 02/05/2023] Open
Abstract
Hepatitis B virus X protein (HBx) plays an important role in HBV-related hepatocarcinogenesis; however, mechanisms underlying HBx-mediated carcinogenesis remain unclear. In this study, an NMR-based metabolomics approach was applied to systematically investigate the effects of HBx on cell metabolism. EdU incorporation assay was conducted to examine the effects of HBx on DNA synthesis, an important feature of nucleic acid metabolism. The results revealed that HBx disrupted metabolism of glucose, lipids, and amino acids, especially nucleic acids. To understand the potential mechanism of HBx-induced abnormalities of nucleic acid metabolism, gene expression profiles of HepG2 cells expressing HBx were investigated. The results showed that 29 genes involved in DNA damage and DNA repair were differentially expressed in HBx-expressing HepG2 cells. HBx-induced DNA damage was further demonstrated by karyotyping, comet assay, Western blotting, immunofluorescence and immunohistochemistry analyses. Many studies have previously reported that DNA damage can induce abnormalities of nucleic acid metabolism. Thus, our results implied that HBx initially induces DNA damage, and then disrupts nucleic acid metabolism, which in turn blocks DNA repair and induces the occurrence of hepatocellular carcinoma (HCC). These findings further contribute to our understanding of the occurrence of HCC.
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Chappell G, Pogribny IP, Guyton KZ, Rusyn I. Epigenetic alterations induced by genotoxic occupational and environmental human chemical carcinogens: A systematic literature review. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2016; 768:27-45. [PMID: 27234561 PMCID: PMC4884606 DOI: 10.1016/j.mrrev.2016.03.004] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 03/24/2016] [Accepted: 03/25/2016] [Indexed: 01/30/2023]
Abstract
Accumulating evidence suggests that epigenetic alterations play an important role in chemically-induced carcinogenesis. Although the epigenome and genome may be equally important in carcinogenicity, the genotoxicity of chemical agents and exposure-related transcriptomic responses have been more thoroughly studied and characterized. To better understand the evidence for epigenetic alterations of human carcinogens, and the potential association with genotoxic endpoints, we conducted a systematic review of published studies of genotoxic carcinogens that reported epigenetic endpoints. Specifically, we searched for publications reporting epigenetic effects for the 28 agents and occupations included in Monograph Volume 100F of the International Agency for the Research on Cancer (IARC) that were classified as "carcinogenic to humans" (Group 1) with strong evidence of genotoxic mechanisms of carcinogenesis. We identified a total of 158 studies that evaluated epigenetic alterations for 12 of these 28 carcinogenic agents and occupations (1,3-butadiene, 4-aminobiphenyl, aflatoxins, benzene, benzidine, benzo[a]pyrene, coke production, formaldehyde, occupational exposure as a painter, sulfur mustard, and vinyl chloride). Aberrant DNA methylation was most commonly studied, followed by altered expression of non-coding RNAs and histone changes (totaling 85, 59 and 25 studies, respectively). For 3 carcinogens (aflatoxins, benzene and benzo[a]pyrene), 10 or more studies reported epigenetic effects. However, epigenetic studies were sparse for the remaining 9 carcinogens; for 4 agents, only 1 or 2 published reports were identified. While further research is needed to better identify carcinogenesis-associated epigenetic perturbations for many potential carcinogens, published reports on specific epigenetic endpoints can be systematically identified and increasingly incorporated in cancer hazard assessments.
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Affiliation(s)
- Grace Chappell
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA
| | - Igor P Pogribny
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR, USA
| | | | - Ivan Rusyn
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA.
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