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Islam R, Zhao L, Wang Y, Lu-Yao G, Liu LZ. Epigenetic Dysregulations in Arsenic-Induced Carcinogenesis. Cancers (Basel) 2022; 14:cancers14184502. [PMID: 36139662 PMCID: PMC9496897 DOI: 10.3390/cancers14184502] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/13/2022] [Accepted: 09/13/2022] [Indexed: 11/16/2022] Open
Abstract
Arsenic is a crucial environmental metalloid whose high toxicity levels negatively impact human health. It poses significant health concerns to millions of people in developed and developing countries such as the USA, Canada, Bangladesh, India, China, and Mexico by enhancing sensitivity to various types of diseases, including cancers. However, how arsenic causes changes in gene expression that results in heinous conditions remains elusive. One of the proposed essential mechanisms that still has seen limited research with regard to causing disease upon arsenic exposure is the dysregulation of epigenetic components. In this review, we have extensively summarized current discoveries in arsenic-induced epigenetic modifications in carcinogenesis and angiogenesis. Importantly, we highlight the possible mechanisms underlying epigenetic reprogramming through arsenic exposure that cause changes in cell signaling and dysfunctions of different epigenetic elements.
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Zhang Y, Li Y, Luo L, He Q, Gao Y, Feng H, Zhao L, Wei W, Fu S, Sun D. Factors Affecting Differential Methylation of DNA Promoters in Arsenic-Exposed Populations. Biol Trace Elem Res 2019; 189:437-446. [PMID: 30220071 DOI: 10.1007/s12011-018-1504-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 08/30/2018] [Indexed: 01/15/2023]
Abstract
The exposure/biotransformation of inorganic arsenic (iAs) may perturb DNA methylation patterns and subsequently influence disease risk by altering the expression of key genes. Interindividual variation in patterns of DNA methylation can be explained by the influence of environmental, genetic, and stochastic factors. Here, we examined promoter DNA methylation levels with urinary arsenical concentrations and investigated the genetic and nongenetic determinants of DNA methylation in 105 samples collected from populations in Shanxi Province, China, with high levels of arsenic in drinking water. Arsenic concentrations in water were determined by atomic absorption spectrophotometry (AA-6800, Shimadzu Co., Kyoto, Japan). Urine samples were measured using an atomic absorption spectrophotometer with an arsenic speciation pretreatment system (ASA-2sp, Shimadzu Co. Kyoto, Japan) for detection. Gene-specific (CDH1, EREG, ERCC2, GSTP1, and MGMT) DNA methylation was quantified by targeted bisulfite sequencing. Single-nucleotide polymorphism (SNP) genotyping was performed using a custom-by-design 2 × 48-Plex SNPscan™ Kit. These results revealed CDH1 with promoter DNA methylation levels associated with iAs. After the exclusion of confounding factors, age was correlated with increased methylation of the CDH1 gene. The susceptibility of the CDH1 and GSTP1 gene promoters to methylation was increased in individuals carrying the DNMT3B (SNP rs2424932) GA genotype, and the susceptibility of the CDH1 gene promoters to methylation was increased in individuals carrying the DNMT3B (SNP rs6087990) TC genotype. Although the above results must still be replicated in larger samples, the findings improve our understanding of the pathogenesis of arsenic and may highlight certain DNA methylation markers as attractive surrogate markers for prevention research.
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Affiliation(s)
- Yanting Zhang
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, 150081, China
- Key Lab of Etiology and Epidemiology, Education Bureau of Hei Long Jiang Province & Ministry of Health, Harbin, 150081, China
| | - Yuanyuan Li
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, 150081, China
- Key Lab of Etiology and Epidemiology, Education Bureau of Hei Long Jiang Province & Ministry of Health, Harbin, 150081, China
| | - Lanrong Luo
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, 150081, China
- Key Lab of Etiology and Epidemiology, Education Bureau of Hei Long Jiang Province & Ministry of Health, Harbin, 150081, China
| | - Qian He
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, 150081, China
- Key Lab of Etiology and Epidemiology, Education Bureau of Hei Long Jiang Province & Ministry of Health, Harbin, 150081, China
| | - Yanhui Gao
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, 150081, China
- Key Lab of Etiology and Epidemiology, Education Bureau of Hei Long Jiang Province & Ministry of Health, Harbin, 150081, China
| | - Hongqi Feng
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, 150081, China
- Key Lab of Etiology and Epidemiology, Education Bureau of Hei Long Jiang Province & Ministry of Health, Harbin, 150081, China
| | - Lijun Zhao
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, 150081, China
- Key Lab of Etiology and Epidemiology, Education Bureau of Hei Long Jiang Province & Ministry of Health, Harbin, 150081, China
| | - Wei Wei
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, 150081, China
- Key Lab of Etiology and Epidemiology, Education Bureau of Hei Long Jiang Province & Ministry of Health, Harbin, 150081, China
| | - Songbo Fu
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, 150081, China.
- Key Lab of Etiology and Epidemiology, Education Bureau of Hei Long Jiang Province & Ministry of Health, Harbin, 150081, China.
| | - Dianjun Sun
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, 150081, China.
- Key Lab of Etiology and Epidemiology, Education Bureau of Hei Long Jiang Province & Ministry of Health, Harbin, 150081, China.
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Epigenetic Regulation of Autophagy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1206:221-236. [DOI: 10.1007/978-981-15-0602-4_11] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Zhou Q, Xi S. A review on arsenic carcinogenesis: Epidemiology, metabolism, genotoxicity and epigenetic changes. Regul Toxicol Pharmacol 2018; 99:78-88. [PMID: 30223072 DOI: 10.1016/j.yrtph.2018.09.010] [Citation(s) in RCA: 119] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 09/08/2018] [Accepted: 09/12/2018] [Indexed: 12/19/2022]
Abstract
Long-term exposure to arsenic (inorganic arsenic) is a world-wide environmental health concern. Arsenic is classified as the Group 1 human carcinogen by the International Agency for Research on Cancer (IARC). Epidemiological studies have established a strong association between inorganic arsenic (iAs) exposure in drinking water and an increased incidence of cancer including bladder, liver, lung, prostate, and skin cancer. iAs also increases the risk of other diseases such as cardiovascular disease, hypertension and diabetes. The molecular mechanisms of carcinogenesis of iAs remain poorly defined, several mechanisms have been proposed, including genotoxicity, altered cell proliferation, oxidative stress, changes to the epigenome, disturbances of signal transduction pathways, cytotoxicity and regenerative proliferation. In this article, we will summarize current knowledge on the mechanisms of arsenic carcinogenesis and focus on integrating all these issues to garner a broader perspective.
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Affiliation(s)
- Qing Zhou
- Department of Environmental and Occupational Health, Liaoning Provincial Key Laboratory of Arsenic Biological Effect and Poisoning, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning Province, People's Republic of China
| | - Shuhua Xi
- Department of Environmental and Occupational Health, Liaoning Provincial Key Laboratory of Arsenic Biological Effect and Poisoning, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning Province, People's Republic of China.
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Suzuki T, Watanabe H, Kita K, Honma T, Ochi T. Arsenite-induced histone H3 modification and its effects onEGR1andFOSexpression in HeLa cells. J Appl Toxicol 2018; 38:734-743. [DOI: 10.1002/jat.3581] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/14/2017] [Accepted: 11/28/2017] [Indexed: 01/08/2023]
Affiliation(s)
- Toshihide Suzuki
- Faculty of Pharma-Science; Teikyo University; 2-11-1 Kaga, Itabashi-ku Tokyo 173-8605 Japan
| | - Hiroshi Watanabe
- Faculty of Pharma-Science; Teikyo University; 2-11-1 Kaga, Itabashi-ku Tokyo 173-8605 Japan
| | - Kayoko Kita
- Faculty of Pharma-Science; Teikyo University; 2-11-1 Kaga, Itabashi-ku Tokyo 173-8605 Japan
| | - Taro Honma
- Faculty of Pharma-Science; Teikyo University; 2-11-1 Kaga, Itabashi-ku Tokyo 173-8605 Japan
| | - Takafumi Ochi
- Faculty of Pharma-Science; Teikyo University; 2-11-1 Kaga, Itabashi-ku Tokyo 173-8605 Japan
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Dai L, Ma C, Zhang Z, Zeng S, Liu A, Tang S, Ren Q, Sun Y, Xu C. DAPK Promoter Methylation and Bladder Cancer Risk: A Systematic Review and Meta-Analysis. PLoS One 2016; 11:e0167228. [PMID: 27907054 PMCID: PMC5132202 DOI: 10.1371/journal.pone.0167228] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 11/10/2016] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Methylation of tumor suppressor gene promoter leads to transcription inactivation and is involved in tumorigenesis. Several studies demonstrate a potential association between the Death-Associated Protein Kinase (DAPK) gene promoter methylation and bladder cancer risk, tumor stage and histological grade. Due to inconsistent results of these studies, we performed this meta-analysis to ascertain the association. METHODS Studies were retrieved from the PubMed, Embase, Web of Science and the Cochrane Library databases. Study selection and data extraction were executed by two reviewers independently. Meta-analysis was performed using Stata 13.0 and Review Manager 5.3 software. RESULTS A total of 21 articles involving 15 case control and 8 case series studies were included in this meta-analysis. DAPK promoter methylation was associated with bladder cancer risk (OR: 5.81; 95%CI = 3.83-8.82, P<0.00001). The frequency of DAPK promoter methylation was equal in bladder cancer tissue and paired adjacent normal tissue (OR: 0.87; 95%CI = 0.31-2.48, P = 0.794). Furthermore, DAPK promoter methylation was associated with higher histological grade (OR: 1.52; 95%CI = 1.10-2.09, P = 0.011) but not associated with tumor stage (OR: 1.12; 95%CI = 0.67-1.87, P = 0.668). CONCLUSIONS The result suggests that DAPK promoter methylation is significantly increased in bladder cancer patients compared to normal controls. DAPK promoter methylation could serve as a biomarker for bladder cancer detection and management.
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Affiliation(s)
- Lihe Dai
- Department of Urology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Chong Ma
- Department of Urology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Zhensheng Zhang
- Department of Urology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Shuxiong Zeng
- Department of Urology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Anwei Liu
- Department of Urology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Shijie Tang
- Department of Urology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Qian Ren
- Department of Urology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Yinghao Sun
- Department of Urology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Chuanliang Xu
- Department of Urology, Changhai Hospital, Second Military Medical University, Shanghai, China
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Huangfu L, Liang H, Wang G, Su X, Li L, Du Z, Hu M, Dong Y, Bai X, Liu T, Yang B, Shan H. miR-183 regulates autophagy and apoptosis in colorectal cancer through targeting of UVRAG. Oncotarget 2016; 7:4735-45. [PMID: 26717041 PMCID: PMC4826239 DOI: 10.18632/oncotarget.6732] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 11/25/2015] [Indexed: 12/22/2022] Open
Abstract
Ultraviolet radiation resistance-associated gene (UVRAG) is a well-known regulator of autophagy by promoting autophagosome formation and maturation. Multiple studies have implicated UVRAG in the pathogenesis of colorectal cancer. However, the mechanisms underlying the regulation of UVRAG are unclear. Here, we describe miR-183 as a new autophagy-inhibiting miRNA. Our results showed that induction of autophagy lead to down-regulation of miR-183 in colorectal cancer cells. And, over-expression of miR-183 resulted in the attenuation of rapamycin- or starvation-induced autophagy in cancer cells, whereas inhibition of endogenous miR-183 stimulated autophagy and apoptosis. Additionally, either autophagy inhibitor 3-MA or pan-caspase inhibitor Z-VAD-FMK respectively or both treatments reversed AMO-183-induced cell death. Further studies showed that UVRAG is a target of miR-183 and as a key regulator promotes autophagy and apoptosis. More importantly, over-expression of UVRAG rescued autophagic activity and induced apoptosis in presence of miR-183. Therefore, the present study investigated the promoting effect of miR-183 on colorectal cancer progression, which was considered to be mediated by autophagy and apoptosis through targeting of UVRAG.
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Affiliation(s)
- Longtao Huangfu
- Department of Pharmacology State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education, Harbin Medical University, Harbin, Heilongjiang 150081, P. R. China
| | - Haihai Liang
- Department of Pharmacology State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education, Harbin Medical University, Harbin, Heilongjiang 150081, P. R. China
| | - Guojie Wang
- Department of Pharmacology State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education, Harbin Medical University, Harbin, Heilongjiang 150081, P. R. China
| | - Xiaomin Su
- Department of Pharmacology State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education, Harbin Medical University, Harbin, Heilongjiang 150081, P. R. China
| | - Linqiang Li
- Department of General Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150081, P. R. China
| | - Zhimin Du
- Institute of Clinical Pharmacy, The 2nd Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150081, P. R. China
| | - Meiyu Hu
- Department of Pharmacology State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education, Harbin Medical University, Harbin, Heilongjiang 150081, P. R. China
| | - Yuechao Dong
- Department of Pharmacology State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education, Harbin Medical University, Harbin, Heilongjiang 150081, P. R. China
| | - Xue Bai
- Department of Pharmacology State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education, Harbin Medical University, Harbin, Heilongjiang 150081, P. R. China
| | - Tianyi Liu
- Department of Pharmacology State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education, Harbin Medical University, Harbin, Heilongjiang 150081, P. R. China
| | - Baofeng Yang
- Department of Pharmacology State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education, Harbin Medical University, Harbin, Heilongjiang 150081, P. R. China
| | - Hongli Shan
- Department of Pharmacology State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education, Harbin Medical University, Harbin, Heilongjiang 150081, P. R. China
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Erturk FA, Aydin M, Sigmaz B, Taspinar MS, Arslan E, Agar G, Yagci S. Effects of As2O3 on DNA methylation, genomic instability, and LTR retrotransposon polymorphism in Zea mays. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:18601-6. [PMID: 26396013 DOI: 10.1007/s11356-015-5426-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 09/14/2015] [Indexed: 05/07/2023]
Abstract
Arsenic is a well-known toxic substance on the living organisms. However, limited efforts have been made to study its DNA methylation, genomic instability, and long terminal repeat (LTR) retrotransposon polymorphism causing properties in different crops. In the present study, effects of As2O3 (arsenic trioxide) on LTR retrotransposon polymorphism and DNA methylation as well as DNA damage in Zea mays seedlings were investigated. The results showed that all of arsenic doses caused a decreasing genomic template stability (GTS) and an increasing Random Amplified Polymorphic DNAs (RAPDs) profile changes (DNA damage). In addition, increasing DNA methylation and LTR retrotransposon polymorphism characterized a model to explain the epigenetically changes in the gene expression were also found. The results of this experiment have clearly shown that arsenic has epigenetic effect as well as its genotoxic effect. Especially, the increasing of polymorphism of some LTR retrotransposon under arsenic stress may be a part of the defense system against the stress.
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Affiliation(s)
- Filiz Aygun Erturk
- Department of Biology, Faculty of Science, Atatürk University, 25240, Erzurum, Turkey
| | - Murat Aydin
- Department of Field Crops, Faculty of Agriculture, Ataturk University, 25240, Erzurum, Turkey
| | - Burcu Sigmaz
- Department of Biology, Faculty of Science, Atatürk University, 25240, Erzurum, Turkey.
| | - M Sinan Taspinar
- Department of Agricultural Biotechnology, Faculty of Agriculture, Ataturk University, 25240, Erzurum, Turkey
| | - Esra Arslan
- Department of Biology, Faculty of Science, Atatürk University, 25240, Erzurum, Turkey
| | - Guleray Agar
- Department of Biology, Faculty of Science, Atatürk University, 25240, Erzurum, Turkey
| | - Semra Yagci
- Department of Biology, Faculty of Science, Atatürk University, 25240, Erzurum, Turkey
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Li Y, Zhu M, Zhang X, Cheng D, Ma X. Clinical significance of DAPK promoter hypermethylation in lung cancer: a meta-analysis. DRUG DESIGN DEVELOPMENT AND THERAPY 2015; 9:1785-96. [PMID: 25848215 PMCID: PMC4378294 DOI: 10.2147/dddt.s78012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Death-associated protein kinase 1 (DAPK) is an important serine/threonine kinase involved in various cellular processes, including apoptosis, autophagy, and inflammation. DAPK expression and activity are deregulated in a variety of diseases including cancer. Methylation of the DAPK gene is common in many types of cancer and can lead to loss of DAPK expression. However, the association between DAPK promoter hypermethylation and the clinicopathological significance of lung cancer remains unclear. In this study, we searched the MEDLINE, PubMed, Web of Science, and Scopus databases, systematically investigated the studies of DAPK promoter hypermethylation in lung cancer and quantified the association between DAPK promoter hypermethylation and its clinicopathological significance by meta-analysis. We observed that the frequency of DAPK methylation was significantly higher in lung cancer than in non-malignant lung tissues (odds ratio 6.02, 95% confidence interval 3.17-11.42, P<0.00001). The pooled results also showed the presence of a prognostic impact of DAPK gene methylation in lung cancer patients (odds ratio 3.63, 95% confidence interval 1.09-12.06, P=0.04). In addition, we summarized these findings and discuss tumor suppressor function, clinicopathological significance, and potential drug targeting of DAPK in lung cancer.
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Affiliation(s)
- Ying Li
- Department of Respiratory and Critical Care Medicine, Henan Provincial People's Hospital, Zhengzhou, People's Republic of China
| | - Min Zhu
- Department of Respiratory and Critical Care Medicine, Henan Provincial People's Hospital, Zhengzhou, People's Republic of China
| | - Xiaoju Zhang
- Department of Respiratory and Critical Care Medicine, Henan Provincial People's Hospital, Zhengzhou, People's Republic of China
| | - Dongjun Cheng
- Department of Respiratory and Critical Care Medicine, Henan Provincial People's Hospital, Zhengzhou, People's Republic of China
| | - Xitao Ma
- Department of Respiratory and Critical Care Medicine, Henan Provincial People's Hospital, Zhengzhou, People's Republic of China
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Caffo M, Caruso G, Fata GL, Barresi V, Visalli M, Venza M, Venza I. Heavy metals and epigenetic alterations in brain tumors. Curr Genomics 2015; 15:457-63. [PMID: 25646073 PMCID: PMC4311389 DOI: 10.2174/138920291506150106151847] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Revised: 11/19/2014] [Accepted: 11/19/2014] [Indexed: 02/08/2023] Open
Abstract
Heavy metals and their derivatives can cause various diseases. Numerous studies have evaluated the possible link between exposure to heavy metals and various cancers. Recent data show a correlation between heavy metals and aberration of genetic and epigenetic patterns. From a literature search we noticed few experimental and epidemiological studies that evaluate a possible correlation between heavy metals and brain tumors. Gliomas arise due to genetic and epigenetic alterations of glial cells. Changes in gene expression result in the alteration of the cellular division process. Epigenetic alterations in brain tumors include the hypermethylation of CpG group, hypomethylation of specific genes, aberrant activation of genes, and changes in the position of various histones. Heavy metals are capable of generating reactive oxygen assumes that key functions in various pathological mechanisms. Alteration of homeostasis of metals could cause the overproduction of reactive oxygen species and induce DNA damage, lipid peroxidation, and alteration of proteins. In this study we summarize the possible correlation between heavy metals, epigenetic alterations and brain tumors. We report, moreover, the review of relevant literature.
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Affiliation(s)
- Maria Caffo
- Neurosurgical Clinic, Department of Neuroscience, University of Messina, Messina, Italy
| | - Gerardo Caruso
- Neurosurgical Clinic, Department of Neuroscience, University of Messina, Messina, Italy
| | - Giuseppe La Fata
- Neurosurgical Clinic, Department of Neuroscience, University of Messina, Messina, Italy
| | - Valeria Barresi
- Department of Human Pathology, University of Messina, Messina, Italy
| | - Maria Visalli
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Mario Venza
- Department of Experimental Specialized Medical and Surgical and Odontostomatology Sciences, University of Messina, Messina, Italy
| | - Isabella Venza
- Department of Experimental Specialized Medical and Surgical and Odontostomatology Sciences, University of Messina, Messina, Italy
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Ray PD, Yosim A, Fry RC. Incorporating epigenetic data into the risk assessment process for the toxic metals arsenic, cadmium, chromium, lead, and mercury: strategies and challenges. Front Genet 2014; 5:201. [PMID: 25076963 PMCID: PMC4100550 DOI: 10.3389/fgene.2014.00201] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 06/16/2014] [Indexed: 12/24/2022] Open
Abstract
Exposure to toxic metals poses a serious human health hazard based on ubiquitous environmental presence, the extent of exposure, and the toxicity and disease states associated with exposure. This global health issue warrants accurate and reliable models derived from the risk assessment process to predict disease risk in populations. There has been considerable interest recently in the impact of environmental toxicants such as toxic metals on the epigenome. Epigenetic modifications are alterations to an individual's genome without a change in the DNA sequence, and include, but are not limited to, three commonly studied alterations: DNA methylation, histone modification, and non-coding RNA expression. Given the role of epigenetic alterations in regulating gene and thus protein expression, there is the potential for the integration of toxic metal-induced epigenetic alterations as informative factors in the risk assessment process. In the present review, epigenetic alterations induced by five high priority toxic metals/metalloids are prioritized for analysis and their possible inclusion into the risk assessment process is discussed.
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Affiliation(s)
- Paul D. Ray
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North CarolinaChapel Hill, NC, USA
- Curriculum in Toxicology, School of Medicine, University of North CarolinaChapel Hill, NC, USA
| | - Andrew Yosim
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North CarolinaChapel Hill, NC, USA
| | - Rebecca C. Fry
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North CarolinaChapel Hill, NC, USA
- Curriculum in Toxicology, School of Medicine, University of North CarolinaChapel Hill, NC, USA
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Yang TY, Hsu LI, Chiu AW, Pu YS, Wang SH, Liao YT, Wu MM, Wang YH, Chang CH, Lee TC, Chen CJ. Comparison of genome-wide DNA methylation in urothelial carcinomas of patients with and without arsenic exposure. ENVIRONMENTAL RESEARCH 2014; 128:57-63. [PMID: 24268366 DOI: 10.1016/j.envres.2013.10.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Revised: 09/28/2013] [Accepted: 10/29/2013] [Indexed: 06/02/2023]
Abstract
BACKGROUND Arsenic is a well-documented carcinogen of human urothelial carcinoma (UC) with incompletely understood mechanisms. OBJECTIVES This study aimed to compare the genome-wide DNA methylation profiles of arsenic-induced UC (AsUC) and non-arsenic-induced UC (Non-AsUC), and to assess associations between site-specific methylation levels and cumulative arsenic exposure. METHODS Genome-wide DNA methylation profiles in 14 AsUC and 14 non-AsUC were analyzed by Illumina Infinium methylation27 BeadChip and validated by bisulfite pyrosequencing. Mean methylation levels (β¯) in AsUC and non-AsUC were compared by their ratio (β¯ ratio) and difference (Δβ¯). Associations between site-specific methylation levels in UC and cumulative arsenic exposure were examined. RESULTS Among 27,578 methylation sites analyzed, 231 sites had β¯ ratio >2 or <0.5 and 45 sites had Δβ¯ >0.2 or <-0.2. There were 13 sites showing statistically significant (q<0.05) differences in β¯ between AsUC and non-AsUC including 12 hypermethylation sites in AsUC and only one hypermethylation site in non-AsUC. Significant associations between cumulative arsenic exposure and DNA methylation levels of 28 patients were observed in nine CpG sites of nine gens including PDGFD (Spearman rank correlation, 0.54), CTNNA2 (0.48), KCNK17 (0.52), PCDHB2 (0.57), ZNF132 (0.48), DCDC2 (0.48), KLK7 (0.48), FBXO39 (0.49), and NPY2R (0.45). These associations remained statistically significant for CpG sites in CTNNA2, KLK7, NPY2R, ZNF132 and KCNK17 in 20 non-smoking women after adjustment for tumor stage and age. CONCLUSIONS Significant associations between cumulative arsenic exposure and methylation level of CTNNA2, KLK7, NPY2R, ZNF132 and KCNK17 were found in smoking-unrelated urothelial carcinoma. Arsenic exposure may cause urothelial carcinomas through the hypermethylation of genes involved in cell adhesion, proteolysis, transcriptional regulation, neuronal pathway, and ion transport. The findings of this study, which are limited by its small sample size and moderate dose-response relation, remain to be validated by further studies with large sample sizes.
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Affiliation(s)
- Tse-Yen Yang
- Graduate Institute of Life Science, National Defense Medical Center, Taipei, Taiwan; Genomics Research Center, Academia Sinica, Taipei, Taiwan; Molecular and Genomic Epidemiology Center, China Medical University Hospital, Taichung, Taiwan; China Medical University, Taichung, Taiwan
| | - Ling-I Hsu
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Allen W Chiu
- College of Medicine, National Yang-Ming University Hospital, Taipei, Taiwan
| | - Yeong-Shiau Pu
- Department of Urology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Sheng-Hsin Wang
- Department of Urology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ya-Tang Liao
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Meei-Maan Wu
- Graduate Institute of Oncology, National Taiwan University, Taipei, Taiwan
| | - Yuan-Hung Wang
- Division of General Surgery, Department of Urology, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chin-Hao Chang
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Te-Chang Lee
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chien-Jen Chen
- Graduate Institute of Life Science, National Defense Medical Center, Taipei, Taiwan; Genomics Research Center, Academia Sinica, Taipei, Taiwan; Graduate Institute of Epidemiology and Preventive Medicine, National Taiwan University, Taipei, Taiwan.
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14
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Banerjee N, Paul S, Sau TJ, Das JK, Bandyopadhyay A, Banerjee S, Giri AK. Epigenetic Modifications of DAPK and p16 Genes Contribute to Arsenic-Induced Skin Lesions and Nondermatological Health Effects. Toxicol Sci 2013; 135:300-8. [DOI: 10.1093/toxsci/kft163] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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15
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Baspinar S, Bircan S, Yavuz G, Kapucuoglu N. Beclin 1 and bcl-2 expressions in bladder urothelial tumors and their association with clinicopathological parameters. Pathol Res Pract 2013; 209:418-23. [PMID: 23722017 DOI: 10.1016/j.prp.2013.04.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Revised: 03/27/2013] [Accepted: 04/16/2013] [Indexed: 02/08/2023]
Abstract
Beclin 1 plays a critical role in the regulation of autophagy, apoptosis, differentiation, as well as in the development and progression of cancer. The aim of this study was to examine the expression of beclin 1 and bcl-2 in bladder urothelial tumors, and to investigate the relationship between these two markers and clinicopathological parameters. Our study included 84 bladder urothelial tumors and 10 non-tumoral bladder tissues. Immunohistochemistry was performed on tissue microarray (TMA) sections and was evaluated semiquantitatively on the basis of the percentage of positively stained cells (proportion) and staining intensity. A significant association was found between the expression score of beclin 1 and pT stages of the urothelial tumors (p=0.012). Also, the level of beclin 1 expression inversely correlated with histological grade and pT stages (p=0.009, r=-0.284; p=0.001, r=-0.361, respectively). The bcl-2 expression level positively correlated with histological grade and pT stages of the urothelial tumors (p=0.026, r=0.243; p<0.0001, r=0.491, respectively). In addition, the level of beclin 1 expression tended to be inversely correlated with the bcl-2 expression level in urothelial tumors (p=0.055, r=-0.210). According to our data, down-regulation of beclin 1 expression and also bcl-2 overexpression seem to play an important role in the progression and aggressiveness of bladder urothelial tumors.
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Affiliation(s)
- Sirin Baspinar
- Department of Pathology, Suleyman Demirel University, School of Medicine, Isparta, Turkey.
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16
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Arsenic inhibits autophagic flux, activating the Nrf2-Keap1 pathway in a p62-dependent manner. Mol Cell Biol 2013; 33:2436-46. [PMID: 23589329 DOI: 10.1128/mcb.01748-12] [Citation(s) in RCA: 174] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Nrf2-Keap1 signaling pathway is a protective mechanism promoting cell survival. Activation of the Nrf2 pathway by natural compounds has been proven to be an effective strategy for chemoprevention. Interestingly, a cancer-promoting function of Nrf2 has recently been observed in many types of tumors due to deregulation of the Nrf2-Keap1 axis, which leads to constitutive activation of Nrf2. Here, we report a novel mechanism of Nrf2 activation by arsenic that is distinct from that of chemopreventive compounds. Arsenic deregulates the autophagic pathway through blockage of autophagic flux, resulting in accumulation of autophagosomes and sequestration of p62, Keap1, and LC3. Thus, arsenic activates Nrf2 through a noncanonical mechanism (p62 dependent), leading to a chronic, sustained activation of Nrf2. In contrast, activation of Nrf2 by sulforaphane (SF) and tert-butylhydroquinone (tBHQ) depends upon Keap1-C151 and not p62 (the canonical mechanism). More importantly, SF and tBHQ do not have any effect on autophagy. In fact, SF and tBHQ alleviate arsenic-mediated deregulation of autophagy. Collectively, these findings provide evidence that arsenic causes prolonged activation of Nrf2 through autophagy dysfunction, possibly providing a scenario similar to that of constitutive activation of Nrf2 found in certain human cancers. This may represent a previously unrecognized mechanism underlying arsenic toxicity and carcinogenicity in humans.
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17
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Hubaux R, Becker-Santos DD, Enfield KS, Rowbotham D, Lam S, Lam WL, Martinez VD. Molecular features in arsenic-induced lung tumors. Mol Cancer 2013; 12:20. [PMID: 23510327 PMCID: PMC3626870 DOI: 10.1186/1476-4598-12-20] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 03/07/2013] [Indexed: 11/10/2022] Open
Abstract
Arsenic is a well-known human carcinogen, which potentially affects ~160 million people worldwide via exposure to unsafe levels in drinking water. Lungs are one of the main target organs for arsenic-related carcinogenesis. These tumors exhibit particular features, such as squamous cell-type specificity and high incidence among never smokers. Arsenic-induced malignant transformation is mainly related to the biotransformation process intended for the metabolic clearing of the carcinogen, which results in specific genetic and epigenetic alterations that ultimately affect key pathways in lung carcinogenesis. Based on this, lung tumors induced by arsenic exposure could be considered an additional subtype of lung cancer, especially in the case of never-smokers, where arsenic is a known etiological agent. In this article, we review the current knowledge on the various mechanisms of arsenic carcinogenicity and the specific roles of this metalloid in signaling pathways leading to lung cancer.
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Affiliation(s)
- Roland Hubaux
- British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC V5Z 1L3, Canada
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18
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Toxicogenomic approaches for understanding molecular mechanisms of heavy metal mutagenicity and carcinogenicity. Int J Hyg Environ Health 2013; 216:587-98. [PMID: 23540489 DOI: 10.1016/j.ijheh.2013.02.010] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 02/26/2013] [Accepted: 02/26/2013] [Indexed: 12/24/2022]
Abstract
Heavy metals that are harmful to humans include arsenic, cadmium, chromium, lead, mercury, and nickel. Some metals or their related compounds may even cause cancer. However, the mechanism underlying heavy metal-induced cancer remains unclear. Increasing data show a link between heavy metal exposure and aberrant changes in both genetic and epigenetic factors via non-targeted multiple toxicogenomic technologies of the transcriptome, proteome, metabolome, and epigenome. These modifications due to heavy metal exposure might provide a better understanding of environmental disorders. Such informative changes following heavy metal exposure might also be useful for screening of biomarker-monitored exposure to environmental pollutants and/or predicting the risk of disease. We summarize advances in high-throughput toxicogenomic-based technologies and studies related to exposure to individual heavy metal and/or mixtures and propose the underlying mechanism of action and toxicant signatures. Integrative multi-level expression analysis of the toxicity of heavy metals via system toxicology-based methodologies combined with statistical and computational tools might clarify the biological pathways involved in carcinogenic processes. Although standard in vitro and in vivo endpoint testing of mutagenicity and carcinogenicity are considered a complementary approach linked to disease, we also suggest that further evaluation of prominent biomarkers reflecting effects, responses, and disease susceptibility might be diagnostic. Furthermore, we discuss challenges in toxicogenomic applications for toxicological studies of metal mixtures and epidemiological research. Taken together, this review presents toxicogenomic data that will be useful for improvement of the knowledge of carcinogenesis and the development of better strategies for health risk assessment.
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19
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Erman A, Resnik N, Romih R. Autophagic activity in the mouse urinary bladder urothelium as a response to starvation. PROTOPLASMA 2013; 250:151-160. [PMID: 22407469 DOI: 10.1007/s00709-012-0387-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 02/08/2012] [Indexed: 05/31/2023]
Abstract
The urinary bladder urothelium is subjected to mechanical forces during cycles of distension and contraction, and its superficial cells are constantly flushed by toxic urine. Yet, the urothelium shows a very slow turnover of cells and superficial cells are extremely long lived. Autophagy has a well-known role in tissue homeostasis and serves as a protective mechanism against cellular stress. Therefore, the presence of autophagy as one of possible processes of survival in an unpleasant environment and during long lifetime of superficial cells was examined in mouse urothelium. We detected and evaluated autophagic activity of superficial urothelial cells under normal and stress conditions, caused by short-term starvation of newborn and 24-h-starved adult mice. Immunolabeling and Western blotting of essential effectors of autophagy, LC3 and Beclin 1, showed a weak signal in superficial urothelial cells. On the other hand, ultrastructural analysis, which proved to be the most reliable method in our study, revealed the presence of autophagic vacuoles, some of them containing specific urothelial structures, fusiform vesicles. Quantitative analysis showed increased autophagy in newborn and starved mice in comparison to a low basic level of autophagy in the urothelium of normal mice. Interestingly, some superficial cells of adults and neonates exhibit intense immunoreactions against LC3 and Beclin 1 and the typical ultrastructural characteristics of autophagy-dependent cell death. We conclude that autophagy, despite low basic activity under physiological conditions, plays an important role in urothelial homeostasis and stability under stress.
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Affiliation(s)
- Andreja Erman
- Institute of Cell Biology, Faculty of Medicine, Lipičeva 2, 1000 Ljubljana, Slovenia.
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20
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Bailey KA, Wu MC, Ward WO, Smeester L, Rager JE, García-Vargas G, Del Razo LM, Drobná Z, Stýblo M, Fry RC. Arsenic and the epigenome: interindividual differences in arsenic metabolism related to distinct patterns of DNA methylation. J Biochem Mol Toxicol 2013; 27:106-15. [PMID: 23315758 DOI: 10.1002/jbt.21462] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 10/09/2012] [Accepted: 10/24/2012] [Indexed: 12/17/2022]
Abstract
Biotransformation of inorganic arsenic (iAs) is one of the factors that determines the character and magnitude of the diverse detrimental health effects associated with chronic iAs exposure, but it is unknown how iAs biotransformation may impact the epigenome. Here, we integrated analyses of genome-wide, gene-specific promoter DNA methylation levels of peripheral blood leukocytes with urinary arsenical concentrations of subjects from a region of Mexico with high levels of iAs in drinking water. These analyses revealed dramatic differences in DNA methylation profiles associated with concentrations of specific urinary metabolites of arsenic (As). The majority of individuals in this study had positive indicators of As-related disease, namely pre-diabetes mellitus or diabetes mellitus (DM). Methylation patterns of genes with known associations with DM were associated with urinary concentrations of specific iAs metabolites. Future studies will determine whether these DNA methylation profiles provide mechanistic insight into the development of iAs-associated disease, predict disease risk, and/or serve as biomarkers of iAs exposure in humans.
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Affiliation(s)
- Kathryn A Bailey
- Department of Environmental Sciences and Engineering, UNC Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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21
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Banerjee C, Singh A, Raman R, Mazumder S. Calmodulin–CaMKII mediated alteration of oxidative stress: interplay of the cAMP/PKA–ERK 1/2-NF-κB–NO axis on arsenic-induced head kidney macrophage apoptosis. Toxicol Res (Camb) 2013. [DOI: 10.1039/c3tx50026h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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22
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Treas JN, Tyagi T, Singh KP. Effects of chronic exposure to arsenic and estrogen on epigenetic regulatory genes expression and epigenetic code in human prostate epithelial cells. PLoS One 2012; 7:e43880. [PMID: 22952798 PMCID: PMC3428278 DOI: 10.1371/journal.pone.0043880] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 07/26/2012] [Indexed: 02/05/2023] Open
Abstract
Chronic exposures to arsenic and estrogen are known risk factors for prostate cancer. Though the evidence suggests that exposure to arsenic or estrogens can disrupt normal DNA methylation patterns and histone modifications, the mechanisms by which these chemicals induce epigenetic changes are not fully understood. Moreover, the epigenetic effects of co-exposure to these two chemicals are not known. Therefore, the objective of this study was to evaluate the effects of chronic exposure to arsenic and estrogen, both alone and in combination, on the expression of epigenetic regulatory genes, their consequences on DNA methylation, and histone modifications. Human prostate epithelial cells, RWPE-1, chronically exposed to arsenic and estrogen alone and in combination were used for analysis of epigenetic regulatory genes expression, global DNA methylation changes, and histone modifications at protein level. The result of this study revealed that exposure to arsenic, estrogen, and their combination alters the expression of epigenetic regulatory genes and changes global DNA methylation and histone modification patterns in RWPE-1 cells. These changes were significantly greater in arsenic and estrogen combination treated group than individually treated group. The findings of this study will help explain the epigenetic mechanism of arsenic- and/or estrogen-induced prostate carcinogenesis.
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Affiliation(s)
- Justin N. Treas
- Department of Environmental Toxicology, The Institute of Environmental and Human Health (TIEHH), Texas Tech University, Lubbock, Texas, United States of America
| | - Tulika Tyagi
- Department of Environmental Toxicology, The Institute of Environmental and Human Health (TIEHH), Texas Tech University, Lubbock, Texas, United States of America
| | - Kamaleshwar P. Singh
- Department of Environmental Toxicology, The Institute of Environmental and Human Health (TIEHH), Texas Tech University, Lubbock, Texas, United States of America
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23
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Hou L, Zhang X, Wang D, Baccarelli A. Environmental chemical exposures and human epigenetics. Int J Epidemiol 2012; 41:79-105. [PMID: 22253299 PMCID: PMC3304523 DOI: 10.1093/ije/dyr154] [Citation(s) in RCA: 279] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2011] [Indexed: 02/06/2023] Open
Abstract
Every year more than 13 million deaths worldwide are due to environmental pollutants, and approximately 24% of diseases are caused by environmental exposures that might be averted through preventive measures. Rapidly growing evidence has linked environmental pollutants with epigenetic variations, including changes in DNA methylation, histone modifications and microRNAs. Environ mental chemicals and epigenetic changes All of these mechanisms are likely to play important roles in disease aetiology, and their modifications due to environmental pollutants might provide further understanding of disease aetiology, as well as biomarkers reflecting exposures to environmental pollutants and/or predicting the risk of future disease. We summarize the findings on epigenetic alterations related to environmental chemical exposures, and propose mechanisms of action by means of which the exposures may cause such epigenetic changes. We discuss opportunities, challenges and future directions for future epidemiology research in environmental epigenomics. Future investigations are needed to solve methodological and practical challenges, including uncertainties about stability over time of epigenomic changes induced by the environment, tissue specificity of epigenetic alterations, validation of laboratory methods, and adaptation of bioinformatic and biostatistical methods to high-throughput epigenomics. In addition, there are numerous reports of epigenetic modifications arising following exposure to environmental toxicants, but most have not been directly linked to disease endpoints. To complete our discussion, we also briefly summarize the diseases that have been linked to environmental chemicals-related epigenetic changes.
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Affiliation(s)
- Lifang Hou
- Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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24
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Liao WT, Lan CCE, Lee CH, Yu HS. Concentration-dependent cellular responses of arsenic in keratinocytes. Kaohsiung J Med Sci 2011; 27:390-5. [DOI: 10.1016/j.kjms.2011.05.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 11/18/2010] [Indexed: 01/31/2023] Open
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25
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Ren X, McHale CM, Skibola CF, Smith AH, Smith MT, Zhang L. An emerging role for epigenetic dysregulation in arsenic toxicity and carcinogenesis. ENVIRONMENTAL HEALTH PERSPECTIVES 2011; 119:11-9. [PMID: 20682481 PMCID: PMC3018488 DOI: 10.1289/ehp.1002114] [Citation(s) in RCA: 172] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Accepted: 08/02/2010] [Indexed: 05/08/2023]
Abstract
BACKGROUND Exposure to arsenic, an established human carcinogen, through consumption of highly contaminated drinking water is a worldwide public health concern. Several mechanisms by which arsenical compounds induce tumorigenesis have been proposed, including oxidative stress, genotoxic damage, and chromosomal abnormalities. Recent studies have suggested that epigenetic mechanisms may also mediate toxicity and carcinogenicity resulting from arsenic exposure. OBJECTIVE We examined the evidence supporting the roles of the three major epigenetic mechanisms-DNA methylation, histone modification, and microRNA (miRNA) expression-in arsenic toxicity and, in particular, carcinogenicity. We also investigated future research directions necessary to clarify epigenetic and other mechanisms in humans. DATA SOURCES AND SYNTHESIS We conducted a PubMed search of arsenic exposure and epigenetic modification through April 2010 and summarized the in vitro and in vivo research findings, from both our group and others, on arsenic-associated epigenetic alteration and its potential role in toxicity and carcinogenicity. CONCLUSIONS Arsenic exposure has been shown to alter methylation levels of both global DNA and gene promoters; histone acetylation, methylation, and phosphorylation; and miRNA expression, in studies analyzing mainly a limited number of epigenetic end points. Systematic epigenomic studies in human populations exposed to arsenic or in patients with arsenic-associated cancer have not yet been performed. Such studies would help to elucidate the relationship between arsenic exposure, epigenetic dysregulation, and carcinogenesis and are becoming feasible because of recent technological advancements.
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Affiliation(s)
- Xuefeng Ren
- Division of Environmental Health Sciences, School of Public Health, University of California–Berkeley, Berkeley, California 94720, USA.
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26
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Rossman TG, Klein CB. Genetic and epigenetic effects of environmental arsenicals. Metallomics 2011; 3:1135-41. [DOI: 10.1039/c1mt00074h] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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27
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McHale CM, Zhang L, Hubbard AE, Smith MT. Toxicogenomic profiling of chemically exposed humans in risk assessment. Mutat Res 2010; 705:172-83. [PMID: 20382258 PMCID: PMC2928857 DOI: 10.1016/j.mrrev.2010.04.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 04/01/2010] [Indexed: 12/13/2022]
Abstract
Gene-environment interactions contribute to complex disease development. The environmental contribution, in particular low-level and prevalent environmental exposures, may constitute much of the risk and contribute substantially to disease. Systematic risk evaluation of the majority of human chemical exposures, has not been conducted and is a goal of regulatory agencies in the U.S. and worldwide. With the recent recognition that toxicological approaches more predictive of effects in humans are required for risk assessment, in vitro human cell line data as well as animal data are being used to identify toxicity mechanisms that can be translated into biomarkers relevant to human exposure studies. In this review, we discuss how data from toxicogenomic studies of exposed human populations can inform risk assessment, by generating biomarkers of exposure, early effect, and/or susceptibility, elucidating mechanisms of action underlying exposure-related disease, and detecting response at low doses. Good experimental design incorporating precise, individual exposure measurements, phenotypic anchors (pre-disease or traditional toxicological markers), and a range of relevant exposure levels, is necessary. Further, toxicogenomic studies need to be designed with sufficient power to detect true effects of the exposure. As more studies are performed and incorporated into databases such as the Comparative Toxicogenomics Database (CTD) and Chemical Effects in Biological Systems (CEBS), data can be mined for classification of newly tested chemicals (hazard identification), and, for investigating the dose-response, and inter-relationship among genes, environment and disease in a systems biology approach (risk characterization).
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Affiliation(s)
- Cliona M. McHale
- School of Public Health, Division of Environmental Health Sciences, University of California, Berkeley, CA 94720
| | - Luoping Zhang
- School of Public Health, Division of Environmental Health Sciences, University of California, Berkeley, CA 94720
| | - Alan E. Hubbard
- School of Public Health, Division of Biostatistics, University of California, Berkeley, CA 94720
| | - Martyn T. Smith
- School of Public Health, Division of Environmental Health Sciences, University of California, Berkeley, CA 94720
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28
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Huang YC, Hung WC, Chen WT, Jiang WH, Yu HS, Chai CY. Effects of MEK and DNMT inhibitors on arsenic-treated human uroepithelial cells in relation to Cyclin-D1 and p16. Toxicol Lett 2010; 200:59-66. [PMID: 21040761 DOI: 10.1016/j.toxlet.2010.10.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 10/20/2010] [Accepted: 10/21/2010] [Indexed: 11/28/2022]
Abstract
Arsenic compounds are well-known toxic and carcinogenic agents, and they are widely distributed throughout the earth's crust. These compounds are associated with various human malignancies. It has been reported that there is an elevated risk of bladder cancer in an area highly contaminated with arsenic on the southwest coast of Taiwan. However, the underlying mechanisms of arsenic-associated carcinogenesis are still unclear. The cell cycle regulatory proteins are important indicators in control of cell cycle progression. Moreover, the high expression of Cyclin-D1 and loss of p16 has been associated with a worse prognosis in a variety of human cancers. Therefore, we investigated the effect of arsenic on Cyclin-D1 and p16 expression and evaluated the role of the ERK signaling pathway and DNA methylation in arsenic carcinogenesis. Our study results showed that Cyclin-D1 high expression was found in 56.3% (9/16) of urothelial carcinomas (UC) from a blackfoot disease (BFD) area and 6.3% (1/16) of UC from a non-BFD area (p=0.002). The p16 low expression in 81.2% (13/16) of UC from BFD areas was significantly lower than in non-BFD areas (25.0%; 4/16) (p=0.001). In addition, the Cyclin-D1 increased expression but decreased p16 expression in arsenite-treated SV-HUC-1 cells. However, when cells were pretreated with inhibitors (5-aza-CdR or U0126), the effects of arsenite on Cyclin-D1 and p16 expression were suppressed. Finally, these results indicated that Cyclin-D1 and p16 both might play important roles in carcinogenesis as a result of arsenic.
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Affiliation(s)
- Ya-Chun Huang
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
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29
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Beclin-1 expression in normal bladder and in Cd2+ and As3+ exposed and transformed human urothelial cells (UROtsa). Toxicol Lett 2010; 195:15-22. [PMID: 20206246 DOI: 10.1016/j.toxlet.2010.02.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 02/22/2010] [Accepted: 02/23/2010] [Indexed: 11/20/2022]
Abstract
The expression of beclin-1 in normal human bladder and in Cd(2+) and As(3+) exposed and transformed urothelial cells (UROtsa) was examined in this study. It was shown using a combination of real-time PCR, Western analysis and immunohistochemistry that beclin-1 was expressed in the urothelial cells of the normal bladder. It was also demonstrated that the parental UROtsa cell line expressed beclin-1 mRNA and protein at levels similar to that of the in situ urothelium. The level of beclin-1 expression underwent only modest alterations when the UROtsa cells were malignantly transformed by Cd(2+) or As(3+) or when the parental cells were exposed acutely to Cd(2+) or As(3+). While there were instances of significant alterations at individual time points and within cell line-to-cell line comparisons there was no evidence of a dose-response relationship or correlations to the phenotypic properties of the cell lines. Similar results were obtained for the expression of the Atg-5, Atg-7, Atg-12 and LC3B autophagy-related proteins. The findings provide initial evidence for beclin-1 expression in normal bladder and that large alterations in the expression of beclin-1 and associated proteins do not occur when human urothelial cells are malignantly transformed with, or exposed to, either Cd(2+) or As(3+.).
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30
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Abstract
Autophagy is a physiological process that is activated not only in response to stress (e.g., degradation of damaged organelles or nutrient starvation) but also during carcinogenesis and tumor progression. Furthermore, a number of commonly used anticancer drugs activate the autophagic program, a response that, in most cases, suppresses the cytotoxic effects of the drugs, where in some other cases, autophagy promotes drug-induced cell death. Significant progress has been made on delineating the signaling cascades activated during autophagy. A number of known or candidate tumor-suppressor genes that are involved in autophagy have been shown to be activated or inactivated in various cancer types. These genetic perturbations do not only affect carcinogenesis but also the responses of the cancer cells to treatment. The current state-of-the-art with respect to the genes regulating autophagy and the importance of autophagy in the cytotoxic response of cancer treatments will be discussed in this review.
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31
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Peng CY, Jiang J, Zheng HT, Liu XS. Growth-inhibiting effects of arsenic trioxide plus epigenetic therapeutic agents on leukemia cell lines. Leuk Lymphoma 2009; 51:297-303. [DOI: 10.3109/10428190903486212] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Jo WJ, Ren X, Chu F, Aleshin M, Wintz H, Burlingame A, Smith MT, Vulpe CD, Zhang L. Acetylated H4K16 by MYST1 protects UROtsa cells from arsenic toxicity and is decreased following chronic arsenic exposure. Toxicol Appl Pharmacol 2009; 241:294-302. [PMID: 19732783 DOI: 10.1016/j.taap.2009.08.027] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 08/20/2009] [Accepted: 08/24/2009] [Indexed: 01/08/2023]
Abstract
Arsenic, a human carcinogen that is associated with an increased risk of bladder cancer, is commonly found in drinking water. An important mechanism by which arsenic is thought to be carcinogenic is through the induction of epigenetic changes that lead to aberrant gene expression. Previously, we reported that the SAS2 gene is required for optimal growth of yeast in the presence of arsenite (As(III)). Yeast Sas2p is orthologous to human MYST1, a histone 4 lysine 16 (H4K16) acetyltransferase. Here, we show that H4K16 acetylation is necessary for the resistance of yeast to As(III) through the modulation of chromatin state. We further explored the role of MYST1 and H4K16 acetylation in arsenic toxicity and carcinogenesis in human bladder epithelial cells. The expression of MYST1 was knocked down in UROtsa cells, a model of bladder epithelium that has been used to study arsenic-induced carcinogenesis. Silencing of MYST1 reduced acetylation of H4K16 and induced sensitivity to As(III) and to its more toxic metabolite monomethylarsonous acid (MMA(III)) at doses relevant to high environmental human exposures. In addition, both As(III) and MMA(III) treatments decreased global H4K16 acetylation levels in a dose- and time-dependent manner. This indicates that acetylated H4K16 is required for resistance to arsenic and that a reduction in its levels as a consequence of arsenic exposure may contribute to toxicity in UROtsa cells. Based on these findings, we propose a novel role for the MYST1 gene in human sensitivity to arsenic.
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Affiliation(s)
- William Jaime Jo
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA 94720, USA.
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Charoensuk V, Gati WP, Weinfeld M, Le XC. Differential cytotoxic effects of arsenic compounds in human acute promyelocytic leukemia cells. Toxicol Appl Pharmacol 2009; 239:64-70. [DOI: 10.1016/j.taap.2009.05.016] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 05/15/2009] [Accepted: 05/15/2009] [Indexed: 12/21/2022]
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Huang YC, Hung WC, Chen WT, Yu HS, Chai CY. Sodium arsenite-induced DAPK promoter hypermethylation and autophagy via ERK1/2 phosphorylation in human uroepithelial cells. Chem Biol Interact 2009; 181:254-62. [PMID: 19577553 DOI: 10.1016/j.cbi.2009.06.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Revised: 06/16/2009] [Accepted: 06/25/2009] [Indexed: 12/19/2022]
Abstract
Arsenic compounds or arsenicals are well-known toxic and carcinogenic agents. The toxic effects of arsenic that are of most concern to humans are those that occur from chronic, low-level exposure, and are associated with various human malignancies, including skin, lung and bladder cancers. In addition, arsenic could induce cell death, including apoptosis or autophagy in malignant cells. Previously, we have demonstrated that arsenite can induce autophagy and death-associated protein kinase (DAPK) promoter hypermethylation in the SV-40 immortalized human uroepithelial cell line (SV-HUC-1). However, the underlying mechanism of arsenite-induced autophagy is still unclear. In the present study, we demonstrate that arsenite can activate the extracellular signaling-regulated protein kinase 1/2 (ERK1/2) signaling pathway after treatment in SV-HUC-1 cells by using immunocytochemistry and Western blotting. In addition, our results also show an increase of autophagosomes was produced in arsenite-treated SV-HUC-1 cells by using electron microscopy. We found that, by incrementally increasing the dosages, microtubule-associated protein light chain 3B (LC3B) and Beclin-1 are important regulators for the formation of autophagosomes, in a dose-dependent manner. When the cells were pretreated with inhibitors 5-aza-CdR or U0126 for 24h, the effect of arsenite on ERK1/2, LC3B, Beclin-1 and DAPK proteins expression is suppressed. Furthermore, our results support the notion that arsenite can induce the ERK1/2 signaling pathway to stimulate autophagy and DAPK promoter hypermethylation in human uroepithelial SV-HUC-1 cells. These findings may contribute to a better understanding of the carcinogenesis of arsenite.
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Abstract
Although carcinogenic metals have been known to disrupt a wide range of cellular processes the precise mechanism by which these exert their carcinogenic effects is not known. Over the last decade or two, studies in the field of metal carcinogenesis suggest that epigenetic mechanisms may play a role in metal-induced carcinogenesis. In this review we summarize the evidence demonstrating that exposure to carcinogenic metals such as nickel, arsenic, chromium, and cadmium can perturb DNA methylation levels as well as global and gene specific histone tail posttranslational modification marks. We also wish to emphasize the importance in understanding that gene expression can be regulated by both genetic and epigenetic mechanisms and both these must be considered when studying the mechanism underlying the toxicity and cell-transforming ability of carcinogenic metals and other toxicants, and aberrant changes in gene expression that occur during disease states such as cancer.
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Affiliation(s)
- Adriana Arita
- Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, NY 10987, USA
| | - Max Costa
- Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, NY 10987, USA
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Zhou X, Sun H, Ellen TP, Chen H, Costa M. Arsenite alters global histone H3 methylation. Carcinogenesis 2008; 29:1831-6. [PMID: 18321869 DOI: 10.1093/carcin/bgn063] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Arsenic (As) is a well-characterized human carcinogen but is generally not mutagenic. The evidence that As induces both loss of global DNA methylation and gene promoter DNA hypermethylation has suggested that epigenetic mechanisms may play an important role in As-induced carcinogenesis. In the present study, we examined the change in histone methylation by As exposure. In human lung carcinoma A549 cells, exposure to inorganic trivalent As (arsenite) increased H3K9 dimethylation (H3K9me2) and decreased H3K27 trimethylation (H3K27me3), both of which represent gene silencing marks, while increasing the global levels of the H3K4 trimethylation (H3K4me3), a gene-activating mark. The increase in H3K9me2 was mediated by an increase in the histone methyltransferase G9a protein and messenger RNA levels. We also observed strikingly significant altered histone modifications induced by very low-dose (0.1 microM) arsenite. Taken together, these results suggest a potential mechanism by which As induces carcinogenesis through the alteration of specific histone methylations that represent both gene silencing and activating marks. Furthermore, these marks are known to affect DNA methylation, and it is likely that arsenic's effect is not limited to histone modifications alone, but extends, perhaps by them, to DNA methylations as well. Future studies in our laboratory will address the genomic location of these silencing and activating marks using ChIP-on-chip technology.
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Affiliation(s)
- Xue Zhou
- Department of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, NY 10987, USA
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