1
|
Rea M, Kimmerer G, Mittendorf S, Xiong X, Green M, Chandler D, Saintilnord W, Blackburn J, Gao T, Fondufe-Mittendorf YN. A dynamic model of inorganic arsenic-induced carcinogenesis reveals an epigenetic mechanism for epithelial-mesenchymal plasticity. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 347:123586. [PMID: 38467368 PMCID: PMC11005477 DOI: 10.1016/j.envpol.2024.123586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 02/12/2024] [Accepted: 02/14/2024] [Indexed: 03/13/2024]
Abstract
Inorganic arsenic (iAs) causes cancer by initiating dynamic transitions between epithelial and mesenchymal cell phenotypes. These transitions transform normal cells into cancerous cells, and cancerous cells into metastatic cells. Most in vitro models assume that transitions between states are binary and complete, and do not consider the possibility that intermediate, stable cellular states might exist. In this paper, we describe a new, two-hit in vitro model of iAs-induced carcinogenesis that extends to 28 weeks of iAs exposure. Through week 17, the model faithfully recapitulates known and expected phenotypic, genetic, and epigenetic characteristics of iAs-induced carcinogenesis. By 28 weeks, however, exposed cells exhibit stable, intermediate phenotypes and epigenetic properties, and key transcription factor promoters (SNAI1, ZEB1) enter an epigenetically poised or bivalent state. These data suggest that key epigenetic transitions and cellular states exist during iAs-induced epithelial-to-mesenchymal transition (EMT), and that it is important for our in vitro models to encapsulate all aspects of EMT and the mesenchymal-to-epithelial transition (MET). In so doing, and by understanding the epigenetic systems controlling these transitions, we might find new, unexpected opportunities for developing targeted, cell state-specific therapeutics.
Collapse
Affiliation(s)
- Matthew Rea
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, 49502, USA
| | - Greg Kimmerer
- Department of Biology, University of Kentucky, Lexington, KY, 40506, USA
| | - Shania Mittendorf
- Department of Biology, University of Kentucky, Lexington, KY, 40506, USA
| | - Xiaopeng Xiong
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, 40536, USA; Markey Cancer Center, University of Kentucky, Lexington, KY, 40536, USA
| | - Meghan Green
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, 40536, USA; Markey Cancer Center, University of Kentucky, Lexington, KY, 40536, USA
| | - Darrell Chandler
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, 49502, USA
| | - Wesley Saintilnord
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, 49502, USA; Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, 40536, USA
| | - Jessica Blackburn
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, 40536, USA; Markey Cancer Center, University of Kentucky, Lexington, KY, 40536, USA
| | - Tianyan Gao
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, 40536, USA; Markey Cancer Center, University of Kentucky, Lexington, KY, 40536, USA
| | | |
Collapse
|
2
|
Ivanova B. Special Issue with Research Topics on "Recent Analysis and Applications of Mass Spectra on Biochemistry". Int J Mol Sci 2024; 25:1995. [PMID: 38396673 PMCID: PMC10888122 DOI: 10.3390/ijms25041995] [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: 01/20/2024] [Accepted: 02/04/2024] [Indexed: 02/25/2024] Open
Abstract
Analytical mass spectrometry applies irreplaceable mass spectrometric (MS) methods to analytical chemistry and chemical analysis, among other areas of analytical science [...].
Collapse
Affiliation(s)
- Bojidarka Ivanova
- Lehrstuhl für Analytische Chemie, Institut für Umweltforschung, Fakultät für Chemie und Chemische Biologie, Universität Dortmund, Otto-Hahn-Straße 6, 44221 Dortmund, Germany
| |
Collapse
|
3
|
George S, Cassidy RN, Saintilnord WN, Fondufe-Mittendorf Y. Epigenomic reprogramming in iAs-mediated carcinogenesis. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2022; 96:319-365. [PMID: 36858778 DOI: 10.1016/bs.apha.2022.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Arsenic is a naturally occurring metal carcinogen found in the Earth's crust. Millions of people worldwide are chronically exposed to arsenic through drinking water and food. Exposure to inorganic arsenic has been implicated in many diseases ranging from acute toxicities to malignant transformations. Despite the well-known deleterious health effects of arsenic exposure, the molecular mechanisms in arsenic-mediated carcinogenesis are not fully understood. Since arsenic is non-mutagenic, the mechanism by which arsenic causes carcinogenesis is via alterations in epigenetic-regulated gene expression. There are two possible ways by which arsenic may modify the epigenome-indirectly through an arsenic-induced generation of reactive oxygen species which then impacts chromatin remodelers, or directly through interaction and modulation of chromatin remodelers. Whether directly or indirectly, arsenic modulates epigenetic gene regulation and our understanding of the direct effect of this modulation on chromatin structure is limited. In this chapter we will discuss the various ways by which inorganic arsenic affects the epigenome with consequences in health and disease.
Collapse
Affiliation(s)
- Smitha George
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, United States
| | - Richard N Cassidy
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, United States
| | - Wesley N Saintilnord
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, United States; Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, United States
| | | |
Collapse
|
4
|
Saintilnord WN, Fondufe-Mittendorf Y. Arsenic-induced epigenetic changes in cancer development. Semin Cancer Biol 2021; 76:195-205. [PMID: 33798722 PMCID: PMC8481342 DOI: 10.1016/j.semcancer.2021.03.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/22/2021] [Accepted: 03/23/2021] [Indexed: 12/29/2022]
Abstract
Arsenic is a ubiquitous metalloid whose high levels of toxicity pose major health concerns to millions of people worldwide by increasing susceptibility to various cancers and non-cancer illnesses. Since arsenic is not a mutagen, the mechanism by which it causes changes in gene expression and disease pathogenesis is not clear. One possible mechanism is through generation of reactive oxygen species. Another equally important mechanism still very much in its infancy is epigenetic dysregulation. In this review, we discuss recent discoveries underlying arsenic-induced epigenetic changes in cancer development. Importantly, we highlight the proposed mechanisms targeted by arsenic to drive oncogenic gene expression.
Collapse
Affiliation(s)
- Wesley N Saintilnord
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA.
| | | |
Collapse
|
5
|
Abstract
Metal exposure is pervasive and not limited to sporadic poisoning events or toxic waste sites. Hundreds of millions of people around the globe are affected by chronic metal exposure, which is associated with serious health concerns, including cancer, as demonstrated in a variety of studies at the molecular, systemic, and epidemiologic levels. Metal-induced toxicity and carcinogenicity are sophisticated and complex in nature. This review provides a broad context and holistic view of currently available studies on the mechanisms of metal-induced carcinogenesis. Specifically, we focus on the five most prevalent carcinogenic metals, arsenic, nickel, cadmium, chromium, and beryllium, and their potential to drive carcinogenesis in humans. A comprehensive understanding of the mechanisms behind the development of metal-induced cancer can provide valuable insights for therapeutic intervention involving molecular targets in metal-induced carcinogenesis.
Collapse
Affiliation(s)
- Qiao Yi Chen
- Departments of Environmental Medicine, and Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10010, USA;
| | - Thomas DesMarais
- Departments of Environmental Medicine, and Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10010, USA;
| | - Max Costa
- Departments of Environmental Medicine, and Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10010, USA;
| |
Collapse
|
6
|
Jiang T, Hoover ME, Holt MV, Freitas MA, Marshall AG, Young NL. Middle-Down Characterization of the Cell Cycle Dependence of Histone H4 Posttranslational Modifications and Proteoforms. Proteomics 2018; 18:e1700442. [PMID: 29667342 PMCID: PMC8087174 DOI: 10.1002/pmic.201700442] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 02/28/2018] [Indexed: 12/12/2022]
Abstract
Post-translational modifications (PTMs) of histones are important epigenetic regulatory mechanisms that are often dysregulated in cancer. We employ middle-down proteomics to investigate the PTMs and proteoforms of histone H4 during cell cycle progression. We use pH gradient weak cation exchange-hydrophilic interaction liquid chromatography (WCX-HILIC) for on-line liquid chromatography-mass spectrometry analysis to separate and analyze the proteoforms of histone H4. This procedure provides enhanced separation of proteoforms, including positional isomers, and simplifies downstream data analysis. We use ultrahigh mass accuracy and resolution Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometer to unambiguously distinguish between acetylation and tri-methylation (∆m = 0.036 Da). In total, we identify and quantify 233 proteoforms of histone H4 in two breast cancer cell lines. We observe significant increases in S1 phosphorylation during mitosis, implicating an important role in mitotic chromatin condensation. A decrease of K20 unmodified proteoforms is observed as the cell cycle progresses, corresponding to an increase of K20 mono- and di-methylation. Acetylation at K5, K8, K12, and K16 declines as cells traverse from S phase to mitosis, suggesting cell cycle-dependence and an important role during chromatin replication and condensation. These new insights into the epigenetics of the cell cycle may provide new diagnostic and prognostic biomarkers.
Collapse
Affiliation(s)
- Tingting Jiang
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftain Way, Tallahassee, FL, 32306, USA
| | - Michael E Hoover
- Department of Cancer Biology and Genetics, Ohio State University, 460 West 12th Avenue, Columbus, OH, 43210, USA
| | - Matthew V Holt
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Michael A Freitas
- Department of Cancer Biology and Genetics, Ohio State University, 460 West 12th Avenue, Columbus, OH, 43210, USA
| | - Alan G Marshall
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftain Way, Tallahassee, FL, 32306, USA
- Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL, 32310, USA
| | - Nicolas L Young
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| |
Collapse
|
7
|
Mito M, Kadota M, Tanaka K, Furuta Y, Abe K, Iwasaki S, Nakagawa S. Cell Type-Specific Survey of Epigenetic Modifications by Tandem Chromatin Immunoprecipitation Sequencing. Sci Rep 2018; 8:1143. [PMID: 29348483 PMCID: PMC5773701 DOI: 10.1038/s41598-018-19494-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 01/02/2018] [Indexed: 12/17/2022] Open
Abstract
The nervous system of higher eukaryotes is composed of numerous types of neurons and glia that together orchestrate complex neuronal responses. However, this complex pool of cells typically poses analytical challenges in investigating gene expression profiles and their epigenetic basis for specific cell types. Here, we developed a novel method that enables cell type-specific analyses of epigenetic modifications using tandem chromatin immunoprecipitation sequencing (tChIP-Seq). FLAG-tagged histone H2B, a constitutive chromatin component, was first expressed in Camk2a-positive pyramidal cortical neurons and used to purify chromatin in a cell type-specific manner. Subsequent chromatin immunoprecipitation using antibodies against H3K4me3-a chromatin modification mainly associated with active promoters-allowed us to survey the histone modifications in Camk2a-positive neurons. Indeed, tChIP-Seq identified hundreds of H3K4me3 modifications in promoter regions located upstream of genes associated with neuronal functions and genes with unknown functions in cortical neurons. tChIP-Seq provides a versatile approach to investigating the epigenetic modifications of particular cell types in vivo.
Collapse
Affiliation(s)
- Mari Mito
- RNA Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako, 351-0198, Japan.,RNA Systems Biochemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, 351-0198, Japan
| | - Mitsutaka Kadota
- Phyloinformatics Unit, RIKEN Center for Life Science Technologies, 2-2-3 Minatojima-Minamimachi, Chuou-ku, Kobe, 650-0047, Japan
| | - Kaori Tanaka
- Phyloinformatics Unit, RIKEN Center for Life Science Technologies, 2-2-3 Minatojima-Minamimachi, Chuou-ku, Kobe, 650-0047, Japan
| | - Yasuhide Furuta
- Animal Resource Development Unit and RIKEN Center for Life Science Technologies, 2-2-3 Minatojima Minami-machi, Chuou-ku, Kobe, 650-0047, Japan.,Genetic Engineering Team, RIKEN Center for Life Science Technologies, 2-2-3 Minatojima Minami-machi, Chuou-ku, Kobe, 650-0047, Japan
| | - Kuniya Abe
- Technology and Development Team for Mammalian Genome Dynamics, RIKEN BioResource Center, 3-1-1 Koyadai, Tsukuba, Ibaraki, 305-0074, Japan
| | - Shintaro Iwasaki
- RNA Systems Biochemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, 351-0198, Japan. .,Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 2-1 Hirosawa, Wako, 351-0198, Japan.
| | - Shinichi Nakagawa
- RNA Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako, 351-0198, Japan. .,RNA Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, 060-0812, Japan.
| |
Collapse
|
8
|
Affiliation(s)
- Bifan Chen
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Kyle A. Brown
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Ziqing Lin
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Human Proteomics Program, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Ying Ge
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Human Proteomics Program, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| |
Collapse
|
9
|
Rea M, Gripshover T, Fondufe-Mittendorf Y. Selective inhibition of CTCF binding by iAs directs TET-mediated reprogramming of 5-hydroxymethylation patterns in iAs-transformed cells. Toxicol Appl Pharmacol 2018; 338:124-133. [PMID: 29175454 PMCID: PMC5738917 DOI: 10.1016/j.taap.2017.11.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 11/17/2017] [Accepted: 11/19/2017] [Indexed: 12/22/2022]
Abstract
Methylation at cytosine (5mC) is a fundamental epigenetic DNA modification recently associated with iAs-mediated carcinogenesis. In contrast, the role of 5-hydroxymethylcytosine (5hmC), the oxidation product of 5mC in iAs-mediated carcinogenesis is unknown. Here we assess the hydroxymethylome in iAs-transformed cells, showing that dynamic modulation of hydroxymethylated DNA is associated with specific transcriptional networks. Moreover, this pathologic iAs-mediated carcinogenesis is characterized by a shift toward a higher hydroxymethylation pattern genome-wide. At specific promoters, hydroxymethylation correlated with increased gene expression. Furthermore, this increase in hydroxymethylation occurs concurrently with an upregulation of ten-eleven translocation (TET) enzymes that oxidize 5-methylcytosine (5mC) in DNA. To gain an understanding into how iAs might impact TET expression, we found that iAs inhibits the binding of CTCF at the proximal, weak CTCF binding sites of the TET1 and TET2 gene promoters and enhances CTCF binding at the stronger distal binding site. Further analyses suggest that this distal site acts as an enhancer, thus high CTCF occupancy at the enhancer region of TET1 and TET2 possibly drives their high expression in iAs-transformed cells. These results have major implications in understanding the impact of differential CTCF binding, genome architecture and its consequences in iAs-mediated pathogenesis.
Collapse
Affiliation(s)
- Matthew Rea
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
| | - Tyler Gripshover
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA; Eastern Kentucky University, Richmond, KY 40475, USA
| | - Yvonne Fondufe-Mittendorf
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA.
| |
Collapse
|
10
|
Eckstein M, Rea M, Fondufe-Mittendorf YN. Transient and permanent changes in DNA methylation patterns in inorganic arsenic-mediated epithelial-to-mesenchymal transition. Toxicol Appl Pharmacol 2017; 331:6-17. [PMID: 28336213 PMCID: PMC5747965 DOI: 10.1016/j.taap.2017.03.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 03/16/2017] [Indexed: 12/12/2022]
Abstract
Chronic low dose inorganic arsenic exposure causes cells to take on an epithelial-to-mesenchymal phenotype, which is a crucial process in carcinogenesis. Inorganic arsenic is not a mutagen and thus epigenetic alterations have been implicated in this process. Indeed, during the epithelial-to-mesenchymal transition, morphologic changes to cells correlate with changes in chromatin structure and gene expression, ultimately driving this process. However, studies on the effects of inorganic arsenic exposure/withdrawal on the epithelial-to-mesenchymal transition and the impact of epigenetic alterations in this process are limited. In this study we used high-resolution microarray analysis to measure the changes in DNA methylation in cells undergoing inorganic arsenic-induced epithelial-to-mesenchymal transition, and on the reversal of this process, after removal of the inorganic arsenic exposure. We found that cells exposed to chronic, low-dose inorganic arsenic exposure showed 30,530 sites were differentially methylated, and with inorganic arsenic withdrawal several differential methylated sites were reversed, albeit not completely. Furthermore, these changes in DNA methylation mainly correlated with changes in gene expression at most sites tested but not at all. This study suggests that DNA methylation changes on gene expression are not clear-cut and provide a platform to begin to uncover the relationship between DNA methylation and gene expression, specifically within the context of inorganic arsenic treatment.
Collapse
Affiliation(s)
- Meredith Eckstein
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
| | - Matthew Rea
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
| | | |
Collapse
|
11
|
Chen QY, Costa M. A comprehensive review of metal-induced cellular transformation studies. Toxicol Appl Pharmacol 2017; 331:33-40. [DOI: 10.1016/j.taap.2017.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 04/30/2017] [Accepted: 05/05/2017] [Indexed: 01/07/2023]
|
12
|
Eckstein M, Rea M, Fondufe-Mittendorf YN. Microarray dataset of transient and permanent DNA methylation changes in HeLa cells undergoing inorganic arsenic-mediated epithelial-to-mesenchymal transition. Data Brief 2017; 13:6-9. [PMID: 28589171 PMCID: PMC5443927 DOI: 10.1016/j.dib.2017.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 04/04/2017] [Accepted: 05/03/2017] [Indexed: 11/25/2022] Open
Abstract
The novel dataset presented here represents the results of the changing pattern of DNA methylation profiles in HeLa cells exposed to chronic low dose (0.5 µM) sodium arsenite, resulting in epithelial-to-mesenchymal transition, as well as DNA methylation patterns in cells where inorganic arsenic has been removed. Inorganic arsenic is a known carcinogen, though not mutagenic. Several mechanisms have been proposed as to how inorganic arsenic drives carcinogenesis such as regulation of the cell׳s redox potential and/or epigenetics. In fact, there are gene specific studies and limited genome-wide studies that have implicated epigenetic factors such as DNA methylation in inorganic arsenic-mediated epithelial-to-mesenchymal transition (EMT). However, genome-wide studies about the impact of 1) chronic, low-dose inorganic arsenic exposure on DNA methylation patterns during inorganic arsenic-induced epithelial-to-mesenchymal transition, and 2) the removal inorganic arsenic (reversal) on DNA methylation patterns, is lacking. For this dataset, two replicates were performed with each of the samples - non-treated, inorganic arsenic-treated, and reverse-treated cells. We provide normalized and processed data, and log2 fold change in DNA methylation. The raw microarray data are available through NCBI GEO, accession number GSE95232 and a related research paper has been accepted for published in Toxicology and Applied Pharmacology (Eckstein et al., 2017) [1].
Collapse
|
13
|
Eckstein M, Eleazer R, Rea M, Fondufe-Mittendorf Y. Epigenomic reprogramming in inorganic arsenic-mediated gene expression patterns during carcinogenesis. REVIEWS ON ENVIRONMENTAL HEALTH 2017; 32:93-103. [PMID: 27701139 DOI: 10.1515/reveh-2016-0025] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 08/08/2016] [Indexed: 05/22/2023]
Abstract
Arsenic is a ubiquitous metalloid that is not mutagenic but is carcinogenic. The mechanism(s) by which arsenic causes cancer remain unknown. To date, several mechanisms have been proposed, including the arsenic-induced generation of reactive oxygen species (ROS). However, it is also becoming evident that inorganic arsenic (iAs) may exert its carcinogenic effects by changing the epigenome, and thereby modifying chromatin structure and dynamics. These epigenetic changes alter the accessibility of gene regulatory factors to DNA, resulting in specific changes in gene expression both at the levels of transcription initiation and gene splicing. In this review, we discuss recent literature reports describing epigenetic changes induced by iAs exposure and the possible epigenetic mechanisms underlying these changes.
Collapse
|
14
|
Rea M, Eckstein M, Eleazer R, Smith C, Fondufe-Mittendorf YN. Genome-wide DNA methylation reprogramming in response to inorganic arsenic links inhibition of CTCF binding, DNMT expression and cellular transformation. Sci Rep 2017; 7:41474. [PMID: 28150704 PMCID: PMC5288714 DOI: 10.1038/srep41474] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 12/20/2016] [Indexed: 12/31/2022] Open
Abstract
Chronic low dose inorganic arsenic (iAs) exposure leads to changes in gene expression and epithelial-to-mesenchymal transformation. During this transformation, cells adopt a fibroblast-like phenotype accompanied by profound gene expression changes. While many mechanisms have been implicated in this transformation, studies that focus on the role of epigenetic alterations in this process are just emerging. DNA methylation controls gene expression in physiologic and pathologic states. Several studies show alterations in DNA methylation patterns in iAs-mediated pathogenesis, but these studies focused on single genes. We present a comprehensive genome-wide DNA methylation analysis using methyl-sequencing to measure changes between normal and iAs-transformed cells. Additionally, these differential methylation changes correlated positively with changes in gene expression and alternative splicing. Interestingly, most of these differentially methylated genes function in cell adhesion and communication pathways. To gain insight into how genomic DNA methylation patterns are regulated during iAs-mediated carcinogenesis, we show that iAs probably targets CTCF binding at the promoter of DNA methyltransferases, regulating their expression. These findings reveal how CTCF binding regulates DNA methyltransferase to reprogram the methylome in response to an environmental toxin.
Collapse
Affiliation(s)
- Matthew Rea
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
| | - Meredith Eckstein
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
| | - Rebekah Eleazer
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
| | - Caroline Smith
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA.,Bellarmine University, Louisville, KY 40205, USA
| | | |
Collapse
|
15
|
Howe CG, Gamble MV. Influence of Arsenic on Global Levels of Histone Posttranslational Modifications: a Review of the Literature and Challenges in the Field. Curr Environ Health Rep 2016; 3:225-37. [PMID: 27352015 PMCID: PMC4967376 DOI: 10.1007/s40572-016-0104-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Arsenic is a human carcinogen and also increases the risk for non-cancer outcomes. Arsenic-induced epigenetic dysregulation may contribute to arsenic toxicity. Although there are several reviews on arsenic and epigenetics, these have largely focused on DNA methylation. Here, we review investigations of the effects of arsenic on global levels of histone posttranslational modifications (PTMs). Multiple studies have observed that arsenic induces higher levels of H3 lysine 9 dimethylation (H3K9me2) and also higher levels of H3 serine 10 phosphorylation (H3S10ph), which regulate chromosome segregation. In contrast, arsenic causes a global loss of H4K16ac, a histone PTM that is a hallmark of human cancers. Although the findings for other histone PTMs have not been entirely consistent across studies, we discuss biological factors which may contribute to these inconsistencies, including differences in the dose, duration, and type of arsenic species examined; the tissue or cell line evaluated; differences by sex; and exposure timing. We also discuss two important considerations for the measurement of histone PTMs: proteolytic cleavage of histones and arsenic-induced alterations in histone expression.
Collapse
Affiliation(s)
- Caitlin G. Howe
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University. Address: 11 Floor, 722 W. 168 Street, New York, New York, 10032. . Phone: 212-305-1205. Fax: 212-305-3857
| | - Mary V. Gamble
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University. Address: 11 Floor, 722 W. 168 Street, New York, New York, 10032. . Phone: 212-305-7949. Fax: 212-305-3857
| |
Collapse
|