title: Epigenetic remodeling during arsenical-induced malignant transformation.
abstract: Humans are exposed to arsenicals through many routes with the most common being in drinking water. Exposure to arsenic has been associated with an increase in the incidence of cancer of the skin, lung and bladder. Although the relationship between exposure and carcinogenesis is well documented, the mechanisms by which arsenic participates in tumorigenesis are not fully elucidated. We evaluated the potential epigenetic component of arsenical action by assessing the histone acetylation state of 13 000 human gene promoters in a cell line model of arsenical-mediated malignant transformation. We show changes in histone H3 acetylation occur during arsenical-induced malignant transformation that are linked to the expression state of the associated gene. DNA hypermethylation was detected in hypoacetylated promoters in the select cases analyzed. These epigenetic changes occurred frequently in the same promoters whether the selection was performed with arsenite [As(III)] or with monomethylarsonous acid, suggesting that these promoters were targeted in a non-random fashion, and probably occur in regions important in arsenical-induced malignant transformation. Taken together, these data suggest that arsenicals may participate in tumorigenesis by altering the epigenetic terrain of select genes.
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA.
authors.forename: Taylor J
authors.initials: TJ
authors.lastname: Jensen
authors.forename: Petr
authors.initials: P
authors.lastname: Novak
authors.forename: Kylee E
authors.initials: KE
authors.lastname: Eblin
authors.forename: A Jay
authors.initials: AJ
authors.lastname: Gandolfi
authors.forename: Bernard W
authors.initials: BW
authors.lastname: Futscher
mesh_terms: D000107:Acetylation; D001152:Arsenicals / Q000009:adverse effects*; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D002460:Cell Line; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000187:drug effects*; D000077209:Decitabine; D004781:Environmental Exposure; D006657:Histones / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D008175:Lung Neoplasms / Q000139:chemically induced; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012878:Skin Neoplasms / Q000139:chemically induced; D013723:Teratogens / Q000494:pharmacology; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced; D019459:Urothelium
chemical_list: D001152:Arsenicals; D006657:Histones; D006877:Hydroxamic Acids; D013723:Teratogens; C012589:trichostatin A; D000077209:Decitabine; D001374:Azacitidine