title: Effects of acute and chronic arsenic exposure of human-derived keratinocytes in an In Vitro human skin equivalent system: a novel model of human arsenicism.
abstract: An organotypic culture (OTC) of a human keratinocyte cell line (HaCaT) over a human fibroblast-embedded collagen gel was used to model human epidermis in arsenicism, a syndrome that currently lacks valid experimental models. Keratinocytes were exposed acutely or chronically to a mixture of arsenate (0.5 muM), monomethylarsonic acid (MMA; 0.5 muM) and dimethylarsinic acid (DMA; 1.5 muM), or to the individual components of the mixture. OTCs were assayed for microscopic morphology, the proliferating cell marker, Ki-67, labelling and cytokeratin expression. Acute exposures resulted in an epidermal phenotype that accurately modelled early human lesions, including hyperkeratosis, acanthosis and keratin 16 induction. Chronic exposures resulted in a de-differentiated epidermal phenotype with focal nests of keratinocytes growing into the collagen gel. The keratin 8 18 pair was induced by either acute or chronic arsenic exposure, as was the proliferating cell marker, Ki-67. Exposure of keratinocytes to individual arsenic compounds demonstrated that all arsenic mixture-induced changes could be duplicated by exposure to arsenate alone. In contrast, MMA and DMA were inactive. This study establishes OTC as a useful model of arsenicism, and implicates inorganic arsenic as the ultimate carcinogen.
authors.affiliation: Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: W T
authors.initials: WT
authors.lastname: Klimecki
authors.forename: A H
authors.initials: AH
authors.lastname: Borchers
authors.forename: R E
authors.initials: RE
authors.lastname: Egbert
authors.forename: R B
authors.initials: RB
authors.lastname: Nagle
authors.forename: D E
authors.initials: DE
authors.lastname: Carter
authors.forename: G T
authors.initials: GT
authors.lastname: Bowden