title: Sodium arsenite induces chromosome endoreduplication and inhibits protein phosphatase activity in human fibroblasts.
abstract: Arsenic, strongly associated with increased risks of human cancers, is a potent clastogen in a variety of mammalian cell systems. The effect of sodium arsenite (a trivalent arsenic compound) on chromatid separation was studied in human skin fibroblasts (HFW). Human fibroblasts were arrested in S phase by the aid of serum starvation and aphidicolin blocking and then these cells were allowed to synchronously progress into G2 phase. Treatment of the G2-enriched HFW cells with sodium arsenite (0-200 microM) resulted in arrest of cells in the G2 phase, interference with mitotic division, inhibition of spindle assembly, and induction of chromosome endoreduplication in their second mitosis. Sodium arsenite treatment also inhibited the activities of serine/threonine protein phosphatases and enhanced phosphorylation levels of a small heat shock protein (HSP27). These results suggest that sodium arsenite may mimic okadaic acid to induce chromosome endoreduplication through its inhibitory effect on protein phosphatase activity.
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, Republic of China.
authors.forename: R N
authors.initials: RN
authors.lastname: Huang
authors.forename: I C
authors.initials: IC
authors.lastname: Ho
authors.forename: L H
authors.initials: LH
authors.lastname: Yih
authors.forename: T C
authors.initials: TC
authors.lastname: Lee
mesh_terms: D018053:Arsenites / Q000633:toxicity*; D002455:Cell Division / Q000187:drug effects / Q000235:genetics; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D002869:Chromosome Aberrations; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000187:drug effects* / Q000201:enzymology; D005434:Flow Cytometry; D016195:G2 Phase / Q000187:drug effects; D006360:Heat-Shock Proteins / Q000378:metabolism; D006657:Histones / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007231:Infant, Newborn; D008938:Mitosis / Q000187:drug effects / Q000235:genetics; D005810:Multigene Family; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D012854:Sister Chromatid Exchange / Q000187:drug effects / Q000235:genetics; D012867:Skin / Q000166:cytology / Q000187:drug effects; D017670:Sodium Compounds / Q000633:toxicity*; D013439:Sulfhydryl Reagents / Q000633:toxicity*
chemical_list: D018053:Arsenites; D006360:Heat-Shock Proteins; D006657:Histones; D017670:Sodium Compounds; D013439:Sulfhydryl Reagents; C017947:sodium arsenite; D010749:Phosphoprotein Phosphatases