title: Arsenic trioxide-induced apoptosis through oxidative stress in cells of colon cancer cell lines.
abstract: Exposure of three colon cancer cell lines, SW480, DLD-1, and COLO201, to arsenic trioxide in the medium induced a marked concentration-dependent suppression of cell growth. The intracellular contents of reduced glutathione (GSH) in these cell lines tended to be inversely correlated with the sensitivity of the cells to arsenic trioxide. Among the cell lines, SW480 cells underwent apoptosis at the low arsenic trioxide concentration of 2 microM, which was prevented by pretreatment of the cells with N-acetylcysteine and was enhanced by buthionine sulfoximine. The production of reactive oxygen intermediates which were examined by 2',7'-dichlorodihydrofluorescein diacetate (H2DCF-DA), increased with time after treatment with arsenic trioxide. The apoptosis was executed by the activation of caspase 3, which was shown by Western blot, enzymatic activity, and apoptosis inhibition assay. The mitochondrial membrane potential of adherent apoptotic SW480 cells and the cells from intermediate layer separated by density gradient centrifugation, both of which showed the active form of caspase 3 by Western blot analysis, was not lost. The overexpression of Bcl-2 protein in SW480 cells could not prevent the apoptosis induced by the treatment with arsenic trioxide. All these findings indicate that arsenic trioxide-induced apoptosis in SW480 cells is executed by the activation of caspase 3 without mediating by mitochondria under the overproduction of reactive oxygen species.
authors: Institute of Applied Biochemistry, Yagi Memorial Park, Mitake, Gifu, Japan.
authors: Yoshihito
authors: Y
authors: Nakagawa
authors: Yukihiro
authors: Y
authors: Akao
authors: Hiroshi
authors: H
authors: Morikawa
authors: Ichiro
authors: I
authors: Hirata
authors: Kenichi
authors: K
authors: Katsu
authors: Tomoki
authors: T
authors: Naoe
authors: Nobuko
authors: N
authors: Ohishi
authors: Kunio
authors: K
authors: Yagi
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology*; D053148:Caspase 3; D020169:Caspases / Q000502:physiology; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D005978:Glutathione / Q000032:analysis; D006801:Humans; D018384:Oxidative Stress; D010087:Oxides / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000502:physiology; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D001152:Arsenicals; D010087:Oxides; D019253:Proto-Oncogene Proteins c-bcl-2; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D005978:Glutathione; D000077237:Arsenic Trioxide