title: Arsenic trioxide-induced apoptosis and its enhancement by buthionine sulfoximine in hepatocellular carcinoma cell lines.
abstract: We treated four hepatocellular carcinoma cell lines, HLE, HLF, HuH7, and HepG2 with ATO and demonstrated that arsenic trioxide (ATO) at low doses (1--3 muM) induced a concentration-dependent suppression of cell growth in HLE, HLF, and HuH7. HLE cells underwent apoptosis at 2 microM ATO, which was executed by the activation of caspase-3 through the mitochondrial pathway mediated by caspase-8 activation and Bid truncation. When these cell lines were exposed to ATO in combination with l-S,R-buthionine sulfoximine (BSO) which inhibits GSH synthesis, a synergistic growth suppression was induced, even in HepG2 showing a lower sensitivity to ATO than other cell lines tested. The intracellular GSH levels after the treatment with ATO plus BSO were considerably decreased in HLE cells compared with those after the treatment with ATO or BSO alone. The production of reactive oxygen species (ROS) which was examined by 2' ,7' -dichlorodihydrofluorescein diacetate, increased significantly after the treatment with ATO plus BSO in HLE cells. These findings indicate that ATO at low concentrations induces growth inhibition and apoptosis, and furthermore that the ATO-BSO combination treatment enhances apoptosis through increased production of ROS in hepatocellular carcinoma cells.
authors.affiliation: Institute of Applied Biochemistry, Yagi Memorial Park, Mitake, Gifu 505-0116, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Kito
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Akao
authors.forename: Nobuko
authors.initials: N
authors.lastname: Ohishi
authors.forename: Kunio
authors.initials: K
authors.lastname: Yagi
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Nozawa
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology*; D019328:Buthionine Sulfoximine / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D020169:Caspases / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002467:Cell Nucleus / Q000648:ultrastructure; D053938:DNA Fragmentation; D004273:DNA, Neoplasm / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D010087:Oxides / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D001152:Arsenicals; D004273:DNA, Neoplasm; D010087:Oxides; D017382:Reactive Oxygen Species; D019328:Buthionine Sulfoximine; D020169:Caspases; D005978:Glutathione; D000077237:Arsenic Trioxide