title: Induction of apoptosis in arsenic trioxide-treated lung cancer A549 cells by buthionine sulfoximine.
abstract: Arsenic trioxide (ATO) affects many biological processes such as cell proliferation, apoptosis, differentiation and angiogenesis. L-buthionine sulfoximine (BSO) is an inhibitor of GSH synthesis. We tested whether ATO reduced the viability of lung cancer A549 cells in vitro, and investigated the in vitro effect of the combination of ATO and BSO on cell viability in relation to apoptosis and the cell cycle. ATO caused a dose-dependant decrease of viability of A549 cells with an IC50 of more than 50 microM. Low doses of ATO or BSO (1 approximately 10 microM) alone did not induce cell death. However, combined treatment depleted GSH content and induced apoptosis, loss of mitochondrial transmembrane potential (DeltaPsi(m)) and cell cycle arrest in G2. Reactive oxygen species (ROS) increased or decreased depending on the concentration of ATO. In addition, BSO generally increased ROS in ATO-treated A549 cells. ROS levels were at least in part related to apoptosis in cells treated with ATO and/or BSO. In conclusion, we have demonstrated that A549 lung cells are very resistant to ATO, and that BSO synergizes with clinically achievable concentration of ATO. Our results suggest that combination treatment with ATO and BSO may be useful for treating lung cancer.
authors.affiliation: Department of Physiology, Medical School, Institute for Medical Sciences, Center for Healthcare Technology Development, Chonbuk National University, Jeonju 561-180, Korea.
authors.forename: Yong Hwan
authors.initials: YH
authors.lastname: Han
authors.forename: Sung Zoo
authors.initials: SZ
authors.lastname: Kim
authors.forename: Suhn Hee
authors.initials: SH
authors.lastname: Kim
authors.forename: Woo Hyun
authors.initials: WH
authors.lastname: Park
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology* / Q000627:therapeutic use; D019328:Buthionine Sulfoximine / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D019008:Drug Resistance, Neoplasm; D004357:Drug Synergism; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D010087:Oxides / Q000494:pharmacology* / Q000627:therapeutic use; D017382:Reactive Oxygen Species / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D001152:Arsenicals; D010087:Oxides; D017382:Reactive Oxygen Species; D019328:Buthionine Sulfoximine; D005978:Glutathione; D000077237:Arsenic Trioxide