title: 2'-Epi-2'-O-acetylthevetin B induces apoptosis partly via Ca(2+)-mediated mitochondrial pathway in human hepatocellular carcinoma HepG2 cells.
abstract: 2'-Epi-2'-O-acetylthevetin B (GHSC-74), a cardiac glycoside, can be isolated from the seeds of Cerbera manghas L. We demonstrated that GHSC-74 reduced the viability of HepG2 cells in a time- and dose-dependent manner, and efficiently induced apoptosis without significantly decreasing the viability of Chang human liver cells and Swiss albino 3T3 fibroblasts, as indicated by annexin-V/PI binding assay and Hoechst 33342 staining. In addition, stimulation of HepG2 cells with GHSC-74 induced a series of intracellular events: (1) loss of mitochondrial membrane potential; (2) sustained elevation of cytosolic [Ca2+]; and (3) downregulation of Bcl-2. BAPTA-AM, a cytosolic Ca2+ chelator, partly suppressed cell death and prevented mitochondrial membrane potential from losing in GHSC-74-treated HepG2 cells. In contrast, EGTA, an extracellular Ca2+ chelator, exhibited a weaker effect as compared to that of BAPTA-AM. Taken together, the Ca(2+)-mediated mitochondrial pathway was found to be involved in GHSC-74-induced HepG2 cell apoptosis.
authors.affiliation: Department of Biochemistry and Molecular Biology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Feng
authors.forename: Cai-Guo
authors.initials: CG
authors.lastname: Huang
authors.forename: Ruo-Hua
authors.initials: RH
authors.lastname: Chen
authors.forename: Yue-Wei
authors.initials: YW
authors.lastname: Guo
authors.forename: Bing-Hua
authors.initials: BH
authors.lastname: Jiao
mesh_terms: D016475:3T3 Cells; D000818:Animals; D016588:Anticarcinogenic Agents / Q000737:chemistry / Q000494:pharmacology*; D029062:Apocynaceae / Q000737:chemistry; D017209:Apoptosis; D002118:Calcium / Q000378:metabolism; D002301:Cardiac Glycosides / Q000737:chemistry / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002614:Chelating Agents / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D005347:Fibroblasts / Q000187:drug effects; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
chemical_list: C545239:2'-epi-2'-O-acetylthevetin B; D016588:Anticarcinogenic Agents; D002301:Cardiac Glycosides; D002614:Chelating Agents; D004791:Enzyme Inhibitors; D019253:Proto-Oncogene Proteins c-bcl-2; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D004533:Egtazic Acid; D002118:Calcium