Celastrus orbiculatus extract induces mitochondrial-mediated apoptosis in human hepatocellular carcinoma cells

OBJECTIVE: To investigate the apoptotic effects and underlying molecular mechanisms of Celastrus orbiculatus (C. orbiculatus) extract in human hepatocellular carcinoma cells. METHODS: Human hepatocellular carcinoma cells (HCCLM6) were treated with C. orbiculatus extract (COE) at different nontoxic concentrations (10, 20, 40, 80, and 160 mu g/mL). The effect of COE on HCCLM6 viability was examined using 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays. Cellular apoptosis following COE treatment was assessed by flow cytometry and western blot analysis. RESULTS: COE significantly inhibited cell viability and induced apoptosis of HCCLM6 cells in a dose-dependent manner. Apoptosis was accompanied by increased Bax expression and decreased BcI-2 expression. In addition, COE treatment led to the release of cytochrome c, activation of caspase-3, and cleavage of poly (ADP-ribose) polymerase (PARP). Furthermore, activation of extracellular signal-regulated kinase (ERK), p38 kinase, and c-Jun N-terminal kinase (JNK) phosphorylation, and down-regulation of Akt phosphorylation was observed. CONCLUSION: COE induces mitochondrial-mediated, caspase-dependent apoptosis in HCCLM6 cells, which might be attributed to the activation of mitogen-activated protein kinase (MAPK) and inhibition of Akt signaling pathways. These data suggest that COE may be a potential treatment for human hepatocellular carcinoma. (C) 2012 JTCM. All rights reserved.