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

Abstract

ObjectiveTo investigate the apoptotic effects and underlying molecular mechanisms of Celastrus orbiculatus (C. orbiculatus) extract in human hepatocellular carcinoma cells. MethodsHuman hepatocellular carcinoma cells (HCCLM6) were treated with C. orbiculatus extract (COE) at different nontoxic concentrations (10, 20, 40, 80, and 160 μg/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. ResultsCOE significantly inhibited cell viability and induced apoptosis of HCCLM6 cells in a dose-dependent manner. Apoptosis was accompanied by increased Bax expression and decreased Bcl-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. ConclusionCOE 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.