Berberine induces cell cycle arrest and apoptosis in human gastric carcinoma SNU-5 cell line

AIM: To investigate the relationship between the inhibited growth (cytotoxic activity) of berberine and apoptotic pathway with its molecular mechanism of action. METHODS: The in vitro cytotoxic techniques were complemented by cell cycle analysis and determination of sub-G(1) for apoptosis in human gastric carcinoma SNU-5 cells. Percentage of viable cells, cell cycle, and sub-G(1) group (apoptosis) were examined and determined by the flow cytometric methods. The associated proteins for cell cycle arrest and apoptosis were examined by Western blotting. RESULTS: For SNU-5 cell line, the IC (50) was found to be 48 mu mol/L of berberine. In SNU-5 cells treated with 25-200 mu mol/L berberine, G(2)/M cell cycle arrest was observed which was associated with a marked increment of the expression of p53, Wee1 and CDk1 proteins and decreased cyclin B. A concentration-dependent decrease of cells in G(0)/G(1) phase and an increase in G(2)/M phase were detected. In addition, apoptosis detected as sub-G(0) cell population in cell cycle measurement was proved in 25-200 mu mol/L berberine-treated cells by monitoring the apoptotic pathway. Apoptosis was identified by sub-G(0) cell population, and upregulation of Bax, downregulation of Bcl-2, release of Ca2+, decreased the mitochondrial membrane potential and then led to the release of mitochondrial cytochrome C into the cytoplasm and caused the activation of caspase-3, and finally led to the occurrence of apoptosis. CONCLUSION: Berberine induces p53 expression and leads to the decrease of the mitochondrial membrane potential, Cytochrome C release and activation of caspase-3 for the induction of apoptosis. (C) 2006 The WJG Press. All rights reserved.