ObjectiveTo study effects of oxymatrine on proliferation and apoptosis of gastric cancer cell line BGC-823 and explore role of endoplasmic reticulum stress in apoptosis of gastric cancer cells induced by oxymatrine and elucidate its mechanism.MethodsThe gastric cancer BGC-823 cells at the logarithmic phase were divided into a control group, oxymatrine alone group (oxymatrine at 10, 30, 60 and 90 μmol/L concentrations), and combination group (oxymatrine at various concentrations combined with 2 μmol/L endoplasmic reticulum stress inhibitor salubrinal). The MTT assay was used to observe the inhibitory effect of the oxymatrine on the growth of BGC-823 cells. The flow cytometry was used to analyze the apoptosis and cell cycle. The Western blot and RT-PCR methods were used to detect the expressions of GRP78/Bip and the caspase-12 protein and gene, respectively.Results① Compared with the control group, the oxymatrine could significantly inhibit the growth of gastric cancer BGC-823 cells in a concentration-time dependent manner (P<0.05) and its IC50 (48 h) value was (59.5±0.5) μmol/L. The inhibitory effect of the combination group of 30, 60, and 90 μmol/L oxymatrine was significantly weakened as compared with the the corresponding oxymatrine alone group (P<0.05). ② The oxymatrine could significantly induce the apoptosis and arrest the G2/M phase in the gastric cancer BGC-823 cells in a concentration-dependent manner (P<0.05). The combination group of 60 μmol/L oxymatrine could significantly decreased the apoptosis rate and the number of cells in the G2/M phase in the gastric cancer BGC-823 cells after treating 48 h (P<0.05). ③ The protein and gene levels of GRP78/Bip and caspase-12 showed significant increases with the increase of oxymatrine concentrations in the oxymatrine alone group (except the protein and gene levels of caspase-12 at 10 μmol/L oxymatrine) as compared with the control group (P<0.05), which in the combination group of 60 μmol/L and 90 μmol/L oxymatrines were significantly decreased as compared with the corresponding oxymatrine alone group (P<0.05).ConclusionOxymatrine can inhibit growth of human gastric cancer cell line BGC-823, which maybe related to caspase-12-dependent induction of apoptosis and up-regulation of GRP78/Bip expression, which needs further experimental verification.
