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.
Targeting p21-activated kinase 1 (PAK1) is a novel strategy for pancreatic cancer treatment. Compound Kushen injection contains many anti-pancreatic cancer components, but the specific targets are unknown. In this study, 14α-hydroxymatrine, an active component of Kushen injection, was found to possess high binding free energy with the allosteric site of PAK1 by molecular docking based virtual screening. Molecular dynamics simulations suggested that 14α-hydroxymatrine caused the α1 and α2 helices of the allosteric site of PAK1 to extend outward to form a deep allosteric regulatory pocket. Meanwhile, 14α-hydroxymatrine induced the β-folding region at the adenosine triphosphate (ATP)-binding pocket of PAK1 to close inward, resulting in the ATP-binding pocket in a “semi-closed” state which caused the inactivation of PAK1. After removal of 14α-hydroxymatrine, PAK1 showed a tendency to change from the inactive conformation to the active conformation. We supposed that 14α-hydroxymatrine of compound Kushen injection might be a reversible allosteric inhibitor of PAK1. This study used modern technologies and methods to study the active components of traditional Chinese medicine, which laid a foundation for the development and utilization of natural products and the search for new treatments for pancreatic cancer.