Mechanism of Apoptosis Induction in Gastric Cancer Cell Line by Epigallocatechin-3-gallate

[Purpose] To investigate the effect of epigallocatechin-3-gallate on apoptosis induction in gastric cancer cell line MGC-803 and its antitumor mechanisms.[Methods] MGC-803 cells growth inhibition was measured by MTT assay.The effect of EGCG on apoptotic induction in MGC-803 cells was determined with light microscopy,flow cytometry and DNA agarose,respectively.S-P immunohistochemical technique was performed to detect the expression changes of apoptosis-related genes Bcl-2,Bax and Caspase-3 protein.[Results] EGCG significantly inhibited the growth of MGC-803 cells with a dose-dependent and time-dependent effect in those cells.After 48 hours exposure to EGCG,partial cells showed typical apoptotic morphological changes with light microscopy.Sub-G1 peak was found by flow cytometry.When MGC-803 cells were exposed to EGCG(60,80,100,120μmol/L,48h;80μmol/L,48,72h),the apoptosis indexes were increased.In MGC-803 cells Ladder bands occurred after exposure to EGCG(80,100,120μmol/L,48h).S-P immunohistochemistry revealed that the Bcl-2 expression was decreased while Bax and Caspase-3 expression was increased after 48 hours exposure to EGCG(80μmol/L).[Conclusion] EGCG could significantly induce apoptosis of human stomach cell MGC-803,apoptosis of tumor cells is closely associated with up-regulation of the ratio of Bcl-2/Bax,then leading to the activation of Caspase-3 and the initiation of cell apoptosis.