Apoptosis induction of human gastric carcinoma cells by Epigallocatechin-3-gallate(EGCG) through down-regulation of Bcl-2,NF-κB(p65) and the activation of Caspase-3

Objective:To study the inhibitory effect of EGCG on human gastric carcinoma cells in nude mice xenografts and to investigate the molecular mechanism of the apoptotic cell induced by EGCG.Methods: Human gastric carcinoma cells were planted into nude mice to establish the cancer model . The xenograft tumor growth in nude mice was observed after treated with intraperitoneal injection of EGCG at different dosages . TUNEL staining method was used to detect the apoptosis of implanted tumor cells . Expression of NF-κB(p65) ,Bcl-2 ,Bax,Caspase-3 in every group xenograft tumor were determined by Western Blot analysis. Results: EGCG significantly inhibited tumor growth after being injecting intraperitoneally in the nude mice. The apoptotic cells in implanted tumor induced by EGCG were detected by TUNEL staining. Western Blot analysis showed that the expression level of NF-κB(p65) was down-regulated by EGCG ; the ratio of Bax protein and Bcl-2 protein in xenograft tumor was adding as increasing the concentration of EGCG ; EGCG may accelerate the activation of procaspase-3. Conclusion: EGCG could significantly inhibit tumor growth in xenograft nude mice with human gastric carcinoma cells through inducing apoptosis. This action may be mediated by down-regulation of NF-κB(p65) expression , up-regulation of Bax and Bcl-2 , and resulting in Caspase-3 activation.