Apoptosis Inducation Of Human Gastric Carcinoma Cells By Epigallocatechin-3-gallate Through Down-regulation Bcl-2 And The Activation Of Caspase-3

Objective: The aim of this work was to study the effect of epigallocatechin-3-gallate (EGCG) on apoptosis of human gastric carcinoma cells and the inhibitory effect of EGCG on human gastric carcinoma cell nude mice xenograft. To investigate the molecular mechanism of the apoptotic cell induced by EGCG.Methods: MTT assay was used to measure proliferation activity of MGC803 cell by EGCG . DNA agarose gel electrophoresis was used to detect the fragment of DNA of MGC803 cell . Apoptosis of MGC803 cell induced by EGCG was determined using flow cytometry to analyse apoptosis rate . 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 doses . TUNEL staining method was used to detect the apoptosis of implanted tumor cells . The rate of apoptotic cells of xenograft tumor was analyzed by PI stained flow cytometry (FCM) . Immunohistochemical technique was performed to detect changes of Bax , Bcl-2 and Caspase-3 protein expression in MGC803 cell. Immunohistochemical staining was used to detect the expression of apoptosis-related genes bcl-2 ,bax and caspase-3 in implanted tumor. Expression of NF-κB(p65), Bcl-2, Bax, Caspase-3 in every group xenograft tumor were determined by Western Blot analysis.Results: MTT assay showed that EGCG significantly inhibited the growth of MGC803 cells in a dose- and time- dependent manner . In MGC803 cells occurred " Ladder" bands after being exposed to EGCG 100μmol/L for 48 h . Sub-G₁ peak...