Objective   This study investigates the biological effects and explores the molecular mechanisms of epigallocatechin- 3-gallate (EGCG) on the apoptosis of the human gastric cancer MGC-803 cells.

  Methods   After treatment with EGCG, cell apoptosis was verified by flow cytometry with Annexin V and propidium iodide staining, DNA agarose gel electrophoresis, and transmission electron microscopy. The expression profiles of the apoptosis-related genes in the MGC-803 cells with or without treatment by EGCG for 12 h (100 μmol/L), was identified using SuperArray Human Apoptosis Gene Array. The upregulated Fas-L gene and down-regulated Bag-1 gene were confirmed by reverse transcription polymerase chain reaction (RT-PCR) and Western blot.

  Results   When the MGC-803 cells were treated with EGCG at 25, 50, 100, and 200 μmol/L for 24 h, evident sub-diploid peaks were observed. Under treatment with 100 μmol/L for 4, 8, 12, and 24 h, the number of early apoptotic cells was greatly increased. When the cells were treated with 100 μmol/L for 24 h, the DNA extracted from the cells displayed a characteristic ladder pattern with agarose gel electrophoresis. Typical morphological changes were observed by electron microscopy, including cell shrinkage, karyo-pyknosis, and the formation of apoptotic bodies. The differential expressions of eight apoptosis-associated genes were determined by gene array detection. The results of Fas-L and Bag-1 selected for RT-PCR and Western blot were consistent with those of gene array.

  Conclusion   EGCG induces apoptosis in MGC-803 cells, which might be mediated by a number of specific genes and various signal transduction pathways.