A Proteomic Investigation into a Human Gastric Cancer Cell Line BGC823 Treated with Diallyl Trisulfide

Garlic is generally used as a therapeutic reagent against various diseases worldwide. Although a great effort is made to understand the pharmaceutical mechanisms of garlic and its derivatives, there are many mysteries to be uncovered. Using proteomic means, herein we have systematically studied the responses of protein expression in BGC823 cells, a gastric cancer cell line, induced by diallyl trisulfide (DATS), a major component of garlic derivatives. A total of 41 unique proteins in BGC823 were detected with significant changes in their expression levels corresponding with DATS administration. Of these proteins, five typical ones, glutathione S-transferase-pi (GST-pi), voltage-dependent anion channel-1 (VDAC-1), Annexin I, Galectin and S100A11, were further examined by Western blotting, resulting in coincident data with the proteomic evidence. Moreover quantitative real-time RT-PCR experiments offered dynamic data of mRNA expression, indicating the responses of Annexin I and GST-pi expression within a short period after DATS treatment. Interestingly, approximately 50% of DATS-sensitive proteins (19/41) in BGC823 are tightly associated with apoptotic pathways. These proteomic results presented, therefore, provide additional support to the hypothesis that garlic is a strong inducer of apoptosis in tumor cells.