Research Project
Grant-in-Aid for Scientific Research (C)
Mcl-1(Myeloid cell leukemia-1) is an anti-apoptotic protein that regulates apoptosis sensitivity particularly in hematological and gastrointestinal malignancies. Here, we formulated the hypothesis that suppression of Mcl-1 would be an attractive strategy to overcome apoptosis resistance in Mcl-1 overexspressing gastric cancer. The AIMs was ; i) to examine Mcl-1 expression profiling among gastric cancer cell lines, and ii) to evaluate if Mcl-1 depletion sensitizes apoptosis by anti-cancer drugs. METHOD : 7 gastric cancer cell lines were used. Expression of Mcl-1 was assessed by Western blot analysis. Cells were exposed to anti-cancer drugs such as 5-fluorouracil and cisplatin. Apoptosis was quantitated by a morphological observation and caspase activity measurement. Adenovirus-mediated RNA interference (RNAi) technology was used to knock down the expression of Mcl-1. Releasing cytochrome C was evaluated by subcellular fractionation and immunoblot analysis. To evaluate if Mcl-l expressio … More n levels in cancer stem cells and non-stem cancer cells, side population (SP) cells, a cancer stem cell-enriched fraction, were identified and isolated by Hoechst 33342 staining and flowcytometry. RESULTS : 6 of 7 gastric cancer cell lines overexpressed Mcl-1 protein. There was correlation between Mcl-1 protein level and chemotherapy resistance. Depletion of Mcl-1 protein by RNAi technology effectively sensitizes the Mcl-1 expressing cells to anti-cancer drug-induced apoptosis. Mcl-1 knockdowned apoptosis was associated with mitochondrial depolarization, cytochrome c release from mitochondria and caspase activation. In addition, vast amounts of Mcl-1 mRNA were expressed in SP cells, implying that Mcl-1 mediates chemotherapy resistance in cancer stem cells. IN CONCLUSION : These results suggest that Mcl-1 mediates the resistance of apoptosis in gastric cancer cells by blocking the mitochondrial pathway of cell death. Mcl-1 depletion appears to be an attractive strategy to overcome chemotherapy resistance in gastric cancer cells. Less
All 2007
All Presentation (4 results)
