The Anti-tumor Effect of CADPE and Inducing Apoptosis in Human Gastric Cancer Cells

Objectives:The present study aimed to research the anti-tumor activity of CADPE in vivo and in vitro, and to study mechanism of CADPE inducing apoptosis in human gastric cancer cell lines. Furthermore, The effect of CADPE on human normal cells and hemocytes will be determined to evaluated the security.Methods:In vitro, the cytotoxic effect of CADPE and IC50 were determined by SRB assay in human gastric cancer cell lines (AGS and HGC-27 cells). The effect of CADPE, 5-fluorouracil (5-FU) and doxorubicin (DOX) on cell viability of Hepatic cell line of HL-7702 was determined by SRB assay. Furthermore, proapoptotic activity of CADPE was determined by Annexin v/PI Staining assay and Hoechst 33342 staining assay.. Finally, the ptotein level of Bcl-2, Bax and Casepase-3 was measured by Western Blot assay. The ROS (Reactive oxygen species)level of HGC-27 was determined by DCFH-DA staining assay. In vivo, the anti-tumor effect were tested using S180 tumor model and H22 tumor model. Additionally, the effect of CADPE,5-FU, DOX on hemocytes was determined by auto hematology analyzer.Results:In vitro, CADPE showed significant anti-tumor effect in human gastric cell lines of AGS and HGC-27, and their IC50 were 13.1μM and 18.5μM when treated by CADPE for 72 hours. CADPE did not cause significant cytotoxicity to normal hepatic cell line of HL-7702; by contrast,5-FU and DOX significantly decreased the cell viability of HL-7702 cells. Furthermore, CADPE induced apoptosis of HGC-27 cells, and decreased Bcl-2 protein level while increased the protein levels of Bax and Casepase-3. In vivo, CADPE significantly inhibited tumor growth in S180 and H22 tumor models.5-FU and CTX significantly decreased the number of WBC, but CADPE did not have this side effect.Conclusions:CADPE has significant anti-tumor activity in vitro and in vivo. The proapoptotic action of CADPE may contribute to its anti-tumor activity, while downregulation of anti-apoptotic protein Bcl-2 protein level and upregulations of proapoptotic protein Bax protein level and its down stream protein Casepase-3 can be associated with the proapoptotic effect of this compound. Interestingly, what CADPE did not affect normal hepatic cell viability and the number of WBC suggests a selective cytotoxicity of CADPE to cancer cells.