Effect of combination of TRAIL and paclitaxel on human gastric cancer cell line SGC7901

Background and purpose:Tumor necrosis factor related apoptosis-inducing ligand (TRAIL) is a death receptor ligand that can induce apoptosis in a variety of cancer cell lines, but not all cancer cells . Past studies suggested that some chemotherapeutic drugs intensified the sensitivity of TRAIL induced apoptosis.We investigated the effect and potential mechanism of combined paclitaxel and TRAIL on apoptosis of human gastric cancer cell in vitro. Methods:SGC7901 cells were cultured with paclitaxel at different concentrations(1,5,10,20,40 μg/ml) and different time(12,24,36,48 hr), methyl thiazolyl tetrazolium (MTT) assay was used to measure the anticancer activity of paclitaxel.The ability of TRAIL alone,paclitaxel alone and TRAIL in combination with paclitaxel to induce apoptosis was measured by a flow cytometer. Expression of DR4,DR5, DcR1,DcR2,Caspase-8 and Bcl-2 mRNA was examined by RT-PCR.Results:The apoptosis rates of control group(C group),paclitaxel group(P group),TRAIL group (T group)and combination group(T+P)in 24 hr were 2.09%,10.65%,7.79% and 24.51%, respectively. The apoptosis rate in T+P group was significantly higher than that in C group, T group and P group(P0.05).Before exposure to paclitaxel,DR5 mRNA expression was low and was up-regulated in SGC7901 cells after treatment with paclitaxel.Conclusions:There might be a synergistcal interaction between paclitaxel in terms of cytotoxicity and its mechanisms might be involved in the up-regulation of DR5 gene.