The Effect Of CpG-ODN Alone Or Combination With Chemotherapeutic Drugs On T24 Human Bladder Cancer Cells

Objective Bladder cancer is the most common malignancy of the urinary system. In this study, we evaluated the effect of un-methylated Cp G oligodeoxynucleotides(Cp G-ODN)that has been considered as a potential immunologic adjuvant on T24 human bladder cancer cells. In addition, we probed the chemosensitizing effects of Cp G-ODN with 5-FU or DOX on T24 human bladder cancer cells.Methods T24 were cultured in RPMI-1640 medium supplemented with 10% FBS in 25 cm2 polystyrene flasks at 37°C in an incubator with maximal humidity and 5% CO2 in air. Routine passage was carried out every 2 or 3 days. The direct cytotoxic activity of different group was evaluated by MTS cell viability assay in T24 cells. Cell morphology was examined by fluorescence microscopy with Hoechst 33258 reagent. Apoptosis and cellcycle phase distribution was confirmed by flow cytometry analysis. Further molecular mechanisms were studied by Real Time quantitative PCR assay in vitro.Results The inhibition effect of Cp G-ODN on T24 cells was more obvious than the effect of BCG. The inhibition ratio of T24 cells growth treated with liposome-Cp G-ODN was higher than treated with Cp G-ODN in cell viability assay. Both groups could reduce the expression of Bcl-2, but liposome group reduced more. Cp G-ODN or DOX alone could inhibit T24 cells viability. But when the two drugs were combined, inhibition ratio would decrease. In contrast, there is a synergistic effect between 5-FU and Cp G-ODN when they were used together. In combination group, the apoptosis rate is significantly increased and more cells arrest at S and G2/M phase compared with Cp G-ODN or 5-FU alone in flow cytometry analysis assay. The results of Real Time quantitative PCR assay showed that Cp G-ODN and 5-FU alone could down-regulate the expression of Bcl-2 within T24 cells. But combination of both could reduce the expression of Bcl-2 at most.Conclusion Our research proved that Cp G-ODN promoted apoptosis of T24 and enhanced the chemosentivity of 5-FU in T24 human bladder cancer cells at least in part by downregulating the expression of Bcl-2 and inducing cell cycle arrest at S and G2/M phase. Therefore, Cp G-ODN may be a potential candidate drug for human bladder cancer.