Mdm2-P53 Interaction Inhibitor with Cisplatin Enhances Apoptosis in Colon and Prostate Cancer Cells In-Vitro

OBJECTIVE: To study the effect of RITA (MDM2-p53 interaction inhibitor) and its action along with genotoxic drug cisplatin was evaluated on COLO-205 colon cancer and PC-3 prostate cancer cells. METHOD: Various in-vitro parameters to determine cytotoxic and apoptotic potential of RITA with genotoxic drug cisplatin were evaluated. The potentiation of cytotoxic effect was evaluated using MTT assay and colony forming assay, mechanism of cell death by Etbr/AcO assay and the mechanism of apoptosis was determined by caspase-3 release assay. RESULTS: The findings from MTT confirmed the best possible potent combination of 5+5µM and 10+10µM concentration of Cisplatin and RITA respectively. These combinations were further evaluated for its chemo sensitizing effect which confirmed the significant reduction in number of colonies in combination as compared to monotherapy. Also, the results of Etbr/AcO assay were in line with the colony forming assay. For apoptotic activity, it was noted that increasing the concentration of cisplatin and RITA (10µM), did not affect much to apoptotic activity and was found to be equally effective to that of low dose (5µM) concentration. The same results were seen in Caspase-3 release effect on both the cell lines. CONCLUSION: Our present study provides compelling evidence that pharmacological activation of the p53 by blocking the MDM2–p53 interaction is a promising cancer therapeutic strategy and using RITA in combination with Cisplatin not only decrease the toxic effect of Cisplatin by decreasing its dose but also increasing the apoptotic effect, warrants clinical evaluation on both colon and prostate cancer.