Suppression of MDR1 gene expression and reversal of cisplatin resistance in renal carcinoma cells by RNA interference / 肿瘤

ABSTRACT

Objective:To investigate the inhibitory effect of RNA interference (RNAi) on the expression of multidrug resistance (MDR1) gene and analyze the altered sensitivities of human renal carcinoma cell line to cisplatin.Methods:Three small interfering RNA (siRNA) sequences targeted MDR1 gene were synthesized and transfected into renal carcinoma A498 cells. The expression level of MDRl mRNA was measured by RT-PCR to identify the most effective siRNA sequence. The recombinant plasmid was packed by lentivirus and transfected into A498 cells. RT-PCR was used to screen the A498 cells with the optimal silencing efficacy. The MDR1 protein expression level in the cloned cells was verified by Western blotting. The inhibitory effect of cisplatin on the proliferation of A498 cells was assessed by MTT assay and the IC_(50) value was calculated. Results:The 3 siRNA sequences suppressed MDR1 gene expression at different degrees. The siRNA 1 sequence silenced MDR1 gene more effectively with a significant reduction of 67%. The MDR1 protein expression greatly decreased in screened A498 cells compared with non-transfected cells (P<0.01), and the IC_(50) value of cisplatin on screened A498 cells was significantly decreased by 83.37% (P<0.01). Conclusion: The RNAi could effectively inhibit the expression of MDR1 gene and increase the sensibility to cisplatin in human renal carcinoma A498 cell line, which make it possible to reverse the resistance of renal carcinoma to chemotherapy.