Study on the change of drug resistance and apoptosis of carcinoma cells after transfecting siRNA targeting multidrug resistance related protein

Aim:To study the regulation of drug resistance and the apoptosis ratio of drug resistance carcinoma cells after transfer siRNA targeting MRP. Methods: We transfected siRNA,targeting MRP(100 μmol/L),by lipofectamine into SW1575/R20(pretreated by DNR at 0.8,1.6,3.2,6.4,12.8 μg/mL),K562/ADM(pretreated by ADM at 1.6,3.2,6.4,12.8,25.6 μg/mL),and CNE2/DDP(pretreated by DDP at 0.125,0.25,0.5,1.0,2.0,4.0 μmol/mL).The negative control group is cell without any treatment,the positive control group is cell only treated by chemicaltherapy.After transfected for 6 hours,we added 20% FBS serum OPTI-MEM.The cell's viability was detected at 24,48 and 72 h by MTT method.After transfecting for 24 hours,we collected the cells to detect the mRNA level of MRP by RT-PCR.After transfecting for 48 hours,we collected the cells to detect the transfect ratio,the apoptosis ratio and the expression ratio of MRP by FCM.Results: After transfected siRNA targeting MRP and bcl-2,the level of mRNA and MRP and bcl-2 decrease significantly.Meanwhile the IC50 decreased significantly and apoptosis ratio increased significantly compared with ADM group(P0.05).For the group transfected with siRNA targeting MRP combining with bcl-2,the IC50 is the lowest and the apoptosis ratio is the highest among all groups(P0.05).Conclusion:As we transfect siRNA targeting MRP and bcl-2,the drug sensitivity and apoptosis increased with level of MRP and bcl-2 decreasing.