Effect Of MDR1 SiRNA On Drug Resistance Of Human Carcinoma Of The Tongue Cell Line TCA8113

Objective: To investigate the effect of MDR1 siRNA on multidrug resistance(MDR1)of Human carcinoma of the tongue cells.Method: Human multidrug-resistant Human carcinoma of the tongue cell line TCA8113 over expressing mdr1 gene was used as the target. The siRNA speciafically targeting mdr1 gene was chemically synthesized and identified, then was transfected into TCA8113 cells with RNAi-MATE. Clone cells were screened by G418. The silencing efficiency of siRNA was evaluated by the inhibition of mdr1 mRNA expression measured with RT-PCR and the inhabition of P-glycoprotein(P-gp) expression with immunohistochemical analysis. The sensitivity of the cells to PYM, Cisplatin(DDP) and 5-fluorouracil(5-Fu)was detected with a MTT colorimetric assay.Result: The expression of MDR1 mRNA and P-gp in positive clone cells(TCA8113) were all inhibited . IC50 of DDP, 5-Fu and PYM for TCA8113 cells were 3.43μmol/L,1.72μmol/L and 1.05μmol/L , respectively ( P<0 .01).Conclusion: Stable trasfection of plasmid vector encoding MDR1 siRNA can speciafically depress the expression of mdr1 gene and its product P-gp in drug-resistant TCA8113 cells and reverse multidrug resistance to chemotherapeutical agents.