Study On RNA Interference MRP1Gene Expression To Reverse Chemotherapy Drug Resistance In NSCLC

Objective:To explore the expression of multidrug resistance–associa-ted proteinMRP1in NSCLC, the relationship between RNA interference and the expression ofMRP1in NSCLC Multidrug Resistant Cell Line,and the method of efficiency andspecific reversible lung cancer resistance in vitro test.Methods: The expression level of MRP1mRNA and its protein were detected byReal Time quantitative fluorescence PCR and immunohisto chemistry in30cases oflung cancer tissue and adjacent mucos-a． Targeting MRP1siRNA were designed andsynthetized, and then directly transfect in to A549/DDP．Before and after transfection,the expression level of MRP1mRNA were detected by Real Time quantitativefluorescence PCR, the expression of MRP1protein were detected by Western blot, andthe changes of A549/DDP cells to cis-platinum drug resistance were detected by MTTmethod.Results:1. In30cases of pathologic tissue, the positive rate of MRP1protein was70%(21/30) in lung cancer tissue and16.67%(5/30) in adjacent mucosa, which withstatistical differences (P <0.05); for lung cancer tissue, the positive rate of MRP1protein was90.9%(10/11) in chemotherapeutic pathologic tissue and57.89%(11/19) inpathologic tissue which not receiving chemotherapy, with statistical differences betweenthem (P<0.05), indicating high-level expression in chemotherapeutic tissue. In addition,PCR results showed the expression of MRP1mRNA in lung cancer tissue was alsohigher than that of adjacent mucosa, with significant differences (P<0.05) by statisticalanalysis.2. After MRP1siRNA were transfected into A549/DDP cell in vitro test, theexpression of MRP1mRNA decreased significantly with marked differences(P<0.05),78%of inhibition ration in comparison with the one which before transfection., Relative expression strength of MRP1protein decreased to0.435±0.042fromprevious0.820±0.037After transfection,which with significant differences (P<0.05); theresults of MTT showed the sensitivity of cells to cis-platinum increased by1.43timesafter transfection.Conclusions:1. High-level expression of MRP1in lung cancer tissue espec-iallyafter chemotherapy,which verified there existed primary drug resista-nce in NSCLCpatients.2. Vitro experiments verified transcription and translation of MRP1were in-hibitted after drug resistance cells were transfected by MRP1siRNA.In add-ition, drugsensitivity of cells to cis-platinum strengthened, which indicat-ing the reversal of drugresistance.