Objective    To construct the RNAi eukaryotic vector of inhibitory member of MRP family (MRP2) gene and after the vector transfection into HCT-8/V cell line to observe its interfering effect on MRP2 expression and the changed sensibility to vinblastine.     Methods    The specific siRNA sequence was designed according to the MRP2 sequence. The sequence was cloned into pGenSil-1 and then sequenced. The recombinant plasmid was transfected into HCT-8/V cells by liposome. Then MRP2 expression in the transfected cells was analyzed by FQ-PCR and Western blotting. MTT test was used to measure the inhibitory effects of pGenSil-1-MRP2-siRNA on the proliferation of HCT-8/V cells treated with vinblastine.      Results    The overexpression of MRP2 was suppressed efficiently by the introduction of small interfering RNA that caused sequence-specific gene silence. The apoptotic rate of HCT-8/V cells transfected with pGenSil-1-MRP2-siRNA increased significantly when the cells were exposed to vinblastine as compared with that of nontransfected cells (P0.01)

indicating the drug resistance of the transfected cells decreased.     Conclusion    The RNAi eukaryotic vector pGenSil-1-MRP2-siRNA is constructed successfully. The RNAi we constructed inhibits MRP2 expression effectively and reverses the drug resistance of HCT-8/V cells.