Objective To construct the eukaryotic expression plasmids of tumor susceptibitity gene(TSG) 101-siRNA and investigate the effect of RNA interference targeting tsg101 gene and cisplatin on liver cancer resistant strain QGY/CDDP.   Methods The targeting fragments specifically against TSG101 were designed according to the principle of small interfering RNA designation using computer software. The sequences were cloned into siRNA expression plasmids through DNA recombinant technology. The expressions of tsg101mRNA and TSG101 after TSG101-siRNA transfection was detected by RT-PCR and Western blot respectively. MTT test were applied to measure the proliferation of QGY/CDDP strain.   Results The fragments of interest were obtained by digestion and further confirmed by DNA sequencing. TSG101-siRNA inhibited the expressions of tsg101mRNA and TSG101 and the proliferation of QGY/CDDP

especially in combination with cisplatin.   Conclusion The eukaryotic expression vector of TSG101-siRNA combined with cisplatin inhibits the proliferation of QGY/CDDP and increases the sensitivity of liver cancer resistant strain QGY/CDDP to chemotherapy.