Objective:To construct eukaryotic expression vectors by usingthep Silencer2.0 vector for inhibiting human livin gene by RNA interference

and to detect the effect of the silenced livin gene on the growth and apoptosis of U251 cells. Methods:Two target gene segments were synthesized and cloned into the pSilencer2.0 vectorrespectively to construct two recombinant eukaryotic expression vectors: pSilencer2.0-liv1 and pSilencer2.0-liv2

both of which were identified by enzyme digestion analysis. Then the U251 cells were transfected with the recombinant vectors and the interfering effects were detected by RT-PCR and Western blot. The proliferation of the U251 cells was detected by MTT method and their apoptosis index detected by flow cytometry. Results:The results of Enzyme digestion analysis showed that two target segments were cloned into pSilencer2.0 vectors. The results of RT-PCR and Western blot indicated that pSilencer2. 0-liv1 and pSilencer2.0-liv2 vectors could knock down the transcription and expression of livin gene

but the effect of pSilencer2.0-liv2 vectors was better than that of the pSilencer2.0-liv1 vectors. Obvious decrease in growth of the U251 cells was observed after transfected with pSilencer2.0-liv1 and pSilencer2.0-liv2 vectors

along with 17%increase of the apoptosis index in the U251 cells transfected with pSilencer2.0-liv2 vectors. Conclusion:The transcription and expression of livin gene were inhibited effectively in the glioma cell line U251. Aftertransfected with pSilencer2.0-liv2 vectors

the apoptosis index of the U251 cells was increased and the growth inhibited.