OBJECTIVE To study the efficiency of silencing survivin gene expression by an anti-survivin small RNA expression plasmid and to examine its impact on apoptosis, proliferation and invasive ability of the SW480 colorectal cancer cell line.METHODS An expression plasmid of survivin siRNA (pRNAT/sur-siRNA) was constructed and transduced into SW480 cells. Western blot analysis and a semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) were used to measure the change in expression level of the survivin protein and mRNA after transduction of the expression plasmid into the SW480. Apoptosis, proliferation, and invasive ability of the SW480 cells was evaluated by flow cytometry, MTT assay and Boyden Chamber Assay, respectively.RESULTS The expression plasmid (pRNAT/sur-siRNA) against survivin down-regulated survivin protein and mRNA expression dramatically, with a down-regulation of 85% and 80%, respectively. After transfection of the pRNAT/sur-siRNA to the SW480 cells, the apoptotic rate of the pRNAT/sur-siRNA/SW480 cells was 16.9%, and the proliferation rate was 37.4%,significantly different compared to the controls (P＜0.01). Cell invasive studies (Boyden Chamber Assay) showed that number of cells penetrating the membrane for the pRNAT/sur-siRNA/SW480, pRNAT/SW480 and the SW480 cells was 153±66, 505±65 and 578±98, respectively (P＜0.01).CONCLUSION siRNA against survivin can significantly inhibit the expression of survivin in SW480 cells, and thus promote apoptosis, inhibit proliferation and invasive ability.