[Effects of survivin small interfering RNA on biological behaviors of bladder cancer T24 cells].

BACKGROUND & OBJECTIVE: Bladder cancer, a common tumor of urinary system, is related to genetic mutations that deregulate cell cycle and render tumor cells resistant to apoptosis. Survivin, a new member of the inhibitor-of-apoptosis (IAP) family, participates in the genesis of several human cancers, including bladder cancer, through inducing cell proliferation and inhibiting apoptosis. This study was to explore the effects of small interfering RNA (siRNA) targeting survivin on the biological behaviors of bladder cancer T24 cells. METHODS: A pair of survivin siRNA were designed and synthesized, and transfected into T24 cells with increasing concentrations (50-200 nmol/L) and injected in tumor-bearing mice at different doses (5 and 50 microg). The effects of survivin siRNA on the biological behaviors of T24 cells were assessed. RESULTS: Survivin siRNA efficiently down-regulated the expression of survivin mRNA. Its maximal effect was achieved at the concentration of 100 nmol/L, at which survivin expression level was down-regulated by 75.91%, the inhibition rate of cell proliferation was 55.29% (P<0.01), and the apoptosis rate was significantly higher in siRNA-transfected cells than in control cells (45.70% vs. 2.8%, P<0.01). Intratumoral injection of 50 microg survivin siRNA significantly inhibited the growth of bladder cancer in mice (P<0.01). CONCLUSIONS: Survivin siRNA could markedly inhibit survivin expression in T24 cells, induce cell apoptosis and inhibit the growth of transplanted tumor in mice. It might be a new gene therapy tool for bladder cancer.