siRNA-mediated down-regulation of survivin inhibits bladder cancer cell growth.

Survivin is recognized as a general target in cancer therapy because of its selective overexpression in the majority of tumors. In bladder cancer (BCa), its expression correlates with tumor grade, recurrence risk and survival. In this study, we compared the therapeutic efficiency of two survivin specific small interfering RNA (siRNA) constructs, SVV284 and SVV094, to inhibit the growth of five human BCa cell lines (EJ28, 5637, J82, RT112, RT4). In a period between 24 to 72 h after siRNA SVV284 transfection, EJ28 and 5637 showed a significant reduction (up to 47%) of viability. For both cell lines cell cycle analysis and quantitation of apoptosis revealed both a specific G2/M arrest and an induction of apoptosis, as well as the occurrence of multinucleated cells. The cell lines EJ28, 5637 and J82 exhibited a prolonged duplication time up to 1.4-fold at 72 h after treatment. Furthermore, in these three cell lines the mRNA and protein expression quantified by real time RT-PCR and ELISA was reduced by at least 50% and up to 99%, respectively. However, RT112 and RT4 cells did not show an effective down-regulation of survivin expression. In comparison to siRNA SVV284, the treatment with siRNA SVV094 exhibited less inhibitory effects on cell growth and survivin expression in all BCa cell lines tested. In summary, the results suggest that the anti-survivin siRNA treatment might represent a suitable therapeutic approach to selectively inhibit growth of BCa cells in addition to commonly applied therapy schemes.