Growth inhibition and enhanced chemosensitivity induced by down-regulation of Aurora-A in human renal cell carcinoma Caki-2 cells using short hairpin RNA.

The objective of this study was to investigate the inhibitory effects of Aurora-A expression on the growth and chemosensitivity of Caki-2 cells in human renal cell carcinoma (RCC). Caki-2 cells were established, in which an expression vector containing short hairpin RNA (shRNA) targeting Aurora-A was introduced (Caki-2/sh-A). The growth and sensitivity of chemotherapeutic agents in Caki-2/sh-A cells were compared to those in Caki-2 cells transfected with control vector alone (Caki-2/C). The expression levels of both Aurora-A mRNA and protein in Caki-2/sh-A cells were less than 10% of those in Caki-2/C cells. The in vitro growth of Caki-2/sh-A cells was significantly inferior to that of Caki-2/C cells, and the proportion of Caki-2/sh-A cells in the G2-M phase was significantly greater compared to that of Caki-2/C cells. In addition, the expression level of Bax in Caki-2/sh-A cells was significantly higher as compared to that in Caki-2/C cells, while phosphorylated Akt in Caki-2/sh-A cells was markedly down-regulated compared to that in Caki-2/C cells. Among several chemotherapeutic agents examined, the most significant difference between Caki-2/sh-A and Caki-2/C cells was observed in the sensitivity to docetaxel. Thus, the IC(50) value of docetaxel in Caki-2/sh-A cells was decreased by approximately 90% compared to that in Caki-2/C cells. Treatment of Caki-2/sh-A cells, but not Caki-2/C ones, with 5 nM docetaxel resulted in the induction of apoptotic cell death accompanying the induction of p53. The findings suggest that the suppression of Aurora-A expression using shRNA is a useful therapeutic strategy against RCC through growth inhibition as well as enhanced chemosensitivity.