Efficiency of HDAC8 knockdown by a specific siRNA in the urothelial cancer cell lines. (A) Relative HDAC8 expression after siRNA mediated knockdown in urothelial carcinoma cell lines compared to irrelevant control as examined by quantitative RT-PCR analysis (72 h). The HDAC8 expression values were normalized to TBP as a reference gene and are displayed on the y-axis. p < 0.01 and p < 0.001 were defined as highly significant and marked as * and **. (B) Western blot analysis confirmed the effects of HDAC8-siRNA mediated knockdown at the HDAC8 protein level in comparison to normal and irrelevant siRNA controls (72 h). As a loading control α-tubulin was stained on each blot.