(B) Protein expression of HDAC8 in urothelial cancer cell lines (UCCs) and a normal uroepithelial control (NUC) analyzed by western blotting. XAV939 As a loading control α-tubulin was stained on each blot. Accordingly the urothelial carcinoma cell lines SW-1710 (protein level Sepantronium price strongly increased), UM-UC-3, VM-CUB1 (protein level moderately increased), RT-112 (protein level as normal) and 639-V (protein level decreased) were selected for further experiments. Effects of siRNA-mediated knockdown of HDAC8 on cell proliferation and clonogenic growth of urothelial carcinoma cells The endogenous HDAC8 expression was reduced by

transiently transfecting HDAC8 siRNA and irrelevant siRNA into RT-112, VM-CUB1, SW-1710, 639-V and UM-UC-3 cells. The knockdown efficacy 72 h after transfection was shown by RT-PCR (Figure 2A) and western blot analysis (Figure 2B). The UCCs RT-112, VM-CUB1, SW-1710 and UM-UC-3 indicated a HDAC8 knockdown of about 90% to

95%. In 639-V cells, a knockdown of 55% was achieved. Figure 2 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 check details 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. To investigate the impact of HDAC8 on cell proliferation of UCCs we performed viability assays after

72 h of transfection. Targeting HDAC8 with siRNA caused a 20% to 45% reduction of cell growth compared to the irrelevant control (Figure 3A). Colony Edoxaban forming assays were performed to evaluate the role of HDAC8 for anchorage-dependent clonal growth capability. The siRNA mediated HDAC8 knockdown inhibited clonogenic growth of UCCs (Figure 3B). The transfection of HDAC8 siRNA in VM-CUB1 and UM-UC-3 cells caused a moderate reduction of colony numbers compared to transfection of irrelevant siRNA by up to 30%. The relative size of the HDAC8 siRNA transfected colonies is reduced in 639-V in comparison to irrelevant siRNA. In VM-CUB1, SW-1710, RT-112 and UM-UC-3 cells the colony size remains constant between irrelevant control and HDAC8 siRNA transfection (data not shown). Figure 3 Proliferation and clonogenicity in urothelial cancer cells after siRNA mediated knockdown of HDAC8. (A) Relative cell viability in several urothelial carcinoma cell lines after siRNA mediated knockdown of HDAC8 compared to irrelevant control (72 h). The percentage of viable cells was measured by ATP-assay and is displayed on the y-axis. p < 0.01 and p < 0.