Inhibition of class I histone deacetylases 1 and 2 promotes urothelial carcinoma cell death by various mechanisms (HDAC inhibitor treatments)

Preliminary manuscript abstract: Class I histone deacetylases HDAC1 and HDAC2 contribute to cell proliferation and are commonly upregulated in urothelial carcinoma (UC). To evaluate whether specific inhibition of HDAC1 and HDAC2 might serve as an appropriate therapy of UC we applied specific pharmacological inhibition of HDAC1 and HDAC2 with the two selective class I HDAC inhibitors Romidepsin and Givinostat. Treatment with the pan HDAC inhibitor SAHA served as an additional control. Romidepsin and Givinostat significantly reduced proliferation and clonogenicity of UC cells with minor effects on non-tumorigenic cells. Furthermore, compounds induced primarily S-phase disturbances and non-apoptotic cell death. Results of microarray analysis of HDAC inhibitor treated cells match with observed phenotype after pharmacological HDAC1 and HDAC2 inhibition in UC cells. For differential gene expression analyses three independent high quality RNA preparations from VM-CUB1 and UM-UC-3 cells, treated with the HDAC inhibitors Romidepsin, Givinostat and SAHA, were compared to DMSO treated control cells.