Vorinostat (SAHA) is an HDAC1/3 inhibitor with IC50 of ~10 nM.
Vorinostat inhibits the activities of HDAC1 and HDAC3 with IC50 of 10 nM and 20 nM, respectively. Vorinostat also results in a marked hyperacetylation of histone H4. Vorinostat inhibits the growth of three prostate cancer cell lines LNCaP, PC-3 and TSU-Pr1 at micromolar concentrations (2.5-7.5 M), and induces dose-dependent cell death in LNCaP cells. Vorinostat treatment in MCF-7 cells inhibits cell proliferation at an IC50 of 0.75 M resulting in the accumulation of cells in the G1 and G2-M phase of the cell cycle. Vorinostat also induces differentiation in the estrogen receptor-negative cell line SKBr-3 and the retinoblastoma-negative cell line MDA-468. Vorinostat treatment at 1 M for 8 hours or more is sufficient to irreversibly induce apoptosis of human multiple myeloma (MM) cells. The gene expression profiles of Vorinostat treated MM cells are not hallmarked by global transcriptional activation, but by coordinated transcriptional changes of specific functional groups of genes such as cytokine-induced proliferative/survival signaling cascades, oncogenes-tumor suppressor genes, regulators of apoptosis, DNA synthesis-repair and cell cycle, and proteasome-ubiquitin function.