Notes: HPOB is a potent inhibitor of histone deacetylase 6 (HDAC6; IC50 = 56 nM).{28379} It is at least 30-fold less effective against other HDACs.{28379} Through its effects on HDAC6, HPOB induces acetylation of α-tubulin but not histones.{28379} HPOB reduces the growth, but not the viability, of normal and transformed cells.{28379} It enhances the death of transformed cells as triggered by the topoisomerase II inhibitors etoposide and doxorubicin.{28379} HPOB enhances the cytotoxicity of the broad spectrum HDAC inhibitor SAHA (Item No. 10009929) against cancer cells in nude mice carrying an androgen-dependent CWR22 human prostate cancer xenograft.{28379}