Acetylon: Homing in on HDAC6

Acetylon Pharmaceuticals Inc. hopes that by targeting an isoform of histone deacetylase that operates only in diseased cells, its cancer compounds will produce fewer side effects than less specific HDAC inhibitors. The company expects to choose a lead HDAC6 inhibitor for multiple myeloma this quarter.

There are 18 known isoforms of HDAC proteins. Seven of these are sirtuins, or Class III HDACs, whose exact mechanism is unknown. The remaining 11 are more classical HDACs, which catalyze the removal of acetyl groups from lysine residues...