Chlamydocin is a histone deacetylase (HDAC) inhibitor that was originally isolated from D. chlamydosporia and has anticancer properties. It is selective for HDAC1 over HDAC6 (IC50 = 0.15 and 1,100 nM, respectively). Chlamydocin increases acetylation of histone H3 and histone H4 in A2780 cells when used at concentrations ranging from 1 to 1,000 nM. It inhibits growth of A2780, Malme-3M, MCF-7, HT-29, and HeLa cancer cells (IC50s = 0.36, 45, 5.3, 4.3, and 14 nM, respectively). Chlamydocin increases lifespan by 10% in a P185 mouse allograft model when administered at doses ranging from 20 to 160 mg/kg.
