Abstract 1660: Unraveling isoform selectivities of a broad class of HDAC inhibitors with QM/MM molecular dynamics simulations

Therapeutics that have been used by large populations and showed limited or little adverse effects can be good candidates for cancer chemo-prevention. As an example of such therapeutics, statins, i.e., HMG-CA reductase inhibitors, have been widely prescribed for lowering the blood cholesterol level and for treating cardiovascular diseases. In 2008, we discovered that statins are moderate inhibitors of histone deacetylases (HDACs), which provides an epigenetic mechanism for their efficacy in cancer prevention. HDACs have been long recognized for as an important class of therapeutic targets, and these enzymes utilize a Zn2+ ion at its active site for catalysis. Subsequently, in our 2013 J. Med. Chem. article, we showed that we are able to strengthen this epigenetic mechanism and designed more potent and effective therapeutic agents for cancer prevention and treatment, including cancer metastasis, and published in Clin. Cancer Res. in 2016. To investigate the structure-activity relationships of a broad class of HDAC inhibitors with distinct chemical moieties, we have conducted QM/MM molecular dynamics simulations of several systems of HDAC isoforms bound with various ligands. In contrast to molecular dynamics simulations with classical force fields, which always rendered over-coordinated configurations of the Zn2+ at the active site, with the coordination numbers (CN) to be either 6 or 7, in our QM/MM molecular dynamics simulations, the CNs of Zn2+ remain 4 or 5. With the structural and energetics analysis from these QM/MM molecular dynamics simulations, we are able to delineate the origins of isoform-selectivity of different HDAC inhibitors, including the aforementioned HMGR-HDAC dual-action inhibitors that we recently developed. Citation Format: Jung-Hsin Lin. Unraveling isoform selectivities of a broad class of HDAC inhibitors with QM/MM molecular dynamics simulations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1660.