Design of a Biased Potent Small Molecule Inhibitor of the Bromodomain and PHD Finger-Containing (BRPF) Proteins Suitable for Cellular and in Vivo Studies

The BRPF (bromodomain and PHD finger-containing) family are scaffolding proteins important for the recruitment of histone acetyltransferases of the MYST family to chromatin. Evaluation of the BRPF family as a potential drug target is at an early stage although there is an emerging understanding of a role in acute myeloid leukemia (AML). We report the optimization of fragment hit <b>5b</b> to <b>13-d</b> as a biased, potent inhibitor of the BRD of the BRPFs with excellent selectivity over nonclass IV BRD proteins. Evaluation of <b>13-d</b> in a panel of cancer cell lines showed a selective inhibition of proliferation of a subset of AML lines. Pharmacokinetic studies established that <b>13-d</b> had properties compatible with oral dosing in mouse models of disease (<i>F</i>_po 49%). We propose that <b>NI-42</b> (<b>13-d</b>) is a new chemical probe for the BRPFs suitable for cellular and in vivo studies to explore the fundamental biology of these proteins