Molecular Basis for the N-Terminal Bromodomain-and-Extra-Terminal-Family Selectivity of a Dual Kinase-Bromodomain Inhibitor.
Divakaran, A., Talluri, S.K., Ayoub, A.M., Mishra, N.K., Cui, H., Widen, J.C., Berndt, N., Zhu, J.Y., Carlson, A.S., Topczewski, J.J., Schonbrunn, E.K., Harki, D.A., Pomerantz, W.C.K.(2018) J Med Chem 61: 9316-9334
- PubMed: 30253095 
- DOI: https://doi.org/10.1021/acs.jmedchem.8b01248
- Primary Citation of Related Structures:  
6MH1, 6MH7 - PubMed Abstract: 
As regulators of transcription, epigenetic proteins that interpret post-translational modifications to N-terminal histone tails are essential for maintaining cellular homeostasis. When dysregulated, "reader" proteins become drivers of disease. In the case of bromodomains, which recognize N-ε-acetylated lysine, selective inhibition of individual bromodomain-and-extra-terminal (BET)-family bromodomains has proven challenging. We describe the >55-fold N-terminal-BET bromodomain selectivity of 1,4,5-trisubstituted-imidazole dual kinase-bromodomain inhibitors. Selectivity for the BRD4 N-terminal bromodomain (BRD4(1)) over its second bromodomain (BRD4(2)) arises from the displacement of ordered waters and the conformational flexibility of lysine-141 in BRD4(1). Cellular efficacy was demonstrated via reduction of c-Myc expression, inhibition of NF-κB signaling, and suppression of IL-8 production through potential synergistic inhibition of BRD4(1) and p38α. These dual inhibitors provide a new scaffold for domain-selective inhibition of BRD4, the aberrant function of which plays a key role in cancer and inflammatory signaling.
Organizational Affiliation: 
Department of Medicinal Chemistry , University of Minnesota , 2231 6th Street SE , Minneapolis , Minnesota 55455 , United States.