Structural Basis of Inhibitor Selectivity in the BRD7/9 Subfamily of Bromodomains

J Med Chem. 2020 Mar 26;63(6):3227-3237. doi: 10.1021/acs.jmedchem.9b01980. Epub 2020 Mar 6.

Abstract

Inhibition of the bromodomain containing protein 9 (BRD9) by small molecules is an attractive strategy to target mutated SWI/SNF chromatin-remodeling complexes in cancer. However, reported BRD9 inhibitors also inhibit the closely related bromodomain-containing protein 7 (BRD7), which has different biological functions. The structural basis for differential potency and selectivity of BRD9 inhibitors is largely unknown because of the lack of structural information on BRD7. Here, we biochemically and structurally characterized diverse inhibitors with varying degrees of potency and selectivity for BRD9 over BRD7. Novel cocrystal structures of BRD7 liganded with new and previously reported inhibitors of five different chemical scaffolds were determined alongside BRD9 and BRD4. We also report the discovery of first-in-class dual bromodomain-kinase inhibitors outside the bromodomain and extraterminal family targeting BRD7 and BRD9. Combined, the data provide a new framework for the development of BRD7/9 inhibitors with improved selectivity or additional polypharmacologic properties.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Calorimetry / methods
  • Cell Cycle Proteins / antagonists & inhibitors
  • Cell Cycle Proteins / metabolism
  • Chromosomal Proteins, Non-Histone / antagonists & inhibitors*
  • Chromosomal Proteins, Non-Histone / metabolism
  • Crystallography, X-Ray
  • Fluorometry / methods
  • Heterocyclic Compounds, 2-Ring / chemistry*
  • Heterocyclic Compounds, 2-Ring / metabolism
  • Humans
  • Ligands
  • Molecular Structure
  • Protein Binding
  • Protein Domains / drug effects*
  • Structure-Activity Relationship
  • Transcription Factors / antagonists & inhibitors*
  • Transcription Factors / metabolism

Substances

  • BRD4 protein, human
  • BRD7 protein, human
  • BRD9 protein, human
  • Cell Cycle Proteins
  • Chromosomal Proteins, Non-Histone
  • Heterocyclic Compounds, 2-Ring
  • Ligands
  • Transcription Factors