High-throughput screening with nucleosome substrate identifies small-molecule inhibitors of the human histone lysine methyltransferase NSD2

J Biol Chem. 2018 Aug 31;293(35):13750-13765. doi: 10.1074/jbc.RA118.004274. Epub 2018 Jun 26.

Abstract

The histone lysine methyltransferase nuclear receptor-binding SET domain protein 2 (NSD2, also known as WHSC1/MMSET) is an epigenetic modifier and is thought to play a driving role in oncogenesis. Both NSD2 overexpression and point mutations that increase its catalytic activity are associated with several human cancers. Although NSD2 is an attractive therapeutic target, no potent, selective, and bioactive small molecule inhibitors of NSD2 have been reported to date, possibly due to the challenges of developing high-throughput assays for NSD2. Here, to establish a platform for the discovery and development of selective NSD2 inhibitors, we optimized and implemented multiple assays. We performed quantitative high-throughput screening with full-length WT NSD2 and a nucleosome substrate against a diverse collection of bioactive small molecules comprising 16,251 compounds. We further interrogated 174 inhibitory compounds identified in the primary screen with orthogonal and counter assays and with activity assays based on the clinically relevant NSD2 variants E1099K and T1150A. We selected five confirmed inhibitors for follow-up, which included a radiolabeled validation assay, surface plasmon resonance studies, methyltransferase profiling, and histone methylation in cells. We found that all five NSD2 inhibitors bind the catalytic SET domain and one exhibited apparent activity in cells, validating the workflow and providing a template for identifying selective NSD2 inhibitors. In summary, we have established a robust discovery pipeline for identifying potent NSD2 inhibitors from small-molecule libraries.

Keywords: MMSET; NSD2; WHSC1; cancer; epigenetics; high-throughput screening (HTS); histone methylation; lysine methyltransferase inhibitor; nucleosome; oncogene; small molecule.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Cell Line, Tumor
  • Drug Evaluation, Preclinical / methods*
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • High-Throughput Screening Assays / methods
  • Histone-Lysine N-Methyltransferase / antagonists & inhibitors*
  • Histone-Lysine N-Methyltransferase / metabolism
  • Humans
  • Nucleosomes / drug effects
  • Nucleosomes / metabolism*
  • Repressor Proteins / antagonists & inhibitors*
  • Repressor Proteins / metabolism
  • Small Molecule Libraries / chemistry
  • Small Molecule Libraries / pharmacology*

Substances

  • Enzyme Inhibitors
  • Nucleosomes
  • Repressor Proteins
  • Small Molecule Libraries
  • Histone-Lysine N-Methyltransferase
  • NSD2 protein, human