Design and Synthesis of EZH2-Based PROTACs to Degrade the PRC2 Complex for Targeting the Noncatalytic Activity of EZH2

J Med Chem. 2021 Mar 11;64(5):2829-2848. doi: 10.1021/acs.jmedchem.0c02234. Epub 2021 Feb 19.

Abstract

EZH2 mediates both PRC2-dependent gene silencing via catalyzing H3K27me3 and PRC2-independent transcriptional activation in various cancers. Given its oncogenic role in cancers, EZH2 has constituted a compelling target for anticancer therapy. However, current EZH2 inhibitors only target its methyltransferase activity to downregulate H3K27me3 levels and show limited efficacy because of inadequate suppression of the EZH2 oncogenic activity. Therefore, therapeutic strategies to completely block the oncogenic activity of EZH2 are urgently needed. Herein, we report a series of EZH2-targeted proteolysis targeting chimeras (PROTACs) that induce proteasomal degradation of PRC2 components, including EZH2, EED, SUZ12, and RbAp48. Preliminary assessment identified E7 as the most active PROTAC molecule, which decreased PRC2 subunits and H3K27me2/3 levels in various cancer cells. Furthermore, E7 strongly inhibited transcriptional silencing mediated by EZH2 dependent on PRC2 and transcriptional activation mediated by EZH2 independent of PRC2, showing significant antiproliferative activities against cancer cell lines dependent on the enzymatic and nonenzymatic activities of EZH2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Antineoplastic Agents / chemical synthesis
  • Antineoplastic Agents / pharmacology*
  • Benzamides / chemical synthesis
  • Benzamides / pharmacology*
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Drug Design
  • Drug Screening Assays, Antitumor
  • Enhancer of Zeste Homolog 2 Protein / antagonists & inhibitors*
  • Enhancer of Zeste Homolog 2 Protein / metabolism
  • Humans
  • Phthalimides / chemical synthesis
  • Phthalimides / pharmacology*
  • Proteolysis / drug effects*
  • Ubiquitin-Protein Ligases / metabolism
  • Ubiquitination / drug effects

Substances

  • Adaptor Proteins, Signal Transducing
  • Antineoplastic Agents
  • Benzamides
  • CRBN protein, human
  • Phthalimides
  • EZH2 protein, human
  • Enhancer of Zeste Homolog 2 Protein
  • Ubiquitin-Protein Ligases