Functional characterization of a PROTAC directed against BRAF mutant V600E

Nat Chem Biol. 2020 Nov;16(11):1170-1178. doi: 10.1038/s41589-020-0609-7. Epub 2020 Aug 10.

Abstract

The RAF family kinases function in the RAS-ERK pathway to transmit signals from activated RAS to the downstream kinases MEK and ERK. This pathway regulates cell proliferation, differentiation and survival, enabling mutations in RAS and RAF to act as potent drivers of human cancers. Drugs targeting the prevalent oncogenic mutant BRAF(V600E) have shown great efficacy in the clinic, but long-term effectiveness is limited by resistance mechanisms that often exploit the dimerization-dependent process by which RAF kinases are activated. Here, we investigated a proteolysis-targeting chimera (PROTAC) approach to BRAF inhibition. The most effective PROTAC, termed P4B, displayed superior specificity and inhibitory properties relative to non-PROTAC controls in BRAF(V600E) cell lines. In addition, P4B displayed utility in cell lines harboring alternative BRAF mutations that impart resistance to conventional BRAF inhibitors. This work provides a proof of concept for a substitute to conventional chemical inhibition to therapeutically constrain oncogenic BRAF.

Publication types

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

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Chimera / metabolism
  • Drug Design
  • Drug Resistance, Neoplasm
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Female
  • Gene Expression Regulation
  • Humans
  • MAP Kinase Signaling System
  • Mice
  • Mitogen-Activated Protein Kinase Kinases / metabolism
  • Models, Molecular
  • Molecular Structure
  • Molecular Targeted Therapy
  • Mutation
  • Phosphorylation / drug effects
  • Protein Binding
  • Protein Kinase Inhibitors / pharmacology*
  • Proteolysis
  • Proto-Oncogene Proteins B-raf / antagonists & inhibitors*
  • Proto-Oncogene Proteins B-raf / genetics*
  • Signal Transduction
  • Structure-Activity Relationship
  • Thalidomide / analogs & derivatives*
  • Thalidomide / chemistry
  • Ubiquitin / chemistry*

Substances

  • Antineoplastic Agents
  • Protein Kinase Inhibitors
  • Ubiquitin
  • Thalidomide
  • pomalidomide
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf
  • Extracellular Signal-Regulated MAP Kinases
  • Mitogen-Activated Protein Kinase Kinases