Discovery of First-In-Class Potent and Selective Tropomyosin Receptor Kinase Degraders

J Med Chem. 2020 Dec 10;63(23):14562-14575. doi: 10.1021/acs.jmedchem.0c01342. Epub 2020 Oct 15.

Abstract

We report compounds 5 (CG416) and 6 (CG428) as two first-in-class tropomyosin receptor kinase (TRK) degraders that target the intracellular kinase domain of TRK. Degraders 5 and 6 reduced levels of the tropomyosin 3 (TPM3)-TRKA fusion protein in KM12 colorectal carcinoma cells and inhibited downstream PLCγ1 signaling at sub-nanomolar concentrations. Both degraders also degraded human wild-type TRKA with similar potency. Interestingly, both degraders, especially 6, showed selectivity for the degradation of endogenous TPM3-TRKA over ectopically expressed ATP/GTP binding protein-like 4 (AGBL4)-TRKB or ETS variant transcription factor 6 (ETV6)-TRKC fusion proteins in KM12 cells. Global proteomic profiling assays demonstrated that 5 is highly selective for the intended target. TPM3-TRKA protein degradation induced by 5 and 6 was further confirmed to be mediated through cereblon and the ubiquitin-proteasome system. Compared with the parental TRK kinase inhibitor, both degraders exhibited higher potency for inhibiting growth of KM12 cells. Moreover, both 5 and 6 showed good plasma exposure levels in mice. Therefore, 5 and 6 are valuable chemical tool compounds for investigating the in vivo function of TRK fusion during tumorigenesis. Our study also paves the way for pharmacological degradation of TRK.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Down-Regulation / drug effects
  • Drug Design
  • Drug Discovery
  • Humans
  • Male
  • Mice, Inbred ICR
  • Molecular Structure
  • Protein Kinase Inhibitors / chemical synthesis
  • Protein Kinase Inhibitors / pharmacokinetics
  • Protein Kinase Inhibitors / pharmacology*
  • Proteolysis / drug effects
  • Pyridazines / chemical synthesis
  • Pyridazines / pharmacokinetics
  • Pyridazines / pharmacology*
  • Receptor Protein-Tyrosine Kinases / antagonists & inhibitors*
  • Receptor Protein-Tyrosine Kinases / metabolism
  • Receptor, trkA / antagonists & inhibitors
  • Receptor, trkA / metabolism
  • Receptor, trkB / antagonists & inhibitors
  • Receptor, trkB / metabolism
  • Receptor, trkC / antagonists & inhibitors
  • Receptor, trkC / metabolism
  • Structure-Activity Relationship
  • Thalidomide / analogs & derivatives*
  • Thalidomide / pharmacokinetics
  • Thalidomide / pharmacology*
  • Ubiquitin-Protein Ligases / metabolism

Substances

  • IL17RB protein, human
  • Protein Kinase Inhibitors
  • Pyridazines
  • Thalidomide
  • Ubiquitin-Protein Ligases
  • Receptor Protein-Tyrosine Kinases
  • Receptor, trkA
  • Receptor, trkB
  • Receptor, trkC