Enhancing Antiproliferative Activity and Selectivity of a FLT-3 Inhibitor by Proteolysis Targeting Chimera Conversion

J Am Chem Soc. 2018 Dec 5;140(48):16428-16432. doi: 10.1021/jacs.8b10320. Epub 2018 Nov 19.

Abstract

The receptor tyrosine kinase FLT-3 is frequently mutated in acute myeloid leukemia; however, current small molecule inhibitors suffer from limited efficacy in the clinic. Conversion of a FLT-3 inhibitor (quizartinib) into a proteolysis targeting chimera (PROTAC) results in a compound that induces degradation of FLT-3 ITD mutant at low nanomolar concentrations. Furthermore, the PROTAC is capable of inhibiting cell growth more potently than the warhead alone while inhibiting fewer off-target kinases. This enhanced antiproliferative activity occurs, despite a slight reduction in the PROTAC's kinase inhibitory activity, via an increased level of apoptosis induction suggesting nonkinase roles for the FLT-3 ITD protein. Additionally, the PROTAC is capable of inducing FLT-3 ITD degradation in vivo. These results suggest that degradation of FLT-3 ITD may provide a useful method for therapeutic intervention.

Publication types

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

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacokinetics
  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents / therapeutic use*
  • Benzothiazoles / pharmacokinetics
  • Benzothiazoles / pharmacology
  • Benzothiazoles / therapeutic use*
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Humans
  • Mice, Nude
  • Phenylurea Compounds / pharmacokinetics
  • Phenylurea Compounds / pharmacology
  • Phenylurea Compounds / therapeutic use*
  • Protein Kinase Inhibitors / pharmacokinetics
  • Protein Kinase Inhibitors / pharmacology
  • Protein Kinase Inhibitors / therapeutic use*
  • Proteolysis
  • Ubiquitin-Protein Ligases / metabolism
  • Xenograft Model Antitumor Assays
  • fms-Like Tyrosine Kinase 3 / antagonists & inhibitors*
  • fms-Like Tyrosine Kinase 3 / metabolism

Substances

  • Antineoplastic Agents
  • Benzothiazoles
  • Phenylurea Compounds
  • Protein Kinase Inhibitors
  • quizartinib
  • Ubiquitin-Protein Ligases
  • FLT3 protein, human
  • fms-Like Tyrosine Kinase 3