Dual Binding to Orthosteric and Allosteric Sites Enhances the Anticancer Activity of a TRAP1-Targeting Drug

J Med Chem. 2020 Mar 26;63(6):2930-2940. doi: 10.1021/acs.jmedchem.9b01420. Epub 2020 Mar 2.

Abstract

The molecular chaperone TRAP1 is the mitochondrial paralog of Hsp90 and is overexpressed in many cancer cells. The orthosteric ATP-binding site of TRAP1 has been considered the primary inhibitor binding location, but TRAP1 allosteric modulators have not yet been investigated. Here, we generated and characterized the Hsp90 inhibitor PU-H71, conjugated to the mitochondrial delivery vehicle triphenylphosphonium (TPP) with a C10 carbon spacer, named SMTIN-C10, to enable dual binding to orthosteric and allosteric sites. In addition to tight binding with the ATP-binding site through the PU-H71 moiety, SMTIN-C10 interacts with the E115 residue in the N-terminal domain through the TPP moiety and subsequently induces structural transition of TRAP1 to a tightly packed closed form. The data indicate the existence of a druggable allosteric site neighboring the orthosteric ATP pocket that can be exploited to develop potent TRAP1 modulators.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allosteric Site / drug effects*
  • Antineoplastic Agents / chemistry*
  • Antineoplastic Agents / pharmacology*
  • Benzodioxoles / chemistry*
  • Benzodioxoles / pharmacology*
  • Cell Line, Tumor
  • HSP90 Heat-Shock Proteins / antagonists & inhibitors*
  • HSP90 Heat-Shock Proteins / chemistry
  • HSP90 Heat-Shock Proteins / metabolism
  • Humans
  • Molecular Docking Simulation
  • Neoplasms / drug therapy
  • Neoplasms / metabolism
  • Protein Conformation / drug effects
  • Purines / chemistry*
  • Purines / pharmacology*

Substances

  • Antineoplastic Agents
  • Benzodioxoles
  • HSP90 Heat-Shock Proteins
  • Purines
  • TRAP1 protein, human
  • 9H-purine-9-propanamine, 6-amino-8-((6-iodo-1,3-benzodioxol-5-yl)thio)-N-(1-methylethyl)-