Dual Allosteric Inhibition of SHP2 Phosphatase

ACS Chem Biol. 2018 Mar 16;13(3):647-656. doi: 10.1021/acschembio.7b00980. Epub 2018 Jan 18.

Abstract

SHP2 is a cytoplasmic protein tyrosine phosphatase encoded by the PTPN11 gene and is involved in cell proliferation, differentiation, and survival. Recently, we reported an allosteric mechanism of inhibition that stabilizes the auto-inhibited conformation of SHP2. SHP099 (1) was identified and characterized as a moderately potent, orally bioavailable, allosteric small molecule inhibitor, which binds to a tunnel-like pocket formed by the confluence of three domains of SHP2. In this report, we describe further screening strategies that enabled the identification of a second, distinct small molecule allosteric site. SHP244 (2) was identified as a weak inhibitor of SHP2 with modest thermal stabilization of the enzyme. X-ray crystallography revealed that 2 binds and stabilizes the inactive, closed conformation of SHP2, at a distinct, previously unexplored binding site-a cleft formed at the interface of the N-terminal SH2 and PTP domains. Derivatization of 2 using structure-based design resulted in an increase in SHP2 thermal stabilization, biochemical inhibition, and subsequent MAPK pathway modulation. Downregulation of DUSP6 mRNA, a downstream MAPK pathway marker, was observed in KYSE-520 cancer cells. Remarkably, simultaneous occupation of both allosteric sites by 1 and 2 was possible, as characterized by cooperative biochemical inhibition experiments and X-ray crystallography. Combining an allosteric site 1 inhibitor with an allosteric site 2 inhibitor led to enhanced pharmacological pathway inhibition in cells. This work illustrates a rare example of dual allosteric targeted protein inhibition, demonstrates screening methodology and tactics to identify allosteric inhibitors, and enables further interrogation of SHP2 in cancer and related pathologies.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Allosteric Regulation*
  • Allosteric Site*
  • Binding Sites
  • Cell Line, Tumor
  • Crystallography, X-Ray
  • Drug Evaluation, Preclinical
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology
  • Humans
  • Neoplasms / drug therapy
  • Piperidines / pharmacology*
  • Protein Conformation
  • Protein Stability
  • Protein Tyrosine Phosphatase, Non-Receptor Type 11 / antagonists & inhibitors*
  • Pyrimidines / pharmacology*

Substances

  • Enzyme Inhibitors
  • Piperidines
  • Pyrimidines
  • SHP099
  • Protein Tyrosine Phosphatase, Non-Receptor Type 11