SHP2 mediates the protective effect of interleukin-6 against dexamethasone-induced apoptosis in multiple myeloma cells

J Biol Chem. 2000 Sep 8;275(36):27845-50. doi: 10.1074/jbc.M003428200.

Abstract

Our previous studies have shown that activation of a related adhesion focal tyrosine kinase (RAFTK) (also known as Pyk2) is required for dexamethasone (Dex)-induced apoptosis in multiple myeloma (MM) cells and that human interleukin-6 (IL-6), a known growth and survival factor for MM cells, blocks both RAFTK activation and apoptosis induced by Dex. However, the mechanism whereby IL-6 inhibits Dex-induced apoptosis is undefined. In this study, we demonstrate that protein-tyrosine phosphatase SHP2 mediates this protective effect. We show that IL-6 triggers selective activation of SHP2 and its association with RAFTK in Dex-treated MM cells. SHP2 interacts with RAFTK through a region other than its Src homology 2 domains. We demonstrate that RAFTK is a direct substrate of SHP2 both in vitro and in vivo, and that Tyr(906) in the C-terminal domain of RAFTK mediates its interaction with SHP2. Moreover, overexpression of dominant negative SHP2 blocked the protective effect of IL-6 against Dex-induced apoptosis. These findings demonstrate that SHP2 mediates the anti-apoptotic effect of IL-6 and suggest SHP2 as a novel therapeutic target in MM.

Publication types

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

MeSH terms

  • Apoptosis / drug effects
  • Apoptosis / physiology*
  • Dexamethasone / pharmacology*
  • Focal Adhesion Kinase 2
  • Humans
  • Interleukin-6 / pharmacology*
  • Intracellular Signaling Peptides and Proteins
  • Kinetics
  • Multiple Myeloma
  • Phosphorylation
  • Protein Tyrosine Phosphatase, Non-Receptor Type 11
  • Protein Tyrosine Phosphatase, Non-Receptor Type 6
  • Protein Tyrosine Phosphatases / metabolism*
  • Protein-Tyrosine Kinases / metabolism
  • Recombinant Proteins / metabolism
  • SH2 Domain-Containing Protein Tyrosine Phosphatases
  • Transfection
  • Tumor Cells, Cultured
  • src Homology Domains

Substances

  • Interleukin-6
  • Intracellular Signaling Peptides and Proteins
  • Recombinant Proteins
  • Dexamethasone
  • Protein-Tyrosine Kinases
  • Focal Adhesion Kinase 2
  • PTPN11 protein, human
  • PTPN6 protein, human
  • Protein Tyrosine Phosphatase, Non-Receptor Type 11
  • Protein Tyrosine Phosphatase, Non-Receptor Type 6
  • Protein Tyrosine Phosphatases
  • SH2 Domain-Containing Protein Tyrosine Phosphatases