Proximal events in signaling by plasma membrane estrogen receptors

J Biol Chem. 2003 Jan 24;278(4):2701-12. doi: 10.1074/jbc.M205692200. Epub 2002 Nov 5.

Abstract

Estradiol (E2) rapidly stimulates signal transduction from plasma membrane estrogen receptors (ER) that are G protein-coupled. This is reported to occur through the transactivation of the epidermal growth factor receptor (EGFR) or insulin-like growth factor-1 receptor, similar to other G protein-coupled receptors. Here, we define the signaling events that result in EGFR and ERK activation. E2-stimulated ERK required ER in breast cancer and endothelial cells and was substantially prevented by expression of a dominant negative EGFR or by tyrphostin AG1478, a specific inhibitor for EGFR tyrosine kinase activity. Transactivation/phosphorylation of EGFR by E2 was dependent on the rapid liberation of heparin-binding EGF (HB-EGF) from cultured MCF-7 cells and was blocked by antibodies to this ligand for EGFR. Expression of dominant negative mini-genes for Galpha(q) and Galpha(i) blocked E2-induced, EGFR-dependent ERK activation, and Gbetagamma also contributed. G protein activation led to activation of matrix metalloproteinases (MMP)-2 and -9. This resulted from Src-induced MMP activation, implicated using PP2 (Src family kinase inhibitor) or the expression of a dominant negative Src protein. Antisense oligonucleotides to MMP-2 and MMP-9 or ICI 182780 (ER antagonist) each prevented E2-induced HB-EGF liberation and ERK activation. E2 also induced AKT up-regulation in MCF-7 cells and p38beta MAP kinase activity in endothelial cells, blocked by an MMP inhibitor, GM6001, and tyrphostin AG1478. Targeting of only the E domain of ERalpha to the plasma membrane resulted in MMP activation and EGFR transactivation. Thus, specific G proteins mediate the ability of E2 to activate MMP-2 and MMP-9 via Src. This leads to HB-EGF transactivation of EGFR and signaling to multiple kinase cascades in several target cells for E2. The E domain is sufficient to enact these events, defining additional details of the important cross-talk between membrane ER and EGFR in breast cancer.

Publication types

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

MeSH terms

  • Animals
  • Breast Neoplasms / metabolism
  • Cattle
  • Cell Membrane / metabolism*
  • Cells, Cultured
  • Dipeptides / pharmacology
  • Enzyme Activation
  • Enzyme Inhibitors / pharmacology
  • ErbB Receptors / metabolism
  • Heterotrimeric GTP-Binding Proteins / metabolism
  • Humans
  • Ligands
  • Matrix Metalloproteinase 2 / metabolism
  • Matrix Metalloproteinase 9 / metabolism
  • Mitogen-Activated Protein Kinase 11
  • Mitogen-Activated Protein Kinases / metabolism
  • Models, Biological
  • Oligonucleotides, Antisense / pharmacology
  • Protease Inhibitors / pharmacology
  • Protein Binding
  • Protein Structure, Tertiary
  • Quinazolines
  • Receptors, Estrogen / metabolism*
  • Signal Transduction
  • Structure-Activity Relationship
  • Transcriptional Activation
  • Transfection
  • Tumor Cells, Cultured
  • Tyrphostins / pharmacology

Substances

  • Dipeptides
  • Enzyme Inhibitors
  • Ligands
  • N-(2(R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl)-L-tryptophan methylamide
  • Oligonucleotides, Antisense
  • Protease Inhibitors
  • Quinazolines
  • Receptors, Estrogen
  • Tyrphostins
  • RTKI cpd
  • ErbB Receptors
  • Mitogen-Activated Protein Kinase 11
  • Mitogen-Activated Protein Kinases
  • Matrix Metalloproteinase 2
  • Matrix Metalloproteinase 9
  • Heterotrimeric GTP-Binding Proteins