EGFR phosphorylation-dependent formation of cell-cell contacts by Ras/Erks cascade inhibition

Biochim Biophys Acta. 2007 Jun;1773(6):833-43. doi: 10.1016/j.bbamcr.2007.02.003. Epub 2007 Feb 17.

Abstract

Cell-cell contacts play important roles in the homeostasis of normal epithelium and in the steps of metastasis of tumor cells, although signaling mechanisms to regulate cell-cell contacts are unclear. In this study, we observed that phenotype of no cell-cell contacts in rat intestinal epithelial cell subline (RIE1-Sca) correlated with increased Erk1/2 signaling activity, compared to that of parental RIE1 cells growing in colonies. Furthermore, cell-cell contacts between RIE1-Sca cells were reformed by treatment with a specific MEK inhibitor (U0126), with translocation of ZO1 and beta-catenin to cell-cell contacts, without changes of their expression levels. U0126 treatment also increased EGFR phosphorylation in a ligand-independent manner. Pretreatment with EGFR kinase inhibitor abolished U0126 treatment-mediated EGFR phosphorylation, and expression of dominant negative H-Ras N17 allowed EGFR phosphorylation and cell-cell contacts even without U0126 treatment. Furthermore, the expression of a nonphosphorylatable EGFR Y5F mutant abolished U0126-mediated cell-cell contacts. U0126 treatment also caused less efficient wound healing by keeping monolayer integrity intact, compared to control untreated cells. This U0126-mediated reduction in wound healing was further altered either by pretreatment of EGFR kinase inhibitor or expression of H-Ras N17 or EGFR Y5F. Taken together, this study supports a unique mechanism of cell-cell contact formation through MEK/Erks inhibition-mediated EGFR phosphorylation.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution
  • Animals
  • Butadienes / pharmacology
  • Cell Communication* / genetics
  • Cell Line, Tumor
  • Enzyme Inhibitors / pharmacology
  • ErbB Receptors / genetics
  • ErbB Receptors / metabolism*
  • Genes, Dominant
  • Humans
  • MAP Kinase Signaling System* / genetics
  • Membrane Proteins / metabolism
  • Mitogen-Activated Protein Kinase 1 / antagonists & inhibitors
  • Mitogen-Activated Protein Kinase 1 / metabolism*
  • Mitogen-Activated Protein Kinase 3 / antagonists & inhibitors
  • Mitogen-Activated Protein Kinase 3 / metabolism*
  • Mutation, Missense
  • Neoplasm Metastasis
  • Neoplasms / genetics
  • Neoplasms / metabolism
  • Nitriles / pharmacology
  • Phosphoproteins / metabolism
  • Phosphorylation
  • Protein Processing, Post-Translational* / genetics
  • Proto-Oncogene Proteins p21(ras) / genetics
  • Proto-Oncogene Proteins p21(ras) / metabolism*
  • Rats
  • Wound Healing / genetics
  • Zonula Occludens-1 Protein
  • beta Catenin / metabolism

Substances

  • Butadienes
  • Enzyme Inhibitors
  • Membrane Proteins
  • Nitriles
  • Phosphoproteins
  • TJP1 protein, human
  • Tjp1 protein, rat
  • U 0126
  • Zonula Occludens-1 Protein
  • beta Catenin
  • Egfr protein, rat
  • ErbB Receptors
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Proto-Oncogene Proteins p21(ras)