title: EGFR phosphorylation-dependent formation of cell-cell contacts by Ras/Erks cascade inhibition.
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.
authors: Cancer Research Institute, Department of Molecular and Clinical Oncology, College of Medicine, Seoul National University, 28, Yeongeon-dong, Jongno-gu, Seoul 110-799, South Korea.
authors: Eun-Sil
authors: ES
authors: Kang
authors: Min-A
authors: MA
authors: Oh
authors: Sin-Ae
authors: SA
authors: Lee
authors: Tae Young
authors: TY
authors: Kim
authors: Sung-Hoon
authors: SH
authors: Kim
authors: Noriko
authors: N
authors: Gotoh
authors: Yong-Nyun
authors: YN
authors: Kim
authors: Jung Weon
authors: JW
authors: Lee
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D002070:Butadienes / Q000494:pharmacology; D002450:Cell Communication / Q000235:genetics; D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D005799:Genes, Dominant; D006801:Humans; D020935:MAP Kinase Signaling System / Q000235:genetics; D008565:Membrane Proteins / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020125:Mutation, Missense; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism; D009570:Nitriles / Q000494:pharmacology; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D014945:Wound Healing / Q000235:genetics; D062826:Zonula Occludens-1 Protein; D051176:beta Catenin / Q000378:metabolism
chemical_list: D002070:Butadienes; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; D009570:Nitriles; D010750:Phosphoproteins; C569042:TJP1 protein, human; C569044:Tjp1 protein, rat; C113580:U 0126; D062826:Zonula Occludens-1 Protein; D051176:beta Catenin; C483803:Egfr protein, rat; D066246:ErbB Receptors; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D016283:Proto-Oncogene Proteins p21(ras)