Gab2 regulates the migratory behaviors and E-cadherin expression via activation of the PI3K pathway in ovarian cancer cells

Oncogene. 2012 May 17;31(20):2512-20. doi: 10.1038/onc.2011.435. Epub 2011 Sep 26.


Ovarian cancer, the most deadly gynecologic malignancy, is often diagnosed late and at the advanced stage when the cancer cells have already migrated and invaded into other tissues and organs. Better understanding of the mechanism of metastasis in ovarian cancer cells is essential to the design of effective therapy. In this study, we investigated the function of scaffolding adaptor protein Gab2 in ovarian cancer cells. Gab2 is found to be overexpressed in a subset of ovarian tumors and cancer cell lines. Gab2 expression mainly regulates the migratory behaviors of ovarian cancer cells. Overexpression of Gab2 promotes the migration and invasion, and downregulates E-cadherin expression in ovarian cancer cells with low-Gab2 expression. Conversely, knockdown of Gab2 expression inhibits the migration and invasion, and promotes E-cadherin expression in ovarian cancer cells with high-Gab2 expression. By expressing Gab2 wild-type and Gab2 mutants that are defective in activation of the PI3K and Shp2-Erk pathways, we find that Gab2 inhibits E-cadherin expression and enhances the expression of Zeb1, a transcription factor involved in epithelial-to-mesenchymal transition (EMT), and cell migration and invasion through the activation of the PI3K pathway. Knockdown of Zeb1 expression blocks Gab2-induced suppression of E-cadherin expression and increase in cell invasion. LY294002 and GDC-0941, inhibitors of PI3K, or Rapamycin, an inhibitor of PI3K downstream target mTOR, can reverse the effects of Gab2 on migration and invasion. Overall, our studies reveal that Gab2 overexpression, via activation of the PI3K-Zeb1 pathway, promotes characteristics of EMT in ovarian cancer cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / biosynthesis
  • Adaptor Proteins, Signal Transducing / genetics*
  • Cadherins / biosynthesis*
  • Cadherins / genetics
  • Cell Line, Tumor
  • Cell Movement / genetics*
  • Enzyme Inhibitors / pharmacology
  • Epithelial-Mesenchymal Transition / genetics
  • Female
  • Gene Expression Regulation, Neoplastic
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism
  • Humans
  • Indazoles / pharmacology
  • Mutant Proteins / genetics
  • Mutant Proteins / metabolism
  • Ovarian Neoplasms / metabolism*
  • Ovarian Neoplasms / pathology*
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphoinositide-3 Kinase Inhibitors
  • Signal Transduction
  • Sulfonamides / pharmacology
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Zinc Finger E-box-Binding Homeobox 1


  • 2-(1H-indazol-4-yl)-6-(4-methanesulfonylpiperazin-1-ylmethyl)-4-morpholin-4-ylthieno(3,2-d)pyrimidine
  • Adaptor Proteins, Signal Transducing
  • Cadherins
  • Enzyme Inhibitors
  • GAB2 protein, human
  • Homeodomain Proteins
  • Indazoles
  • Mutant Proteins
  • Phosphoinositide-3 Kinase Inhibitors
  • Sulfonamides
  • Transcription Factors
  • ZEB1 protein, human
  • Zinc Finger E-box-Binding Homeobox 1