GLI2 cooperates with ZEB1 for transcriptional repression of CDH1 expression in human melanoma cells

Pigment Cell Melanoma Res. 2013 Nov;26(6):861-73. doi: 10.1111/pcmr.12149. Epub 2013 Aug 12.

Abstract

In melanoma cells, high expression of the transcription factor GLI2 is associated with increased invasive potential and loss of E-cadherin expression, an event reminiscent of the epithelial-to-mesenchymal transition (EMT). Herein, we provide evidence that GLI2 represses E-cadherin gene (CDH1) expression in melanoma cells via distinct mechanisms, enhancing transcription of the EMT-activator ZEB1 and cooperative repression of CDH1 gene transcription via direct binding of both GLI2 and ZEB1 to two closely positioned Kruppel-like factor-binding sites within the CDH1 promoter. GLI2 silencing rescued CDH1 expression except in melanoma cell lines in which the CDH1 promoter was hypermethylated. Proximity ligation assays identified GLI2-ZEB1 complexes in melanoma cell nuclei, proportional to endogenous GLI2 and ZEB1 expression, and whose accumulation was enhanced by the classical EMT inducer TGF-β. These data identify GLI2 as a critical modulator of the cadherin switch in melanoma, a molecular process that is critical for metastatic spread of the disease.

Keywords: E-cadherin; GLI2; ZEB1; gene expression; melanoma.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, CD
  • Base Sequence
  • Binding Sites
  • Cadherins / genetics*
  • Cell Line, Tumor
  • Cell Nucleus / drug effects
  • Cell Nucleus / pathology
  • DNA Methylation / genetics
  • Gene Expression Regulation, Neoplastic* / drug effects
  • Gene Knockdown Techniques
  • Gene Silencing / drug effects
  • Homeodomain Proteins / metabolism*
  • Humans
  • Kruppel-Like Transcription Factors / metabolism*
  • Melanoma / genetics*
  • Melanoma / pathology
  • Models, Biological
  • Molecular Sequence Data
  • Nuclear Proteins / metabolism*
  • Promoter Regions, Genetic
  • Protein Binding / drug effects
  • Repressor Proteins / metabolism
  • Skin Neoplasms / genetics*
  • Skin Neoplasms / pathology
  • Snail Family Transcription Factors
  • Transcription Factors / metabolism*
  • Transcription, Genetic* / drug effects
  • Transforming Growth Factor beta / pharmacology
  • Zinc Finger E-box-Binding Homeobox 1
  • Zinc Finger Protein Gli2

Substances

  • Antigens, CD
  • CDH1 protein, human
  • Cadherins
  • GLI2 protein, human
  • Homeodomain Proteins
  • Kruppel-Like Transcription Factors
  • Nuclear Proteins
  • Repressor Proteins
  • Snail Family Transcription Factors
  • Transcription Factors
  • Transforming Growth Factor beta
  • ZEB1 protein, human
  • Zinc Finger E-box-Binding Homeobox 1
  • Zinc Finger Protein Gli2