Epithelial-mesenchymal transition downregulates laminin alpha5 chain and upregulates laminin alpha4 chain in oral squamous carcinoma cells

Histochem Cell Biol. 2008 Sep;130(3):509-25. doi: 10.1007/s00418-008-0443-6. Epub 2008 May 22.

Abstract

Basement membranes maintain the epithelial phenotype and prevent invasion and metastasis. We hypothesized that expression of basement membrane laminins might be regulated by epithelial-mesenchymal transition (EMT), hallmark of cancer progression. As EMT is mediated by transcription factor Snail, we used oral squamous carcinoma cells obtained from a primary tumor (43A), from its EMT-experienced recurrence (43B) and Snail-transfected 43A cells (43A-SNA) displaying full EMT, as a model to study laminins and their receptors. Northern blotting, immunofluorescence, and immunoprecipitation showed a gradual loss of laminin-511 and its receptor Lutheran from 43A to 43B and 43A-SNA cells. In contrast, neoexpression of laminin alpha4 mRNA was found congruent with synthesis of laminin-411. Chromatin immunoprecipitation disclosed direct binding of Snail to regions upstream of laminin alpha5 and alpha4 genes. Immunofluorescence and immunoprecipitation showed a switch from hemidesmosomal integrin alpha(6)beta(4) to alpha(6)beta(1) and neoexpression of alpha(1)beta(1) in 43A-SNA cells, and upregulation of integrin-linked kinase in both 43B and 43A-SNA cells. The cells adhered potently to laminin-511 and fibronectin, whereas adhesion to laminin-411 was minimal. In contrast, laminin-411 inhibited cell adhesion to other extracellular matrix proteins. In conclusion, EMT induces a switch from laminin-511 to laminin-411 expression, which may be directly controlled by Snail. Concomitant changes take place in laminin- and collagen-binding receptors. Laminin-411 reduces adhesion to laminin-511 and fibronectin, suggesting that tumor cells could utilize laminin-411 in their invasive behavior.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Carcinoma, Squamous Cell / genetics
  • Carcinoma, Squamous Cell / metabolism*
  • Carcinoma, Squamous Cell / pathology
  • Cell Differentiation*
  • Cell Line, Tumor
  • Down-Regulation
  • Epithelial Cells / cytology
  • Epithelial Cells / metabolism*
  • Female
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Laminin / genetics
  • Laminin / metabolism*
  • Mesenchymal Stem Cells / cytology
  • Mesenchymal Stem Cells / metabolism*
  • Mouth Neoplasms / genetics
  • Mouth Neoplasms / metabolism*
  • Mouth Neoplasms / pathology
  • Neoplasm Invasiveness / pathology
  • Promoter Regions, Genetic / genetics
  • Protein Binding
  • Protein Subunits / metabolism
  • Receptors, Laminin / metabolism
  • Snail Family Transcription Factors
  • Transcription Factors / metabolism
  • Up-Regulation

Substances

  • LAMA4 protein, human
  • Laminin
  • Protein Subunits
  • Receptors, Laminin
  • Snail Family Transcription Factors
  • Transcription Factors
  • laminin alpha5