Decreased expression of TGF-beta cell surface receptors during progression of human oral squamous cell carcinoma

J Pathol. 2001 Apr;193(4):458-67. doi: 10.1002/1096-9896(2000)9999:9999<::AID-PATH822>3.0.CO;2-V.


This study examined the immunocytochemical expression of the transforming growth factor-beta (TGF-beta) isoforms TGF-beta1, TGF-beta2, and TGF-beta3, together with the TGF-beta cell surface receptors TbetaR-I and TbetaR-II, in patient-matched tissue pairs of normal human oral epithelium, primary squamous cell carcinomas, and metastatic lymph node tumour deposits. There were no significant differences in the intensity of TGF-beta isoform specific staining between the normal oral epithelium, the primary tumours, and the lymph node metastases. By contrast, there was significantly less TbetaR-II in the metastases than in the primary tumour and between the primary tumour and the normal oral epithelium. Similar trends were evident with TbetaR-I, but not at a statistically significant level. This study also examined the structure of TbetaR-I and TbetaR-II in normal human oral keratinocytes in vitro and in 14 human oral carcinoma cell lines with known responses to TGF-beta1. No structural abnormalities of TbetaR-II were present in the normal keratinocytes or in 13 of 14 malignant cell lines; in one line, there were both normal and mutant forms of TbetaR-II, the latter being in the form of a frameshift mutation with the insertion of a single adenine base (bases 709-718, codons 125-128), predicting a truncated receptor having no kinase domain. No defects were present in TbetaR-I. The structures of TbetaR-I and TbetaR-II did not correlate with growth inhibition by TGF-beta1. The data suggest that decreased expression of TGF-beta receptors, rather than structural defects of these genes, may be important in oral epithelial tumour progression. In order to examine the functional significance of a specific decrease in TbetaR-II expression, a dominant-negative TbetaR-II construct (dnTbetaR-II) was transfected into a human oral carcinoma cell line with a normal TGF-beta receptor profile and known to be markedly inhibited by TGF-beta1. In those clones that overexpressed the dnTbetaR-II, growth inhibition and Smad binding activity were decreased, whilst the regulation of Fra-1 and collagenase-1 remained unchanged following treatment with TGF-beta1. The results demonstrate that a decrease in TbetaR-II relative to TbetaR-I leads to selective gene regulation with loss of growth inhibition but continued transcription of AP-1-dependent genes that are involved in the regulation of the extracellular matrix.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoma, Squamous Cell / metabolism*
  • Carcinoma, Squamous Cell / secondary
  • Disease Progression
  • Female
  • Humans
  • Immunoenzyme Techniques
  • Lymphatic Metastasis
  • Male
  • Middle Aged
  • Mouth Neoplasms / metabolism*
  • Mutation
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism
  • Protein Isoforms / metabolism
  • Receptors, Transforming Growth Factor beta / genetics
  • Receptors, Transforming Growth Factor beta / metabolism*
  • Transforming Growth Factor beta / metabolism
  • Tumor Cells, Cultured


  • Neoplasm Proteins
  • Protein Isoforms
  • Receptors, Transforming Growth Factor beta
  • Transforming Growth Factor beta