WNT pathway in oral cancer: epigenetic inactivation of WNT-inhibitors

Oncol Rep. 2010 Oct;24(4):1035-41. doi: 10.3892/or.2010.1035.

Abstract

Epigenetic DNA methylations plays an important role in oral carcinogenesis. The soluble frizzled receptor protein (SFRP) family together with WIF-1 and DKK-3 encodes antagonists of the WNT pathway. Silencing of these genes leads to constitutive WNT signalling. Because aberrant expression of beta-catenin might be associated with the epigenetic inactivation of WNT inhibitors, we analyzed, in a collection of primary OSCC with matched normal oral mucosa, the methylation status of a complete panel of genes, SFRP-1, SFRP-2, SFRP-4, SFRP-5, WIF-1, DKK-3, that are involved directly and indirectly in WNT pathway, in order to demonstrate WNT-pathway activation in the absence of beta-catenin and/or APC/Axin mutations during oral carcinogenesis. Methylation-specific PCR (MSP) was performed to study inactivation of SFRP-1, SFRP-2, SFRP-4, SFRP-5, WIF-1, DKK-3 genes in 37 cases of paraffin embedded oral cancer. This study showed that the methylation is an important epigenetic alteration in oral cancer. In particular, SFRP-2, SFRP-4, SFRP-5, WIF-1, DKK-3 revealed methylation status of their promoter in OSCC, whereas SFRP-1 showed demethylation in cancer. Fisher's exact test revealed statistically significant results (p<0.05) for all genes. The Wald test confirmed the statistically significant association between SFRP2-4-5 gene methylation and OSCC (p<0.05). SFRP-1 was also characterized by a different statistically significant epigenetic behaviour, because of it was demethylated in cancer (p<0.05). Statistical regression test showed high levels of sensitivity, specificity and accuracy for SFRP genes, while WIF-1 and DKK-3 have reportedly high specificity, moderate accuracy but low sensitivity. This study suggests that a cause of catenin delocalization in oral cancer could be due to WNT pathway activation, by epigenetic alterations of SFRP, WIF-1 and DKK-3 genes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism
  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / genetics
  • Carcinoma, Squamous Cell / genetics*
  • Carcinoma, Squamous Cell / metabolism
  • Chemokines
  • DNA Methylation / genetics*
  • Epigenesis, Genetic*
  • Eye Proteins / genetics
  • Eye Proteins / metabolism
  • Female
  • Humans
  • Intercellular Signaling Peptides and Proteins / genetics
  • Intercellular Signaling Peptides and Proteins / metabolism
  • Male
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Middle Aged
  • Mouth Neoplasms / genetics*
  • Mouth Neoplasms / metabolism
  • Polymerase Chain Reaction
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism
  • ROC Curve
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism
  • Sensitivity and Specificity
  • Signal Transduction / genetics*
  • Wnt Proteins / genetics*
  • Wnt Proteins / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Biomarkers, Tumor
  • Chemokines
  • DKK3 protein, human
  • Eye Proteins
  • Intercellular Signaling Peptides and Proteins
  • Membrane Proteins
  • Proto-Oncogene Proteins
  • Repressor Proteins
  • SFRP1 protein, human
  • SFRP2 protein, human
  • SFRP4 protein, human
  • SFRP5 protein, human
  • WIF1 protein, human
  • Wnt Proteins