Promoter methylation regulates cadherin switching in squamous cell carcinoma

Biochem Biophys Res Commun. 2004 Mar 19;315(4):850-6. doi: 10.1016/j.bbrc.2004.01.143.


Cadherins are cell adhesion molecules that modulate the epithelial phenotype and regulate tumor invasion. To identify the role of promoter methylation in regulating E-cadherin expression and in the "switching" of cadherins in oral squamous cell carcinoma (SCC), we studied 14 cell lines for cadherin expression. Immunoblotting revealed that only two (HOC-313 and HA-376) showed strong up-regulation of N-cadherin, and neither expressed E-cadherin. These results were confirmed by PCR. Furthermore, analysis of genomic DNA showed that the lack of E-cadherin expression in the two cell lines was not due to gene deletion. In both cell lines, methylation-specific PCR indicated extensive methylation of the 5' CpG island in the E-cadherin promoter. After treatment with a DNA methylation inhibitor (5-Aza-2-deoxycytidine), both immunoblotting and immunofluorescence staining showed that HA-376 cells newly expressed E-cadherin with a parallel decrease in their N-cadherin expression. Multiplex RT-PCR demonstrated that the down-regulation of N-cadherin mRNA was coordinately regulated with E-cadherin expression. Thus, methylation of the 5' CpG island in the E-cadherin promoter induces reciprocal expression of E- and N-cadherins in oral SCC by an unknown mechanism that appears to be mediated at the level of N-cadherin gene expression. These events may play an important role in the regulation of tumor cell mobility and invasion.

MeSH terms

  • Antimetabolites, Antineoplastic / pharmacology
  • Azacitidine / pharmacology
  • Cadherins / biosynthesis
  • Cadherins / drug effects
  • Cadherins / genetics*
  • Carcinoma, Squamous Cell / genetics*
  • Carcinoma, Squamous Cell / metabolism
  • Cell Line, Tumor
  • CpG Islands / genetics
  • DNA Methylation*
  • Down-Regulation
  • Fluorescent Antibody Technique, Direct
  • Gene Expression Regulation, Neoplastic / genetics*
  • Humans
  • Immunoblotting
  • Mouth Neoplasms / genetics*
  • Mouth Neoplasms / metabolism
  • Promoter Regions, Genetic / genetics
  • RNA, Messenger / biosynthesis
  • Reverse Transcriptase Polymerase Chain Reaction / methods


  • Antimetabolites, Antineoplastic
  • Cadherins
  • RNA, Messenger
  • Azacitidine