Promoter hypermethylation of the 14-3-3 sigma, SYK and CAGE-1 genes is related to the various phenotypes of urinary bladder carcinomas and associated with progression of transitional cell carcinomas.
To explore the significance of epigenetic mechanisms in urinary bladder carcinogenesis mediated by methylation of cytosine in CpG dinucleotides at 5' promoter regions, we analysed the methylation status of a broad panel of different genes in transitional cell carcinomas (TCC) and nonurothelial cancers, among which the 14-3-3 sigma, SYK and CAGE-1 genes were recognised as promising target genes. Using methylation-specific PCR, the rate of DNA hypermethylation proved to be related to the various histopathological cancer subtypes. The higher frequency of promoter methylation of the 14-3-3 sigma (57.1%) and SYK (64.3%) genes in high-grade, high-stage TCC in association with a reduced or even lacking immunohistochemical protein expression than in low-grade, low-stage TCC (28.6% and 42.9%, respectively), indicates that aberrant methylation of these genes plays an essential role in the progression of TCC. The importance of DNA hypermethylation in the conversion of TCC from a low to a high malignant potential was strongly supported by the finding that, unlike superficial low-grade TCC, advanced muscle invasive TCC showed a concurrent promoter methylation of the 14-3-3 sigma, SYK and CAGE-1 genes. Squamous cell carcinomas revealed a peak incidence of hypermethylation of the 14-3-3 sigma gene (80%), and conversely, the lowest methylation frequency of the SYK gene (13.3%). Undifferentiated small cell carcinomas disclosed a promoter methylation of the 14-3-3 sigma, SYK and CAGE-1 genes in only a quarter each for the cases. Although a correlation between the methylation status and gene activity in squamous cell and undifferentiated small cell carcinomas was not observed, the underexpression of the SYK protein products in both cancer types and additionally of the 14-3-3 sigma protein in small cell carcinomas appeared to be related to the aggressive clinical behaviour of both these nonurothelial bladder carcinomas. The relevance of the high frequency of DNA hypermethylation of the CAGE-1 antigen in TCC and squamous cell carcinomas merits further study, particularly in relation to anticancer immunotherapy. The methylation status of the PTEN, COX-2, RUNX-3 and HIC-1 genes was found to be unaltered. In conclusion, the different patterns of aberrant methylation of the 14-3-3 sigma, SYK and CAGE-1 genes in the various histopathological cancer types of the urinary bladder point to a role in tumor cell differentiation, resulting in the phenotypical conversion of TCC into nonurothelial carcinomas and in the progression of TCC to a more malignant potential.
Kunze
Ekkehard
E
Department of Osteopathology and Haematopathology, University of Göttingen, D-37099 Göttingen, Germany. ekunze@med.uni-goettingen.de
Wendt
Maike
M
Schlott
Thilo
T
D048948:14-3-3 Proteins; D000951:Antigens, Neoplasm / Q000032:analysis / Q000235:genetics*; D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics*; D002295:Carcinoma, Transitional Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D050677:Core Binding Factor Alpha 3 Subunit / Q000235:genetics; D051546:Cyclooxygenase 2 / Q000235:genetics; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics; D018450:Disease Progression; D005092:Exonucleases / Q000032:analysis / Q000235:genetics*; D005095:Exoribonucleases; D006801:Humans; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000032:analysis / Q000235:genetics*; D051741:Kruppel-Like Transcription Factors; D008565:Membrane Proteins / Q000235:genetics; D009092:Mucous Membrane / Q000378:metabolism; D009363:Neoplasm Proteins / Q000032:analysis / Q000235:genetics*; D009687:Nuclear Proteins / Q000032:analysis / Q000235:genetics*; D051059:PTEN Phosphohydrolase / Q000235:genetics; D010641:Phenotype; D016133:Polymerase Chain Reaction / Q000379:methods; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011505:Protein-Tyrosine Kinases / Q000032:analysis / Q000235:genetics*; D000072377:Syk Kinase; D014157:Transcription Factors / Q000235:genetics; D001749:Urinary Bladder Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*
D048948:14-3-3 Proteins; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; C473315:CAGE1 protein, human; D050677:Core Binding Factor Alpha 3 Subunit; D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; C499808:HIC1 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D051741:Kruppel-Like Transcription Factors; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C493729:Runx3 protein, human; D014157:Transcription Factors; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase; D005092:Exonucleases; D005095:Exoribonucleases; C413442:SFN protein, human; C446603:TPTE protein, human; D051059:PTEN Phosphohydrolase