A gene expression profile of tumor suppressor genes commonly methylated in bladder cancer.
OBJECTIVE
The functional relationship between promoter hypermethylation and gene inactivation has been demonstrated for few genes only. We examined the promoter methylation status of two important tumor suppressor genes APAF-1 and DAPK-1 in bladder cancer as well as the mRNA expression pattern of these two genes for possible correlation between promoter hypermethylation and transcriptional repression.


METHODS
The methylation status and mRNA expression levels were related to clinicopathological features in 34 patients with transitional cell carcinoma (TCC) of the bladder with a median clinical follow-up of more than 45 months. Tissue from ten patients with nonmalignant disease served as a control group. Quantitative real-time PCR-based detection methods were used for determination of the normalized index of methylation (NIM) as well as the mRNA expression level.


RESULTS
APAF-1 and DAPK-1 methylation and mRNA expression was observed in all tumor and normal control samples investigated. Methylation (NIM) levels were significantly higher in tumor tissue for APAF-1 and DAPK-1, but median mRNA expression levels did not differ significantly comparing tumorous and non tumorous tissue. No correlation between expression levels of APAF-1 and DAPK-1 mRNA and tumor stage or grade was observed. However, in superficial TCC a strong correlation between higher NIM levels and lower mRNA expression of the APAF-1 gene was observed (P = 0.014).


CONCLUSIONS
Our results, although preliminary, provide first time in vivo expression analysis of the APAF-1 gene in bladder cancer specimen, suggesting expression control by promoter methylation in early stage tumor disease of the bladder.
Christoph
Frank
F
Department of Urology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany. frank.christoph@charite.de
Hinz
Stefan
S
Kempkensteffen
Carsten
C
Weikert
Steffen
S
Krause
Hans
H
Schostak
Martin
M
Schrader
Mark
M
Miller
Kurt
K
D000368:Aged; D051017:Apoptosis Regulatory Proteins / Q000235:genetics*; D053477:Apoptotic Protease-Activating Factor 1 / Q000235:genetics*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics*; D002295:Carcinoma, Transitional Cell / Q000235:genetics*; D019175:DNA Methylation; D064550:Death-Associated Protein Kinases; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D016147:Genes, Tumor Suppressor; D006801:Humans; D008297:Male; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D001749:Urinary Bladder Neoplasms / Q000235:genetics*
C506592:APAF1 protein, human; D051017:Apoptosis Regulatory Proteins; D053477:Apoptotic Protease-Activating Factor 1; D012333:RNA, Messenger; C579096:DAPK1 protein, human; D064550:Death-Associated Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases