title: Analyses in human urothelial cells identify methylation of miR-152, miR-200b and miR-10a genes as candidate bladder cancer biomarkers.
abstract: Urinary miRNAs are discussed as potential biomarkers for bladder cancer. The majority of miRNAs, however, are downregulated, making it difficult to utilize reduced miRNA signals as reliable diagnostic tools. Because the downregulation of miRNAs is frequently associated with hypermethylation of the respective regulative sequences, we studied whether DNA hypermethylation might serve as an improved diagnostic tool compared to measuring downregulated miRNAs. miRNA expression arrays and individual qPCR were used to identify and confirm miRNAs that were downregulated in malignant urothelial cells (RT4, 5637 and J82) when compared to primary, non-malignant urothelial cells (HUEPC). DNA methylation was determined by customized PCR-arrays subsequent to methylation-sensitive DNA-restriction and by mass spectrometry. miRNA expression and DNA methylation were determined in untreated cells and in cultures treated with the demethylating agent 5-Aza-2'-deoxycytidine. miR-200b, miR-152 and miR-10a displayed differential expression and methylation among untreated cancer cell lines. In addition, reduced miRNA expression of miR-200b, miR-152, and miR-10a was associated with increased DNA methylation in malignant cells versus HUEPC. Finally, the demethylation approach revealed a causal relationship between both parameters for miR-152 in 5637 and also suggests a causal connection of both parameters for miR-200b in J82 and miR-10a in 5637. In conclusion, our studies in multiple bladder cancer cell lines and primary non-malignant urothelial cells suggest that hypermethylation of miR-152, miR-10a and miR-200b regulative DNA sequences might serve as epigenetic bladder cancer biomarkers.
authors.affiliation: Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr-University Bochum (IPA), Bürkle-de-la-Camp Platz 1, 44789 Bochum, Germany. koehler@ipa-dguv.de
authors.forename: Christina U
authors.initials: CU
authors.lastname: Köhler
authors.forename: Oleksandr
authors.initials: O
authors.lastname: Bryk
authors.forename: Swetlana
authors.initials: S
authors.lastname: Meier
authors.forename: Kerstin
authors.initials: K
authors.lastname: Lang
authors.forename: Peter
authors.initials: P
authors.lastname: Rozynek
authors.forename: Thomas
authors.initials: T
authors.lastname: Brüning
authors.forename: Heiko U
authors.initials: HU
authors.lastname: Käfferlein
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics*; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D019175:DNA Methylation / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; C547183:MIRN10 microRNA, human; C550856:MIRN152 microRNA, human; C533896:MIRN200 microRNA, human; D035683:MicroRNAs
keywords: 5-Aza-2′-deoxycytidine; Aza; Bladder cancer; DNA methylation; HUEPC; Primary urothelial cells; Urothelial cell lines; human urothelial epithelial cells; miRNA expression