title: Regulation of miR-200c and miR-141 by Methylation in Prostate Cancer.
abstract: In prostate cancer (PCa), abnormal expression of several microRNAs (miRNAs) has been previously reported. Increasing evidence shows that aberrant epigenetic regulation of miRNAs is a contributing factor to their altered expression in cancer. In this study, we investigate whether expression of miR-200c and miR-141 in PCa is related to the DNA methylation status of their promoter.
  
  
  
  PCR analysis of miR-200c and miR-141, and CpG methylation analysis of their common promoter, was performed in PCa cell-lines and in archived prostate biopsy specimens. The biological significance of miR-200c and miR-141 expression in prostate cancer cells was assessed by a series of in vitro bioassays and the effect on proposed targets DNMT3A and TET1/TET3 was investigated. The effect on promoter methylation status in cells treated with demethylating agents was also examined.
  
  
  
  miR-200c and miR-141 are both highly elevated in LNCaP, 22RV1, and DU145 cells, but significantly reduced in PC3 cells. This correlates inversely with the methylation status of the miR-200c/miR-141 promoter, which is unmethylated in LNCaP, 22RV1, and DU145 cells, but hypermethylated in PC3. In PC3 cells, miR-200c and miR-141 expression is subsequently elevated by treatment with the demethylating drug decitabine (5-aza-2'deoxycytidine) and by knockdown of DNA methyltransferase 1 (DNMT1), suggesting their expression is regulated by methylation. Expression of miR-200c and miR-141 in prostate biopsy tissue was inversely correlated with methylation in promoter CpG sites closest to the miR-200c/miR-141 loci. In vitro, over-expression of miR-200c in PC3 cells inhibited growth and clonogenic potential, as well as inducing apoptosis. Expression of the genes DNMT3A and TET1/TET3 were down-regulated by miR-200c and miR-141 respectively. Finally, treatment with the soy isoflavone genistein caused demethylation of the promoter CpG sites closest to the miR-200c/miR-141 loci resulting in increased miR-200c expression.
  
  
  
  Our findings provide evidence that miR-200c and miR-141 are under epigenetic regulation in PCa cells. We propose that profiling their expression and methylation status may have potential as a novel biomarker or focus of therapeutic intervention in the diagnosis and prognosis of PCa. Prostate 76:1146-1159, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Biomedical Sciences Research Institute, University of Ulster, Coleraine, UK.
authors.forename: Seodhna M
authors.initials: SM
authors.lastname: Lynch
authors.affiliation: Biomedical Sciences Research Institute, University of Ulster, Coleraine, UK.|School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK.
authors.forename: Karla M
authors.initials: KM
authors.lastname: O'Neill
authors.affiliation: Department of Cellular Pathology, Western Health and Social Care Trust, Altnagelvin Area Hospital, Derry, UK.
authors.forename: Michael M
authors.initials: MM
authors.lastname: McKenna
authors.affiliation: Biomedical Sciences Research Institute, University of Ulster, Coleraine, UK.
authors.forename: Colum P
authors.initials: CP
authors.lastname: Walsh
authors.affiliation: Biomedical Sciences Research Institute, University of Ulster, Coleraine, UK.
authors.forename: Declan J
authors.initials: DJ
authors.lastname: McKenna
mesh_terms: D000818:Animals; D002417:Cattle; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000502:physiology; D019175:DNA Methylation / Q000502:physiology*; D044127:Epigenesis, Genetic / Q000502:physiology; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000502:physiology*; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000378:metabolism*
chemical_list: C533895:MIRN141 microRNA, human; C533896:MIRN200 microRNA, human; D035683:MicroRNAs
keywords: DNA methylation; miR-141; miR-200c; microRNA; prostate cancer