title: Hypermethylation of the GABRE~miR-452~miR-224 promoter in prostate cancer predicts biochemical recurrence after radical prostatectomy.
abstract: OBJECTIVE
  Available tools for prostate cancer diagnosis and prognosis are suboptimal and novel biomarkers are urgently needed. Here, we investigated the regulation and biomarker potential of the GABRE∼miR-452∼miR-224 genomic locus.
  
  
  METHODS
  GABRE/miR-452/miR-224 transcriptional expression was quantified in 80 nonmalignant and 281 prostate cancer tissue samples. GABRE∼miR-452∼miR-224 promoter methylation was determined by methylation-specific qPCR (MethyLight) in 35 nonmalignant, 293 prostate cancer [radical prostatectomy (RP) cohort 1] and 198 prostate cancer tissue samples (RP cohort 2). Diagnostic/prognostic biomarker potential of GABRE∼miR-452∼miR-224 methylation was evaluated by ROC, Kaplan-Meier, uni- and multivariate Cox regression analyses. Functional roles of miR-224 and miR-452 were investigated in PC3 and DU145 cells by viability, migration, and invasion assays and gene-set enrichment analysis (GSEA) of posttransfection transcriptional profiling data.
  
  
  RESULTS
  GABRE∼miR-452∼miR-224 was significantly downregulated in prostate cancer compared with nonmalignant prostate tissue and had highly cancer-specific aberrant promoter hypermethylation (AUC = 0.98). Functional studies and GSEA suggested that miR-224 and miR-452 inhibit proliferation, migration, and invasion of PC3 and DU145 cells by direct/indirect regulation of pathways related to the cell cycle and cellular adhesion and motility. Finally, in uni- and multivariate analyses, high GABRE∼miR-452∼miR-224 promoter methylation was significantly associated with biochemical recurrence in RP cohort 1, which was successfully validated in RP cohort 2.
  
  
  CONCLUSIONS
  The GABRE∼miR-452∼miR-224 locus is downregulated and hypermethylated in prostate cancer and is a new promising epigenetic candidate biomarker for prostate cancer diagnosis and prognosis. Tumor-suppressive functions of the intronic miR-224 and miR-452 were demonstrated in two prostate cancer cell lines, suggesting that epigenetic silencing of GABRE∼miR-452∼miR-224 may be selected for in prostate cancer.
authors.affiliation: Authors' Affiliations: Departments of Molecular Medicine and Urology and Institute of Pathology, Aarhus University Hospital, Aarhus, Denmark; Institute of Surgical Pathology, University Hospital Zurich, Zurich, Switzerland; Department of Urology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany; Institute of Biomedical Technology and BioMediTech, University of Tampere and Tampere University Hospital, Tampere, Finland; Departments of Oncology and Pathology and Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden.
authors.forename: Helle
authors.initials: H
authors.lastname: Kristensen
authors.forename: Christa
authors.initials: C
authors.lastname: Haldrup
authors.forename: Siri
authors.initials: S
authors.lastname: Strand
authors.forename: Kamilla
authors.initials: K
authors.lastname: Mundbjerg
authors.forename: Martin M
authors.initials: MM
authors.lastname: Mortensen
authors.forename: Kasper
authors.initials: K
authors.lastname: Thorsen
authors.forename: Marie Stampe
authors.initials: MS
authors.lastname: Ostenfeld
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Wild
authors.forename: Christian
authors.initials: C
authors.lastname: Arsov
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Goering
authors.forename: Tapio
authors.initials: T
authors.lastname: Visakorpi
authors.forename: Lars
authors.initials: L
authors.lastname: Egevad
authors.forename: Johan
authors.initials: J
authors.lastname: Lindberg
authors.forename: Henrik
authors.initials: H
authors.lastname: Grönberg
authors.forename: Søren
authors.initials: S
authors.lastname: Høyer
authors.forename: Michael
authors.initials: M
authors.lastname: Borre
authors.forename: Torben F
authors.initials: TF
authors.lastname: Ørntoft
authors.forename: Karina D
authors.initials: KD
authors.lastname: Sørensen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics; D002460:Cell Line; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D002470:Cell Survival / Q000235:genetics; D015331:Cohort Studies; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation; D020869:Gene Expression Profiling / Q000706:statistics & numerical data; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D011401:Promoter Regions, Genetic / Q000235:genetics*; D016016:Proportional Hazards Models; D011468:Prostatectomy / Q000379:methods; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000601:surgery; D011963:Receptors, GABA-A / Q000235:genetics*
chemical_list: D014408:Biomarkers, Tumor; C546274:GABRE protein, human; C546140:MIRN224 microRNA, human; C574051:MIRN452 microRNA, human; D035683:MicroRNAs; D011963:Receptors, GABA-A