Hypermethylation of the GABRE~miR-452~miR-224 promoter in prostate cancer predicts biochemical recurrence after radical prostatectomy

Clin Cancer Res. 2014 Apr 15;20(8):2169-81. doi: 10.1158/1078-0432.CCR-13-2642.

Abstract

Purpose: 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.

Experimental design: 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.

Conclusion: 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / genetics
  • Cell Line
  • Cell Line, Tumor
  • Cell Movement / genetics
  • Cell Survival / genetics
  • Cohort Studies
  • CpG Islands / genetics
  • DNA Methylation*
  • Gene Expression Profiling / statistics & numerical data
  • Humans
  • Kaplan-Meier Estimate
  • Male
  • MicroRNAs / genetics*
  • Middle Aged
  • Multivariate Analysis
  • Neoplasm Recurrence, Local
  • Prognosis
  • Promoter Regions, Genetic / genetics*
  • Proportional Hazards Models
  • Prostatectomy / methods
  • Prostatic Neoplasms / genetics*
  • Prostatic Neoplasms / surgery
  • Receptors, GABA-A / genetics*

Substances

  • Biomarkers, Tumor
  • GABRE protein, human
  • MIRN224 microRNA, human
  • MIRN452 microRNA, human
  • MicroRNAs
  • Receptors, GABA-A