MP70-15 TRANSCRIPTIONAL ACTIVATION OF ?-CATENIN BY MIR-138 PROMOTES UP-REGULATION OF ALPHA-METHYLACYL-COA RACEMASE IN PROSTATE CANCER CELLS

Abstract

You have accessJournal of UrologyProstate Cancer: Basic Research & Pathophysiology III1 Apr 2018MP70-15 TRANSCRIPTIONAL ACTIVATION OF ?-CATENIN BY MIR-138 PROMOTES UP-REGULATION OF ALPHA-METHYLACYL-COA RACEMASE IN PROSTATE CANCER CELLS Kati Erdmann, Knut Kaulke, Susanne Fuessel, and Manfred P. Wirth Kati ErdmannKati Erdmann More articles by this author , Knut KaulkeKnut Kaulke More articles by this author , Susanne FuesselSusanne Fuessel More articles by this author , and Manfred P. WirthManfred P. Wirth More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.2259AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The tumor-suppressive microRNA miR-138 has been shown to be down-regulated in prostate cancer (PCa) and has been suggested as a direct regulator of alpha-methylacyl-CoA racemase (AMACR), which is highly over-expressed in PCa. The aim of this study was to validate the direct interaction of miR-138 with the 3′-UTR of AMACR. Furthermore, the influence of miR-138 on the expression of AMACR and selected AMACR regulators was investigated in PCa cells. METHODS DU-145, PC-3 and LNCaP PCa cells were transfected with 100 nM of miR-138 mimic or a control construct for 4 h. A specific siRNA targeting AMACR was used as a positive control for the expression knockdown. 48 h after transfection, mRNA and protein expression levels of AMACR and selected AMACR regulators were determined by quantitative PCR and Western Blot, respectively. Luciferase reporter assays were used to verify target and promoter interaction. RESULTS A direct interaction of miR-138 with the AMACR-3′-UTR was confirmed by using a luciferase reporter assay. Surprisingly, AMACR mRNA and protein expression were up-regulated by up to 125% and 100%, respectively, following transfection of PCa cells with miR-138. In contrast, a specific siRNA targeting AMACR led to a significant reduction of the AMACR mRNA and protein expression by up to 75% in all three PCa cell lines. The lack of any miR-138 binding sites within the AMACR promoter pointed to an indirect mechanism of up-regulation. Subsequently, the effect of miR-138 on selected AMACR regulators including CTNNB1/β-catenin, RELA, SMAD4, SP1 and TCF4 was evaluated. MiR-138 only promoted an up-regulation of CTNNB1 mRNA expression and β-catenin protein levels by up to 75%. Interestingly, a binding site for miR-138 was present within the CTNNB1 promoter. By using a luciferase reporter assay the direct activation of the CTNNB1 promoter by miR-138 was demonstrated, which consequently could contribute to the observed AMACR up-regulation. CONCLUSIONS The present findings suggest that miR-138 can indirectly up-regulate AMACR expression via transcriptional induction of CTNNB1 expression, at least in vitro in PCa cells. These results further fortify the function of miRNAs as transcriptional gene activators in addition to their established role as post-transcriptional silencers. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e940 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Kati Erdmann More articles by this author Knut Kaulke More articles by this author Susanne Fuessel More articles by this author Manfred P. Wirth More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...