222 MIR-124 TARGETS ANDROGEN RECEPTOR AND INHIBITS TUMORIGENESIS OF PROSTATE CANCER CELLS

Abstract

You have accessJournal of UrologyProstate Cancer: Basic Research I1 Apr 2012222 MIR-124 TARGETS ANDROGEN RECEPTOR AND INHIBITS TUMORIGENESIS OF PROSTATE CANCER CELLS Xu-Bao Shi, Lingru Xue, and Ralph deVere White Xu-Bao ShiXu-Bao Shi Sacramento, CA More articles by this author , Lingru XueLingru Xue Sacramento, CA More articles by this author , and Ralph deVere WhiteRalph deVere White Sacramento, CA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.276AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Recent studies demonstrated that miR-124 is significantly decreased in several cancer types and dysregulation of miR-124 may involve in the pathogenesis of human cancer. Until now, however, whether miR-124 contributes to the initiation and progression of prostate cancer (CaP) remains poorly understood. The purpose of this study is to explore the role of miR-124 in CaP. METHODS Total RNA was isolated from fresh-frozen prostatic tissues or cell lines. The miR-124 level in these samples was measured using qPCR. Since the 3'UTR of androgen receptor (AR) mRNA contains a broadly conserved miR-124-binding site, Western blotting and luciferase assay were performed to validate miR-124-mediated regulation of AR. In addition, the effects of miR-124 on growth of CaP cells were evaluated by WST assay and tumorigenesis in nude mice. RESULTS Seven prostate cell lines (2 benign and 5 malignant) and 18 matched benign/malignant prostatic tissues were examined for their miR-124 levels. We observed a reduced expression of miR-124 in all CaP cell lines compared to that in benign cell lines, and in 15 of 18 (83%) CaP samples relative to benign matches. These data provide strong evidence that miR-124 is significantly reduced in CaP cells. In order to validate regulation of AR by miR-124, CaP cells were transfected with synthetic miR-124 mimic (miR-124m). We observed miR-124-mediated downregulation of the AR protein and its effectors PSA and miR-125b. To verify that the miR-124 binding site is responsible for regulation by miR-124, the AR 3'UTR was cloned into a reporter-luciferase vector and then cotransfected with miR-124m into CaP cells. Transfection of miR-124m resulted in 40% reduction of the luciferase activity, indicating a direct interaction between miR-124 and AR mRNA. Using IHC analysis, we also found a reverse correlation between miR-124 and AR protein levels in 7 of 8 CaP samples. These data suggest that miR-124 targets the AR. In addition, we tested whether miR-124 inhibits the growth of CaP cells, and found that treatment with miR-124m induced significant in vitro inhibition of cell proliferation. We also evaluated the effect of miR-124 on tumorigenesis of 22Rv1 CaP cells and observed miR-124-induced inhibition of tumor growth. CONCLUSIONS Loss of miR-124 expression may be a common event in CaP. Since miR-124 directly targets the AR, downregulation of this miRNA results in increased expression of the AR in clinical CaP tissue. Our data also suggest that downregulation of miR-124 may contributes to tumorogenesis of CaP. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e92 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Xu-Bao Shi Sacramento, CA More articles by this author Lingru Xue Sacramento, CA More articles by this author Ralph deVere White Sacramento, CA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...