1323 RNA-BINDING MOTIF PROTEIN 3 ATTENUATES THE STEM CELL-LIKE PROPERTIES OF PROSTATE CANCER CELLS BY INTERFERING WITH CD44 VARIANT SPLICING

Abstract

You have accessJournal of UrologyProstate Cancer: Basic Research (VI)1 Apr 20131323 RNA-BINDING MOTIF PROTEIN 3 ATTENUATES THE STEM CELL-LIKE PROPERTIES OF PROSTATE CANCER CELLS BY INTERFERING WITH CD44 VARIANT SPLICING Yu Zeng, Dong Gao, Dana Wodzenski, Takumi Shiraishi, Naoki Terada, Jun Luo, Robert Getzenberg, and Prakash Kulkarni Yu ZengYu Zeng Baltimore, MD More articles by this author , Dong GaoDong Gao Baltimore, MD More articles by this author , Dana WodzenskiDana Wodzenski Baltimore, MD More articles by this author , Takumi ShiraishiTakumi Shiraishi Baltimore, MD More articles by this author , Naoki TeradaNaoki Terada Baltimore, MD More articles by this author , Jun LuoJun Luo Baltimore, MD More articles by this author , Robert GetzenbergRobert Getzenberg Baltimore, MD More articles by this author , and Prakash KulkarniPrakash Kulkarni Baltimore, MD More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.2677AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Stress response pathways appear to play an important role in cancer evolution. RNA-binding motif protein 3 (RBM3) is a stress-response protein that is down-regulated under certain micro-environmental stress effects. Further, RBM3 expression in primary tumors is inversely correlated with poorer prognosis suggesting that RBM3 may suppress tumor progression. The goal of this study was to investigate the effects of RBM3 on stem cell-like features of prostate cancer cells. METHODS RBM3 mRNA expression was detected by RT-PCR. The normal prostate cell line, PrEC, was sorted using CD133 by flow cytometry. PC3 cells were transfected with pCMV6-RBM3 vector. Soft agar clonogenic assay and prostasphere assay were performed to evaluate stem cell-like features. The expressions of stem cell-related genes were determined using PCR arrays. PC3-RBM3 and PC3-GFP clones were subcutaneously inoculated in nude mice and tumor growth were compared. RESULTS RBM3 expression was low in human fetal tissues and in the CD133+ PrEC cells. In human prostate cancer, the expression of RBM3 was up-regulated in primary tumor tissues in comparison to adjacent normal glands but was decreased in metastatic tumors. RBM3 mRNA expression was down-regulated when cells were grown in soft agar or exposed to heat or cytotoxic stress. Over-expressing RBM3 in PC3 cells greatly attenuated their stem cell-like properties including the capability to re-colonize in soft agar, the ability to form prostaspheres, as well as tumorgenic potential in nude mice. Further, forced expression of RBM3 or culturing cells at 32∥C suppressed splicing of the CD44 variant v8-v10 but increased the expression of standard CD44 (CD44s) isoform. By contrast, lowering RBM3 expression by siRNA or culturing cells in soft agar that enrich the stem cell-like cell population, increased the ratio of mRNA levels of CD44v8-v10 to CD44s. Importantly, knocking down CD44v8-v10 using variant-specific siRNAs impaired PC3 cells to form colonies in soft agar, suggesting strongly that splicing of CD44v8-v10 that is inhibited by RBM3, contribute to the stem cell-like properties of the PC3 cells. CONCLUSIONS Thus down-regulation of RBM3 in order to maintain ‘stemness' may represent a natural response of cancer cells to adapt to microenvironmental stress, which could be the driving force behind cancer evolution. Accordingly, modulating RBM3 levels pharmacologically may help develop novel therapeutic strategies against the so-called ?cancer stem cells'. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e540-e541 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Yu Zeng Baltimore, MD More articles by this author Dong Gao Baltimore, MD More articles by this author Dana Wodzenski Baltimore, MD More articles by this author Takumi Shiraishi Baltimore, MD More articles by this author Naoki Terada Baltimore, MD More articles by this author Jun Luo Baltimore, MD More articles by this author Robert Getzenberg Baltimore, MD More articles by this author Prakash Kulkarni Baltimore, MD More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...