369 NUB1, AN INTERFERON-INDUCIBLE PROTEIN, MEDIATES ANTI-PROLIFERATIVE ACTIONS AND APOPTOSIS IN RENAL CELL CARCINOMA CELLS THROUGH CELL CYCLE REGULATION

Abstract

You have accessJournal of UrologyKidney Cancer: Basic Research III1 Apr 2010369 NUB1, AN INTERFERON-INDUCIBLE PROTEIN, MEDIATES ANTI-PROLIFERATIVE ACTIONS AND APOPTOSIS IN RENAL CELL CARCINOMA CELLS THROUGH CELL CYCLE REGULATION Tomoaki Tanaka, Tomoko Hosono, Katsuyuki Kuratsukuri, and Tatsuya Nakatani Tomoaki TanakaTomoaki Tanaka More articles by this author , Tomoko HosonoTomoko Hosono More articles by this author , Katsuyuki KuratsukuriKatsuyuki Kuratsukuri More articles by this author , and Tatsuya NakataniTatsuya Nakatani More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.436AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES NEDD8 is a ubiquitin-like protein that regulates fundamental biological events via target protein conjugation. NEDD8 ultimate buster 1 (NUB1) is an interferon-inducible protein, which down-regulates NEDD8 expression and its conjugation system. Although overexpression of NUB1 induces a growth-inhibitory effect in cells, the mechanisms underlying the anti-mitogenic actions of NUB1 in cancer cells remain uncertain. We investigated the anticancer effects of NUB1 in human renal cell carcinoma (RCC) cells. METHODS Nine human RCC cell lines including ACHN, Caki-1, A-498, 786-0, 10RGB, OS-RC2, 4TUHR, OCUU1, and OCUU3 were used for this study. Cell-growth inhibition by exposure to interferon alpha (IFNα) was determined using the water-soluble tetrazolium salt (WST-1) assay. The expression levels of NUB1 mRNA and protein in those cell lines were measured by real-time RT-PCR and western blot analysis, respectively. A498 cells were transfected with pcDNA3/FLAG-NUB1 or pcDNA3 (control) and an apoptosis assay was performed by flow cytometry (FCM). To examine the process associated with the apoptotic effect of NUB1, cell-cycle analysis using FCM and western blot analysis for cell-cycle regulators was performed in A498 cells transfected with pcDNA3/FLAG-NUB1 or empty control vector. The effect of NUB1 knock-down on cell-growth in RCC cells was examined using the RNA interference technique. RESULTS First, both NUB1 messenger RNA and protein were significantly induced by IFNα in 7 out of 9 selected RCC cell lines, and the NUB1 expressions induced by IFNα correlated positively with the cell growth inhibition rate. Second, overexpression of NUB1 remarkably induced S-phase transition during the cell cycle and apoptosis in IFNα-resistant A498 cells, in which NUB1 is not induced by IFNα. Third, the expression levels of two cell-cycle regulator proteins, cyclin E and p27, were increased under the aforementioned conditions. Forth, knock-down of NUB1 clearly enhanced A498 cell-growth as compared with control cells. CONCLUSIONS Our results suggest that NUB1-mediated apoptosis might result from cell cycle arrest in S-phase via regulation of cyclin E and p27. Thus, NUB1 may be a key factor involved in IFNα-induced apoptosis in human RCC cells, even IFNα-resistant RCC cells. Osaka, Japan© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e146 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Tomoaki Tanaka More articles by this author Tomoko Hosono More articles by this author Katsuyuki Kuratsukuri More articles by this author Tatsuya Nakatani More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...