PD64-05 THE UBIQUITIN-PROTEASOME PATHWAY VIA NPL4 SUPPRESSION IS A PROMISING THERAPEUTIC TARGET IN CLEAR CELL RENAL CELL CARCINOMA

Abstract

You have accessJournal of UrologyKidney Cancer: Basic Research & Pathophysiology III (PD64)1 Apr 2020PD64-05 THE UBIQUITIN-PROTEASOME PATHWAY VIA NPL4 SUPPRESSION IS A PROMISING THERAPEUTIC TARGET IN CLEAR CELL RENAL CELL CARCINOMA Hirofumi Yoshino*, Yoichi Osako, Masaya Yonemori, Masafumi Tsuruta, Kazuki Kuroshima, Hideki Enokida, and Masayuki Nakagawa Hirofumi Yoshino*Hirofumi Yoshino* More articles by this author , Yoichi OsakoYoichi Osako More articles by this author , Masaya YonemoriMasaya Yonemori More articles by this author , Masafumi TsurutaMasafumi Tsuruta More articles by this author , Kazuki KuroshimaKazuki Kuroshima More articles by this author , Hideki EnokidaHideki Enokida More articles by this author , and Masayuki NakagawaMasayuki Nakagawa More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000981.05AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Molecular targeted drugs that can inhibit vascular endothelial growth factor receptor (VEGFR), mammalian target of rapamycin (mTOR), or programmed cell death 1 (PD-1) have been widely used for patients with metastatic or recurrent clear cell renal cell carcinoma (ccRCC). However, survival benefit from them is limited due to acquiring resistance. Recently, the ubiquitin-proteasomal proteins such as NPL4 have been identified as a promising therapeutic target, and its inhibitor disulfiram has shown inhibitory effects in several types of cancer. Whereas, anti-cancer effects of disulfiram in RCC is still unclear. In this study, we aimed to elucidate anti-cancer effects of NPL4 inhibition by disulfiram, and the mechanism underlying NPL4 inhibition in ccRCC. METHODS: WE performed statistical analyses of NPL4 based on the TCGA database of ccRCC patients. By using disulfiram and NPL4 si-RNA, we performed functional analyses in vitro in ccRCC cells. We also performed combination analyses between disulfiram and sunitinib in vitro as well as in vivo proliferation assays. In addition, we performed quantificational proteomic analyses to identify the novel mechanism in ccRCC cell fractions from mice treated with disulfiram and sunitinib. RESULTS: According to the TCGA, NPL4 mRNA expression was significantly upregulated in clinical ccRCC samples compared to that in normal kidney samples (P < 0.0001), and patients with high NPL4 expression (n = 261) had poor overall survival (P < 0.0001) in comparison to patients with low expression (n = 261). Disulfiram and NPL4 si-RNAs significantly inhibited cell proliferation (P < 0.05) in ccRCC cells by inducing apoptosis. In addition, significant additive anti-proliferative effects were observed in the combination of disulfiram and sunitinib in in vitro (P < 0.05) and in vivo (P = 0.0005) proliferation assays. Furthermore, proteomic analyses of RCC cell fractions from mice treated with disulfiram and/or sunitinib showed that several genes associated with TCA cycle and serine biosynthesis like IDH3A and PSAT1 were down regulated in cells treated with either disulfiram or sunitinib, and further down regulated in cells treated with a combination of both disulfiram and sunitinib. CONCLUSIONS: This study showed that NPL4 suppression by disulfiram and si-RNA showed tumor suppressive effects in RCCs. In addition, the combination treatment of disulfiram and sunitinib showed additive effect in vitro as well as in vivo. Novel therapeutic implications targeting the ubiquitin-proteasome pathway in RCC were suggested. Source of Funding: none © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e1299-e1300 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Hirofumi Yoshino* More articles by this author Yoichi Osako More articles by this author Masaya Yonemori More articles by this author Masafumi Tsuruta More articles by this author Kazuki Kuroshima More articles by this author Hideki Enokida More articles by this author Masayuki Nakagawa More articles by this author Expand All Advertisement PDF downloadLoading ...