488 THE SEARCH FOR SECRETED PROTEIN IN PROSTATE CANCER BY THE ESCHERICHIA COLI AMPICILLIN SECRETION TRAP: EXPRESSION OF NBL1 IS HIGHLY RESTRICTED IN PROSTATE AND RELATED IN PROGRESSION

Abstract

You have accessJournal of UrologyProstate Cancer: Basic Research III1 Apr 2012488 THE SEARCH FOR SECRETED PROTEIN IN PROSTATE CANCER BY THE ESCHERICHIA COLI AMPICILLIN SECRETION TRAP: EXPRESSION OF NBL1 IS HIGHLY RESTRICTED IN PROSTATE AND RELATED IN PROGRESSION Tetsutaro Hayashi, Shinya Ohara, Jun Teishima, Kazuhiro Sentani, Naohide Oue, Naoya Sakamoto, Wataru Yasui, and Akio Matsubara Tetsutaro HayashiTetsutaro Hayashi Hiroshima, Japan More articles by this author , Shinya OharaShinya Ohara Hiroshima, Japan More articles by this author , Jun TeishimaJun Teishima Hiroshima, Japan More articles by this author , Kazuhiro SentaniKazuhiro Sentani Hiroshima, Japan More articles by this author , Naohide OueNaohide Oue Hiroshima, Japan More articles by this author , Naoya SakamotoNaoya Sakamoto Hiroshima, Japan More articles by this author , Wataru YasuiWataru Yasui Hiroshima, Japan More articles by this author , and Akio MatsubaraAkio Matsubara Hiroshima, Japan More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.557AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Genes encoding secretory proteins expressed specifically in cancers or specific tissues may be ideal serum biomarkers for cancer diagnosis. To identify genes that encode secreted proteins present in prostate cancer (PCa), we used Escherichia coli ampicillin secretion trap (CAST) method, which was a survival-based signal sequence trap method. METHODS We generated cDNA libraries from normal prostate (NP) and two PCa cell lines, LNCaP and DU145. These CAST libraries were ligated into the pCAST which was plasmid with a mutant beta-lactamase lacking the endogenous signal peptide. Survival on ampicillin was observed only when various cDNA fragments encoding a signal sequence were inserted. RESULTS We sequenced 1,344, 960, and 960 ampicillin-resistant colonies and found that 6, 8, and 7 genes encoding secreted proteins from LNCaP, DU145, and NP CAST libraries, respectively. We measured the expression of all 17 candidates in 16 PCa tissue samples, 9 NP issue samples and 14 kinds of normal tissue by quantitative RT-PCR. MSMB, NBL1 and AZGP1 showed high specificity for prostate. MSMB and AZGP1 have already been studied PCa and their utility as serum tumor markers and therapeutic targets have been reported. Thus, we focused on NBL1. NBL1 was originally identified as a putative tumor suppressor gene in a transformed fibroblasts model. In western blot analysis, high NBL1 expression in DU145 cells was noted in both cell lysate and culture medium. In immunohistochemical analysis, NBL1 expression was detected only in a few systemic non-cancerous tissues. In contrast, NBL1 staining was observed in the cytoplasum of NP and PCa cells in all 181 PCa samples. NBL1 expression score was significantly higher in NP adjacent to PCa than in PCa samples (p < 0.0001). Moreover, NBL1 expression score was significantly higher in PCa stage B than in PCa stage C and D (p = 0.0014). NBL1 expression score was reduced in accordance with the elevation of preoperative PSA value (p < 0.0001) and Gleason score (p = 0.0024). Furthermore, NBL1 expression was not associated with AR expression. These results suggest that NBL1 has high potential as a serum marker for PCa. CONCLUSIONS CAST is a useful method to identify secreted proteins. NBL1 could be a novel diagnostic target for PCa. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e200 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Tetsutaro Hayashi Hiroshima, Japan More articles by this author Shinya Ohara Hiroshima, Japan More articles by this author Jun Teishima Hiroshima, Japan More articles by this author Kazuhiro Sentani Hiroshima, Japan More articles by this author Naohide Oue Hiroshima, Japan More articles by this author Naoya Sakamoto Hiroshima, Japan More articles by this author Wataru Yasui Hiroshima, Japan More articles by this author Akio Matsubara Hiroshima, Japan More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...