383 CHARACTERIZATION OF β4-INTEGRIN-MEDIATED CYTOTOXIC EFFECT OF AEXU, A TYPE THREE SECRETION SYSTEM EFFECTOR, ON HUMAN PROSTATE CANCER PC3 CELLS

Abstract

You have accessJournal of UrologyProstate Cancer: Basic Research III1 Apr 2010383 CHARACTERIZATION OF β4-INTEGRIN-MEDIATED CYTOTOXIC EFFECT OF AEXU, A TYPE THREE SECRETION SYSTEM EFFECTOR, ON HUMAN PROSTATE CANCER PC3 CELLS Masafumi Kumano, Hideaki Miyake, Takeshi Honda, and Masato Fujisawa Masafumi KumanoMasafumi Kumano Kobe, Japan More articles by this author , Hideaki MiyakeHideaki Miyake Kobe, Japan More articles by this author , Takeshi HondaTakeshi Honda Osaka, Japan More articles by this author , and Masato FujisawaMasato Fujisawa Kobe, Japan More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.451AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Type three secretion system (TTSS) of gram-negative bacteria is responsible for delivering bacterial proteins, termed effectors, from the bacterial cytosol directly into the host cells. AexU, one of TTSS effectors, has been shown to play an important role during A. hydrophila SSU strain pathogenesis through the ribosylation of ADP. Recently, several investigators have suggested the cytotoxic activities of AexU against a wide variety of tumor cells through the modulation of β4-integrin function. The objectives of this study were to evaluate the cytotoxic effect of AexU on human androgen-independent prostate cancer PC3 cells, and to investigate the mechanism of cytotoxicity induced by AexU focusing on the significance of β4-integrin expression in PC3 cells. METHODS We established pGEX vector encoding GST-AexU-HA fusion protein, and purified AexU protein by affinity chromatography. The cytotoxic effects of AexU either alone or in combination with chemotherapeutic agents on PC3 cells were evaluated. We then established PC3 cells in which the expression vector containing short hairpin RNA (shRNA) targeting β4-integrin was introduced (PC3/sh-In). The sensitivity to AexU in PC3/sh-In cells was compared with that in PC3 cells transfected with control vector alone (PC3/Co). RESULTS Expression level of β4-integrin in PC3 cells was significantly greater than those in other human prostate cancer LNCaP and DU145 cells. The cytotoxic effect of AexU on PC3 cells was more significant than those in the remaining two cell lines. Treatment of PC3 cells with AexU resulted in the upregulation of Bax as well as the downregulation of phosphorylated Akt. The IC50 of docetaxel and cisplatin in PC3 cells were decreased by approximately 90% and 80%, respectively, by the combined treatment with sublethal dose of AexU. The cytotoxic effect of AexU on PC3/Co cells was significantly greater than that on PC3/sh-In cells, accompanied by the upregulation of phosphorylated Akt in PC3/sh-In cells compared with that in PC3/Co cells. CONCLUSIONS These findings suggest that treatment with AexU could be a useful therapeutic option against androgen-independent prostate cancer, particularly that overexpressing β4-integrin, through the growth inhibition and the enhanced chemosensitivity. © 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e151-e152 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Masafumi Kumano Kobe, Japan More articles by this author Hideaki Miyake Kobe, Japan More articles by this author Takeshi Honda Osaka, Japan More articles by this author Masato Fujisawa Kobe, Japan More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...