MP34-20 INHIBITORS OF AUTOPHAGY POTENTIATES THE CYTOTOXIC EFFECT OF CHEMOTHERAPEUTIC AGENTS ON UROTHELIAL CARCINOMA OF URINARY BLADDER

Abstract

You have accessJournal of UrologyBladder Cancer: Basic Research III1 Apr 2014MP34-20 INHIBITORS OF AUTOPHAGY POTENTIATES THE CYTOTOXIC EFFECT OF CHEMOTHERAPEUTIC AGENTS ON UROTHELIAL CARCINOMA OF URINARY BLADDER Rani Ojha, Shrawan Singh, Shalmoli Bhattacharyya, and Vivekanand Jha Rani OjhaRani Ojha More articles by this author , Shrawan SinghShrawan Singh More articles by this author , Shalmoli BhattacharyyaShalmoli Bhattacharyya More articles by this author , and Vivekanand JhaVivekanand Jha More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.1033AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Intravesical chemotherapy in urothelial carcinoma has limited efficacy. Autophagy is a conserved catabolic process and various anticancer agents have been shown to induce autophagy, thus compromising its cytotoxicity. Therefore, inhibition of autophagy may help in potentiating the toxicity of chemotherapeutic agents. METHODS The therapeutic implication of autophagy was studied in T24 bladder cancer cell line by using mitomycin and gemcitabine alone or in combination with autophagy inhibitor, chloroquine. Cell inhibitory concentration (IC) of mitomycin and gemcitabine was determined by MTT assay. Based on IC-30, 5μM concentration of mitomycin and 10μM concentration of gemcitabine was selected for subsequent experiments. Autophagy was studied by acridine orange and LC3 immuno-staining. Cell viability in presence of mitomycin and gemcitabine with or without chloroquine, was measured by annexin-V/7-AAD staining, mitochondrial membrane potential and ATP levels. RESULTS Cells treated with mitomycin or gemcitabine showed increase in autophagosome formation as compared to controls (Fig.1). Cells treated with mitomycin and gemcitabine showed 18% and 19% cells death respectively. Addition of chloroquine along with mitomycin/ gemcitabine increased the cell death from 18% to 52% and 19% to 63% (Fig.2). Inhibition of mitomycin and gemcitabine induced autophagy increased ATP depletion, hyper-polarization of mitochondrial membrane potential and caspase-9 and-3 activation. Cell treated with pan-caspase inhibitor, z-VAD-fmk and specific caspase inhibitor of caspase-9 and -3 blocked the cell death induced by autophagy inhibition. CONCLUSIONS Autophagy induction in response to mitomycin and gemcitabine mounts an adaptive response that suppresses apoptosis. Autophagy inhibition leads to cell death via intrinsic apoptotic pathway. Therefore, autophagy inhibition appears to be of potential clinical significance in minimizing drug resistance and preventing tumor recurrence and relapse. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e370 Advertisement Copyright & Permissions© 2014MetricsAuthor Information Rani Ojha More articles by this author Shrawan Singh More articles by this author Shalmoli Bhattacharyya More articles by this author Vivekanand Jha More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...