MP34-05 THE OXIDATIVE STRESS RESPONSE OF UROTHELIAL CARCINOMA CELLS TO BCG EXPOSURE

Abstract

You have accessJournal of UrologyBladder Cancer: Basic Research III1 Apr 2014MP34-05 THE OXIDATIVE STRESS RESPONSE OF UROTHELIAL CARCINOMA CELLS TO BCG EXPOSURE Gopitkumar Shah, Fanghong Chen, Gina Lockwood, Scott Johnson, Jacek Zielonka, Balaraman Kalyanaraman, and William See Gopitkumar ShahGopitkumar Shah More articles by this author , Fanghong ChenFanghong Chen More articles by this author , Gina LockwoodGina Lockwood More articles by this author , Scott JohnsonScott Johnson More articles by this author , Jacek ZielonkaJacek Zielonka More articles by this author , Balaraman KalyanaramanBalaraman Kalyanaraman More articles by this author , and William SeeWilliam See More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.1018AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Earlier studies have shown that the cellular oxidative stress (COS), post BCG treatment plays a central role in mediating direct effect of BCG on urothelial carcinoma (UC) cells. The recent novel findings that BCG acts as an H2O2 generator provides insight into the genesis of BCG induced COS. To date the net impact of BCG exposure on specific contributors to COS remains poorly defined. The present study reports the results of experiments designed to assess the broad impact of BCG on inducers and regulators of COS as well as downstream “targets” of COS. METHODS Global profiling of reactive oxygen (ROS) and nitrogen species (RNS) was carried out in two human UC cell lines (253J, T24) using fluorescent probes for H2O2, nitric oxide (NO), and superoxides at various time points post BCG exposure. Enzymatic regulators of COS, Superoxide dismutase (SOD), catalase and Glutathione peroxidase (GPx) activities were measured at 6h post BCG exposure. Downstream targets of COS, DNA damage and lipid peroxidation, were determined by measuring 8-hydroxydeoxyguanosine (OHdG) and 4-hydroxynonenal (HNE) adduct, respectively. RESULTS Post BCG treatment, an increase in cellular H2O2 was observed as early as 3h (p ≤ 0.05) and a sustained increase was observed till 12h (p ≤ 0.005). H2O2 levels did not change significantly 24h onwards (p = 0.32). NO levels showed a significant increase at 6h (p ≤ 0.05) but not at 3h (p = 0.2) or 9h (p = 0.14) onwards. Superoxide levels showed significant increase at 6h (p ≤ 0.05) but reduced levels at 24h (p ≤ 0.05). Post BCG exposure, SOD and GPx activities were significantly higher at 6h (p ≤ 0.05), while catalase activity did not show any significant change (p = 0.5) in both cell lines. BCG treatment significantly increased lipid peroxidation (p ≤ 0.001) and DNA damage (p ≤ 0.05) in UC cells after 72h. Addition of iNOS inhibitor 1400W nullified the increase in NO, lipid peroxidation and DNA damage. CONCLUSIONS Exposure of UC cells to BCG initiates a temporally complex COS response in the treated cells. Early production of H2O2 post BCG treatment suggests that H2O2 acts to initiate a primary wave of oxidative stress. Continued production of H2O2 leads to induction of NO and superoxide as a second wave of COS which leads to lipid peroxidation and DNA damage. NO has been shown to play a a direct role in the induction of intracellular signaling, gene expression and phenotypic changes including cellular necrosis and release of HMGB1. COS appears to play a central role in mediating the direct effects of BCG on UC cell biology. COS is a candidate for targeted manipulation with the intent of increasing the efficacy of BCG. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e363 Advertisement Copyright & Permissions© 2014MetricsAuthor Information Gopitkumar Shah More articles by this author Fanghong Chen More articles by this author Gina Lockwood More articles by this author Scott Johnson More articles by this author Jacek Zielonka More articles by this author Balaraman Kalyanaraman More articles by this author William See More articles by this author Expand All Advertisement Advertisement PDF DownloadLoading ...