965 CHARACTERIZATION AND PRECLINICAL TARGETING OF HUMAN BLADDER CANCER STEM CELLS

Abstract

You have accessJournal of UrologyBladder Cancer: Basic Research II1 Apr 2010965 CHARACTERIZATION AND PRECLINICAL TARGETING OF HUMAN BLADDER CANCER STEM CELLS Keith Syson Chan, Jens-Peter Volkmer, Mark Chao, Linda Shortliffe, and Irving Weissman Keith Syson ChanKeith Syson Chan Houston, TX More articles by this author , Jens-Peter VolkmerJens-Peter Volkmer Palo Alto, CA More articles by this author , Mark ChaoMark Chao Palo Alto, CA More articles by this author , Linda ShortliffeLinda Shortliffe Palo Alto, CA More articles by this author , and Irving WeissmanIrving Weissman Palo Alto, CA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.1912AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Recently, we reported the isolation of cancer stem cells (CSC) from human bladder cancer, based on the expression of markers similar to that of normal basal cells (Lineage-CD44+CK5+CD20-) (Chan KS et al, 2009). Studies have demonstrated that CSCs from other cancer types are resistant to radiation and chemotherapy, we hypothesize that specific targeting of CSC will provide better therapeutic efficacy. In the current study, we have characterized the expression of CD47 on bladder CSC and examined the therapeutic effect of a monoclonal antibody against CD47 in bladder xenografts. METHODS With approval from Stanford institutional review board, bladder cancer or passaged xenograft tumors from eight patients were enzymatically dissociated. The resulting tumor cell suspensions or sections were: (I) analyzed by flow cytometry and immunofluorescence staining on the protein expression of CD47, and (II) tested in an assay to determine the effect of an anti-CD47 antibody in blocking phagocytosis, when cocultured with human peripheral blood-derived macrophages in vitro. Finally, the therapeutic effect of the anti-CD47 antibody was examined on three bladder xenograft tumor lines. Xenograft tumors were first established by intradermal injection of 20,000 cells (2 tumors per mouse) onto the dorsal skin of immunocompromised mice. Mice were then randomized into two different treatment arms. Daily intraperitoneal injection of CD47 antibody (400ug) and IgG control were applied for a period of 6 to 8 weeks and the tumor volume was monitored by magnetic resonance imaging (MRI). RESULTS CD47 protein level was found to be expressed higher in bladder CSC in comparison to differentiated tumor cells both by flow cytometry and immunofluorescence analysis (n=8). Furthermore, CD47 mRNA expression was found to be statistically higher in invasive bladder cancer (n=81) in comparison to superficial bladder (n=28). Blockade of the CD47-SIRPα interaction by a monoclonal antibody against CD47 resulted in macrophage engulfment of bladder cancer cells in vitro. Finally, using MRI as a quantitative method for monitoring tumor volume, we found that CD47 antibody treatment on established tumors (n=14) from two human xenograft lines led to a statistically significant reduction in tumor growth in comparison to control. CONCLUSIONS CD47, a protein that provides an inhibitory signal for macrophage phagocytosis, is highly expressed in human bladder CSCs, thus providing an attractive target. We have demonstrated for the first time that an anti-CD47 antibody therapy can target both bladder CSC and differentiated tumor cells. © 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e375 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Keith Syson Chan Houston, TX More articles by this author Jens-Peter Volkmer Palo Alto, CA More articles by this author Mark Chao Palo Alto, CA More articles by this author Linda Shortliffe Palo Alto, CA More articles by this author Irving Weissman Palo Alto, CA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...