title: Clusterin inhibition using OGX-011 synergistically enhances zoledronic acid activity in osteosarcoma.
abstract: OBJECTIVE
  Despite recent improvements in therapeutic management of osteosarcoma, ongoing challenges in improving the response to chemotherapy warrants new strategies still needed to improve overall patient survival. Among new therapeutic approaches, zoledronic acid (ZOL) represents a promising adjuvant molecule to chemotherapy to limit the osteolytic component of bone tumors. However, ZOL triggers the elevation of heat shock proteins (Hsp), including Hsp27 and clusterin (CLU), which could enhance tumor cell survival and treatment resistance. We hypothesized that targeting CLU using siRNA or the antisense drug, OGX-011, will suppress treatment-induced CLU induction and enhance ZOL-induced cell death in osteosarcoma (OS) cells.
  
  
  METHODS
  The combined effects of OGX-011 and ZOL were investigated in vitro on cell growth, viability, apoptosis and cell cycle repartition of ZOL-sensitive or -resistant human OS cell lines (SaOS2, U2OS, MG63 and MNNG/HOS).
  
  
  RESULTS
  In OS cell lines, ZOL increased levels of HSPs, especially CLU, in a dose- and time-dependent manner by mechanism including increased HSF1 transcription activity. The OS resistant cells to ZOL exhibited higher CLU expression level than the sensitive cells. Moreover, CLU overexpression protects OS sensitive cells to ZOL-induced cell death by modulating the MDR1 and farnesyl diphosphate synthase expression. OGX-011 suppressed treatment-induced increases in CLU and synergistically enhanced the activity of ZOL on cell growth and apoptosis. These biologic events were accompanied by decreased expression of HSPs, MDR1 and HSF1 transcriptional activity. In vivo, OGX-011, administered 3 times a week (IP, 20mg/kg), potentiated the effect of ZOL (s.c; 50µg/kg), significantly inhibiting tumor growth by 50% and prolonging survival in MNNG/HOS xenograft model compared to ZOL alone.
  
  
  CONCLUSIONS
  These results indicate that ZOL-mediated induction of CLU can be attenuated by OGX-011, with synergistic effects on delaying progression of osteosarcoma.
authors.affiliation: Université de Nantes, Nantes atlantique universités, Laboratoire de Physiopathologie de la Résorption Osseuse et Thérapie des Tumeurs Osseuses Primitives, Nantes F-44035, France. INSERM, UMR 957, Nantes F-44035, France. LUNAM Université. Equipe labellisée LIGUE 2012, Nantes, cedex.
authors.forename: Francois
authors.initials: F
authors.lastname: Lamoureux
authors.affiliation: Université de Nantes, Nantes atlantique universités, Laboratoire de Physiopathologie de la Résorption Osseuse et Thérapie des Tumeurs Osseuses Primitives, Nantes F-44035, France. INSERM, UMR 957, Nantes F-44035, France. LUNAM Université. CHU de Nantes, Nantes F-44035, France. Equipe labellisée LIGUE 2012, Nantes, cedex.
authors.forename: Marc
authors.initials: M
authors.lastname: Baud'huin
authors.affiliation: Université de Nantes, Nantes atlantique universités, Laboratoire de Physiopathologie de la Résorption Osseuse et Thérapie des Tumeurs Osseuses Primitives, Nantes F-44035, France. INSERM, UMR 957, Nantes F-44035, France. LUNAM Université. Equipe labellisée LIGUE 2012, Nantes, cedex.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Ory
authors.affiliation: Université de Nantes, Nantes atlantique universités,Laboratoire de Physiopathologie de la Résorption Osseuse et Thérapie des Tumeurs Osseuses Primitives, Nantes F-44035, France. INSERM, UMR 957, Nantes F-44035, France. LUNAM Université. Equipe labellisée LIGUE 2012, Nantes, cedex.
authors.forename: Romain
authors.initials: R
authors.lastname: Guiho
authors.affiliation: The Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Amina
authors.initials: A
authors.lastname: Zoubeidi
authors.affiliation: The Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Martin
authors.initials: M
authors.lastname: Gleave
authors.affiliation: Université de Nantes, Nantes atlantique universités, Laboratoire de Physiopathologie de la Résorption Osseuse et Thérapie des Tumeurs Osseuses Primitives, Nantes F-44035, France. INSERM, UMR 957, Nantes F-44035, France. LUNAM Université. CHU de Nantes, Nantes F-44035, France. Equipe labellisée LIGUE 2012, Nantes, cedex.
authors.forename: Dominique
authors.initials: D
authors.lastname: Heymann
authors.affiliation: Université de Nantes, Nantes atlantique universités, Laboratoire de Physiopathologie de la Résorption Osseuse et Thérapie des Tumeurs Osseuses Primitives, Nantes F-44035, France. INSERM, UMR 957, Nantes F-44035, France. LUNAM Université. Equipe labellisée LIGUE 2012, Nantes, cedex.
authors.forename: Françoise
authors.initials: F
authors.lastname: Rédini
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D001859:Bone Neoplasms / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D051152:Clusterin / Q000096:biosynthesis*; D004164:Diphosphonates / Q000008:administration & dosage*; D004357:Drug Synergism; D005260:Female; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage*; D007150:Immunohistochemistry; D051379:Mice; D008819:Mice, Nude; D012516:Osteosarcoma / Q000378:metabolism / Q000473:pathology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013873:Thionucleotides / Q000008:administration & dosage*; D023041:Xenograft Model Antitumor Assays; D000077211:Zoledronic Acid
chemical_list: C495242:CLU protein, human; D051152:Clusterin; D004164:Diphosphonates; D007093:Imidazoles; C503781:OGX-011; D013873:Thionucleotides; D000077211:Zoledronic Acid