title: Efficient virotherapy for osteosarcoma by telomerase-specific oncolytic adenovirus.
abstract: OBJECTIVE
  A telomerase-specific oncolytic adenovirus, Telomelysin, can selectively kill cancer cells, and be attenuated in normal cells. We herein describe the oncolytic effect of Telomelysin on human osteosarcoma both in vitro and in vivo.
  
  
  METHODS
  The anti-tumor effects of Telomelysin were evaluated on human osteosarcoma cell lines in vitro and in a mouse xenograft model of human osteosarcoma in vivo. The replication efficiencies of Telomelysin in human osteosarcoma cell lines and normal cell lines and in osteosarcoma xenografts were determined by the expression levels of E1 mRNA and E1A protein using real-time quantitative PCR, Western blot analysis and immunohistochemistry. The in vitro telomerase-specific replication and the viral infection rate were also confirmed by TelomeScan (Telomelysin-GFP), using fluorescent microscopy and flow cytometry, respectively. The cell viabilities were examined by XTT assay, and the tumor volumes were measured every 2 days. The induction of apoptosis was assessed by Western blot analysis, as well as by TUNEL assay.
  
  
  RESULTS
  TelomeScan and Telomelysin were efficiently replicated in human osteosarcoma cell lines and led to a dose- and time-dependent expression of GFP, E1 mRNA and E1A protein. Telomelysin infection induced marked cytolysis and apoptosis in osteosarcoma cell lines in vitro. Neither cytotoxicity nor apoptosis were induced in normal human cell lines. In the human osteosarcoma cell xenograft model, intratumoral injection of Telomelysin resulted in increased viral replication, significant tumor growth suppression and distinct apoptotic cell death.
  
  
  CONCLUSIONS
  This study indicated that virotherapy with Telomelysin may provide a promising strategy for the treatment of human osteosarcoma.
authors.affiliation: Division of Orthopedic Surgery, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan.
authors.forename: Guidong
authors.initials: G
authors.lastname: Li
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kawashima
authors.forename: Akira
authors.initials: A
authors.lastname: Ogose
authors.forename: Takashi
authors.initials: T
authors.lastname: Ariizumi
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Xu
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Hotta
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Urata
authors.forename: Toshiyoshi
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Naoto
authors.initials: N
authors.lastname: Endo
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D017209:Apoptosis; D001859:Bone Neoplasms / Q000473:pathology / Q000628:therapy*; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D050130:Oncolytic Virotherapy; D012516:Osteosarcoma / Q000473:pathology / Q000628:therapy*; D019098:Telomerase / Q000235:genetics*; D014779:Virus Replication; D023041:Xenograft Model Antitumor Assays
chemical_list: C509186:TERT protein, human; D019098:Telomerase