title: Longterm recombinant adeno-associated, virus-mediated, liver-generated expression of an angiogenesis inhibitor improves survival in mice with disseminated neuroblastoma.
abstract: BACKGROUND
  A gene therapy-mediated approach to the delivery of antiangiogenic agents using adeno-associated virus (AAV) vectors has a number of advantages including the potential for sustained expression. The purpose of this study was to attempt to restrict the growth of disseminated neuroblastoma through delivery of a truncated, soluble form of the vascular endothelial growth factor receptor-2 (VEGFR-2 fetal liver kinase [Flk]-1), a decoy receptor for VEGF.
  
  
  METHODS
  Mice underwent portal vein injection of vector, either AAV-CAGG-tsFlk-1 or control vector. Subsequent truncated soluble fetal liver kinase-1 (tsFlk-1) expression was confirmed and quantified by ELISA. After 8 weeks, mice were given human neuroblastoma cells through the tail vein to establish disseminated disease and were sacrificed after 40 days. The weight of liver metastasis was measured. Intrahepatic tumor microvessel density and levels of apoptosis were determined. Survival was assessed in a second cohort of mice.
  
  
  RESULTS
  After intraportal injection of AAV-CAGG-tsFlk-1, high-level, stable transgene expression was generated. Sera from these mice inhibited endothelial cell activation in vitro and Matrigel plug (BD Biosciences) neovascularization in vivo, suggesting that a systemic state of angiogenesis inhibition had been established. After neuroblastoma injection, mice expressing tsFlk-1 had a smaller tumor burden in the liver when sacrificed, as compared with control mice. The decrease in tumor weight in the liver correlated with lower intratumoral microvessel density and higher levels of tumor cell apoptosis in the tsFlk-1-treated tumors, supporting the hypothesis that decreased angiogenesis had occurred. In a second cohort of mice, survival of tsFlk-1-expressing mice after tumor cell challenge was longer than in control mice.
  
  
  CONCLUSIONS
  Longterm in vivo expression of a functional VEGF inhibitor was established using an AAV-mediated gene therapy approach, and it demonstrated antiangiogenic and anticancer efficacy in a murine model of disseminated neuroblastoma.
authors.affiliation: Department of Surgery, St Jude Children's Research Hospital, Memphis, TN 38105, USA.
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Streck
authors.forename: Junfang
authors.initials: J
authors.lastname: Zhou
authors.forename: Catherine Y
authors.initials: CY
authors.lastname: Ng
authors.forename: Youbin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Amit C
authors.initials: AC
authors.lastname: Nathwani
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Davidoff
mesh_terms: D020533:Angiogenesis Inhibitors / Q000096:biosynthesis* / Q000235:genetics / Q000627:therapeutic use; D000818:Animals; D000970:Antineoplastic Agents / Q000378:metabolism / Q000627:therapeutic use; D002460:Cell Line; D000229:Dependovirus / Q000235:genetics; D018014:Gene Transfer Techniques; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D008113:Liver Neoplasms / Q000628:therapy*; D051379:Mice; D023421:Models, Animal; D009362:Neoplasm Metastasis; D009368:Neoplasm Transplantation; D009447:Neuroblastoma / Q000628:therapy*; D016019:Survival Analysis; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics / Q000627:therapeutic use
chemical_list: D020533:Angiogenesis Inhibitors; D000970:Antineoplastic Agents; D040301:Vascular Endothelial Growth Factor Receptor-2