title: A retroviral packaging cell line for pseudotype vectors based on glioma-infiltrating progenitor cells.
abstract: BACKGROUND
  Early clinical trials for gene therapy of human gliomas with retroviral packaging cells (PC) have been hampered by low transduction efficacy and lack of dissemination of PC within the tumor. In the current approach, these issues have been addressed by creating a stable packaging cell line for retroviral vectors pseudotyped with glycoproteins of lymphocytic choriomeningitis virus (LCMV) based on tumor-infiltrating progenitor cells.
  
  
  METHODS
  Tumor-infiltrating progenitor cells, which had been isolated from adult rat bone marrow (BM-TIC), were modified to stably express Gag-Pol proteins of moloney murine leukemia virus (Mo-MLV) and glycoproteins of LCMV. Packaging of a retroviral vector was measured by titration experiments on human fibroblast cells as well as on mouse and human glioma cell lines. Additionally, gene transfer was tested in a rat glioma model in vivo.
  
  
  RESULTS
  The BM-TIC-derived packaging cell line (BM-TIPC) produced retroviral vectors with titers between 2-8 x 10(3) transducing units (TU)/ml. Extended culturing of BM-TIPC over several weeks and freezing/thawing of cells did not affect vector titers. No replication-competent retrovirus was released from BM-TIPC. In a rat glioma model, BM-TIPC infiltrated the tumors extensively and with high specificity. Moreover, BM-TIPC mediated transduction of glioma cells in vivo.
  
  
  CONCLUSIONS
  This proof-of-principle study shows that primary adult progenitor cells with tumor-infiltrating capacity can be genetically modified to stably produce retroviral LCMV pseudotype vectors. These BM-TIPC may be a useful tool to enhance specificity and efficacy of gene transfer to gliomas in patients.
authors.affiliation: University of Lund, Stem Cell Center, BMC B10, 22184 Lund, Sweden.
authors.forename: Yvonne Heidemarie
authors.initials: YH
authors.lastname: Fischer
authors.forename: Hrvoje
authors.initials: H
authors.lastname: Miletic
authors.forename: Tsanan
authors.initials: T
authors.lastname: Giroglou
authors.forename: Sara
authors.initials: S
authors.lastname: Litwak
authors.forename: Werner
authors.initials: W
authors.lastname: Stenzel
authors.forename: Harald
authors.initials: H
authors.lastname: Neumann
authors.forename: Dorothee
authors.initials: D
authors.lastname: von Laer
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells; D002460:Cell Line; D002465:Cell Movement; D002478:Cells, Cultured; D015316:Genetic Therapy / Q000379:methods; D005822:Genetic Vectors; D005910:Glioma / Q000628:therapy*; D006801:Humans; D008217:Lymphocytic choriomeningitis virus / Q000737:chemistry; D045164:Mesenchymal Stem Cell Transplantation / Q000379:methods; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D008979:Moloney murine leukemia virus / Q000737:chemistry; D051381:Rats; D012190:Retroviridae / Q000235:genetics*; D014161:Transduction, Genetic; D014764:Viral Proteins / Q000235:genetics; D019065:Virus Assembly
chemical_list: D014764:Viral Proteins