title: Transgene amplification and persistence after delivery of retroviral vector and packaging functions with E1/E4-deleted adenoviruses.
abstract: Adenovirus DNA is rapidly lost in actively dividing cells. In addition, first-generation (E1-defective) vectors trigger a strong cytotoxicity that impairs the duration of transgene expression. To solve these issues, we have developed a chimeric vector system that uses E1/E4 doubly defective adenoviruses for efficient production of infectious retroviral vectors. The retroviral vector sequences and packaging functions were split into two E1/E3/E4-deleted adenoviral vectors: the Moloney murine leukemia virus gag-pol cistron was expressed from the human EF1 alpha (elongation factor) promoter (AdGAG/POL), whereas the thymidine kinase transgene, embedded in a retroviral vector context, and an amphotropic retroviral envelope cassette were included within a second adenovirus (AdTK/ENV). This chimeric vector system was evaluated with a special emphasis on recombinant retrovirus production in vitro, as well as transgene amplification and persistence in vivo. Retrovirus titers of >10(5) infectious units/mL were routinely obtained in W162 cells coinfected with both recombinant adenoviruses. Long-term transgene persistence (up to 3 months) was demonstrated in vitro in two different cell lines coinfected with AdGAG/POL and AdTK/ENV, and correlated with the detection of specific provirus sequences. A 10- to 50-fold transgene amplification also was demonstrated in an in vivo tumor model infected with the Ad/Rt chimeric vector system. The chimeric vector system described herein combines the efficiency of gene delivery by recombinant adenoviruses with the integrative properties of infectious retroviral vectors. This versatile vector system may open up new avenues for efficient production of oncogenic, but also non-oncogenic, retroviruses from cells of non-murine origin.
authors.affiliation: Aventis Pharma Gencell-Centre National de la Recherche Scientifique-Institut Gustave Roussy Unité Mixte de Recherche 1582, Institut Gustave Roussy, Villejuif, France. ctorrent@igr.fr
authors.forename: C
authors.initials: C
authors.lastname: Torrent
authors.forename: C
authors.initials: C
authors.lastname: Jullien
authors.forename: D
authors.initials: D
authors.lastname: Klatzmann
authors.forename: M
authors.initials: M
authors.lastname: Perricaudet
authors.forename: P
authors.initials: P
authors.lastname: Yeh
mesh_terms: D016475:3T3 Cells; D000256:Adenoviridae / Q000235:genetics / Q000502:physiology; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D005822:Genetic Vectors; D051379:Mice; D012190:Retroviridae / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019076:Transgenes; D019065:Virus Assembly
chemical_list: D017931:DNA Primers