title: Enhanced suicide gene effect by adenoviral transduction of a VP22-cytosine deaminase (CD) fusion gene.
abstract: The low transduction efficiency of viral and nonviral vectors is a major limitation in tumour gene therapy. The HSV-1 tegument protein VP22 has been shown to exhibit a novel intercellular transport property. VP22 wild-type as well as VP22 fusion proteins efficiently spread from the original expressing cell to numerous neighbouring cells, so that protein transport by VP22 chimaeric polypeptides into the surrounding cells offers a possible compensation for the inadequate gene transfer efficiencies. To improve the therapeutic efficacy of the E. coli cytosine deaminase (CD) suicide gene we made use of the VP22 transport property in CD transducing adenoviral (Ad) vectors. C- and N-terminal fusions of CD linked in-frame with VP22 were generated and cloned into recombinant adenoviral vectors. Following in vitro transduction immunofluorescence analysis of Ad-transduced producer cells coplated with naive cells confirmed that the characteristic foci pattern of central producer and adjoining neighbour cells displaying nuclear staining was retained. After transduction of rat hepatoma cells with adenoviral vectors and subsequent incubation with the prodrug 5-FC, we observed enhanced cell cytotoxicity when comparing the CD-VP22 fusion (Ad-CD-VP22) with Ad-vectors expressing the CD gene only (Ad-CD). Thereby employment of Ad-vectors encoding VP22 fusion proteins opens up new possibilities to potentiate the efficiency of suicide gene therapy for the treatment of solid tumours.
authors.affiliation: Internal Medicine I, Medical University Clinic Tübingen, Germany.
authors.forename: W A
authors.initials: WA
authors.lastname: Wybranietz
authors.forename: C D
authors.initials: CD
authors.lastname: Gross
authors.forename: A
authors.initials: A
authors.lastname: Phelan
authors.forename: P
authors.initials: P
authors.lastname: O'Hare
authors.forename: M
authors.initials: M
authors.lastname: Spiegel
authors.forename: F
authors.initials: F
authors.lastname: Graepler
authors.forename: M
authors.initials: M
authors.lastname: Bitzer
authors.forename: P
authors.initials: P
authors.lastname: Stähler
authors.forename: M
authors.initials: M
authors.lastname: Gregor
authors.forename: U M
authors.initials: UM
authors.lastname: Lauer
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D019556:COS Cells; D043525:Cytosine Deaminase; D029968:Escherichia coli Proteins / Q000235:genetics*; D005260:Female; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000008:administration & dosage*; D006367:HeLa Cells; D006801:Humans; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009700:Nucleoside Deaminases / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000235:genetics; D014161:Transduction, Genetic; D002583:Uterine Cervical Neoplasms / Q000628:therapy*; D015678:Viral Structural Proteins / Q000235:genetics*
chemical_list: D029968:Escherichia coli Proteins; D011993:Recombinant Fusion Proteins; D015678:Viral Structural Proteins; C073413:herpes simplex virus type 1 protein VP22; D009700:Nucleoside Deaminases; D043525:Cytosine Deaminase