title: Adeno-associated virus serotypes 1 to 5 mediated tumor cell directed gene transfer and improvement of transduction efficiency.
abstract: BACKGROUND
  Gene therapy is an attractive new approach for the treatment of cancer. Therefore, the development of efficient vector systems is of crucial importance in this field. Different adeno-associated virus (AAV) serotypes have been characterized so far, which show considerable differences in tissue tropism. Consequently, we aimed to characterize the most efficient serotype for this application.
  
  
  METHODS
  To exclude all influences other than those provided by the capsid, all serotypes contained the same transgene cassette flanked by the AAV2 inverted terminal repeats. We systematically compared these vectors for efficiency in human cancer cell directed gene transfer. In order to identify limiting steps, the influence of second-strand synthesis and proteasomal degradation of AAV in a poorly transducible cell line were examined.
  
  
  RESULTS
  AAV2 was the most efficient serotype in all solid tumor cells and primary melanoma cells with transduction rates up to 98 +/- 0.3%. Transduction above 70% could be reached with serotypes 1 (in cervical and prostate carcinoma) and 3 (in cervical, breast, prostate and colon carcinoma) using 1000 genomic particles per cell. In the colon carcinoma cell line HT-29 proteasomal degradation limited AAV1-AAV4-mediated gene transfer. Moreover, inefficient second-strand synthesis prevents AAV2-mediated transgene expression in this cell line.
  
  
  CONCLUSIONS
  Recent advances in AAV-vector technology suggest that AAV-based vectors can be used for cancer gene therapy. Our comparative analysis revealed that, although AAV2 is the most promising candidate for such an application, serotypes 1 and 3 are valid alternatives. Furthermore, the use of self-complementary AAV vectors and proteasome inhibitors significantly improves cancer cell transduction.
authors.affiliation: Klinik für Innere Medizin I, Klinikum der Universität zu Köln, Joseph-Stelzmann-Strasse 9, 50925 Köln, Germany.
authors.forename: Ulrich T
authors.initials: UT
authors.lastname: Hacker
authors.forename: Lisa
authors.initials: L
authors.lastname: Wingenfeld
authors.forename: David M
authors.initials: DM
authors.lastname: Kofler
authors.forename: Natascha K
authors.initials: NK
authors.lastname: Schuhmann
authors.forename: Sandra
authors.initials: S
authors.lastname: Lutz
authors.forename: Tobias
authors.initials: T
authors.lastname: Herold
authors.forename: Susan B S
authors.initials: SB
authors.lastname: King
authors.forename: Franz M
authors.initials: FM
authors.lastname: Gerner
authors.forename: Luca
authors.initials: L
authors.lastname: Perabo
authors.forename: Joseph
authors.initials: J
authors.lastname: Rabinowitz
authors.forename: Douglas M
authors.initials: DM
authors.lastname: McCarty
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Samulski
authors.forename: Michael
authors.initials: M
authors.lastname: Hallek
authors.forename: Hildegard
authors.initials: H
authors.lastname: Büning
mesh_terms: D045744:Cell Line, Tumor / Q000502:physiology*; D000229:Dependovirus / Q000235:genetics / Q000378:metabolism*; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009369:Neoplasms / Q000235:genetics / Q000628:therapy; D012703:Serotyping; D014161:Transduction, Genetic