Adeno-associated virus serotypes 1 to 5 mediated tumor cell directed gene transfer and improvement of transduction efficiency.
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.
Hacker
Ulrich T
UT
Klinik für Innere Medizin I, Klinikum der Universität zu Köln, Joseph-Stelzmann-Strasse 9, 50925 Köln, Germany.
Wingenfeld
Lisa
L
Kofler
David M
DM
Schuhmann
Natascha K
NK
Lutz
Sandra
S
Herold
Tobias
T
King
Susan B S
SB
Gerner
Franz M
FM
Perabo
Luca
L
Rabinowitz
Joseph
J
McCarty
Douglas M
DM
Samulski
Richard J
RJ
Hallek
Michael
M
Büning
Hildegard
H
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