Gene transfer in ovarian cancer cells: a comparison between retroviral and lentiviral vectors.
Local gene therapy could be a therapeutic option for ovarian carcinoma, a life-threatening malignancy, because of disease containment within the peritoneal cavity in most patients. Lentiviral vectors, which are potentially capable of stable transgene expression, may be useful to vehicle therapeutic molecules requiring long-term production in these tumors. To investigate this concept, we used lentiviral vectors to deliver the enhanced green fluorescent protein (EGFP) gene to ovarian cancer cells. Their efficiency of gene transfer was compared with that of a retroviral vector carrying the same envelope. In vitro, both vectors infected ovarian cancer cells with comparable efficiency under standard culture conditions; however, the lentiviral vector was much more efficient in transducing growth-arrested cells when compared with the retroviral vector. Gene transfer was fully neutralized by an anti-VSV-G antibody, and in vitro stability was similar. In vivo, the lentiviral vector delivered the transgene 10-fold more efficiently to ovarian cancer cells growing i.p. in SCID mice, as evaluated by real-time PCR analysis of the tumors. Confocal microscopy analysis of tumor sections showed a dramatic difference at the level of transgene expression, because abundant EGFP(+) cells were detected only in mice receiving the lentiviral vector. Quantitative analysis by flow cytometry confirmed this and indicated 0.05 and 5.6% EGFP(+) tumor cells after administration of the retroviral and lentiviral vector, respectively. Injection of ex vivo transduced tumor cells, sorted for EGFP expression, indicated that the lentiviral vector was considerably more resistant to in vivo silencing in comparison with the retroviral vector. Finally, multiple administrations of a murine IFN-alpha(1)-lentiviral vector to ovarian carcinoma-bearing mice significantly prolonged the animals' survival, indicating the therapeutic efficacy of this approach. These findings indicate that lentiviral vectors deserve attention in the design of future gene therapy approaches to ovarian cancer aimed at achieving long-term expression of therapeutic genes.
Indraccolo
Stefano
S
IST-Viral and Molecular Oncology Section, Padova, Italy. stefano.indraccolo@unipd.it
Habeler
Walter
W
Tisato
Veronica
V
Stievano
Laura
L
Piovan
Erich
E
Tosello
Valeria
V
Esposito
Giovanni
G
Wagner
Ralf
R
Uberla
Klaus
K
Chieco-Bianchi
Luigi
L
Amadori
Alberto
A
D000256:Adenoviridae / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000235:genetics / Q000493:pharmacokinetics; D049452:Green Fluorescent Proteins; D006801:Humans; D016898:Interferon-alpha / Q000096:biosynthesis / Q000235:genetics; D016086:Lentivirus / Q000235:genetics*; D008164:Luminescent Proteins / Q000096:biosynthesis / Q000235:genetics; D010051:Ovarian Neoplasms / Q000235:genetics / Q000378:metabolism / Q000628:therapy* / Q000821:virology; D014018:Tissue Distribution; D014158:Transcription, Genetic; D019076:Transgenes; D014407:Tumor Cells, Cultured
D016898:Interferon-alpha; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins