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Comparison of viral vectors: gene transfer efficiency and tissue specificity in a bladder cancer model
D Robert Siemens1, Scott Crist, J Christopher Austin
1Department of Urology, Cancer Center and Prostate Cancer Research Group, University of Iowa, Iowa City, IA, USA. siemensr@kgh.kari.net
Purpose:
Gene transfer efficiency and specific cell targeting of vectors is a major obstacle in preclinical studies of gene therapy for malignant disease. Previous attempts at gene transfer in bladder cancer models have resulted in variable urothelial and tumor transgene expression after intravesical administration of recombinant viral vectors. In the current study we compared the gene transfer efficiencies of different viral vectors.
Materials And Methods:
We compared the gene transfer efficiencies of the viral vectors replication-deficient adenovirus, attenuated vaccinia virus (NYVAC) and canarypox virus (ALVAC) in vitro and in an orthotopic murine bladder cancer model. We used beta-galactosidase and firefly luciferase reporter gene expression to compare gene transfer efficiency.
Results:
Significantly higher transgene expression was observed in vitro when these cells were infected with NYVAC or ALVAC compared with adenovirus vectors. Similarly the efficiency of adenovirus vectors to transfer genetic material into bladder urothelium and orthotopic bladder tumors was inferior to that of ALVAC and NYVAC vectors, which interestingly appeared to have a predilection to infect the orthotopic tumor. Analysis of the expression of coxsackie-adenovirus receptor using reverse transcriptase-polymerase chain reaction revealed the bladder tumor cell lines were lacking this adenovirus receptor. While adenovirus transferred genes poorly to normal bladder, coxsackie-adenovirus receptor expression was high in bladder tissue.
Conclusions:
The viral vectors examined in these experiments resulted in significantly different gene transfer in the orthotopic bladder cancer model, underscoring the importance of vector selection in gene therapy protocols.
Insights
For bladder cancer gene therapy, attenuated vaccinia virus (NYVAC) and canarypox virus (ALVAC) show superior gene transfer efficiency compared to adenovirus vectors in preclinical models.
Area of Science:
- Oncology
- Gene Therapy
- Virology
Background:
- Gene transfer efficiency and cell targeting are critical challenges in preclinical gene therapy for malignant diseases.
- Previous intravesical gene transfer attempts in bladder cancer models yielded inconsistent urothelial and tumor transgene expression.
Purpose of the Study:
- To compare the gene transfer efficiencies of different viral vectors in bladder cancer models.
- To evaluate replication-deficient adenovirus, attenuated vaccinia virus (NYVAC), and canarypox virus (ALVAC) for gene therapy applications.
Main Methods:
- In vitro and orthotopic murine bladder cancer models were used to assess gene transfer efficiency.
- Replication-deficient adenovirus, NYVAC, and ALVAC vectors were compared using beta-galactosidase and firefly luciferase reporter genes.
Main Results:
- NYVAC and ALVAC demonstrated significantly higher in vitro transgene expression compared to adenovirus vectors.
- Adenovirus vectors showed inferior gene transfer efficiency into bladder urothelium and orthotopic tumors versus ALVAC and NYVAC.
- Bladder tumor cells lacked the coxsackie-adenovirus receptor, while normal bladder tissue expressed it highly, explaining adenovirus's poor gene transfer.
Conclusions:
- Significant differences in gene transfer were observed among the tested viral vectors in an orthotopic bladder cancer model.
- Vector selection is crucial for optimizing gene therapy protocols in bladder cancer treatment.