Recombinant adeno-associated and adenoviral vectors for the transduction of pancreatic and colon carcinoma.

BACKGROUND: Recombinant adeno-associated viral vectors serotype 2 (rAAV2) can transduce several tissues with high efficiency. MATERIALS AND METHODS: The transduction efficiency of rAAV2 in pancreatic and colon cancer was compared to that of recombinant adenovirus (rAd) in vitro and in vivo using green fluorescent protein (GFP). RESULTS: With the exception of SU.86.86, the percentage of GFP-positive cells was below 10% at a multiplicity of infection (MOI) of 100 for rAAV2. At the same MOI, almost 100% of cells expressed GFP when rAd was used. However, the transduction efficiency for rAA V2 was comparable to that of rAd when coinfected with wt adenovirus, leading to a dramatic increase in the amount of double-stranded rAAV2 DNA. Similar results were obtained in vivo. While widespread GFP expression was readily detected in all xenografts injected with rAd, only one section of all tumors injected with rAAV2 contained GFP-positive cells. CONCLUSION: The results of this study indicate that rAAV2 might be useful for an ex vivo approach in cancer gene therapy, but it does not seem to be feasible for the in vivo treatment of malignant tumors.