engleski

Differential Role OF α vβ 3 and α vβ 5 Integrins in Iinternalization and Transduction Efficacies of Wild Type and RGD4C Fiber-modified Adenoviruses

In order to analyze the role of α vβ 3 and α vβ 5 integrins in gene transfer by adenovirus-based vectors, an RGD4C motif was inserted into the HI-loop of wild type or shortened fiber protein of human adenovirus of serotype 5, thereby creating Ad5RGD4C and Ad5Delta639RGD4C vectors, respectively. Infection by the latter is independent of the coxsackie adenovirus receptor. Internalization of these vectors and transduction were investigated in several stably transfected cell clones derived from a human laryngeal carcinoma cell line (HEp2) expressing different ratios of α vβ 5 and α vβ 3 integrins. We show that α vβ 3 is more successful than α vβ 5 in: (i) mediating adenovirus internalization and transduction when the RGD motif is present only in the penton base (ii) mediating internalization and transduction by RGD4C-fiber modified adenoviruses. The highest amount of internalized virus was found in the cell clone in which α vβ 3 integrin predominated over α vβ 5 integrin (as judged by the % of cells expressing α vβ 3 and α vβ 5 integrins). However the level of transgene expression in this cell line was even lower than that in parental HEp2 cells which do not express α vβ 3 integrin. This discrepancy between internalization and transgene expression (transduction) is likely due to the crucial role of α vβ 5 in membrane permeabilization, indicating that α vβ 5 is a limiting factor for Ad5-mediated gene transfer. We conclude that α vβ 3 integrin is an efficient adenovirus internalization receptor, but cannot functionally replace α vβ 5 in endosomal release.

adenovirus ; α vβ 3integrin ; α vβ 5 integrin ; transduction ; internalization ; fiber ; RGD4C

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