Local delivery of VEGF165b and IFNα by microencapsulated cells as potential antiangiogenic therapy

The objective of this study was to evaluate the potential of two stable cell lines, HEK293-IFNalpha2b (293-IFN) and HEK293-VEGF₁₆₅b (293-VEGFb) to continuously deliver IFNalpha and VEGF₁₆₅b after their encapsulation in alginate-poly-L-lysine-alginate (APA) microcapsules. Encapsulated 293-IFN or 293-VEGFb cells were cultured in vitro and the viability and recombinant protein productivity were determined and compared to non-encapsulated cells. The bioactivity of IFNalpha secreted from encapsulated cells was evaluated using a reporter gene assay and compared with purified IFNalpha. The effect of VEGF₁₆₅b harvested from encapsulated cells on human umbilical vein endothelial cells proliferation was also examined. The results showed that encapsulated cells grew within the microcapsules and continuously produced IFNalpha and VEGF₁₆₅b for over two weeks in vitro. The proteins released from microcapsules were as active as the one produced from non-encapsulated cells or from commercially available sources. Continuous release of high levels of r-proteins by encapsulated cells suggests that this technology could represent a potent system for local and continuous delivery of therapeutic proteins following microcapsules implantation in vivo.