Enhanced expression of bioactive recombinant VEGF-111 with insertion of intronic sequence in mammalian cell lines.

Among all VEGF-A isoforms, VEGF-111 is particularly important in molecular biology research owing to its potent angiogenic properties and its remarkable resistance to proteolysis. These features make it a potential candidate for therapeutic use in ischemic diseases. VEGF-111 is not expressed in normal cells, but expression is induced by UV-B irradiation and exposure to genotoxic agents. Here, to increase expression at the transcriptional and translational levels, we synthesized and cloned recombinant VEGF-111 cDNA. Two fragments encoding exons 1-4 and intron 4/5 plus exon 8a were amplified and cloned into the pBud.CE4.1 vector using a class IIs restriction enzyme-based method. The expression of VEGF-111 in CHO-dhfr - and HEK 293 cell lines was evaluated with real-time PCR, dot blotting, and ELISA. VEGF expression was increased about 10- and 18-fold in transfected CHO-dhfr - and HEK 293 cells, respectively. Dot blotting and ELISA confirmed successful production of VEGF-111 in both cell lines.