VEGF receptor binding peptide-linked amphiphilic peptide with arginines and valines for endothelial cell-specific gene delivery.

An amphiphilic peptide with a 3-arginine stretch and a 6-valine stretch (R3V6) has been previously reported to deliver plasmid DNA (pDNA) into cells with no toxicity. Here, the vascular endothelial growth factor receptor binding peptide (VRBP) was linked to R3V6 to promote endothelial-specific gene delivery. The pDNA/VRBP-linked R3V6 (VRBP-R3V6) complex was physically characterized via various methods. In a gel retardation assay, pDNA was completely retarded by VRBP-R3V6 at a weight ratio of 1:2 (pDNA:peptide). VRBP-R3V6 also protected pDNA from DNase I for longer than 60 min. Heparin competition assay showed that the pDNA/VRBP-R3V6 complex did not release pDNA when heparin was introduced at a two-fold weight excess of pDNA. In vitro transfection showed that VRBP-R3V6 had transfection efficiency into endothelial cells approximately 200 times greater than that of R3V6. In addition, the transfection efficiency was further enhanced into hypoxic endothelial cells. However, in human embryonic kidney 293 and neuroblastoma N2A cells, VRBP-R3V6 only achieved a transfection rate 10 times higher than R3V6, indicating that VRBP-R3V6 has high specificity for endothelial cells. VRBP-R3V6 was also shown to be nontoxic in a cytotoxicity assay. The data presented here suggest that VRBP-R3V6 may prove useful for specific gene delivery to endothelial cells.