An Angiogenic, Endothelial-Cell-Targeted Polymeric Gene Carrier

Abstract

Targeting is one of the primary considerations in designing a specific and efficient gene delivery system. Here, an angiogenic endothelial cell-targeted polymeric gene delivery carrier was developed by conjugating an alpha(v)beta3/alpha(v)beta5 integrin-binding RGD peptide, ACDCRGDCFC, into the cationic polymer polyethyleneimine (PEI) via a hydrophilic poly(ethylene glycol) (PEG) spacer. The incorporation of PEG into PEI improved the poor physicochemical properties of PEI-DNA complexes. At a neutral charge ratio, DNA complexes with PEI were polydisperse and substantially aggregated, whereas DNA complexes with PEI-g-1PEG-RGD were homogeneous with 100-200 nm effective diameter. Their surface charge was also significantly reduced due to the charge shielding effect of PEG. However, the extensive grafting of PEI with PEG was shown to inhibit the DNA condensation process, significantly decreasing transfection efficiency. In in vitro transfection experiments with angiogenic endothelial cells, PEI-g-1PEG-RGD showed an approximately fivefold increase in transfection efficiency over PEI, due to an integrin-mediated internalization pathway. PEI-g-1PEG-RGD also exhibited high specificity to angiogenic endothelial cells compared with normal endothelial cells, which was confirmed by in vitro transfection experiments with non-targeting PEI-g-1PEG-RAE in angiostatic endothelial cells.

PEI-g-PEG-RGD/Small Interference RNA Polyplex-Mediated Silencing of Vascular Endothelial Growth Factor Receptor and Its Potential as an Anti-Angiogenic Tumor Therapeutic Strategy

“…This targeted carrier was developed by the conjugation of the anb3/ anb5 integrin-binding RGD peptide (ACDCRGDCFC) to the cationic polymer, namely, branched polyethylenimine (BPEI) with a hydrophilic polyethylene glycol (PEG) spacer (Suh et al, 2002;Kim et al, 2005bKim et al, , 2006b. In vitro transfection showed that PEI-g-PEG-RGD efficiently transferred therapeutic gene to angiogenic endothelial cells, but not to the nonangiogenic cells (Kim et al, 2005b).…”

A review of RGD-functionalized nonviral gene delivery vectors for cancer therapy

“…38 Kim et al [39][40][41] prepared PEI-g-PEG-RGD copolymer by conjugating a anb3/anb5 integrin-binding RGD peptide (ACDCRGDCFC, dicyclic form) to a cationic polymer (PEI), with a hydrophilic polyethylene glycol (PEG) spacer (Figure 1a). [39][40][41] The successful complexation of plasmid DNA (pDNA) with the synthetic PEI-g-PEG-RGD polymer was confirmed by agarose gel electrophoresis. Although the size of PEI/pDNA complexes depended on the N/P ratio (the ratio of concentrations of total nitrogen atoms (N) of polycation to the phosphate groups (P) of DNA), the size of PEI-g-PEG-RGD/pDNA complexes was proven to be less affected by the N/P ratio.…”

Highly Versatile Polyelectrolyte Complexes for Improving the Enzyme Replacement Therapy of Lysosomal Storage Disorders

“…22,23 Peptide ligands containing the arginine-glycine-aspartic acid (RGD) sequence display a strong binding affinity and 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 6 selectivity to integrins, particularly to integrin α v β 3 , and have been conjugated to several conventional therapeutic agents for EC targeting and endosomal delivery. [24][25][26][27] Previously, we have described for the first time the development of a pH-responsive nanocarrier for lysosomal delivery of proteins, based on the ionotropic gelation of complexes between trimethyl chitosan (TMC) and the lysosomal enzyme GLA, with triphosphate ions. 5 With a good protein loading efficiency (around 65%), these polyelectrolyte complexes (PECs) have appropriate physicochemical properties to remain stable at physiological temperature and pH (around 7.5), and dissociate and release the protein content at endosomal/lysosomal values (pH 4.5 to 5.5).…”