Abstract
Malignant glioma is usually accompanied by vigorous angiogenesis to provide essential nutrients. An effective glioma targeting moiety should include excellent tumor-cell homing ability as well as good neovasculature-targeting efficiency, and should be highly resistant to enzyme degradation in the bloodstream. The phage display-selected heptapeptide, the glioma-initiating cell peptide (GICP), was previously reported as a ligand for the VAV3 protein (a Rho-GTPase guanine nucleotide exchange factor), which is mainly expressed on glioma cells; the stabilized heptapeptide DA7R has been shown to be the ligand of both vascular endothelial growth factor receptor 2 (VEGFR2) and neuropilin-1 (NRP-1), and has demonstrated good neovasculature-targeting ability. By linking DA7R and GICP, a multi-receptor targeting molecule was obtained. The stability of these three peptides was evaluated and their targeting efficiency on tumor-related cells and models was compared. The ability of these peptides to cross the blood--tumor barrier (BTB) was also determined. The results indicate that the coupled Y-shaped peptide DA7R-GICP exhibited improved tumor and neovasculature targeting ability and had higher efficiency in crossing the BTB than either individual peptide.