Carbohydrate-based VEGF inhibitors

Cyclic peptide-carbohydrates (compounds 1a-c, 2, 33, 34) were designed and synthesized to act as mimetics of loop 2 of the proangiogenic molecule vascular endothelial growth factor D (VEGF-D). The mimetics were designed to inhibit dimerization of the receptors (VEGFR-2 and VEGFR-3) by VEGF-D, and thus have the potential to inhibit angiogenesis. To this end, in the previously described cyclic octapeptide CNEESLIC and the cyclic nonapeptide CGNEESLIC inhibitors derived from VEGF-D loop 2, the NEES tetrapeptide residue was replaced by a carbohydrate scaffold having the amino acid side chain mimics in positions proposed by modeling studies. Attachment of the additional amino acids using the Fmoc technology, then formation of the cyclic disulfides, and finally total deprotection afforded the target molecules of which 2 and 34 showed an ability to inhibit the biological activity of VEGF-D through VEGFR-2 in cell-based assays, albeit at high mimetic concentration.