Distinct heparin binding sites on VEGF165 and its receptors revealed by their interaction with a non sulfated glycoaminoglycan (NaPaC)

We previously demonstrated that a non sulfated analogue of heparin, phenylacetate carboxymethyl benzylamide dextran (NaPaC) inhibited angiogenesis. Here, we observed that NaPaC inhibited the VEGF(165) binding to both VEGFR2 and NRP-1 and abolished VEGFR2 activity. Further, we explored the effects of NaPaC on VEGF(165) interactions with its receptors, VEGFR2 and NRP-1, co-receptor of VEGFR2. Surface plasmon resonance and affinity gel electrophoresis showed that NaPaC interacted directly with VEGF(165), VEGFR2 and NRP-1 but not with heparin-independent factor such as VEGF(121), NaPaC completely inhibited the heparin binding to VEGF(165), NRP-1 and VEGFR2. We found that NaPaC bound to all three molecules, VEGF(165), VEGFR2 and NRP-1, but was more effective in inhibiting heparin binding to VEGF(165). These results suggested that heparin binding sites of VEGFR2 and NRP-1 were different from those of VEGF(165). (C) 2008 Elsevier B.V. All rights reserved.