1. ¹Department of Pathology, University Medical Center Nijmegen, Nijmegen, The Netherlands
2. ²Department of Biochemistry, Faculty of Science, University of Nijmegen, Nijmegen, The Netherlands
3. ³Max Planck Institute for Physiological and Clinical Research, Bad Nauheim, Germany
4. ⁴Department of Endocrinology, Leids Universitair Medisch Center, Leiden, The Netherlands

Correspondence: Dr. William Leenders, University Medical Center Nijmegen, Department of Pathology, PO Box 9101, 6500 HB Nijmegen, The Netherlands. E-mail: w.leenders@pathol.azn.nl

Received 27 November 2001.

Abstract

Because of its central role in pathological angiogenesis, vascular endothelial growth factor (VEGF) has become a major target for anti-angiogenic therapies. We report here the construction of a heterodimeric antagonistic VEGF variant (HD-VEGF). In this antagonist, binding domains for the VEGF-receptors KDR/Flk-1 and Flt-1 are present at one pole of the dimer, whereas the other pole carries domain swap mutations, which prevent binding to either receptor. As HD-VEGF can only bind to monomeric receptors, it does not lead to signal transduction. Moreover, it antagonizes VEGF and possibly other members of the VEGF family, which are KDR/Flk-1 and Flt-1 ligands. We show here that HD-VEGF is a potent inhibitor of VEGF-mediated proliferation and tissue factor induction in endothelial cell cultures, requiring only a 20-fold and a 4-fold excess, respectively, to block the activity of wtVEGF completely. A 4-fold excess of HD-VEGF over wtVEGF was also sufficient to abrogate vascular permeability as determined in the Miles assay in vivo. Furthermore, HD-VEGF inhibited fetal bone angiogenesis in an ex vivo assay. Thus, HD-VEGF blocks KDR- and Flt-1-mediated VEGF activities that are crucial in the angiogenic process and is therefore a promising, multipotent compound in the treatment of angiogenesis-related diseases.