The carboxyl terminus of VEGF-A is a potential target for anti-angiogenic therapy

Angiogenesis. 2015 Jan;18(1):23-30. doi: 10.1007/s10456-014-9444-3. Epub 2014 Oct 2.

Abstract

Anti-VEGF-A therapy has become a mainstay of treatment for ocular neovascularisation and in cancer; however, their effectiveness is not universal, in some cases only benefiting a minority of patients. Anti-VEGF-A therapies bind and block both pro-angiogenic VEGF-Axxx and the partial agonist VEGF-Axxxb isoforms, but their anti-angiogenic benefit only comes about from targeting the pro-angiogenic isoforms. Therefore, antibodies that exclusively target the pro-angiogenic isoforms may be more effective. To determine whether C-terminal-targeted antibodies could inhibit angiogenesis, we generated a polyclonal antibody to the last nine amino acids of VEGF-A165 and tested it in vitro and in vivo. The exon8a polyclonal antibody (Exon8apab) did not bind VEGF-A165b even at greater than 100-fold excess concentration, and dose dependently inhibited VEGF-A165 induced endothelial migration in vitro at concentrations similar to the VEGF-A antibody fragment ranibizumab. Exon8apab can inhibit tumour growth of LS174t cells implanted in vivo and blood vessel growth in the eye in models of age-related macular degeneration, with equal efficacy to non-selective anti-VEGF-A antibodies. It also showed that it was the VEGF-Axxx levels specifically that were upregulated in plasma from patients with proliferative diabetic retinopathy. These results suggest that VEGF-A165-specific antibodies can be therapeutically useful.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs / genetics
  • Angiogenesis Inhibitors / pharmacology*
  • Antibodies / pharmacology*
  • Cell Movement / drug effects
  • Dose-Response Relationship, Drug
  • Enzyme-Linked Immunosorbent Assay
  • Human Umbilical Vein Endothelial Cells
  • Humans
  • Neovascularization, Pathologic / prevention & control*
  • Protein Isoforms / antagonists & inhibitors
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Vascular Endothelial Growth Factor A / antagonists & inhibitors*
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism

Substances

  • Angiogenesis Inhibitors
  • Antibodies
  • Protein Isoforms
  • Vascular Endothelial Growth Factor A