A therapeutic aptamer inhibits angiogenesis by specifically targeting the heparin binding domain of VEGF165.
Aptamers recognize their targets with extraordinary affinity and specificity. The aptamer-based therapeutic, Macugen, is derived from a modified 2'fluoro pyrimidine RNA inhibitor to vascular endothelial growth factor (VEGF) and is now being used to treat the wet form of age-related macular degeneration. This VEGF(165) aptamer binds specifically to the VEGF(165) isoform, a dimeric protein with a receptor-binding domain and a heparin-binding domain (HBD). To understand the molecular recognition between VEGF and this aptamer, binding experiments were used to show that the HBD contributes the majority of binding energy in the VEGF(165)-aptamer complex. A tissue culture-based competition assay demonstrated that the HBD effectively competes with VEGF(165) for aptamer binding in vivo. Comparison of NMR spectra revealed that structural features of the smaller HBD-aptamer complex are present in the full-length VEGF(164)-aptamer complex. These data show that the HBD provides the binding site for the aptamer and is the primary determinant for the affinity and specificity in the VEGF(165)-aptamer complex.
Lee
Joon-Hwa
JH
Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA.
Canny
Marella D
MD
De Erkenez
Andrea
A
Krilleke
Dominik
D
Ng
Yin-Shan
YS
Shima
David T
DT
Pardi
Arthur
A
Jucker
Fiona
F
D052157:Aptamers, Nucleotide / Q000494:pharmacology; D001665:Binding Sites; D001667:Binding, Competitive; D002478:Cells, Cultured; D019281:Dimerization; D004730:Endothelium, Vascular / Q000166:cytology; D006493:Heparin / Q000737:chemistry*; D006801:Humans; D008268:Macular Degeneration; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009389:Neovascularization, Pathologic; D010843:Pichia / Q000378:metabolism; D011092:Polyethylene Glycols / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D020033:Protein Isoforms; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011743:Pyrimidines / Q000494:pharmacology; D012313:RNA / Q000737:chemistry; D015398:Signal Transduction; D013816:Thermodynamics; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism / Q000502:physiology*
D052157:Aptamers, Nucleotide; D020033:Protein Isoforms; D011743:Pyrimidines; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C495058:pegaptanib; D011092:Polyethylene Glycols; D012313:RNA; D006493:Heparin