title: Angiogenic synergy of bFGF and VEGF is antagonized by Angiopoietin-2 in a modified in vivo Matrigel assay.
abstract: A murine modification of the Matrigel chamber assay originally developed for use on rats is presented. This modified assay permits improved quantification due to subcutaneous Matrigel implants of constant shape and volume. We have quantitatively assessed the angiogenic potential of the growth factors basic fibroblast growth factor (bFGF), VEGF, and Angiopoietin-2 (Ang-2) with special emphasis on their mutual interactions. A reproducible dose-response relationship for bFGF was established for doses between 150 and 1000 ng per chamber, whereas VEGF did not display angiogenic activity on its own in the tested dose of up to 200 ng per chamber. Conversely, we found a strong synergistic action of bFGF and VEGF when combined in a 3:1 ratio. Two other combinations (ratios) with greater VEGF doses were also tested, but the synergistic effect was only observed when 50 ng of VEGF was added to 150 ng per chamber of bFGF. This synergistic effect of bFGF and VEGF was significantly reduced by further addition of 100 ng Angiopoietin-2. Inhibition of the response to bFGF and VEGF was confirmed by in vitro EC migration experiments, which, together with our in vivo results, indicates that Ang-2 may target chemotactic responses to bFGF and VEGF in vivo.
authors.affiliation: Laboratory of Experimental Oncology, Institute of Molecular Pathology, University of Copenhagen, DK-2100 Copenhagen, Denmark.
authors.forename: Carsten D
authors.initials: CD
authors.lastname: Ley
authors.forename: Minna W B
authors.initials: MW
authors.lastname: Olsen
authors.forename: Eva L
authors.initials: EL
authors.lastname: Lund
authors.forename: Paul E G
authors.initials: PE
authors.lastname: Kristjansen
mesh_terms: D042702:Angiopoietin-2 / Q000502:physiology*; D000818:Animals; D002465:Cell Movement; D002478:Cells, Cultured; D002633:Chemotaxis; D003094:Collagen / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D042783:Endothelial Cells / Q000166:cytology; D004730:Endothelium, Vascular / Q000166:cytology; D016222:Fibroblast Growth Factor 2 / Q000502:physiology*; D006133:Growth Substances; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007797:Laminin / Q000494:pharmacology*; D008297:Male; D051379:Mice; D009389:Neovascularization, Pathologic; D011509:Proteoglycans / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000737:chemistry; D015398:Signal Transduction; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology*
chemical_list: D042702:Angiopoietin-2; D004338:Drug Combinations; D006133:Growth Substances; D007797:Laminin; D011509:Proteoglycans; D011994:Recombinant Proteins; D042461:Vascular Endothelial Growth Factor A; D016222:Fibroblast Growth Factor 2; C059485:matrigel; D003094:Collagen