Interaction of vasculotropin/vascular endothelial cell growth factor with human umbilical vein endothelial cells: binding, internalization, degradation, and biological effects.
Vasculotropin/vascular endothelial cell growth factor (VAS/VEGF) is a newly purified growth factor with a unique specificity for vascular endothelial cells. We have investigated the interactions of VAS/VEGF with human umbilical vein endothelial cells (HUVE cells). 125I-VAS/VEGF was found to HUVE cells in a saturable manner with a half-maximum binding at 2.8 ng/ml. Scatchard analysis did show two classes of high-affinity binding sites. The first class displayed a dissociation constant of 9 pM with 500 sites/cell. The dissociation constant and the number of binding sites of the second binding class were variable for different HUVE cell cultures (KD = 179 +/- 101 pM, 5,850 +/- 2,950 sites/cell). Half-maximal inhibition of 125I-VAS/VEGF occurred with a threefold excess of unlabeled ligand. Basic fibroblast growth factor (bFGF) and heparin did not compete with 125I-VAS/VEGF binding. In contrast, suramin and protamin sulfate completely displaced 125I-VAS/VEGF binding from HUVE cells. VAS/VEGF was shown to be internalized in HUVE cells. Maximum internalization (55% of total cell-associated radioactivity) was observed after 30 min. 125I-VAS/VEGF was completely degraded 2-3 hr after binding. At 3 hr, the trichloroacetic acid (TCA)-soluble radioactivity accumulated in the medium was 60% of the total radioactivity released by HUVE cells. No degradation fragment of 125I-VAS/VEGF was observed. Chloroquine completely inhibited degradation. VAS/VEGF was able to induce angiogenesis in vitro in HUVE cells. However, it did not significantly modulate urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor (PAI-1), and tissue factor (TF). Prostacyclin production was only stimulated at very high VAS/VEGF concentrations. Taken together, these results indicate that VAS/VEGF might be a potent inducer of neovascularization resulting from a direct interaction with endothelial cells. The angiogenic activity seems to be independent of the plasminogen activator or inhibitor system.
Bikfalvi
A
A
INSERM U 150, Hopital Lariboisière, Paris, France.
Sauzeau
C
C
Moukadiri
H
H
Maclouf
J
J
Busso
N
N
Bryckaert
M
M
Plouet
J
J
Tobelem
G
G
D002478:Cells, Cultured; D016228:Endothelial Growth Factors / Q000378:metabolism* / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011464:Epoprostenol / Q000378:metabolism; D006133:Growth Substances / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008222:Lymphokines / Q000378:metabolism* / Q000494:pharmacology; D009389:Neovascularization, Pathologic; D015849:Plasminogen Inactivators / Q000378:metabolism; D013925:Thromboplastin / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000378:metabolism; D014471:Umbilical Veins; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D006133:Growth Substances; D008222:Lymphokines; D015849:Plasminogen Inactivators; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D013925:Thromboplastin; D011464:Epoprostenol; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator