The antiangiogenic agent neovastat (AE-941) inhibits vascular endothelial growth factor-mediated biological effects.
OBJECTIVE
Vascular endothelial growth factor (VEGF) is a potent regulator of angiogenesis, which exerts direct effects on vascular endothelial cells, including endothelial cell proliferation and survival, tubulogenesis, and vascular permeability. In this study, we examined whether Neovastat, a naturally occurring multifunctional antiangiogenic drug, could inhibit the endothelial cell response to VEGF stimulation.


RESULTS
We demonstrated that Neovastat was able to block the VEGF-dependent microvessel sprouting from Matrigel-embedded rat aortic rings, and it also blocked the VEGF-induced endothelial cell tubulogenesis in vitro. In vivo studies showed that Neovastat was able to specifically inhibit VEGF-induced plasma extravasation in numerous tissues, including pancreas and skin. The mechanism of action of Neovastat on VEGF-mediated effects was also evaluated at the molecular level. Neovastat was shown to compete against the binding of VEGF to its receptor in endothelial cells and significantly inhibited the VEGF-dependent tyrosine phosphorylation of VEGF receptor-2, whereas it had no significant effect on VEGF receptor-1 activity. Moreover, the inhibition of receptor phosphorylation was correlated with a marked decrease in the ability of VEGF to induce pERK activation. Neovastat does not compete against the binding of basic fibroblast growth factor, indicating a preferential inhibitory effect on the VEGF receptor.


CONCLUSIONS
Because Neovastat was shown previously to inhibit metalloproteinase activities, these results suggest that Neovastat is able to target multiple steps in tumor neovascularization, further emphasizing its use as a pleiotropic, multifunctional antiangiogenic drug.
Béliveau
Richard
R
Laboratoire de Médecine Moléculaire, Hôpital Ste-Justine-UQAM, Centre de Cancérologie Charles-Bruneau, Centre de Recherche de l'Hôpital Ste-Justine, Montréal, Québec, H3T 1C5 Canada.
Gingras
Denis
D
Kruger
Erwin A
EA
Lamy
Sylvie
S
Sirois
Pierre
P
Simard
Bryan
B
Sirois
Martin G
MG
Tranqui
Leone
L
Baffert
Fabienne
F
Beaulieu
Edith
E
Dimitriadou
Violetta
V
Pépin
Marie-Claude
MC
Courjal
Frank
F
Ricard
Isabelle
I
Poyet
Patrick
P
Falardeau
Pierre
P
Figg
William D
WD
Dupont
Eric
E
D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000254:growth & development; D002196:Capillaries / Q000187:drug effects / Q000254:growth & development; D002199:Capillary Permeability / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D016228:Endothelial Growth Factors / Q000378:metabolism / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008222:Lymphokines / Q000378:metabolism / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D017978:Receptors, Growth Factor / Q000378:metabolism; D040262:Receptors, Vascular Endothelial Growth Factor; D014020:Tissue Extracts / Q000494:pharmacology*; D014443:Tyrosine / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D020533:Angiogenesis Inhibitors; D016228:Endothelial Growth Factors; D008222:Lymphokines; D017978:Receptors, Growth Factor; D014020:Tissue Extracts; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; C111481:shark cartilage extract; D014443:Tyrosine; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor