The antiangiogenic agent Neovastat (AE-941) stimulates tissue plasminogen activator activity.
The plasminogen activator/plasmin system represents a key component of the proteolytic machinery underlying angiogenesis. In this work, we investigated the effect of Neovastat (AE-941), a naturally occurring multifunctional antiangiogenic agent that is currently in Phase III clinical trials, on tissue and urokinase plasminogen activator activities. We found that in vitro, Neovastat at 100 microg/ml markedly stimulates t-PA-mediated plasmin generation, while it slightly inhibits the generation of plasmin mediated by uPA. The stimulatory effect of Neovastat on t-PA activity was markedly increased by a heat treatment, resulting in a 15-fold increase in the rate of activation of plasminogen. Neovastat did not directly stimulate the activity of t-PA or plasmin towards exogenous substrates, suggesting that its effect requires the presence of plasminogen. Accordingly, kinetic analysis showed that Neovastat increases both the k(cat) of t-PA as well as its affinity for plasminogen by 10-fold. The stimulation of t-PA activity by Neovastat was also correlated with a direct interaction of Neovastat with plasminogen as monitored by the surface plasmon resonance technology. Overall, these results identify Neovastat as a potent stimulator of t-PA-dependent activation of plasminogen, further emphasizing its pleiotropic mechanism of action on several molecular events involved in angiogenesis.
Gingras
Denis
D
Laboratoire de médecine moléculaire, Hôpital Ste-Justine-UQAM, Centre de cancérologie Charles-Bruneau, Centre de Recherche de l'Hôpital Ste-Justine, 3175, Chemin Côte-Ste-Catherine, Montréal, Québec, (Canada) H3T 1C5.
Labelle
Dominique
D
Nyalendo
Carine
C
Boivin
Dominique
D
Demeule
Michel
M
Barthomeuf
Chantal
C
Béliveau
Richard
R
D020533:Angiogenesis Inhibitors / Q000737:chemistry*; D002384:Catalysis; D005341:Fibrinolysin / Q000737:chemistry; D006358:Hot Temperature; D010958:Plasminogen / Q000737:chemistry; D014020:Tissue Extracts / Q000737:chemistry*; D010959:Tissue Plasminogen Activator / Q000737:chemistry*; D014568:Urokinase-Type Plasminogen Activator / Q000737:chemistry*
D020533:Angiogenesis Inhibitors; D014020:Tissue Extracts; C111481:shark cartilage extract; D010958:Plasminogen; D010959:Tissue Plasminogen Activator; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator