title: The antiangiogenic agent Neovastat (AE-941) stimulates tissue plasminogen activator activity.
abstract: 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.
authors.affiliation: 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.
authors.forename: Denis
authors.initials: D
authors.lastname: Gingras
authors.forename: Dominique
authors.initials: D
authors.lastname: Labelle
authors.forename: Carine
authors.initials: C
authors.lastname: Nyalendo
authors.forename: Dominique
authors.initials: D
authors.lastname: Boivin
authors.forename: Michel
authors.initials: M
authors.lastname: Demeule
authors.forename: Chantal
authors.initials: C
authors.lastname: Barthomeuf
authors.forename: Richard
authors.initials: R
authors.lastname: Béliveau
mesh_terms: 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*
chemical_list: D020533:Angiogenesis Inhibitors; D014020:Tissue Extracts; C111481:shark cartilage extract; D010958:Plasminogen; D010959:Tissue Plasminogen Activator; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator