Inhibition of endothelial cell movement and tubulogenesis by human recombinant soluble melanotransferrin: involvement of the u-PAR/LRP plasminolytic system.
We have previously demonstrated that human recombinant soluble melanotransferrin (hr-sMTf) interacts with the single-chain zymogen pro urokinase-type plasminogen activator (scu-PA) and plasminogen. In the present work, the impact of exogenous hr-sMTf on endothelial cells (EC) migration and morphogenic differentiation into capillary-like structures (tubulogenesis) was assessed. hr-sMTF at 10 nM inhibited by 50% the migration and tubulogenesis of human microvessel EC (HMEC-1). In addition, in hr-sMTf-treated HMEC-1, the expression of both urokinase-type plasminogen activator receptor (u-PAR) and low-density lipoprotein receptor-related protein (LRP) are down-regulated. However, fluorescence-activated cell sorting analysis revealed a 25% increase in cell surface u-PAR in hr-sMTf-treated HMEC-1, whereas the binding of the urokinase-type plasminogen activator (u-PA)*plasminogen activator inhibitor-1 (PAI-1) complex is decreased. This reduced u-PA-PAI-1 binding is correlated with a strong inhibition of the HMEC-1 plasminolytic activity, indicating that exogenous hr-sMTf treatment alters the internalization and recycling processes of free and active u-PAR at the cellular surface. Overall, these results demonstrate that exogenous hr-sMTf affects plasminogen activation at the cell surface, thus leading to the inhibition of EC movement and tubulogenesis. These results are the first to consider the potential use of hr-sMTf as a possible therapeutic agent in angiogenesis-related pathologies.
Michaud-Levesque
Jonathan
J
Laboratoire de Médecine Moléculaire, Service d'Hémato-Oncologie, Hôpital Ste-Justine-UQAM, C.P. 8888, Succursale Centre-ville, Montréal, Québec, Canada H3C 3P8.
Rolland
Yannève
Y
Demeule
Michel
M
Bertrand
Yanick
Y
Béliveau
Richard
R
D000951:Antigens, Neoplasm; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D015536:Down-Regulation; D042783:Endothelial Cells / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D026502:LDL-Receptor Related Proteins / Q000378:metabolism*; D058950:Melanoma-Specific Antigens; D008870:Microtubules / Q000502:physiology; D009363:Neoplasm Proteins / Q000494:pharmacology*; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D055293:Receptors, Urokinase Plasminogen Activator; D011994:Recombinant Proteins / Q000494:pharmacology; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism
D000951:Antigens, Neoplasm; D026502:LDL-Receptor Related Proteins; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins; C524898:PLAUR protein, human; D017395:Plasminogen Activator Inhibitor 1; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D011994:Recombinant Proteins; D014568:Urokinase-Type Plasminogen Activator