Urokinase induces proliferation of human ovarian cancer cells: characterization of structural elements required for growth factor function

Abstract

Ovarian cancer metastasis is associated with an increase in the urokinase-type plasminogen activator (uPA) and its receptor uPAR. We present evidence that binding of uPA to uPAR provokes a mitogenic response in the human ovarian cancer cell line OV-MZ-6 in which endogenous uPA production had been significantly reduced by stable uPA`antisense' transfection. High molecular weight (HMW) uPA, independent of its enzymatic activity, produced an up to 95% increase in cell number concomitant with 2-fold elevated [Q H]thymidine incorporation as did the catalytically inactive but uPAR binding amino-terminal fragment of uPA, ATF. uPA-induced cell proliferation was significantly decreased by blocking uPA/uPAR interaction by the monoclonal antibody IIIF10 and by soluble uPAR. The efficiency of the uPAR binding synthetic peptide cyclo IWYQI uPA IWÀQI to enhance OV-MZ-6 cell growth proved this molecular domain to be the minimal structural determinant for uPA mitogenic activity. Dependence of uPA-provoked cell proliferation on uPAR was further demonstrated in Raji cells which do not express uPAR and were thus not induced by uPA. However, upon transfection with full-length uPAR, Raji cells acquired a significant growth response to HMW uPA and ATF.z 1998 Federation of European Biochemical Societies.

Elevated expression of polymorphonuclear leukocyte elastase in breast cancer tissue is associated with tamoxifen failure in patients with advanced disease

“…The underlying mechanisms explaining why the primary tumour level of PMN-E is associated with the efficacy of tamoxifen therapy in advanced disease is unclear. In addition to its described role in tumour cell invasion and metastasis, the serine protease PMN-E may, similar as has been suggested for uPA for human ovarian carcinoma cells (Fischer et al, 1998) and breast cancer cells (Foekens et al, 1995), provoke cell proliferation via enzymatic activation of several growth factor (receptor) pathways. In this respect, the ability of elastase to cleave or activate several growth factors or receptors, such as EGF and EGF receptor (Di Camillo et al, 2002), IL-2 and IL-6 receptor (Bank et al, 1999), stromal cellderived factor-1 (Valenzuela-Fernandez et al, 2002), supports such a local elastase-directed growth interfering mechanism.…”

Design of Novel and Selective Inhibitors of Urokinase-type Plasminogen Activator with Improved Pharmacokinetic Properties for Use as Antimetastatic Agents

“…However, in osteosarcoma cells and also in human ovarian cancer cells, the mitogenlike function of uPA was independent of its enzymatic activity. In addition the N-terminal fragment or uPA-derived peptides also exerted a mitogenic effect (52,53). …”

Cyclo19,31[D-Cys19]-uPA19-31 Is a Potent Competitive Antagonist of the Interaction of Urokinase-Type Plasminogen Activator with Its Receptor (CD87)

“…Briefly, fibrin gels were prepared in 24-well cell culture plates by incubating 200 µl of 50 mg/ml plasminogen-depleted fibrinogen (Calbiochem, Frankfurt, Germany), 50 µl of 150 mM CaCl 2 , and 50 µl of 60 U/ml thrombin (Novagen, Schwalbach, Germany) for 1 h at 37°C. uPA-producing ovarian cancer OV-MZ-6 cells (Möbus et al, 1992;Fischer et al, 1998) were seeded on top of the fibrin gel (4 × 10 4 cells/well) in the presence of plasminogen (2 µg/ml medium) and varying amounts of the respective synthetic uPA-peptides. As controls, the inhibitory monoclonal antibody against human uPA B-chain, mAb # 394 (10 µg/ml), or the amino-terminal fragment of uPA, ATF (2 µg/ml) (both from American Diagnostica, Pfungstadt, Germany) were used.…”