Blockage of urokinase receptor reduces in vitro the motility and the deformability of endothelial cells

Abstract

The binding of urokinase (u-PA) to its cell surface receptor (u-PAR) is critical for tumor cell invasion. Here, we report that the disruption of this binding by an u-PAR antagonist ATF-HSA inhibits in vitro the motility of endothelial cells in a dose-dependent manner. This inhibition was also observed when the cells were first stimulated with potent angiogenic factors, including bFGF or VEGF.[3H]thymidine incorporation assay demonstrated that ATF-HSA did not affect the cell proliferation. ATF-HSA was more potent than plasmin inhibitors, suggesting that it exerts its effects not solely by inhibiting the remodeling of the extracellular matrix. In fact, analysis of the cell shape change during migration revealed for the first time that its effect is related to a decrease in cell deformability. These results suggest that u-PAR antagonist may be a new approach to control angiogenesis.

Adenovirus-mediated delivery of a uPA/uPAR antagonist suppresses angiogenesis-dependent tumor growth and dissemination in mice

“…47,48 It is also considered that such a strategy will benefit from the availability of viral vectors allowing long-term transgene expression to increase efficacy. 49,50 Finally, since activated endothelial cells 5,51 and most solid tumors express uPAR, virus-mediated ATF delivery, alone or in combination therapies with cytotoxic strategies (for example, see Ref. 30), may be particularly potent because this broad cell invasion inhibitor is more than an inhibitor of angiogenesis sensus stricto.…”

“…3 The delivery of a secreted inhibitor of tumor angiogenesis with an adenovirus would thus represent a conceptually different, possibly synergistic, approach to fight cancer. Peptidic angiogenesis inhibitors such as angiostatin, 4 uPA/uPAR antagonists, 5,6 platelet factor-4, 7 or thrombospondin 8 have been described. Among them, the amino-terminal fragment of urokinase (ATF) is of particular interest because it can also exert a direct effect on the tumor cells and inhibit metastasis in experimental models.…”

Urokinase-type plasminogen activator induces proliferation in breast cancer cells

“…The established role of uPA in breast cancer is to proteolytically cleave the extracellular matrix (3). Furthermore, interaction of uPA to uPAR is important for adhesion, motility and migration of cells (4). It was assumed that uPA can exert cytokine-like activity by increasing the proliferation of human epidermal tumor cells and malignant renal cells (5,6).…”

Human breast adenocarcinoma cell lines promote angiogenesis by providing cells with uPA‐PAI‐1 and by enhancing their expression

“…Conditioned media were incubated in the absence or presence of amino-terminal fragment (ATF) of human urokinase at 200 mM. 25 The medium was renewed every 24 hr. After 4 days, using inverted microscope and focusing deeper into the gel, the number of elongated cells that have migrated into the collagen matrix were counted manually in different conditions and expressed as number of cells per cm 2 .…”