[Role of PAI-1 plasminogen activator inhibitor in tumor invasion and angiogenesis].

The plasminogen/plasmin system plays a key role in cancer progression, presumably via mediating extracellular matrix degradation and tumor cell migration. High levels of components of the plasminogen activation system, and paradoxically also its inhibitor, plasminogen activator inhibitor 1 (PAI-1), have been correlated with a poor prognosis for patients with cancers of different types. Recent findings clearly suggest that PAI-1 is essential for capillary sprouting during tumor angiogenesis. Moreover, there is an accumulating evidence that both the urokinase receptor and PAI-1 are multifunctional proteins involved not only in extracellular matrix proteolysis, but also in cellular adhesion and migration through their binding site for vitronectin. The understanding of whether PAI-1 plays a regulatory role in angiogenesis by tightly controlling proteolytic activity, or by influencing cell migration, could allow a new anti-angiogenic approach for tumor therapy.