尿激酶是两种血纤维蛋白溶酶原激活剂(PA)之一。它是一种丝氨酸蛋白酶,能使血纤维蛋白溶酶原转变为血纤维蛋白酶而令其活化。因此,尿激酶能调节许多需要胞外蛋白水解作用的变化,如细胞迁移、组织重塑(remodeling)与组织内卷(involu-tion)等。胞外蛋白水解对于肿瘤细胞表达侵袭与转移的恶性表型可能是必要的。许多转化细胞系分泌较大量尿激酶,即与此模式相符合。单核细胞的生理功能要求细胞迁移。这些细胞必须离开血流,进入邻近组织,才能分化成巨噬细胞并参加吞噬作用。血纤维蛋白溶酶原激活剂通过促进基底膜的溶解与细胞间桥的断裂而可能加速这种连续变化的早期阶段。Vassalli等最近的报告证 Urokinase is one of two plasminogen activators (PA). It is a serine protease that activates the conversion of plasminogen to fibrin. Therefore, urokinase regulates many of the changes that require extracellular proteolysis, such as cell migration, remodeling and involu- tion of tissue. Extracellular proteolysis may be necessary for malignant phenotypes in which tumor cells express invasion and metastasis. Many transformed cell lines secrete larger amounts of urokinase, which is consistent with this model. The physiological function of monocytes requires cell migration. These cells must leave the bloodstream and enter adjacent tissues to differentiate into macrophages and participate in phagocytosis. Plasminogen activators may accelerate the early stages of this continuous change by promoting lysis of the basement membrane and breaking of the intercellular bridges. Vassalli and other recent report card