我们调查了尿激酶（UK）及其细胞表面受体在决定前列腺癌细胞侵袭性方面的作用。我们测试了三种人类细胞系，DU-145、PC-3和LNCaP，它们在雄激素反应性和生长特性上有所不同。通过酶联免疫吸附试验对培养基的分析显示，DU-145（63 ng/mL/10（6）个细胞/48小时）和PC-3（682 ng/mL/10（6）个细胞/48小时）分泌了UK，但LNCaP细胞没有分泌。通过西方印迹分析和酶活性分析培养基，证实了这些结果。辣根配体结合Scatchard分析表明，在酸预处理细胞上存在单个高亲和力UK受体群，在DU-145细胞（93,000个位点/细胞，Kd = 0.9 nM）和PC-3细胞（25,000个位点/细胞，Kd = 1.0 nM）上但不在LNCaP细胞上。在体外侵袭实验中，DU-145和PC-3细胞具有高度的侵袭性：在无血清培养基中，约2 x 10（5）个细胞中的4.5 +/- 0.5％和6.5 +/- 0.5％，分别穿透了重构的基底膜（Matrigel）长达72小时孵育。在类似条件下，不到0.25％的LNCaP细胞穿透了Matrigel。这些数据表明具有高转移潜力的雄激素不敏感、侵略性前列腺肿瘤细胞DU-145和PC-3分泌UK并显示细胞表面UK受体，完全充满了蛋白酶。相比之下，转移潜力相对较低的相对温和的LNCaP细胞既不分泌UK也没有其结合位点。与前列腺细胞标记UK竞争结合但不抑制细胞增殖或UK分泌的UK受体拮抗剂UK 12-32和UK 6-135显著减少DU-145和PC-3细胞的侵袭（80-85％的抑制），因此提示受体结合的UK在前列腺肿瘤细胞侵袭中具有重要作用。

We have investigated the role of urokinase (UK) and its cell-surface receptor in determining the invasiveness of prostate cancer cells. Three human cell lines, DU-145, PC-3 and LNCaP, that differ in androgen-responsiveness and growth characteristics, were tested. Analysis of the conditioned medium by an enzyme-linked immunosorbent assay showed secretion of UK by DU-145 (63 ng/mL/10(6) cells/48 hr) and PC-3 (682 ng/mL/10(6) cells/48 hr), but absence of secretion by LNCaP cells. Western blot analysis and enzyme activity assay of the conditioned medium confirmed these results. Scatchard analysis of radioligand binding with acid pretreated cells showed the presence of a single population of high affinity UK receptors on DU-145 cells (93,000 sites/cell, Kd = 0.9 nM) and PC-3 cells (25,000 sites/cell, Kd = 1.0 nM) but not on LNCaP cells. DU-145 and PC-3 cells were found to be highly invasive in in vitro invasion assays: 4.5 +/- 0.5% and 6.5 +/- 0.5%, respectively, of total tumor cells (approximately 2 x 10(5)) had penetrated reconstituted basement membrane (Matrigel) in a 72 hr incubation in serum-free growth medium. Under similar conditions, less than 0.25% LNCaP cells invaded Matrigel. The data indicate that androgen unresponsive, aggressive prostate tumor cells of high metastatic potential, DU-145 and PC-3, secrete UK and display cell-surface UK receptors, fully charged with the protease. Conversely, relatively indolent LNCaP cells of low metastatic potential do not secrete UK nor do they possess its binding sites. UK receptor antagonists, UK 12-32 and UK 6-135, which compete with labeled UK for binding to prostatic cells but do not inhibit cellular proliferation or UK secretion, markedly reduced DU-145 and PC-3 cell invasion (80-85% inhibition), thereby suggesting an important role of receptor-bound UK in prostate tumor cell invasion.