Zucker S, Mirza H, Conner C E, Lorenz A F, Drews M H, Bahou W F, Jesty J
Department of Research, Veterans Affairs Medical Center, Northport, NY 11768, USA.
Int J Cancer. 1998 Mar 2;75(5):780-6. doi: 10.1002/(sici)1097-0215(19980302)75:5<780::aid-ijc19>3.0.co;2-a.
Production of vascular endothelial growth factor (VEGF) by cancer cells at invasive and metastatic sites is an important aspect of tumor angiogenesis. Although known primarily as a mitogen and a vascular permeability factor (VPF) for endothelial cells, VEGF/VPF has been proposed to induce the expression of procoagulant factors in endothelial cells. In this study, we have explored the ramifications of VEGF induction of tissue factor (TF) in human umbilical vein endothelial cells (HUVECs) and subsequent activation of progelatinase A. Within 3 hr of incubation with VEGF/VPF, endothelial cells accelerate TF generation as measured using chromogenic substrate assays for coagulation factors Xa and thrombin. Incubation of VEGF/VPF-pre-treated cells with prothrombin and factors X, Va, and VIIa at 37 degrees C and subsequent generation of thrombin resulted in activation of secreted endothelial progelatinase A as demonstrated by gelatin zymography. Anti-thrombin III or antibodies to TF inhibited thrombin generation and progelatinase A activation. VEGF/VPF also directly increased HUVEC secretion of interstitial collagenase, tissue inhibitor of metalloproteinases (TIMP-1) and, to a lesser extent, gelatinase A. The effect of thrombin on endothelial proliferation in serum-free media was examined. Thrombin was a growth factor for HUVECs at a lower dose than that required for progelatinase A activation. Whereas TIMP-2 abrogated thrombin-induced progelatinase A activation, it had no significant effect on thrombin-induced endothelial cell growth. We propose that an early step in tumor angiogenesis involves VEGF-induced thrombin generation and increased MMP production with subsequent activation of endothelial progelatinase A and degradation of the underlying basement membrane.
癌细胞在侵袭和转移部位产生血管内皮生长因子（VEGF）是肿瘤血管生成的一个重要方面。尽管VEGF主要作为内皮细胞的促有丝分裂原和血管通透性因子（VPF）为人所知，但有人提出VEGF/VPF可诱导内皮细胞中促凝血因子的表达。在本研究中，我们探讨了VEGF诱导人脐静脉内皮细胞（HUVECs）中组织因子（TF）以及随后激活前胶原酶A的影响。在用VEGF/VPF孵育3小时内，通过使用针对凝血因子Xa和凝血酶的显色底物测定法测量，内皮细胞加速了TF的生成。将用VEGF/VPF预处理的细胞与凝血酶原以及因子X、Va和VIIa在37℃下孵育，随后产生凝血酶，这导致了分泌的内皮前胶原酶A的激活，明胶酶谱法证明了这一点。抗凝血酶III或针对TF的抗体抑制了凝血酶的生成和前胶原酶A的激活。VEGF/VPF还直接增加了HUVECs间质胶原酶、金属蛋白酶组织抑制剂（TIMP-1）的分泌，并且在较小程度上增加了明胶酶A的分泌。研究了凝血酶对无血清培养基中内皮细胞增殖的影响。凝血酶在比激活前胶原酶A所需剂量更低的剂量下是HUVECs的生长因子。虽然TIMP-2消除了凝血酶诱导的前胶原酶A激活，但它对凝血酶诱导的内皮细胞生长没有显著影响。我们提出肿瘤血管生成的早期步骤涉及VEGF诱导的凝血酶生成和MMP产生增加，随后激活内皮前胶原酶A并降解下层基底膜。
