Human ECV304 cells respond reproducibly by tube formation to complex basement membrane matrices. Laminins are major glycoproteins of basement membranes. We therefore studied the ability of ECV304 cells to attach to defined laminin isoforms and to fibronectin, and identified the involved laminin receptors. The cells bound poorly to fibronectin, to some extent to laminin-1, whereas laminin-2/4 and -10/11 were strong adhesive substrates. Antibody perturbation assays showed that adhesion to laminin-1 was mediated by integrin alpha6beta1, and adhesion to laminin-2/4 by cooperative activity of integrins alpha3beta1 and alpha6beta1. Adhesion of ECV 304 cells to laminin-10/11 was mainly mediated by integrins alpha3beta1, with minor involvement of alpha6beta1/4 and alphavbeta3. Solid-phase binding assays confirmed that integrin alphavbeta3 binds human laminin-10/11 and -10, in an RGD-dependent fashion. Although integrin alphavbeta3 played a very minor role in cell adhesion to laminin-10/11, this interaction facilitated growth factor-induced proliferation of ECV304 cells. In response to FGF-2 or VEGF, the cells proliferated better when attached on laminin-10/11 than on laminin-1, -2/4, or gelatin. The proliferation induced by the joint application of laminin-10/11 and either one of the growth factors could be blocked by antibodies against integrin alphavbeta3. Fragments of several other basement membrane components are known to interact with alphavbeta3. The current data show that that integrin alphavbeta3 can bind intact alpha5-containing laminin trimers. Since the laminin alpha5 chain is broadly expressed in adult basement membranes, this interaction could be physiologically important. Our data suggest that this interaction is involved in the regulation of cellular responses to growth factors known to be involved in epithelial and endothelial development.

中文翻译：

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整联蛋白αvbeta3绑定到人类α5-laminins促进FGF-2和VEGF诱导的人类ECV304癌细胞增殖。

人类ECV304细胞通过管形成对复杂的基底膜基质具有可再现的反应。层粘连蛋白是基底膜的主要糖蛋白。因此，我们研究了ECV304细胞附着于定义的层粘连蛋白同工型和纤连蛋白的能力，并确定了涉及的层粘连蛋白受体。细胞与纤连蛋白的结合较弱，在一定程度上与层粘连蛋白-1结合，而层粘连蛋白2/4和-10/11是牢固的粘附底物。抗体扰动试验表明，整合素α6beta1介导了层粘连蛋白-1的粘附，整合素α3beta1和α6beta1的协同活性介导了层粘连蛋白-2/4的粘附。ECV 304细胞对层粘连蛋白10/11的粘附主要是由整合素alpha3beta1介导的，而α6beta1/ 4和alphavbeta3的参与较小。固相结合测定法证实整联蛋白αvbeta3以RGD依赖性方式结合人层粘连蛋白-10/11和-10。尽管整联蛋白αvbeta3在细胞与层粘连蛋白10/11的粘附中起着很小的作用，但这种相互作用促进了生长因子诱导的ECV304细胞的增殖。对FGF-2或VEGF的反应是，当粘附在层粘连蛋白10/11上时，细胞的增殖比层粘连蛋白1，-2 / 4或明胶上的细胞增殖更好。层粘连蛋白10/11和任一生长因子联合应用诱导的增殖可被抗整联蛋白alphavbeta3的抗体阻断。已知其他几种基底膜成分的片段会与alphavbeta3相互作用。当前数据表明，整联蛋白αvbeta3可以结合完整的含α5层粘连蛋白三聚体。由于层粘连蛋白α5链在成人基底膜中广泛表达，因此这种相互作用在生理上可能很重要。我们的数据表明，这种相互作用参与了细胞对已知参与上皮和内皮发育的生长因子的反应的调节。