Spreading and Focal Contact Formation of Human Melanoma Cells in Response to the Stimulation of Both Melanoma-associated Proteoglycan (NG2) and α4β1 Integrin
Spreading and Focal Contact Formation of Human Melanoma Cells in Response to the Stimulation of Both Melanoma-associated Proteoglycan (NG2) and α4β1 Integrin
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发表时间：
1995-05
期刊：
影响因子：
11.2
通讯作者：
J. Iida;A. M. Meijne;R. Spiro;E. Roos;L. Furcht;J. McCarthy
中科院分区：
文献类型：
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作者：
J. Iida;A. M. Meijne;R. Spiro;E. Roos;L. Furcht;J. McCarthy
摘要在这项研究中，我们评估了一个特定的黑色素瘤相关硫酸软骨素蛋白聚糖核心蛋白，称为NG 2，与α4β1整合素在人黑色素瘤细胞中的局部接触形成中的潜在作用。尽管黑色素瘤细胞粘附于用α4β1整联蛋白结合纤连蛋白合成肽CS 1-OVA或抗NG 2 mAb包被的基质，但在任一基质上均未观察到扩散或局灶性接触形成。然而，黑色素瘤细胞在包被有CS 1-OVA和抗NG 2 mAb的“嵌合基质”上扩散并形成局灶性接触，9.2.27，表明接合两种粘附受体通过重组细胞骨架改变了黑色素瘤细胞的粘附表型。这两种受体之间的协作是特异性的纤连蛋白，因为细胞粘附在涂有低浓度的层粘连蛋白和9.2.27或IV型胶原和9.2.27的基质上不能扩散，而细胞粘附在低浓度的纤连蛋白和9.2.27上表现出完全扩散的形态。两种选择性酪氨酸激酶抑制剂，染料木素和除莠霉素A，完全抑制细胞在涂有CS 1-OVA和9.2.27的基质上的铺展，表明酪氨酸激酶对于细胞铺展和焦点接触形成是重要的。当细胞培养在涂有CS 1-OVA和9.2.27的基质上时，两种蛋白质（Mr 130，000和120，000）以染料木素和除莠霉素A敏感的方式被酪氨酸磷酸化。这些蛋白质与pp 125 FAK或α4β1整联蛋白没有免疫学相关性。重要的是，当黑色素瘤细胞在用CS 1包被的基质上培养，然后用9.2.27缀合的微球珠刺激时，也观察到了焦点接触和应力纤维的形成，表明当每个受体在不同的和单独的基质上接合时，NG 2可以与α4β1整联蛋白协作。这些结果表明，NG 2在黑素瘤细胞中作为与α4β1整联蛋白相关的扩散和局灶性接触形成的辅助受体，并提出了一种模型，其中NG 2核心蛋白通过由内而外的信号传导机制与α4β1整联蛋白通讯。
Abstract In this study, we evaluated the potential role for a specific melanoma-associated chondroitin sulfate proteoglycan core protein, termed NG2, to collaborate with α4β1 integrin in focal contact formation in human melanoma cells. Although melanoma cells adhered to substrata coated with either the α4β1 integrin binding fibronectin synthetic peptide CS1-OVA or anti-NG2 mAbs, no spreading or focal contact formation was observed on either substratum. However, melanoma cells spread and formed focal contacts on “chimeric substrata” coated with CS1-OVA and the anti-NG2 mAb, 9.2.27, indicating that engaging both adhesion receptors changes the adhesion phenotype of melanoma cells by reorganizing the cytoskeleton. The collaboration between the two receptors is specific to fibronectin, since cells adherent on substrata coated with low concentrations of either laminin and 9.2.27 or type IV collagen and 9.2.27 falled to spread, while cells adherent on low concentrations of fibronectin and 9.2.27 exhibited a fully spread morphology. Two selective tyrosine kinase inhibitors, genistein and herbimycin A, totally inhibited cell spreading on the substrata coated with CS1-OVA and 9.2.27, indicating that tyrosine kinase(s) is important for cell spreading and focal contact formation. When cells were cultured on substrata coated with CS1-OVA and 9.2.27, two proteins ( M r 130,000 and 120,000) were tyrosine phosphorylated in a genistein- and herbimycin A-sensitive fashion. These proteins were not immunologically related to pp125 FAK or α4β1 integrin. Importantly, when melanoma cells were cultured on substrata coated with CS1 and then stimulated with 9.2.27-conjugated microsphere beads, formation of focal contacts and stress fibers was also observed, indicating that NG2 can collaborate with α4β1 integrin when each receptor is engaged on distinct and separate substrata. These results demonstrate that NG2 acts as a coreceptor for spreading and focal contact formation in association with α4β1 integrin in melanoma cells and suggest a model in which the NG2 core protein communicates to α4β1 integrin by an inside-out signaling mechanism.