McCarthy J B, Hagen S T, Furcht L T
J Cell Biol. 1986 Jan;102(1):179-88. doi: 10.1083/jcb.102.1.179.
The active migration of tumor cells through extracellular matrices has been proposed to play a role in certain aspects of metastasis. Metastatic tumor cells migrate in vitro in response to substratum-bound adhesive glycoproteins such as fibronectin. The present studies use affinity-purified proteolytic fragments of fibronectin to determine the nature of adhesion- and/or motility-promoting domains within the protein. Two distinct fragments were identified with cell adhesion-promoting activities. By a number of criteria, the adhesive activity promoted by these two fragments was distinct. One fragment, a 75-kD tryptic fragment purified by monoclonal antibody chromatography, promoted the adhesion, spreading, and haptotactic motility of melanoma cells. Experiments using a synthetic cell attachment peptide in solution indicated that at least part of the attachment activity exhibited by the 75-kD fragment is mediated by the sequence arg-gly-asp-ser. It was not possible to demonstrate migration-stimulating activity using a small (11.5 kD) peptic fragment containing this sequence (Pierschbacher, M.D., E. G. Hayman, and E. Ruoslahti, 1981, Cell, 26:259-267) suggesting that another cell-binding activity within the 75 kD fragment distinct from arg-gly-asp-ser might be required for motility. The second fragment that stimulated melanoma adhesion was a 33-kD tryptic/catheptic carboxyl-terminal heparin-binding fragment, which is localized to the A chain of fibronectin. This fragment promotes adhesion and spreading but not the motility of these cells. Melanoma adhesion to this heparin-binding fragment was sensitive to the effects of cycloheximide, which contrasted adhesion to the haptotaxis-promoting fragment. Importantly, these studies illustrate that haptotaxis in response to fibronectin is not due to simple adhesion gradients of this protein. The results are discussed in light of a model for multiple distinct cell surface constituents mediating cell adhesion and motility on fibronectin.
肿瘤细胞通过细胞外基质的主动迁移被认为在转移的某些方面发挥作用。转移性肿瘤细胞在体外对诸如纤连蛋白等与基质结合的粘附糖蛋白产生反应而迁移。本研究使用亲和纯化的纤连蛋白蛋白水解片段来确定该蛋白内促进粘附和/或运动的结构域的性质。鉴定出两个具有促进细胞粘附活性的不同片段。根据多种标准，这两个片段促进的粘附活性是不同的。一个片段是通过单克隆抗体色谱法纯化的75-kD胰蛋白酶片段，它促进黑色素瘤细胞的粘附、铺展和趋触性运动。使用溶液中的合成细胞附着肽进行的实验表明，75-kD片段表现出的附着活性至少部分是由精氨酸-甘氨酸-天冬氨酸-丝氨酸序列介导的。使用包含该序列的小（11.5 kD）胃蛋白酶片段无法证明其具有迁移刺激活性（皮尔斯巴赫，医学博士，E.G.海曼，和E.鲁斯拉蒂，1981年，《细胞》，26:259 - 267），这表明75 kD片段中可能需要不同于精氨酸-甘氨酸-天冬氨酸-丝氨酸的另一种细胞结合活性来促进运动。第二个刺激黑色素瘤细胞粘附的片段是一个33-kD胰蛋白酶/组织蛋白酶羧基末端肝素结合片段，它定位于纤连蛋白的A链。这个片段促进这些细胞的粘附和铺展，但不促进其运动。黑色素瘤细胞对这个肝素结合片段的粘附对放线菌酮的作用敏感，这与对促进趋触性片段的粘附形成对比。重要的是，这些研究表明对纤连蛋白的趋触性并非由于该蛋白简单的粘附梯度。根据一个模型讨论了结果，该模型认为多种不同的细胞表面成分介导细胞在纤连蛋白上的粘附和运动。
