MOLECULAR MECHANISMS OF CELL SUBSTRATE INTERACTIONS

纤维连接蛋白和整合素受体在这一过程中发挥着重要作用。 如胚胎发育、伤口愈合和癌症的进展。 涉及单抗、分子和细胞生物学的技术， 和物理生物化学来阐明其分子机制。 纤维连接蛋白-受体相互作用与生产的长期目标 新型生物黏附基质及开发合理的医用基础 对涉及异常细胞黏附和 迁移。纤维连接蛋白的中央细胞结合区需要两个 活性的不同序列：RGD序列和协同作用 序列。20 kDa人纤维连接蛋白细胞黏附片段 纤维粘连蛋白，同时含有RGD和协同细胞粘附点 已经被克隆和表达。尽管该片段在 可溶的形式，当直接吸附到 塑料衬底。全细胞黏附活性可以在以下情况下恢复 20 kDa片段与非抑制性抗纤维连接蛋白抗体结合 预吸附在塑料上，建议适当呈现小 纤维连接蛋白片段对于最大的细胞黏附活性可能是重要的。 小鼠20 kDa细胞黏附片段的结构 溶液由核磁共振波谱技术确定。这是一个 迄今为止尝试的最大多肽高分辨率结构中的一种。 到目前为止获得的信息表明，Synergy和RGD站点确实 而不是互动。某些与整合素结合的单抗可以 上调它们的配体结合活性。一种这样的激活抗体 命名为12G10，似乎结合在“配体诱导”的构象上。这个 人α5β1整合素在实验性转移中的作用 抑制性抗α-5和抗-β1单抗分析 抗体。两种抗体对人乳腺癌转移的抑制作用 裸鼠体内的细胞。α5beta1整合素可能正在发挥作用 在包括肿瘤细胞在内的转移级联的几个步骤中 附着、迁移和渗出。函数的调制 一组人乳腺癌细胞的α2beta1整合素 被检查过了。这种整合素被发现存在并在 所有测试细胞上的细胞与胶原蛋白的粘附性。非恶性的 和/或分化良好的细胞也使用α2beta1整合素 粘附层粘连蛋白。相比之下，高度侵袭性和/或很差 分化的细胞不能，这表明配体的特异性 α2β1整合素在恶性进展过程中可能受到调控。

Fibronectin and integrin receptors play important roles in such processes as embryonic development, wound healing, and the progression of cancer. Techniques involving monoclonal antibodies, molecular and cell biology, and physical biochemistry are used to elucidate molecular mechanisms of fibronectin-receptor interactions with the long-term goals of producing novel bioadhesive substrates and developing rational bases for medical intervention in diseases involving abnormal cellular adhesion and migration. The central cell-binding region of fibronectin requires two distinct sequences for activity: an RGD sequence and a synergistic sequence. A 20 kDa fibronectin cell adhesive fragment of human fibronectin and containing both the RGD and synergy cell adhesive sites has been cloned and expressed. Although the fragment is highly active in soluble form, it has only poor activity when adsorbed directly onto plastic substrates. Full cell adhesive activity can be recovered if the 20 kDa fragment is bound to a non-inhibitory anti-fibronectin antibody pre-adsorbed onto plastic, suggesting that proper presentation of small fibronectin fragments may be important for maximal cell adhesive activity. The structure of a similar murine 20 kDa cell adhesive fragment in solution is being determined by NMR spectroscopic techniques. This is one of the largest polypeptide high-resolution structures attempted to date. Information obtained so far indicates that the synergy and RGD sites do not interact. Certain monoclonal antibodies that bind to integrins can up-regulate their ligand-binding activity. One such activating antibody designated 12G10, appears to bind to a "ligand induced" conformation. The role of the human alpha5beta1 integrin in experimental metastasis has been analyzed using inhibitory anti-alpha5 and anti-beta1 monoclonal antibodies. Both antibodies inhibit metastasis of human breast carcinoma cells in athymic nude mice. The alpha5beta1 integrin may be functioning in several steps of the metastatic cascade including in tumor cell attachment, migration, and extravasation. The modulation of the function of the alpha2beta1 integrin by a panel of human breast carcinoma cells has been examined. This integrin was found to be present and to function in cell adhesion to collagen on all of the cells tested. The non-malignant and/or well differentiated cells also used the alpha2beta1 integrin for adhesion to laminin. In contrast, highly invasive and/or poorly differentiated cells could not, suggesting that the ligand specificity of the alpha2beta1 integrin could be regulated during malignant progression.