MOLECULAR MECHANISMS OF CELL SUBSTRATE INTERACTIONS

细胞基质相互作用的分子机制

• 批准号: 5201819
• 负责人: S K AKIYAMA
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF DENTAL & CRANIOFACIAL RESEARCH
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/5201819
• 关键词: athymic mouse; biophysics; breast neoplasms; cell adhesion; cell adhesion molecules; cell cell interaction; cell migration; cellular pathology; collagen; conformation; embryogenesis; fibronectins; human tissue; integrins; laminin; ligands; molecular pathology; monoclonal antibody; neoplastic cell; neoplastic process; nuclear magnetic resonance spectroscopy; protein sequence; protein structure function; receptor binding; wound healing

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.

纤维连接蛋白和整合素受体在这一过程中起重要作用 如胚胎发育、伤口愈合和癌症进展。 涉及单克隆抗体、分子和细胞生物学、 和物理生物化学用于阐明分子机制， 纤连蛋白-受体相互作用的长期目标， 新的生物粘附基质和开发用于医学的合理基质 干预涉及异常细胞粘附的疾病， 迁移 纤连蛋白的中央细胞结合区需要两个 不同的活性序列：RGD序列和协同序列 顺序 人纤连蛋白20kDa细胞粘附片段 纤维连接蛋白和含有RGD和协同细胞粘附位点 已被克隆并表达。 尽管该片段在 可溶形式，当直接吸附到 塑料基材。 完全细胞粘附活性可以恢复，如果 20 kDa片段与非抑制性抗纤连蛋白抗体结合 预吸附到塑料上，这表明适当的介绍小 纤连蛋白片段对于最大的细胞粘附活性可能是重要的。 一个类似的小鼠20 kDa细胞粘附片段的结构， 溶液通过NMR光谱技术测定。 这是一 最大的多肽高分辨率结构的尝试日期。 到目前为止获得的信息表明，协同作用和RGD位点确实 不互动。 某些与整联蛋白结合的单克隆抗体可以 上调其配体结合活性。一种这样的激活抗体 命名为12G10，似乎与"配体诱导的"构象结合。 的 人α 5 β 1整联蛋白在实验性转移中的作用已经被 使用抑制性抗α 5和抗β 1单克隆抗体分析 抗体的 两种抗体均抑制人乳腺癌转移 无胸腺裸鼠中的细胞。 α 5 β 1整联蛋白可能是 在转移级联的几个步骤中，包括在肿瘤细胞中， 附着、迁移和外渗。 功能的调节 一组人乳腺癌细胞对α 2 β 1整合素的作用 被检查过了 这种整合素被发现存在于 在所有测试的细胞上细胞粘附于胶原。 非恶性 和/或分化良好的细胞也使用α 2 β 1整联蛋白 粘附于层粘连蛋白。 相比之下，高度侵入性和/或不良 分化的细胞不能，这表明， α 2 β 1整联蛋白在恶性进展过程中可被调节。