INTEGRIN RECEPTOR FOR LAMININ IN MALIGNANT MELANOMA

恶性黑色素瘤细胞必须穿过基底膜屏障 当他们从原发肿瘤逃脱时，当他们在 远处的微血管构筑。随着肿瘤细胞侵袭基底 膜，它们与层粘连蛋白相互作用，层粘连蛋白是一种主要的基底膜特异的 促进细胞附着和迁移的糖蛋白。这种互动 是由多种类型的黏附受体介导的。一种新型的整合素 特异性结合层粘连蛋白的受体复合体最近被 在人类和小鼠黑色素瘤细胞上鉴定。这种杂二聚体复合体具有 暂定名为字母7beta1。这个项目的总体目标是 建议分离并进一步鉴定这种独特的黑色素瘤- 相关的整合素，并确定该受体如何调节细胞 在层粘连蛋白和基底膜基质上的行为。字母7beta1 通过制备法从人黑色素瘤细胞中纯化受体复合体 配基亲和层析用于详细的免疫化学和生化 分析。受体在不同组织中的表达和分布 组织将被确定。正常人和正常人外周血中α7受体水平 在原发和转移性黑色素瘤中，将比较 为了建立受体表达与肿瘤之间可能的联系 进步。将不同的阿尔法亚基与其他亚基进行比较 已知的整合素β1相关α亚基的肽图和N- 末端氨基酸序列分析。Alpha7和Beta1亚基是如何 通过翻译后修饰进行处理，当配体结合时 活动是后天获得的将被遵循。关于隔离的子域的研究 层粘连蛋白将识别与Alpha7受体结合的特定位点。 阻断受体功能的抗体将被开发出来并进行测试 它们对黏附、迁移和入侵的影响。整合素受体 将对已建立的人类和小鼠黑色素瘤的图谱进行比较 具有高和低转移潜能的细胞系。变异型肿瘤图板 受体谱改变的细胞系将从亲本中选择 流式细胞仪检测细胞数量，并检测其侵袭行为。 这些研究应该会增加我们对层粘连蛋白结合方式的理解 受体，如新的α7复合体，影响转移 恶性黑色素瘤细胞的行为。

Malignant melanoma cells must penetrate the basement membrane barrier both when they escape from the primary tumor and when they arrest in the microvasculature at distant sites. As tumor cells invade basement membrane, they interact with laminin, a major basement-membrane-specific glycoprotein that promotes cell attachment and migration. This interaction is mediated by multiple types of adhesion receptors. A novel integrin receptor complex that specifically binds laminin has recently been identified on human and mouse melanoma cells. This heterodimer complex has been tentatively designated alpha7beta1. The overall objectives of this proposal are to isolate and further characterize this unique melanoma- associated integrin, and to determine how this receptor modulates cell behavior on laminin and basement membrane substrates. The alpha7beta1 receptor complex will be purified from human melanoma cells by preparative ligand affinity chromatography for detailed immunochemical and biochemical analysis. The expression and distribution of the receptor in various tissues will be determined. Levels of the alpha7 receptor in normal and dysplastic nevi, and in primary and metastatic melanoma will be compared in order to establish a possible link between receptor expression and tumor progression. The distinctive alpha subunit will be compared with the other known integrin beta1-associated alpha subunits by peptide mapping and N- terminal amino acid sequence analysis. How the alpha7 and beta1 subunits are processed by post-translational modifications and when ligand binding activity is acquired will be followed. Studies with isolated subdomains of laminin will identify the specific sites that bind the alpha7 receptor. Antibodies that block receptor function will be developed and tested for their effects on adhesion, migration, and invasion. Integrin receptor profiles will be compared in sets of established human and mouse melanoma cell lines with high and low metastatic potential. Panels of variant tumor cell lines with altered receptor profiles will be selected from parental cell populations by flow cytometry and tested for their invasive behavior. These studies should increase our understanding of how laminin-binding receptors, such as the novel alpha7 complex, influence the metastatic behavior of malignant melanoma cells.