INTEGRIN RECEPTOR FOR LAMININ IN MALIGNANT MELANOMA

恶性黑色素瘤细胞必须穿透基底膜屏障， 当它们从原发肿瘤中逃逸， 远端微血管。 当肿瘤细胞侵入基底时 膜，它们与层粘连蛋白，一种主要的基底膜特异性 促进细胞附着和迁移的糖蛋白。 这种相互作用 由多种类型的粘附受体介导。 一种新的整合素 一种特异性结合层粘连蛋白的受体复合物， 在人类和小鼠黑色素瘤细胞上鉴定。 这种异二聚体复合物具有 暂时命名为α 7 β 1。 这一总体目标 建议是分离和进一步表征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 行为的层粘连蛋白和基底膜基板。 alpha7 beta1 受体复合物将通过制备性纯化从人黑素瘤细胞中纯化 配体亲和层析用于详细的免疫化学和生物化学 分析. 受体的表达和分布在不同的 组织将被确定。 正常人和正常人的α 7受体水平 发育不良痣，并在原发性和转移性黑色素瘤将进行比较， 为了建立受体表达和肿瘤之间的可能联系， 进展 独特的α亚基将与其他亚基进行比较。 已知的整联蛋白β 1相关α亚基通过肽图谱和N- 末端氨基酸序列分析。 alpha 7和beta1亚基 通过翻译后修饰进行加工， 活动将继续进行。 与孤立的子域的研究 层粘连蛋白将识别结合α 7受体的特异性位点。 阻断受体功能的抗体将被开发和测试， 它们对粘附、迁移和侵袭的影响。 整合素受体 将在已建立的人和小鼠黑色素瘤组中比较特征 具有高和低转移潜能的细胞系。 变体肿瘤的面板 具有改变的受体谱的细胞系将从亲本中选择 通过流式细胞术检测细胞群并测试它们的侵袭行为。 这些研究应该增加我们对层粘连蛋白结合 受体，如新的α 7复合物， 恶性黑素瘤细胞的行为。

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.