INTEGRIN DISTRIBUTION AND FUNCTION IN TUMOR CELLS

整合素是一个复杂的细胞表面受体家族，参与这两个过程 细胞-基质和细胞-细胞黏附。大多数已知的整合素识别 细胞外基质配体，包括纤维连接蛋白、层粘连蛋白、胶原蛋白、 Vitronectin和Tenascin一些整合素介导细胞间的相互作用 通过与其他膜蛋白结合，如I-CAM。强有力的初步证据 表明与其他类型的细胞黏附受体一起， 整合素家族的许多成员与肿瘤转移有关。 整合素在几年前才被发现，从那时起，大约有20 这个主要基因家族的成员已经被描述过。的表达方式 其中大多数是发育调节的，在某些情况下是受限的 特定的细胞类型。很可能有很多额外的数字 这家人还没有被发现。更好地理解 肿瘤细胞整合素的结构和功能可能导致设计 抗击癌症的新诊断和/或治疗技术。 这项拟议研究的长期目标是分析 整合素与肿瘤转移作为第一步，分发 将研究不同转移潜能的肿瘤细胞中的整合素。 一种新的技术，基于同源的聚合酶链式反应扩增，将被用于 鉴定和克隆肿瘤细胞整合素。这项技术使它成为可能 克隆在特定细胞类型中表达的所有整合素，包括 之前身份不明的家庭成员。不变量的短范围 该家族所有已知成员所共有的氨基酸序列被用作 用于启动已知和新的整合素mRNA的聚合酶链式反应的引物 序列。由此产生的碎片混合对应于不同的 整合素被克隆到一个质粒载体中，单个克隆被 以DNA测序为特征的。克隆的cdna片段将用作 分析肿瘤细胞中整合素表达的初步探讨 不同的转移潜能，以及在肿瘤组织的切片中。整合素 Cdna片段也将以融合蛋白的形式在细菌中表达，这 将其注射到兔体内，以提高抗整合素抗体的水平 预先确定的专一性。这些抗体将是重要的工具 分析亚基的结合、加工和细胞表面表达 并研究整合素在正常组织和肿瘤中的分布。 纸巾。将分析肿瘤细胞整合素的功能特性 利用抗体或反义RNA技术在多种细胞黏附中的应用 以及入侵分析。这些研究将为更多的 通过在异源细胞中表达cDNA进行详细的功能分析。

Integrins are a complex family of cell surface receptors involved in both cell-matrix and cell-cell adhesion. Most of the known integrins recognize extracellular matrix ligands, including fibronectin, laminin, collagens, vitronectin, and tenascin. Some integrins mediate cell-cell interactions by binding to other membrane proteins, like I-CAM. Strong initial evidence suggests that along with other with other types of cell adhesion receptors, many members of the integrin family contribute to tumor metastasis. Integrins were discovered only a few years ago,and since then, about 20 members of this major gene family have been described. The expression of most of these is developmentally regulated, and in some cases restricted to a specific cell type. It is very likely that many additional numbers of the family are yet to be discovered. Improved understanding of the structure and function of tumor cell integrins might lead to the design of novel diagnostic and/or therapeutic techniques in the fight against cancer. The long-term objective of the proposed research is to analyze the role of integrins in tumor metastasis. As a first step, the distribution of integrins in tumor cells of different metastatic potential will be studied. A novel technique, homology-based PCR amplification, will be used to identify and clone tumor cell integrins. This technique makes it possible to clone all the integrins expressed in a given cell type, including previously unidentified members of the family. Short stretches of invariant amino acid sequence shared by all known members of the family are used as primers to initiate PCR amplification of both known and novel integrin mRNA sequences. The resulting mixture of fragments corresponding to different integrins is cloned into a plasmid vector, and individual clones are characterized by DNA sequencing. Cloned cDNA fragments will be used as probes to analyze the expression of integrins in cultured tumor cells of varying metastatic potential, and in sections of tumor tissues. Integrin cDNA fragments will also be expressed in bacteria as fusion proteins, which will be injected into rabbits to raise anti-integrin antibodies of predetermined specificity. These antibodies will be important tools to analyze subunit association, processing and cell surface expression of the respective antigens, and to study integrin distribution in normal and tumor tissues. The functional properties of tumor cell integrins will be analyzed using antibodies or antisense RNA techniques in a variety of cell adhesion and invasion assays. These studies will provide the basis for a more detailed functional analysis by expression of cDNAs in heterologous cells.