ROLE OF METASTASIS GENES AT SPECIFIC STEPS OF METASTASIS

为了让实体肿瘤中的癌细胞完成 确定转移性病变的过程它必须完成一些 成功很可能取决于完全不同的表型的步骤 特征(侵袭、渗入、运输、渗出和 增长)。尽管不同的基因都与这两种疾病有关 增强或延缓术后转移灶的形成 实验性肿瘤植入或静脉注射肿瘤 细胞，还没有对细胞内的阶段进行实验性的解剖 个体“转移”的表达对转移级联的影响 基因。我们有一系列的小鼠乳腺肿瘤细胞系 不同的转移潜能源自单个自发的 小鼠乳腺肿瘤的体内选择。我们已经开发了一些技术 用于确定转移级联中的哪一步不能再 由每条单元线有效地完成。我们这项研究的目标是 是为了确定这个模型系统是否用于转移研究 行为可用于定义受影响的特定进程 促进或抑制转移的基因。 我们选择了两个原型基因，激活的c-Ha-ras和 NM-23。这些基因的表达已被发现与高 在各种肿瘤模型中，[RAS]和低[NM-23]转移潜能。 也有很好的文档表明，引入了 这些基因通过转染法进入肿瘤细胞影响转移 受体细胞的行为。因此，我们在这项提案中的具体目标是 方法：1)转染NM23或活化的Ha-ras的全长cDNA克隆 将适当的表达载体导入高转移或低转移的细胞 潜在的，2)确定每个基因的表达水平 后代克隆，3)评估高水平或低水平表达的效果 这些基因对转基因细胞能力的影响 转移级联中的连续步骤，以及4)重新分离细胞 以确认任何观察到的转移 基因的改变与这些基因的表达水平有关。 这些研究的完成将验证测试系统的有效性 用于确定已知的多种基因在哪里影响转移 行为行为为一种制度的发展打开了可能性，其中 以前未知的影响转移级联步骤的基因可以 被指认出来。

In order for a cancer cell in a solid tumor to complete the process of establishing a metastatic lesion it must complete a number of steps whose success is likely to depend on quite different phenotypic characteristics (invasion, intravasation, transport, extravasation and growth). Although a variety of genes have been implicated in either enhancement or retardation of the formation of metastatic lesions after implantation of experimental tumors or intravenous injection of tumor cells, there has been no experimental dissection of the stages within the metastatic cascade affected by expression of individual "metastasis" genes. We have available a series of mouse mammary tumor cell lines of varying metastatic potential which were derived from a single spontaneous mouse mammary tumor by in vivo selection. We have developed techniques for determining which step in the metastatic cascade can no longer be efficiently completed by each of the cells lines. Our goal in this study is to determine whether this model system for studies of metastatic behavior can be utilized to define the specific process(es) affected by genes that enhance or inhibit metastasis. We have chosen two prototype genes, activated c-Ha-ras and NM-23. Expression of these genes has been found to correlate with high [ras] and low [NM-23] metastatic potential in a variety of tumor models. There is also good documentation indicating that introduction of either of these genes into tumor cells by transfection affects the metastatic behavior of recipient cells. Thus, our specific aims in this proposal are: 1) To transfect full-length cDNA clones of NM23 or activated Ha-ras in appropriate expression vectors into cells of high or low metastatic potential, 2) To determine the level of expression of each gene in progeny clones, 3) To assess the effect of high or low level expression of these genes on the ability of the transfected cells to complete successive steps in the metastatic cascade, and 4) To reisolate cells from different metastatic sites to confirm that any observed metastatic alterations are associated with levels of expression of these genes. Completion of these studies will both validate a test system for determining where a variety genes already known to affect metastatic behavior act and open the possibility for development of a system wherein genes not previously known to affect steps in the metastatic cascade can be identified.