CELL-CELL INTERACTIONS IN MALIGNANCY

拟议研究的总体目标是了解如何 特定黏附分子的变化有助于侵袭性 或肿瘤细胞的转移能力。研究的重点是 主要是神经细胞黏附分子N-CAM，因为 劳斯肉瘤病毒对神经上皮细胞的转化作用 (RSV)导致N-CAM和 相关的细胞粘附性以及细胞数量的增加 能动性。这些研究使用了生化和功能分析。 它们是基于针对特定凸轮的特定抗体，并使 利用克隆序列分析其基因调控 表情。 要确定N-CAM表达的变化如何影响 细胞的恶性行为、黏附、运动和侵袭性 将比较已丢失N-CAM的完全转化细胞的数量 到其中N-CAM水平已经达到的转化细胞 通过基因操作恢复的。要确定N-CAM如何 水平被降低，我们将测量转录，处理， 和N-CAM mRNA的稳定性以及磷酸化和 N-CAM蛋白的稳定性，并将定义控制区在 N-CAM基因是RSV诱导的改变所必需的。这个 转化对其他已定义基因表达的影响 神经黏附系统也将被确定。要确定 可能直接增强肿瘤细胞侵袭力的因素，我们将 测试转化的细胞是否会分泌 特别是改变凸轮的合成和降解在 周围细胞正常。此外，这一影响， 对CAMS表达的转化将在 引起癌症的上皮细胞。 主要细胞黏附系统的丧失可能是一个主要原因 肿瘤细胞脱落和局部侵袭的贡献者。这个 拟议的研究将检验这一想法，并将定义机制 这会改变肿瘤细胞的粘附性。这些发现可能会表明 转移性肿瘤临床干预的新途径 人类肿瘤。

The overall goal of the proposed research is to understand how changes in specific adhesive molecules contribute to the invasive or metastatic capacity of tumor cells. The studies focus primarily on the neural cell adhesion molecule N-CAM because transformation of neuroepithelial cells by Rous sarcoma virus (RSV) results in a dramatic reduction in amount of N-CAM and associated cell adhesiveness together with an increase in cell motility. The studies employ biochemical and functional assays that are based on specific antibodies to defined CAMs, and make use of cloned sequences to analyze the genetic regulation of their expression. To determine how changes in N-CAM expression affect the malignant behavior of cell, the adhesion, motility and invasiveness of fully transformed cells that have lost N-CAM will be compared to that of transformed cells in which N-CAM levels have been restored by genetic manipulation. To determine how N-CAM levels are reduced, we will measure the transcription, processing, and stability of N-CAM mRNA and the phosphorylation and stability of N-CAM protein, and will define control regions in the N-CAM gene that are necessary for the RSV-induced change. The effect of transformation on the expression of other defined neuronal adhesion systems will also be determined. To identify factors that may directly enhance tumor cell invasiveness, we will test whether transformed cells secrete substances that specifically alter the synthesis and degradation of CAMs on normal surrounding cells. In addition, the effect of transformation on expression of CAMs will be assessed in epithelial cells that give rise to carcinomas. The loss of a major cell adhesion system may be a prime contributor to tumor cell detachment and local invasiveness. The proposed studies will test this idea and will define mechanisms that alter adhesiveness in tumor cells. The findings may suggest new approaches for clinical intervention in the metastatic spread of human tumors.