DIFFERENTIATION OF MEDULLARY THYROID CARCINOMA CELLS

这个应用程序是我们实验室整体努力的一部分， 它试图阐明神经内分泌的控制 正常甲状腺C细胞及其肿瘤细胞的分化 对应的是甲状腺髓样癌(MTC)。理解 这一控制将提供对可能改变的功能的把握 在肿瘤的发生和发展中起重要作用。髓质甲状腺 癌症是这项研究的一个很好的模型，因为定义了 进程是可以识别的。 我们已经定义了一个体外系统来研究MTC的这些步骤 分化和进步。培养中的MTC细胞可以 与正常C-的许多特征相区别 细胞，化学或通过ras癌基因导入。 分化反过来又可以被myc癌基因阻断 引言。 目前的提案将通过以下方式进一步描述这些发现 细胞生物学、生物化学和分子生物学 关于分化的机制。 1.正常和激活的细胞皮疹癌基因对肿瘤细胞的影响 将对MTC细胞分化进行研究，以确定 是否对病毒皮疹有特效性。皮疹的影响 关于CT基因的转录将被确定。经济衰退带来的影响 MYC癌基因对TT细胞和ras诱导分化的影响 被刻画出来。最后，阻断内源性c-选择素的作用。 将使用反义技术研究皮疹和c-myc的表达 核糖核酸。 2.ras诱导分化的生化途径 将通过以下方法研究MYC对MTC细胞分化的阻断 信号转导中几种酶和信使的测定 小路。识别这些通路中的改变 分化的细胞，或分化受阻的细胞，将 在定义神经内分泌控制过程中的重要作用 差异化。 3.控制ras诱导CT的DNA序列 将定义基因表达，并将其与序列进行比较 参与TPA或cAMP诱导的CT基因表达，利用基因 转移法和DNA结合法。同样的化验结果，以及 DNA亲和层析，然后将用于部分 Ras介导的相关DNA结合蛋白的纯化 CT基因诱导。这项研究将对阐明 Ras在细胞中的作用机制。

This application is part of an overall effort of our laboratory, which seeks to elucidate the control of neuroendocrine differentiation in normal thyroid C-cells and their neoplastic counterpart, medullary thyroid carcinoma (MTC). Understanding this control will provide a grasp of what functions may be altered in tumor developement and progression. Medullary thyroid carcinoma is a good model for this study, since defined stages of progression can be identified. We have defined an in vitro system to study these steps of MTC differentiation and progression. MTC cells in culture can be differentiated with respect to many characteristics of normal C- cells, either chemically or by ras oncogene introduction. Differentiation in turn can be blocked by myc oncogene introduction. The current Proposal will further characterize these findings, by cell biology, biochemistry, and molecular biology, concentrating on mechanisms of differentiation. 1. The effects of normal and activated cellular rasH oncogenes on MTC cell differentiation will be investigated, to determine whether the effect is specific to viral rasH. The effects of rasH on CT gene transcription will be ascertained. The effects of the myc oncogen on TT cells, and on ras induced differentiation, will be characterized. Finally, the effects of blocking endogenous c- rasH and c-myc expression will be investigated, using antisense RNA. 2. The biochemical pathway of ras-induced differentiation and myc blocking of differentiation in MTC cells will be studied, by assaying several enzymes and messengers in signal transduction pathways. Identifying alterations in these pathways in differentiated cells, or in cells blocked in differentiation, will be important in defining the processses controlling neuroendocrine differentiation. 3. The DNA sequences controlling ras mediated induction of CT gene expression will be defined, and compared to sequences involved in TPA or cAMP induced CT gene expression, using gene transfer and DNA binding assays. These same assays, along with DNA affinity chromatography, will then be used to partially purify a relevant DNA binding protein involved in ras mediated CT gene induction. This study will be important in elucidating the mechanisms of ras function in cells.