Role of Nuclear Tyrosine Rak in Breast Cancer

说明(申请人提供)：酪氨酸激酶是一种调节蛋白 它们在细胞的生长和分化中起着核心作用。在预赛中 研究发现，酪氨酸激酶在乳腺癌细胞系中的表达 与使用酪氨酸激酶差异的正常乳腺细胞进行比较 展示化验。核酪氨酸激酶Rak基因表达下调与否 在几种乳腺癌细胞系中表达。此外，腺病毒 已知抑制乳腺癌细胞生长的早期基因E1a 行，上调了RAK的表达。RAK在乳腺组织中的表达增强 癌细胞具有抑制生长的活性，其衡量标准是 菌落形成效率。令人惊讶的是，人们对它的作用知之甚少 RAK在细胞中的表达及其作用机制。这项提案将考验 假设RAK抑制肿瘤细胞生长，以及Rak基因表达缺失 RAK在乳腺癌中起一定作用。首先，RAK基因的表达对基因表达的影响 肿瘤细胞的体外生长将通过细胞计数、集落数来评估 形成试验和软琼脂试验，并进行体内试验。第二， RAK对乳腺癌细胞凋亡敏感性的影响及机制 将对细胞周期进行研究。RAK的临界域的贡献 将通过缺失和突变分析来研究其功能。第三, RAK在不同分级和转移乳腺癌中的表达 电位将通过免疫组织化学分析来确定。这些研究 将描述RAK在细胞生长中的作用及其作用机制。 从科学的观点来看，确定Rak的作用机制将 极大地增强了我们对细胞生长是如何调控的理解。从… 从临床角度来看，RAK可能是一个有用的预后标志物和一个基因 治疗剂。此外，确定RAK在肿瘤生长中的作用将使 美国将更好地定制用于治疗的酪氨酸激酶抑制剂的特异性 临床试验。

DESCRIPTION (provided by applicant): Tyrosine kinases are regulatory proteins that play a central role in cell growth and differentiation. In preliminary work, the expression of tyrosine kinases in breast cancer cell lines was compared to normal-like breast cells using a tyrosine kinase differential display assay. The nuclear tyrosine kinase Rak was downregulated or not expressed in several breast cancer cell lines. Furthermore, the adenovirus early gene E1A, which is known to inhibit the growth of breast cancer cell lines, upregulated Rak expression. Enhanced expression of Rak in breast cancer cells had a growth suppressing activity as measured by a decrease in colony formation efficiency. Surprisingly, little is known about the role of Rak in cells and its mechanism of action. This proposal will test the hypothesis that Rak inhibits tumor cell growth, and that loss of expression of Rak plays a role in breast cancer. First, the effect of Rak expression on tumor cell growth will be assessed in vitro by cell counts, the colony formation assay and the soft agar assay, and tested in vivo. Second, the effect of Rak on the sensitivity of breast cancer cells to apoptosis and on the cell cycle will be studied. The contribution of critical domains of Rak to its function will be studied by deletion and mutation analysis. Third, expression of Rak in breast cancers of various grades and metastatic potentials will be determined by immunohistochemical analysis. These studies will delineate the role of Rak in cell growth and its mechanism of action. From a scientific standpoint, determining Rak's mechanism of action will significantly enhance our understanding of how cell growth is regulated. From a clinical standpoint, Rak may be a useful prognostic marker, and a gene therapy agent. Furthermore, identifying Rak's role in tumor growth will allow us to better tailor the specificity of tyrosine kinase inhibitors used in clinical trials.