FUNCTIONAL STUDY OF A CARCINOMA-ASSOCIATED MUCIN MUC-1

我们的目标是了解肿瘤相关粘蛋白MUC1的功能 在乳腺肿瘤的发展过程中。MUC1蛋白 (也称为PEM，多形性上皮粘蛋白)是一种高度糖基化的 高表达且异常的跨膜粘蛋白糖蛋白 大多数癌症的糖基化，尤其是92%的 原发和转移性乳腺癌。MUC1蛋白是一种大的杆状- 就像分子一样，在细胞表面外延伸超过250纳米，它 通常是被肢解的。结构和生化特征可以 使这种蛋白质通过掩蔽细胞表面蛋白来发挥作用，可能 那些参与黏附或免疫识别的人。我们的假设是 该蛋白的表达有利于肿瘤细胞及其转移 相应的，可能是通过减少细胞的粘附性或通过 在细胞周围提供保护层，该保护层可以保护细胞免受 免疫监视。MUC1蛋白也存在于根尖表面。 正常的简单上皮细胞，并受发育调节， 器官发生过程中管腔形成时间的初步探讨 (小鼠的第11天)。我们的假设是MUC1可能参与了 上皮形态发生，可能起到掩盖黏附分子的作用 存在于细胞表面，有助于管腔的形成。自.以来 小鼠的乳腺癌与人类的乳腺癌非常相似， 我们提议的实验将使我们能够分析 MUC-L(人类基因命名为Muc1；小鼠基因命名为MUC-L) 肿瘤的进展和发展。目前的提案将 通过解决以下具体目标来直接测试假设： (L)通过在胚胎干细胞中使用基因打靶，我们将制造一只小鼠 具有MUC-L基因突变的菌株，从而产生缺乏MUC-L的动物 用于检测其在肿瘤进展和发展中功能的蛋白质(2) 我们将测定MUC-L缺乏对上皮细胞的影响 器官发生，因为了解它在正常情况下的功能是重要的 在组织和癌症中也是如此。(3)我们将使突变的小鼠与 发生乳腺肿瘤或诱发肿瘤的转基因小鼠 这些小鼠用化学药物或辐射来测定慕克-L的效果。 肿瘤形成和进展(生长和发展)不足 差异化)。(4)我们会产生转移的肿瘤，因此 分析MUC-L蛋白对细胞周期的影响 转移、转移的肿瘤百分比和器官特异性 转移性病变。(5)我们将检查肿瘤的易感性 MUC-L缺陷小鼠的发育及免疫溶血对照研究 效应细胞(NK细胞和细胞毒性T淋巴细胞)。我们的发现应该是 与更多地了解乳腺癌的进展有关 最终，希望能更好地调节 疾病。

Our goal is to understand the function of the tumor-associated mucin MUC1 in the progression of neoplasia in the mammary gland. The MUC1 protein (also called PEM, polymorphic epithelial mucin) is a heavily glycosylated transmembrane mucin glycoprotein that is highly expressed and aberrantly glycosylated by the majority of carcinomas and in particular, by >92% of primary and metastatic breast cancers. The MUC1 protein is a large, rod- like molecule, extending more than 250 nm beyond the cell surface, and it is often sialylated. The structural and biochemical characteristics may enable this protein to act by masking cell surface proteins, possibly those involved in adhesion or immune recognition. Our hypothesis is that expression of this protein benefits tumor cells and their metastatic counterparts, perhaps by reducing the adhesive properties of cells or by providing a protective layer around cells which may shield them from immune surveillance. MUC1 protein is also present at the apical surfaces of normal simple epithelial cells and is developmentally regulated, appearing initially about the time of lumen formation during organogenesis (day 11 in the mouse). Our hypothesis is that MUC1 may be involved in epithelial morphogenesis, perhaps acting to mask adhesive molecules present on the cell surface and aiding in the formation of a lumen. Since mammary gland cancer in the mouse closely resembles human breast cancer, our proposed experiments will allow us to analyze the functional role of Muc-l (the human gene designation is MUC1; the mouse gene is Muc- l) in the progression of neoplasia and in development. The current proposal will directly test the hypotheses by addressing the following specific aims: (l) By using gene targeting in embryonic stem cells, we will make a mouse strain with a mutated Muc-l gene, thus generating animals lacking Muc-l protein for testing its function in tumor progression and development (2) We will determine the effect of Muc-l deficiency on epithelial organogenesis, since it is important to understand its function in normal tissues as well as in cancer. (3) We will mate the mutant mice with transgenic mice that develop mammary gland tumors or induce tumors in these mice with chemicals or radiation to determine the effect of Muc-l deficiency on tumor formation and progression (growth and differentiation). (4) We will generate tumors that metastasize, thus enabling an analysis of the effect of the Muc-l protein on the rate of metastasis, percentage of tumors that metastasize, and organ specificity of metastatic lesions. (5) We will examine the susceptibility of tumors developing in the Muc-l-deficient and control mice to lysis by immune effector cells (NK cells and cytotoxic T lymphocytes). Our findings should be relevant to understanding more about the progression of breast cancer with the hope, ultimately, of better modulating progression of the disease.