BREAST CANCER & AGING--A SOMATIC CELL GENETICS APPROACH

描述：乳腺癌是发病率和死亡率的主要原因之一。 美国和其他工业化国家的女性死亡率； 最新的统计数据显示，乳腺癌的发病率有所增加。 癌症发生在60岁以上的女性中。自然和环境 雌激素似乎参与了致癌的几个阶段。 绝经过程，尤其是在更年期和绝经后时期。 雌激素通过调节其靶细胞的增殖 两步机制。在第一步中，雌激素起调节作用。 在第二步中，它们抑制细胞的增殖 (关闭)。未能严格应对后一种正常的故障- 安全机制可能最终导致乳腺肿瘤的发生。虽然 第二步比第一步理解得更少，它提供了理论上的 晚期乳腺癌DES治疗成功的解释。 本应用程序声明的目的是了解 参与雌激素诱导的增殖性细胞关闭。使用MCF7 细胞，我们已经成功地分离出只表达固定表型的 雌激素介导的两个步骤之一：a)变异型E8CASS表达 只有关闭(STEP-II)和b)变体A2E8CASS仅表达STEP- 一、除上述与致癌有关外， 在乳房的过程中，这些变体提供了一个研究的模型 从雌激素敏感到耐药。这代表了 我们探索细胞调节的一个重要里程碑 正常情况下的扩散，并进入初始和 逐渐走向恶性的道路。 这一建议的具体目的是分离独特的mrna序列。 介导雌激素对细胞增殖的抑制作用 乳腺癌细胞。流式细胞术将被用来表征 扩散关闭的动力学；这是找到 引发核扩散关闭的适当条件。独一无二的mRNA 负责关闭的序列将使用两个 互补方法：a)消减文库/基因筛查 方法(Wang&Brown)，以及b)差异显示方法(Leung& 帕蒂)。这样获得的候选基因将被克隆到哺乳动物体内 由可诱导启动子控制的表达载体。他们的 表达和唤起关闭反应的能力将在细胞中进行测试 培养和在裸鼠体内。从这次实验中收集到的知识 设计将有助于设计出更好的预后和治疗工具 抗击乳腺癌，尤其是雌激素受体阳性 老年女性的多样性。

DESCRIPTION: Breast cancer is one of the leading causes of morbidity and mortality among women in America and other industrialized countries; latest statistics show that there is an increased incidence of breast cancer among women above 60 years of age. Natural and environmental estrogens appear to be involved at several stages of the carcinogenetic process, especially during menopause and postmenopausic periods. Estrogens regulate the proliferation of their target cells through a two-step mechanism. In the first step, estrogens mediate an increase of the cell number; in the second step, they inhibit cell proliferation (shutoff). Failure to stringently respond to this latter normal fail- safe mechanism may eventually result in breast tumorigenesis. Although this Step-II is less understood than Step-I, it provides the theoretical explanation for the success of DES treatment in advanced breast cancer. The stated purpose of this application is to understand the mechanisms involved in the estrogen-induced proliferative shutoff. Using MCF7 cells, we have succeeded in segregating fixed phenotypes expressing only one of the two estrogen-mediated steps: a) variant E8CASS expresses only the shutoff (Step- II) and b) variant A2E8CASS expresses only Step- I. In addition to the above mentioned relevance to the carcinogenetic process in the breast, these variants provide a model to study progression from estrogen sensitivity to resistance. This represents an important milestone in our quest to explore the regulation of cell proliferation under normal conditions and into the initial and progressive paths toward malignancy. The specific aim of this proposal is to isolate unique mRNA sequences that mediate the estrogen-induced inhibition of the proliferation of breast cancer cells. Flow cytometry will be used to characterize the kinetics of the proliferative shutoff; this is required to find the appropriate conditions to evoke a proliferative shutoff. Unique mRNA sequences responsible for the shutoff will be isolated using two complementary approaches: a) a subtraction library/genetic screen method (Wang & Brown), and b) a differential display method (Liang & Pardee). Candidates thus obtained will be cloned into mammalian expression vectors controlled by an inducible promoter. Their expression and ability to evoke a shutoff response will be tested in cell culture and in nude mice. Knowledge gathered from this experimental design will contribute to devise better prognostic and therapeutic tools to fight breast cancer, especially the estrogen receptor-positive variety in older women.