CAV-1 in Jak/STAT Signaling, Lactation, & Breast Cancer

BB首席调查员/项目主任(最后、第一、中间)：利桑蒂，迈克尔·P·描述。说明申请的广泛、长期目标和具体目标，并参考该项目与健康有关的内容。简明扼要地描述实现这些目标的研究设计和方法。避免总结过去的成绩z_L，使用第一人称。此描述的目的是在脱离应用程序时，作为对拟议工作的简洁而准确的描述。如果申请得到资助，这一描述将成为公开信息。因此，不包括专有/机密信息。这项建议的长期目标是了解小窝蛋白-1在i)JAK/STAT信号转导、ii)哺乳和iii)乳腺癌发病机制中的作用。小窝是调节信号转导的“信息中心”。小窝蛋白-1(Cav-1)是小窝细胞膜的主要结构蛋白，存在于大多数细胞中。我们将人CAV-1定位于一个可疑的肿瘤抑制基因(7q31.1/D7S522)。此外，在多达16%的人类乳腺癌中，Cav-1基因发生了突变(P132L)。这一建议的目的是验证Cav-1的表达对调节哺乳的重要作用的假说，该假说是通过调节JAK/STAT信号来实现的，并且Cav-1的缺失有助于乳腺癌细胞的致瘤性。为了验证这一假设，我们将使用多种体内互补的方法，例如i)Cav-1缺失的小鼠模型和ii)在人类乳腺癌中发现的表达显性阴性Cav-1(PI32L)的转基因小鼠的发展。该项目的三个具体目标是：1)确定Cav-1在负调控JAK/STAT信号中的作用。我们将研究Cav-1在对催乳素反应的培养乳腺上皮细胞中Jak/STAT信号激活的影响。我们的初步结果表明，Cav-1通过抑制Jak介导的Stat5a的磷酸化来负向调节Jak/Stat5a信号转导；2)研究Cav-1在哺乳期和上皮I细胞增殖中的作用。正常的乳腺发育是由荷尔蒙催乳素通过Jak/STAT途径发出的信号控制的。因此，如果Cav-I是JAK/STAT信号的负调控因子，我们可以预测Cav-1的表达缺失会导致早产。事实上，我们的初步结果表明，Cav-1基因缺失的小鼠表现出早产，以及JAK/Stat5a信号级联的过度激活；以及3)确定Cav-1(P132L)的转基因表达是否有利于乳腺肿瘤的发生。为此，我们将产生在乳腺中转基因表达这种形式的Cav-1(P132L)的小鼠。我们的初步结果表明，Cav-1(P132L)在培养细胞中的作用是显性-负性的。此外，我们对Cav-1基因缺失的小鼠的初步结果显示，广泛的乳腺上皮增生发生在早期。我们预测，这种表型将加速Cav-I(P132L)转基因小鼠。我们将把Cav-1(P132L)转基因小鼠与其他成熟的乳腺肿瘤发生模型进行杂交，如MMTV-ErbB2和MMTV-多瘤中T小鼠。这些研究有望为了解Cav-1在JAK/STAT信号转导和体内乳腺肿瘤发生中的作用提供基础知识。表演网站========================================Section End===========================================

BB Principal Investigator/Program Director (Last, first, middle): Lisanti, Michael P. DESCRIPTION. State the application's broad, long-term objectives and specific aims, making reference to the health relatedness of the project. Describe concisely the research design and methods for achieving these goals. Avoid summaries of past accomplishments z_l the use of the first person. This description is meant to serve as a succinct and accurate description of the proposed work when separated from the application. If the application is funded, this description, as is, will become public information. Therefore, do not include proprietary/confidential information. D O NOT E XC E ED T H E SPA C E P R O VI D E D. The long-term objective of this proposal is to understand the role of caveolin-1 in i) Jak/STAT signaling, ii) lactation, and iii) the pathogenesis of breast cancer. Caveolae function as "message centers" for regulating signal transduction. Caveolin-1 (Cav-1) is the principal structural protein of caveolae membranes that are found in most cells. We mapped human CAV-1 to a suspected tumor suppressor locus (7q31.1/D7S522). In addition, the Cav-1 gene is mutated (P132L) in up to 16% of human breast cancers. The aim of this proposal is to test the hypothesis that Cav-1 expression is important for regulating lactation via modulation of Jak/STAT signaling and that loss of Cav-1 contributes to the oncogenicity of breast cancer cells. To test this hypothesis, we will use a variety of complementary in vivo approaches, such as i) a Cav-1 null mouse model and ii) the development of transgenic mice that express dominant-negative Cav-1 (PI32L) found in human breast cancers. The three Specific Aims of the project are: 1) To determine the role of Cav-1 in negatively regulating Jak/STAT signaling. We will examine the effects of Cav-1 on the activation of Jak/STAT signaling in cultured mammary epithelial cells that are responsive to prolactin. Our preliminary results indicate that Cav-1 negatively regulates Jak/STAT5a signaling by inhibiting Jak-mediated phosphorylation of STAT5a; 2) To examine the role of Cav-1 in lactation and epithelial i cell hyperplasia. Normal mammary gland development is controlled by signaling from the hormone prolactin vial the Jak/STAT pathway. Thus, if Cav- i is a negative regulator of Jak/STAT signaling, we would predict that a loss of Cav-1 expression leads to premature lactation. Indeed, our preliminary results show that Cav-1 null micei exhibit premature lactation, as well as hyper-activation of the Jak/STAT5a signaling cascade; and 3) To determine if transgenic expression of Cav-1 (P132L) predisposes towards mammary tumor development. For this purpose, we will generate Cav-1 (P132L) mice that transgenically express this form of Cav-1 in the mammary gland. Our preliminary results indicate that Cav-1 (P132L) acts in a dominant-negative fashion in cultured cells. In addition, our preliminary results with Cav-1 null mice show early development of wide-spread mammary epithelial hyperplasia. We predict that this phenotype will be accelerated Cav-I (P132L) transgenic mice. We will cross Cav-1 (P132L) transgenic mice with other well-established models of mammary tumorigenesis, such as MMTV- ErbB2 and MMTV-polyoma middle T mice. It is expected that these studies will contribute fundamental knowledge towards understanding the role of Cav-1 in Jak/STAT signaling and mammary tumorigenesis in vivo. PERFORMANCE SITE ========================================Section End===========================================