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

BB首席研究员/项目主管（最后、第一、中）：Lisanti, Michael P.说明应用程序的广泛、长期目标和具体目的，并参考项目与健康的关系。简要描述为实现这些目标的研究设计和方法。避免总结过去的成就，避免使用第一人称。当与应用程序分离时，此描述旨在作为对所建议工作的简洁而准确的描述。如果该应用程序获得资助，则此描述将成为公共信息。因此，不要包含专有/机密信息。本研究的长期目标是了解caveolin-1在Jak/STAT信号传导、泌乳和乳腺癌发病机制中的作用。小泡是调节信号转导的“信息中心”。小窝蛋白-1 （Cav-1）是在大多数细胞中发现的小窝膜的主要结构蛋白。我们将人类CAV-1定位到一个可疑的肿瘤抑制位点（7q31.1/D7S522）。此外，Cav-1基因（P132L）在多达16%的人类乳腺癌中发生突变。本研究的目的是验证Cav-1表达通过Jak/STAT信号调节泌乳的重要作用，以及Cav-1的缺失导致乳腺癌细胞的致癌性。为了验证这一假设，我们将使用多种互补的体内方法，例如i) Cav-1缺失小鼠模型和ii)开发表达在人类乳腺癌中发现的显性阴性Cav-1 （PI32L）的转基因小鼠。该项目的三个具体目的是：1)确定Cav-1在负调控Jak/STAT信号传导中的作用。我们将研究Cav-1对泌乳素应答的乳腺上皮细胞中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磷酸化来负向调节Jak/STAT5a信号通路；2)探讨Cav-1在哺乳和上皮细胞增生中的作用。正常乳腺发育是由泌乳素激素通过Jak/STAT通路发出的信号控制的。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表达的缺失会导致早产。事实上，我们的初步结果表明，Cav-1缺失的小鼠表现出早泌，以及Jak/STAT5a信号级联的过度激活；3)确定转基因Cav-1 （P132L）的表达是否易导致乳腺肿瘤的发生。为此，我们将产生在乳腺中转基因表达这种形式的Cav-1 （P132L）小鼠。我们的初步结果表明，Cav-1 （P132L）在培养细胞中以显性阴性方式起作用。此外，我们对Cav-1缺失小鼠的初步结果显示，广泛乳腺上皮增生的早期发展。我们预测这种表型将加速cav - 1 （P132L）转基因小鼠。我们将把Cav-1 （P132L）转基因小鼠与其他已建立的乳腺肿瘤发生模型，如MMTV- ErbB2和MMTV-多瘤中T小鼠进行杂交。预计这些研究将为了解Cav-1在Jak/STAT信号传导和体内乳腺肿瘤发生中的作用提供基础知识。网站性能 ======================================== 节结束 ===========================================

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===========================================