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

Jak/STAT 信号传导、哺乳期中的 CAV-1

• 批准号: 6569872
• 负责人: MICHAEL P LISANTI
• 金额: $ 37.16万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-01-23 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6569872
• 关键词: SDS polyacrylamide gel electrophoresis; biological signal transduction; breast neoplasms; caveolins; cell line; fluorescence microscopy; gel mobility shift assay; gene mutation; gene targeting; genetically modified animals; hyperplasia; immunoprecipitation; laboratory mouse; lactation; membrane proteins; neoplastic process; phosphorylation; polymerase chain reaction; prolactin; protein structure function; tissue /cell culture; transfection; western blottings

DESCRIPTION (provided by applicant): 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 cell hyperplasia. Signaling from the hormone prolactin vial the Jak/STAT pathway controls normal mammary gland development. Thus, if Cav-1 were 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 mice 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-1 (P132L) transgenic mice. We will cross Cav-1 (P132L) transgenic mice with other well-established models of mammary tumorigenesis, such as MMTVErbB2 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.

描述（由申请人提供）：本提案的长期目标是了解小窝蛋白-1在i）Jak/STAT信号传导，ii）哺乳和iii）乳腺癌发病机制中的作用。小窝作为调节信号转导的“信息中心”。小窝蛋白-1（Caveolin-1，Cav-1）是存在于大多数细胞中的小窝膜的主要结构蛋白。我们将人CAV-1定位到一个疑似肿瘤抑制基因座（7q31.1/D 7S 522）。此外，Cav-1基因在高达16%的人类乳腺癌中发生突变（P132 L）。该提案的目的是检验Cav-1表达对通过调节Jak/STAT信号传导调节泌乳很重要以及Cav-1的缺失有助于乳腺癌细胞的致癌性的假设。为了检验这一假设，我们将使用各种互补的体内方法，例如i）Cav-1无效小鼠模型和ii）表达在人乳腺癌中发现的显性阴性Cav-1（PI 32 L）的转基因小鼠的开发。本项目的三个具体目的是：1）确定Cav-1在负调控Jak/STAT信号转导中的作用。我们将研究Cav-1对催乳素敏感的培养乳腺上皮细胞中Jak/STAT信号转导激活的影响。我们的初步研究结果表明Cav-1通过抑制Jak介导的STAT 5a磷酸化来负性调节Jak/STAT 5a信号传导; 2）研究Cav-1在哺乳和上皮细胞增生中的作用。来自催乳素小瓶的激素信号传导Jak/STAT途径控制正常乳腺发育。因此，如果Cav-1是Jak/STAT信号传导的负调节因子，我们可以预测Cav-1表达的丧失会导致过早泌乳。实际上，我们的初步结果显示Cav-1缺失小鼠表现出过早泌乳，以及Jak/STAT 5a信号级联的过度激活;和3）确定Cav-1（P132 L）的转基因表达是否倾向于乳腺肿瘤的发展。为此，我们将产生Cav-1（P132 L）小鼠，转基因表达这种形式的Cav-1在乳腺。我们的初步结果表明，Cav-1（P132 L）在培养细胞中以显性负性方式起作用。此外，我们对Cav-1基因敲除小鼠的初步研究结果显示，早期出现广泛的乳腺上皮增生。我们预测这种表型将加速Cav-1（P132 L）转基因小鼠的产生。我们将Cav-1（P132 L）转基因小鼠与其他成熟的乳腺肿瘤发生模型，如MMTVErbB 2和MMTV-polyoma middle T小鼠杂交。预计这些研究将有助于了解Cav-1在体内Jak/STAT信号传导和乳腺肿瘤发生中的作用的基础知识。