Stromal Contributions of Adipocytes in Breast Cancer

脂肪细胞在乳腺癌中的基质贡献

基本信息

批准号：
7072351
负责人：
PHILIPP E SCHERER
金额：
$ 32万
依托单位：
ALBERT EINSTEIN COLLEGE OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-06-01 至 2007-02-28
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The objective of this proposal is to understand the role of mammary adipocytes and adipocyte-secreted factors (such as, Type-VI collagen): i) in the growth/survival of mammary epithelial cells; and ii) in the pathogenesis of breast cancer. Mammary epithelial cells/ducts are embedded in a matrix that consists predominantly of adipocytes. However, it remains unknown what adipocyte-secreted factors are required for the survival of mammary epithelia. Similarly, these unknown adipocyte-specific factors may contribute to the pathogenesis of human breast cancers. To test this hypothesis, we will use a variety of novel in vivo approaches, such as "reconstituted mammary fat pads (RFPs)" employing the transfectable 3T3-L1 model adipocyte cell line, and Type-VI collagen (-/-) null mice. The three specific aims of the project are: 1) To identify paracrine interactions between mammary epithelia and their surrounding adipocytes. We will establish co-culture and conditioned media systems using 3T3-L1 adipocytes and the human breast cancer epithelial cell line, MCF-7. We will use microarray analysis to define adipocyte-induced transcriptional changes in MCF-7 and thereby identify genes that mediate the growth and survival of MCF-7 cells. To functionally examine the role of specific factors, we will generate "reconstituted fat pads (RFPs)" using stably-transfected 3T3-L1 adipocytes over-expressing a given gene product. These RFPs will be co-implanted with MCF-7 cells into nude mice to assess their contribution to tumorigenicity in vivo; 2) To determine the role of Type-VI collagen in mammary tumorigenesis. Our preliminary data demonstrate that Type-VI collagen is an abundant extracellular matrix component of mammary tissue that is secreted by adipocytes and that is up-regulated during mammary tumor progression. We will cross Type-VI collagen null mice with an established mouse model of mammary tumorigenesis, MMTV-ErbB2/Neu. We predict that loss of Type-VI collagen expression will block or diminish the development of mammary tumors; and 3) To determine if selective ablation of mammary adipocytes in the adult mouse prevents or diminishes mammary tumor development. For this purpose, we have developed a novel transgenic inducible system that allows the selective apoptotic ablation of mammary adipocytes, in a temporally controlled fashion that will be crossed to MMTV-PyMT mice. In a complementary approach, we will induce the selective-ablation of mammary epithelial cells. We have placed a ligand-activatable transgenic cassette containing pro-caspase-8 under the control of the aP2-promoter (for expression in adipocytes) and the MMTV-promoter (for expression in mammary epithelia). These studies will help define the role of mammary adipocytes in the pathogenesis of breast cancer.

描述（由申请人提供）：该提案的目的是了解乳腺脂肪细胞和脂肪细胞分泌因子的作用（例如VI型胶原蛋白）：i）在乳腺上皮细胞的生长/存活中； ii）在乳腺癌的发病机理中。乳腺上皮细胞/管道嵌入主要由脂肪细胞组成的基质中。但是，尚不清楚乳腺上皮生存需要哪些脂肪细胞分泌因子。同样，这些未知的脂肪细胞特异性因素可能有助于人类乳腺癌的发病机理。为了检验这一假设，我们将使用各种新型的体内方法，例如使用可转染3T3-L1模型脂肪细胞系和VI型胶原蛋白（ - / - ）无小鼠的“重建乳腺脂肪垫（RFP）”。该项目的三个特定目的是：1）确定乳腺上皮及其周围脂肪细胞之间的旁分泌相互作用。我们将使用3T3-L1脂肪细胞和人类乳腺癌上皮细胞系MCF-7建立共培养和条件培养基系统。我们将使用微阵列分析来定义MCF-7中脂肪细胞诱导的转录变化，从而确定介导MCF-7细胞生长和存活的基因。为了在功能上检查特定因素的作用，我们将使用稳定转染的3T3-L1脂肪细胞过表达给定基因产物的稳定转染的3T3-L1脂肪细胞生成“重构脂肪垫（RFP）”。这些RFP将与MCF-7细胞共植入裸小鼠，以评估它们对体内肿瘤性的贡献。 2）确定VI型胶原蛋白在乳腺肿瘤发生中的作用。我们的初步数据表明，VI型胶原蛋白是乳腺组织分泌的乳腺组织的丰富细胞外基质成分，并且在乳腺肿瘤进展过程中被上调。我们将与已建立的乳腺肿瘤发生的小鼠模型跨越VI型胶原蛋白无效小鼠MMTV-ERBB2/NEU。我们预测，VI型胶原蛋白表达的丧失将阻止或减少乳腺肿瘤的发展。 3）确定成年小鼠中乳腺脂肪细胞的选择性消融是否会阻止或减少乳腺肿瘤的发展。为此，我们开发了一种新型的转基因诱导系统，该系统允许以时间控制的方式进行选择性的乳腺脂肪细胞的凋亡消融，并将越过MMTV-PYMT小鼠。在一种互补的方法中，我们将诱导乳腺上皮细胞的选择性开放。我们已经将含有pro-Caspase-8的配体激活的转基因盒放在AP2启动子（用于脂肪细胞中的表达）和MMTV促销（用于乳腺上皮中的表达）的控制下。这些研究将有助于定义乳腺脂肪细胞在乳腺癌发病机理中的作用。