Syndecan-1 in Stromal Fibroblasts of Breast Carcinomas

描述(申请人提供)：乳腺癌应该被视为一个器官系统，在这个系统中，生长和进展受到肿瘤细胞和周围间质元素之间复杂和相互作用的控制。成纤维细胞是一种主要的间质细胞类型，在正常乳腺中维持组织内稳态，但在乳腺癌中促进肿瘤进展。肿瘤相关成纤维细胞(CAF)在形态、基因表达和分泌因子等方面有别于正常乳腺成纤维细胞(NMF)。我们的实验室已经证明，在大多数乳腺癌中，CAF细胞表面蛋白多糖Syndecan 1(Sdc1)的表达是诱导的，并且Sdc1刺激乳腺癌的增殖。由于成纤维细胞的主要功能之一是组装细胞外基质(ECM)，我们已经开始研究Sdc1的表达是否影响ECM的合成。我们的初步数据表明，Sdc1在CAF中的表达影响ECM支架的结构或精细结构。这项建议的目的是详细了解Sdc1如何调节乳腺癌中的ECM组装，以及依赖Sdc1的ECM改变可能对癌症行为产生什么后果。根据我们的初步观察，我们提出以下假设：乳腺癌间质成纤维细胞异常表达Sdc1导致ECM结构改变，这是允许乳腺癌细胞侵袭的原因。我们假设这种改变的细胞外基质结构在疾病自然病程的早期和晚期导致了侵袭事件，并缩短了患者的生存时间。为了验证这一假说，我们提出了以下具体目标：目的1：研究Sdc1和ECM结构在乳腺癌侵袭中的作用。我们将在人类乳腺癌样本中仔细分析ECM的结构。利用组织芯片，我们将确定细胞外基质的结构特征是否能预测患者的预后。创新的体外侵袭分析将告诉我们Sdc1和/或ECM结构是否调节侵袭。最后，将用缺乏Sdc1的动物来检验Sdc1在确定ECM结构中的参与。目的：分析Sdc1和ECM结构在导管原位癌(DCIS)向浸润性癌发展中的作用。通过将新的细胞外基质成像工具应用于人类样本和DCIS动物模型，我们将确定间质Sdc1的表达是否会产生一种侵袭性的ECM，从而促进从DCIS到浸润性癌的进展。目的3破译侵袭性细胞外基质形成的分子机制。通过结构域缺失和替换实验，将在体外分析特定的Sdc1分子结构域在调节ECM组装中的参与。整合素细胞黏附受体的协同作用将通过功能丧失和功能获得实验来研究。总而言之，这些目标将极大地促进我们对乳腺癌中ECM产生的调控的了解。从机制上理解ECM组装是设计新型治疗药物的关键，这些药物旨在使ECM“正常化”，从而将肿瘤微环境从允许侵袭恢复到限制侵袭。

DESCRIPTION (provided by applicant): Breast cancer should be viewed as an organ system in which growth and progression are governed by complex and reciprocal interactions between tumor cells and surrounding stromal elements. Fibroblasts, which comprise a predominant stromal cell type, maintain tissue homeostasis in normal breast but promote tumor progression in breast cancer. Carcinoma-associated fibroblasts (CAF) distinguish themselves from normal mammary fibroblasts (NMF) by morphology, gene expression and secreted factors. Our lab has shown that expression of the cell surface proteoglycan syndecan 1 (Sdc1) in CAF is induced in the majority of breast carcinomas and that Sdc1 stimulates breast carcinoma proliferation. Because one of the main functions of fibroblasts is the assembly of an extracellular matrix (ECM), we have begun to examine whether Sdc1 expression affects ECM synthesis. Our preliminary data indicate that Sdc1 expression in CAF influences the architecture, or fine structure, of the ECM scaffold. It is the goal of this proposal to understand in detail how Sdc1 regulates ECM assembly in breast carcinomas and what consequences Sdc1-dependent ECM alterations might have on carcinoma behavior. Based on our preliminary observations, we state the following hypothesis: The aberrant expression of Sdc1 by breast carcinoma stromal fibroblasts leads to an altered ECM architecture, which is permissive to breast carcinoma cell invasion. We posit that this altered ECM architecture contributes to invasion events early and late during the natural history of the disease and shortens patient survival. To test this hypothesis, we propose the following specific aims: Aim 1: Examine the role of Sdc1 and ECM architecture in breast carcinoma invasion. The ECM architecture will be carefully analyzed in human breast carcinoma samples. Using tissue microarrays, we will determine whether ECM architectural features predict patient prognosis. Innovative ex vivo invasion assays will inform us whether Sdc1 and/or the ECM architecture regulate invasion. Lastly, the involvement of Sdc1 in determining the ECM architecture will be examined with Sdc1-deficient animals. Aim 2: Analyze the role of Sdc1 and ECM architecture in the progression from ductal carcinoma in situ (DCIS) to invasive carcinoma. By applying novel ECM imaging tools to human samples and to a DCIS animal model, we will determine whether stromal Sdc1 expression creates an invasion-permissive ECM that facilitates progression from DCIS to invasive carcinoma. Aim 3 Decipher the molecular mechanisms responsible for the formation of an invasion-permissive ECM. The involvement of specific Sdc1 molecular domains in regulating ECM assembly will be analyzed in vitro with domain deletion and substitution experiments. The cooperative role of integrin cell adhesion receptors will be investigated with loss of function and gain of function experiments. Together, these aims will significantly advance our knowledge about the regulation of ECM production in breast cancer. A mechanistic understanding of ECM assembly is key to the design of novel therapeutic agents that are aimed at "normalizing" the ECM and thus revert the tumor microenvironment from invasion-permissive to invasion-restrictive.