Lung Resident Mesenchymal Cells in the Pre-Metastatic Niche Formation

项目总结/摘要 转移性疾病仍然是癌症相关死亡的主要原因。在固体的重要器官中， 肿瘤转移，肺部是最常见的。肺转移经常发生在各种晚期 包括乳腺癌在内的实体癌分期。在过去的20年里，肺转移的重大进展 研究揭示了播散性肿瘤细胞（DTC）和肺之间复杂的相互作用 这些微环境对于转移性肺病变的发展至关重要。特别是， 免疫抑制性肺转移前微环境（niche），由以下分泌的因子驱动： 原发性肿瘤，被认为是DTC到来之前的关键准备阶段。本提案的重点 将在肺驻留间充质细胞（MC）上，这是一种特征不足的基质细胞群， 肺转移前小生境。在小鼠乳腺癌模型中的初步研究表明， MC通过重编程不同类型的细胞， 骨髓细胞变得高度免疫抑制或耐受性。这一提议的核心假设是 肺驻留MC通过赋予不同的浸润性细胞， 具有免疫抑制能力的骨髓细胞。为了验证这一假设并揭示其机制， 我们提出了三个具体的目标。目的1：确定肺部驻留MC 使用小鼠内源性MC的遗传操作在转移前生态位中的变化。我们将 使用原位乳腺肿瘤细胞植入和基因工程小鼠（GEM）肿瘤模型， 在转移前阶段测量内源性MC变化。MC也将在体内消融， 确定其转移前小生境形成的必要性。目的2：表征关键肺 间充质因子募集和调节骨髓细胞。我们会用RNA测序 存在于转移前肺与正常肺中的内源性MC之间的转录组变化， 可能在调节骨髓细胞中起作用的基因上调。候选MC基因的贡献 将通过MC特异性基因敲除来评估转移前小生境形成。目标3：靶肺 MCs作为临床前消除免疫抑制性肺转移前小生境的策略 模型使用原位肿瘤植入模型，我们将测试肺MC阻断剂的能力， 增强肺部抗肿瘤免疫力，防止肺转移。这些研究将是迈向我们的重要一步。 长期目标是充分剖析器官特异性基质细胞在乳腺癌向器官转移中的作用 癌我们期望我们的发现将为小说的发展奠定坚实的基础 靶向基质因子预防和治疗乳腺癌肺转移的治疗策略 癌症和其他实体瘤。

PROJECT SUMMARY/ABSTRACT Metastatic disease remains the major cause of cancer-related death. Among the vital organs to which solid tumors metastasize, the lung is one of the most common. Lung metastases frequently occur in various late stage solid cancers including breast cancer. In the past 20 years, significant advances in lung metastasis research have revealed intricate interactions between the disseminated tumor cells (DTCs) and the lung microenvironment that are essential for the development of metastatic lung lesions. In particular, formation of the immunosuppressive lung pre-metastatic microenvironment (niche), which is driven by factors secreted by primary tumors, is regarded as a key preparation stage prior to the arrival of DTCs. The focus of this proposal will be on the lung resident mesenchymal cells (MCs), an under-characterized stromal cell population within the lung pre-metastatic niche. Preliminary studies in mouse models of breast cancer suggest that lung resident MCs serve as a driver of immunosuppressive pre-metastatic niche formation by reprogramming diverse types of myeloid cells to become highly immunosuppressive or tolerogenic. The central hypothesis of this proposal is that lung resident MCs drive formation of the lung pre-metastatic niche by endowing diverse infiltrating myeloid cells with an immunosuppressive capacity. To test this hypothesis and uncover mechanisms by which MCs modulate myeloid cells, we propose three Specific Aims. Aim 1: Determine the lung resident MC changes in the pre-metastatic niche using genetic manipulation of endogenous MCs in mice. We will use orthotopic breast tumor cell implantation and genetically engineered mouse (GEM) tumor models to measure the endogenous MC changes at the pre-metastatic stage. MCs will also be ablated in vivo to determine their necessity for pre-metastatic niche formation. Aim 2: Characterize the key lung mesenchymal factors that recruit and modulate myeloid cells. We will use RNA sequencing to profile transcriptome changes between endogenous MCs residing in pre-metastatic vs. normal lungs to identify upregulated genes that might play a role in modulating myeloid cells. The contribution of candidate MC genes to pre-metastatic niche formation will be evaluated through MC-specific gene knockout. Aim 3: Target lung MCs as a strategy for abolishing the immunosuppressive lung pre-metastatic niche in preclinical models. Using orthotopic tumor implantation models, we will test the ability of lung MC blockade agents to boost lung anti-tumor immunity and prevent lung metastasis. These studies will be a significant step toward our long-term goal to fully dissect the roles of organ-specific stromal cells in organ-tropic metastases of breast cancer. We anticipate that our findings will establish a strong foundation for the development of novel therapeutic strategies that target stromal factors for the prevention and treatment of lung metastases of breast cancer and other solid tumors.