Fibrocytes: A novel cell population promoting obesity-induced breast tumor desmoplasia

项目摘要 肥胖率在全球范围内不断上升。肥胖是乳腺癌发生的重要危险因素， 肥胖的乳腺癌患者预后更差。肥胖患者的乳腺肿瘤增加了 结缔组织增生，具有显著更多的平滑肌肌动蛋白（SMA）阳性细胞，肌成纤维细胞的标志物， 在肿瘤中。肥胖会诱发慢性、巨噬细胞驱动的炎症状态。我们不知道 肥胖乳房内的炎症导致脂肪组织纤维化和肿瘤结缔组织增生。在肥胖症中， 骨髓祖细胞在骨髓中显著增加。纤维细胞，髓系细胞类型 具有巨噬细胞和肌成纤维细胞的特征，来源于骨髓祖细胞， 慢性炎症和纤维化疾病的发病率增加。长期目标是了解系统性 肥胖的炎性病症导致纤维化肿瘤。基本原理是肿瘤纤维化与 更具有侵袭性的肿瘤，了解这种炎症微环境将有助于发现 肥胖癌症患者急需的治疗靶点。本建议的总体目标是确定 肥胖如何增加纤维细胞以增强肿瘤内的胶原沉积，以及减肥干预如何 逆转肥胖的这些影响。核心假设是肥胖可逆性地增加骨髓祖细胞 细胞和纤维细胞分别在骨髓和乳腺，导致增加胶原蛋白 肿瘤内沉积。这一假设将在三个具体目标进行测试：1）确定肥胖如何诱导 纤维细胞有助于乳腺肿瘤间质; 2）阐明肥胖诱导的纤维细胞如何增强纤维化 3）检查体重减轻如何减少正常乳腺内的纤维细胞 和乳腺肿瘤，从而减少纤维化。饮食诱导的肥胖小鼠模型和trp 53-/- 将利用乳腺肿瘤细胞异种移植物来测试这些目标。骨髓祖细胞和单核细胞/ 骨髓和乳腺肿瘤中的巨噬细胞将从瘦的、肥胖的和体重减轻的小鼠中定量 流式细胞仪检测。来自FACS分离的细胞的集落形成将用于定量乳腺癌的发生。 肿瘤纤维细胞流式细胞术连续转移表达GFP的肥胖小鼠骨髓细胞 将被用来检查负责肿瘤纤维化的细胞群。天狼星红染色多重 免疫荧光将用于检查乳腺肿瘤中的胶原沉积和定位纤维细胞。 这种方法是创新的，因为纤维细胞还没有在肥胖症中进行过研究， 肥胖引起的肿瘤结缔组织增生尚不清楚。确定肥胖如何调节纤维细胞， 肿瘤纤维化对于开发新的治疗方法来治疗肥胖患者中观察到的更具侵袭性的肿瘤是重要的。 癌症患者。除了新的技术知识，所描述的培训提供了机会，以提高 在UW的合作研究环境中的科学沟通，网络和指导技能- 麦迪逊。该培训计划将帮助申请人成为一名独立的癌症研究人员。

PROJECT ABSTRACT Obesity rates are rising worldwide. Obesity is a significant risk factor for development of breast cancer, and obese breast cancer patients have a worse prognosis. Breast tumors from obese patients have increased desmoplasia, with significantly more smooth muscle actin (SMA) positive cells, a marker for myofibroblasts, within tumors. Obesity induces a state of chronic, macrophage-driven inflammation. It is not understood how inflammation within the obese breast contributes to adipose tissue fibrosis and tumor desmoplasia. In obesity, myeloid progenitor cells are significantly increased within bone marrow. Fibrocytes, a myeloid lineage cell type with characteristics of both macrophages and myofibroblasts, are derived from myeloid progenitor cells and are increased in chronic inflammatory and fibrotic diseases. The long-term goal is to understand how the systemic inflammatory conditions of obesity contribute to fibrotic tumors. The rationale is that tumor fibrosis is associated with more aggressive tumors, and understanding this inflammatory microenvironment will lead to discoveries of much needed therapeutic targets for obese cancer patients. The overall objective of this proposal is to identify how obesity increases fibrocytes to enhance collagen deposition within tumors, and how weight loss intervention reverses these effects of obesity. The central hypothesis is that obesity reversibly increases myeloid progenitor cells and fibrocytes within the bone marrow and mammary gland, respectively, leading to an increase in collagen deposition within tumors. This hypothesis will be tested in three specific aims: 1) To identify how obesity-induced fibrocytes contribute to mammary tumor stroma; 2) To elucidate how obesity-induced fibrocytes enhance fibrosis during tumor growth; 3) To examine how weight loss decreases fibrocytes within the normal mammary gland and mammary tumors, resulting in reduced fibrosis. A diet-induced mouse model of obesity and trp53-/- mammary tumor cell xenografts will be utilized to test these aims. Myeloid progenitor cells and monocytes/ macrophages in bone marrow and mammary tumors will be quantified from lean, obese, and weight loss mice using FACS and flow cytometry. Colony formation from FACS isolated cells will be used to quantify mammary tumor fibrocytes. Adoptive transfer using FACS isolated GFP-expressing bone marrow cells from obese mice will be used to examine cell populations responsible for tumor fibrosis. Picrosirius red staining multiplexed with immunofluorescence will be used to examine collagen deposition in mammary tumors and localize fibrocytes. This approach is innovative because fibrocytes have not been studied in obesity, and the mechanisms underlying obesity-induced tumor desmoplasia are not well understood. Identifying how obesity regulates fibrocytes and tumor fibrosis is important to develop novel therapies to treat the more aggressive tumors observed in obese cancer patients. Beyond new technical knowledge, the training described provides opportunities to enhance science communication, networking, and mentorship skills within the collaborative research environment at UW- Madison. The training plan will help the applicant work toward a career as an independent cancer researcher.