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

项目摘要 肥胖率在全球范围内都在上升。肥胖是患乳腺癌的一个重要风险因素， 肥胖的乳腺癌患者预后更差。肥胖患者的乳腺肿瘤有所增加 结缔组织增生，有明显更多的平滑肌肌动蛋白(SMA)阳性细胞，这是肌成纤维细胞的标志， 在肿瘤内。肥胖会导致一种由巨噬细胞驱动的慢性炎症状态。目前还不清楚是如何做到的 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。在肥胖方面， 骨髓中的髓系祖细胞显著增加。纤维细胞--一种髓系细胞 同时具有巨噬细胞和肌成纤维细胞的特征，来源于髓系祖细胞，是 在慢性炎症性和纤维性疾病中增加。我们的长期目标是了解系统性的 肥胖症的炎症状态会导致纤维性肿瘤。其基本原理是肿瘤纤维化与 更具侵袭性的肿瘤，了解这种炎性微环境将导致发现 肥胖癌症患者亟需的治疗目标。这项提案的总体目标是确定 肥胖如何增加纤维细胞以增强肿瘤内的胶原沉积，以及如何进行减肥干预 逆转肥胖的这些影响。中心假设是肥胖可逆地增加髓系祖细胞 骨髓和乳腺内的细胞和纤维细胞分别导致胶原蛋白的增加 肿瘤内的沉积。这一假设将在三个具体目标上进行检验：1)确定肥胖是如何导致的 纤维细胞促进乳腺肿瘤间质；2)阐明肥胖诱导的纤维细胞如何促进纤维化 在肿瘤生长过程中；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，导致纤维化减少。饮食诱导的肥胖小鼠模型及TrP53-/- 将利用乳腺肿瘤细胞异种移植来测试这些目的。髓系祖细胞和单核细胞/ 骨髓和乳腺肿瘤中的巨噬细胞将从瘦、肥胖和体重减轻的小鼠中定量 用流式细胞仪和流式细胞仪检测。FACS分离细胞的克隆形成将用于量化乳腺 肿瘤纤维细胞。FACS分离表达GFP的肥胖小鼠骨髓细胞过继转移 将被用来检查导致肿瘤纤维化的细胞群。天狼星红染色与 免疫荧光将被用来检测乳腺肿瘤中的胶原沉积并定位纤维细胞。 这种方法是创新的，因为纤维细胞在肥胖症中还没有被研究过，其机制 肥胖引起的肿瘤结缔组织增生症还不是很清楚。确定肥胖如何调节纤维细胞和 肿瘤纤维化对于开发治疗肥胖者中观察到的更具侵袭性的肿瘤的新疗法很重要 癌症患者。除了新的技术知识外，所描述的培训还提供了增强 威斯康星大学合作研究环境中的科学交流、网络和指导技能- 麦迪逊。培训计划将帮助申请者迈向独立癌症研究人员的职业生涯。

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.