Elucidating fibroblast/immune crosstalk and plasticity in pancreatic ductal adenocarcinoma

项目摘要 胰腺导管腺癌(Pda)是一种致命的恶性肿瘤，只有8%的患者被诊断患有这种疾病。 癌症在确诊后存活5年。PDA患者预后不良归因于晚期 在确诊时处于疾病阶段，缺乏有效的治疗方法，突出了需要新的 接近了。PDA的特征是癌细胞周围有丰富的细胞外基质(ECM)， 称为促结缔组织反应。结缔组织增生为不同类型的基质细胞提供了一个合适的位置， 包括免疫细胞和癌症相关成纤维细胞(CAF)，它们主要来自胰腺 星状细胞(PSC)。最近发现PDA CAF表现出异质性，具有明显的表型和 空间分布：肌成纤维细胞CAF(MyCAF)表达高水平的α-平滑肌肌动蛋白(αSMA)和 与癌细胞直接接触，而炎症性CAF(ICAF)远离肿瘤 细胞和分泌炎性细胞因子。尽管这一发现为新的治疗方法提供了机会 途径，它们与其他类型的细胞相互作用内的免疫抑制，促进肿瘤 PDA的微环境有待进一步研究。肿瘤相关巨噬细胞(TAM)在PDA中表现突出 而且已知具有免疫抑制功能，使其成为有吸引力的治疗靶点。 然而，TAMS信号转导和影响iCAF和myCAF生物学的机制仍然存在 有待探索。本研究旨在了解巨噬细胞与两种CAF亚型之间的串扰。 以及这些细胞群在PDA进展过程中是如何波动的。我的初步研究表明，PSCs 促进巨噬细胞体外增殖和交替激活。此外，在基因上， 胰腺癌的工程化小鼠模型(GEMM)，Panin病变(PDA的前驱)显示了 α-SMA+成纤维细胞和交替激活的巨噬细胞的数量都很接近。 这些结果表明，成纤维细胞和巨噬细胞相互传递信号，参与了CAF和 PDA的巨噬细胞表型。为了确定造成这种串扰的因素，我将使用一个创新的、三个- 三维三重共培养系统，结合了胰腺导管类器官、PSCs和巨噬细胞。至 更好地了解CAF亚型如何影响体内的肿瘤进展和巨噬细胞表型，我将 设计ICAF和myCAF条件性基因敲除小鼠，并在原位上扰乱每个亚型 移植类器官小鼠模型。最终，ICAF/myCAF的鉴定和巨噬细胞动力学 相互作用将阐明这些细胞在疾病中所起的作用，为新的和更多的- 所需的治疗靶点。

Project Summary Pancreatic ductal adenocarcinoma (PDA) is a deadly malignancy, and only 8% of patients diagnosed with this cancer survive 5 years after diagnosis. The poor outcomes of patients with PDA are attributed to the advanced stage of disease at the time of diagnosis and the lack of effective therapies, highlighting the need for new approaches. PDA is characterized by an abundance of extracellular matrix (ECM) around the cancer cells, referred to as a desmoplastic reaction. The desmoplasia provides a niche for different types of stromal cells, including immune cells and cancer-associated fibroblasts (CAFs), which are derived primarily from pancreatic stellate cells (PSCs). PDA CAFs have recently been found to display heterogeneity with distinct phenotypes and spatial distributions: myofibroblastic CAFs (myCAFs) express high levels of α-smooth muscle actin (αSMA) and are in direct physical contact with cancer cells, while inflammatory CAFs (iCAFs) are farther away from tumor cells and secrete inflammatory cytokines. Although this finding has provided opportunities for new therapeutic approaches, their interaction with other cell types within the immunosuppressive, tumor-promoting microenvironment of PDA requires further study. Tumor-associated macrophages (TAMs) are prominent in PDA tumors and are known to have an immunosuppressive function, making them an attractive therapeutic target. However, the mechanisms through which TAMs signal to and impact the biology of iCAFs and myCAFs remains to be explored. This study aims to understand the crosstalk between macrophages and the two CAF subtypes and how these cell populations fluctuate during PDA progression. My preliminary studies show that PSCs promote the proliferation and alternative activation of macrophages in vitro. In addition, in a genetically engineered mouse model (GEMM) of pancreatic cancer, PanIN lesions (precursors of PDA) display an abundance of both αSMA+ fibroblasts and alternatively activated macrophages in close proximity to each other. These results suggest that the fibroblasts and macrophages signal to each other, contributing to the CAF and macrophage phenotypes in PDA. To identify factors responsible for such crosstalk, I will use an innovative, three- dimensional triple co-culture system that combines pancreatic ductal organoids, PSCs, and macrophages. To better understand how the CAF subtypes impact tumor progression and macrophage phenotype in vivo, I will engineer iCAF- and myCAF-conditional knockout mice and perturb each subtype in an orthotopically transplanted organoid mouse model. Ultimately, the identification of iCAF/myCAF and macrophage dynamics and interactions will illuminate the role these cells play in the disease, opening avenues for new and much- needed therapeutic targets.