PO.CL05.03 · 临床研究
内分泌耐药乳腺癌中表达胶原的myCAFs和腔上皮祖细胞对PD-L1+肿瘤相关巨噬细胞的调控
Regulation of PD-L1 + tumor associated macrophages by collagen expressing myCAFs and luminal progenitors in endocrine-resistant breast cancer
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
内分泌耐药是一大临床障碍，削弱了激素类疗法的有效性并驱动疾病进展。约15-20%的ER+乳腺癌具有内在的内分泌耐药性，另有40-50%在治疗期间获得耐药，导致转移性进展。这些患者的五年生存率降至20-25%，其中许多进展为TNBC——一种极具侵袭性的乳腺癌亚型。近期，我们证明PD-L1+肿瘤相关巨噬细胞（TAMs）是内分泌耐药的核心介导因素，并由Dll1介导的Notch信号募集。然而，内分泌耐药中PD-L1+ TAMs的调控尚未完全阐明。单细胞RNA测序（scRNA-seq）继以CellChat细胞通讯分析表明，PD-L1+ TAMs受myCAFs（肌成纤维细胞，一种癌症相关成纤维细胞）和LPs（腔上皮祖细胞）的调控。CD61+腔上皮祖细胞与肿瘤异质性相关，富含致瘤潜能，可作为乳腺癌的起源细胞。机制研究揭示myCAFs富含胶原，这在内分泌耐药乳腺癌患者样本以及经三色染色和SMA染色的ER+小鼠乳腺肿瘤中得到进一步证实。更深入的研究还显示，这些SMA+ myCAFs与PD-L1+ TAMs紧密相邻，有助于近分泌（juxtracrine）信号传导。进一步分析强调，胶原信号高表达的myCAFs通过APP-CD74以及Col1a1/Col4a1/Col4a2/Col6a3串扰介导与PD-L1+ TAMs的相互作用。另一方面，对CD61+ LPs的scRNA-seq详细分析显示，LPs同样通过APP-CD74信号与PD-L1+ TAM串扰。APP（淀粉样前体蛋白）是一种跨膜蛋白，常与较差的临床结局相关。功能上，PD-L1+ TAMs增强了LP活性，表现为球体数目增加。详细研究表明，这些PD-L1+ TAMs为CD74+且对IFN-γ有反应。此外，用FDA批准的药物Milatuzumab（一种CD74抑制剂）处理的PD-L1+ TAMs共培养，导致肿瘤球体更少更小，凸显了CD74在介导这种串扰中的关键功能。对下游调控因子的分析证实CD8+ T细胞处于耗竭状态，提示存在强烈的免疫抑制性TME。总之，我们在内分泌耐药肿瘤中鉴定出表达APP和胶原的myCAF-腔上皮祖细胞与CD74+/PD-L1+ TAMs之间复杂的细胞信号网络，为这些乳腺癌患者确定了新的可干预脆弱靶点。
查看英文原文 English abstract
Endocrine resistance is a major clinical obstacle that undermines the effectiveness of hormone-based therapies and drives disease progression. Around 15-20% of ER+ breast cancers are intrinsically endocrine resistant and an additional 40-50% acquire resistant during treatment, leading to metastatic progression. The five-year survival rate of these patients drops to 20-25%, while many of them progress to TNBC, a very aggressive subset of breast cancer.Recently, we demonstrated that PD-L1 + tumor-associated macrophages (TAMs) are a central mediator for endocrine resistance and are recruited by Dll1-mediated Notch signaling. However, regulation of the PD-L1 + TAMs in endocrine resistance is not completely understood. Single-cell RNA sequencing (scRNA-seq) followed by cell chat communication analysis depicts that PD-L1 + TAMs are regulated by myCAFs (Myofibroblasts, a type of cancer-associated fibroblasts) and LPs (Luminal progenitors). CD61+ luminal progenitor cells are linked to tumor heterogeneity and enriched with tumorigenic potential, serving as a cell of origin for breast cancers. Mechanistic studies reveal myCAFs are enriched in collagen, which is further corroborated in endocrine-resistant breast cancer patients' samples and ER+ mouse mammary tumors stained with trichrome and SMA staining. Closer investigation also shows that these SMA+ myCAFs are in close proximity to PD-L1 + TAMs, aiding juxtracrine signaling. Further analysis highlights that myCAFs which are high in collagen signaling, are mediating interaction with PD-L1 + TAMs through APP-CD74 and Col1a1/Col4a1/Col4a2/Col6a3 crosstalk. Detailed analysis on CD61 + LPs, on the other hand, by scRNA-seq show that LPs crosstalk to PDL1 + TAM through APP-CD74 signaling as well. APP (Amyloid precursor protein) is a transmembrane protein that is often correlated with worse clinical outcomes. Functionally, PD-L1 + TAMs augments LP activity, as seen by increasing sphere number. Detailed investigation shows that these PD-L1 + TAMs are CD74 + and IFN-gamma responsive. Moreover, co-culture of PD-L1 + TAMs treated with FDA approved drug Milatuzumab, a CD74 inhibitor, resulted in fewer and smaller tumor spheres, underscoring the crucial function of CD74 in mediating this crosstalk. Analysis of downstream regulators confirm that CD8 + T cells are exhausted, suggesting a strongly immune-suppressive TME. Together, we identified a complex cell signaling network between myCAF-luminal progenitor expressing APP and collagens with CD74 + /PD-L1 + TAMs in endocrine resistant tumors, identifying novel actionable vulnerabilities in these breast cancer patients.
利益披露 Disclosure
N. Das, None..
C. Hsieh, None..
R. Chakrabarti, None.