Zhang Yijia, Zhu Xinya, Chen Liyuan, Gao Tianyu, Chen Guang, Zhu Jin, Wang Guoyu, Zuo Daiying
Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, Liaoning 110016, PR China; Department of Pharmacology, Taizhou University, Taizhou, Zhejiang 318000, PR China.
Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, Liaoning 110016, PR China.
Neoplasia. 2025 Feb;60:101096. doi: 10.1016/j.neo.2024.101096. Epub 2024 Dec 30.
Pancreatic ductal adenocarcinoma (PDAC) is characterized by its aggressive nature and dismal prognosis, largely attributed to its unique tumor microenvironment. However, the molecular mechanisms by which tumor-associated macrophages (TAMs) promote PDAC progression, particularly the role of β-catenin signaling in regulating TAM phenotype and function, remain incompletely understood. Initially, we performed comprehensive analyses of RNA-seq and single-cell RNA-seq (scRNA-seq) datasets to investigate OSM and LOXL2 expression patterns in PDAC. Subsequently, the regulatory relationship between β-catenin and OSM in TAMs was examined using THP-1-derived macrophages. Furthermore, the functional impact of TAM-derived OSM on PDAC progression was evaluated through in vitro co-culture systems and an in vivo Panc02 lung metastasis model. Additionally, mechanistic studies employed pharmacological inhibitors and genetic approaches targeting β-catenin, OSM, and STAT3 signaling. Notably, elevated expression of OSM and LOXL2 in PDAC specimens significantly correlated with poor patient survival. Intriguingly, scRNA-seq analysis revealed that β-catenin signaling was uniquely activated in TAMs among immune cells, which consequently regulated both TAM polarization and OSM expression. These OSM-expressing TAMs exhibited a distinct hybrid M1/M2 phenotype. Besides, our transcriptional profiling of TAMs revealed concurrent activation of both pro- and anti-inflammatory programs, with enrichment in Wnt signaling pathways. RNA-seq analysis of PDAC cells exposed to TAM-derived factors demonstrated enhanced mesenchymal transition and stemness properties, with direct enrichment of OSM signaling and extracellular matrix remodeling pathways. Mechanistically, β-catenin activation directly regulated both TAM phenotype and OSM expression, while TAM-conditioned medium enhanced PDAC cell migration, invasion, and lung metastasis. Importantly, inhibition of β-catenin signaling simultaneously altered TAM polarization and reduced OSM expression, which substantially attenuated epithelial-mesenchymal transition (EMT) in co-cultured PDAC cells. Moreover, STAT3 inhibition abolished OSM-induced LOXL2 expression and subsequent EMT programming. Collectively, we identified a novel β-catenin/OSM-STAT3/LOXL2 signaling axis mediating TAM-induced PDAC progression. This pathway not only elucidates a previously unrecognized mechanism of β-catenin-mediated regulation of TAM function and phenotype but also presents potential therapeutic targets for intervention.
胰腺导管腺癌（PDAC）具有侵袭性强和预后差的特点，这在很大程度上归因于其独特的肿瘤微环境。然而，肿瘤相关巨噬细胞（TAM）促进PDAC进展的分子机制，特别是β-连环蛋白信号在调节TAM表型和功能中的作用，仍未完全了解。首先，我们对RNA测序和单细胞RNA测序（scRNA-seq）数据集进行了全面分析，以研究PDAC中抑瘤素M（OSM）和赖氨酰氧化酶样蛋白2（LOXL2）的表达模式。随后，使用THP-1来源的巨噬细胞研究了TAM中β-连环蛋白与OSM之间的调控关系。此外，通过体外共培养系统和体内Panc02肺转移模型评估了TAM来源的OSM对PDAC进展的功能影响。此外，机制研究采用了针对β-连环蛋白、OSM和信号转导与转录激活因子3（STAT3）信号的药理学抑制剂和基因方法。值得注意的是，PDAC标本中OSM和LOXL2的高表达与患者的不良生存显著相关。有趣的是，scRNA-seq分析显示，β-连环蛋白信号在免疫细胞中的TAM中被独特激活，从而调节TAM极化和OSM表达。这些表达OSM的TAM表现出独特的混合M1/M2表型。此外，我们对TAM的转录谱分析揭示了促炎和抗炎程序的同时激活，且富含Wnt信号通路。对暴露于TAM来源因子的PDAC细胞进行RNA测序分析表明，间充质转化和干性特性增强，OSM信号和细胞外基质重塑通路直接富集。从机制上讲，β-连环蛋白激活直接调节TAM表型和OSM表达，而TAM条件培养基增强了PDAC细胞的迁移、侵袭和肺转移。重要的是，抑制β-连环蛋白信号同时改变了TAM极化并降低了OSM表达，这大大减弱了共培养的PDAC细胞中的上皮-间质转化（EMT）。此外，抑制STAT3消除了OSM诱导的LOXL2表达和随后的EMT编程。总的来说，我们确定了一条新的β-连环蛋白/OSM-STAT3/LOXL2信号轴，介导TAM诱导的PDAC进展。该途径不仅阐明了β-连环蛋白介导的TAM功能和表型调节的一种先前未被认识的机制，而且还提供了潜在的干预治疗靶点。
