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posted on 2024-02-02, 08:20 authored by Kun Wu, Yan Li, Yikang Ji, Chun Liu, Xiaoning Wang, Haiyan Guo, Jianjun Zhang, Yue He Supplementary Figure 2. (a) Immunofluorescence staining of CD68 distribution (Red) in macrophage. Scale bar: 50 μm; (b-d) Macrophages, BEAS-2B and HBE were cocultured with EpCAM-GFP labelled sEVs from HNSCC cell lines for 8 h (b), 16h (c) and 24h (d). Confocal Microscopy was used to analyze the internalization of HNSCC-derived sEVs into macrophages, BEAS-2B and HBE. (e) Quantitative analysis for integrin-β1 in macrophage, BEAS-2B and HBE. (f) Quantitative analysis for RAB21 in sEVs. (g) The mouse pulmonary epithelial cells and macrophages were isolated by flow cytometry. The Immunoblotting analysis was used to detect integrin-β1 in mouse macrophage and pulmonary epithelial cells. (h) Quantitative analysis for integrin-β1 in mouse pulmonary epithelial cells and macrophages. (i) The schematic of preparing pre-metastatic niche formation with sEVs injection via tail vein, followed with tail vein injection of SCC7luciferase for performing lung metastasis vivo experiment;
Funding
National Natural Science Foundation of China (NSFC)
Natural Science Foundation of Hunan Province (湖南省自然科学基金)
China Postdoctoral Science Foundation (China Postdoctoral Foundation Project)
History
ARTICLE ABSTRACT
Tumor metastasis is a spatial and temporal process that starts with remodeling to generate a proper premetastatic niche in a distant tissue. Infiltration of immunosuppressive macrophages is one of the notable characteristics in the premetastatic niche, which is a fundamental requirement for primary tumor metastasis. Here, we demonstrated that small extracellular vesicles (sEV) carrying RAB21 homed to lung macrophages and interacted with integrin-β1 on macrophages. ABHD12 expression was high in lung metastatic tumors and was mostly expressed by macrophages. Head and neck squamous cell carcinoma (HNSCC)–derived sEVs carrying ABHD12-polarized macrophages toward an immunosuppressive phenotype, driving premetastatic niche formation, which facilitated lung metastasis. ABHD12 additionally upregulated S1PR1 by activating the AKT–FoxO1 pathway in macrophages, and significantly enhanced antitumor responses were observed in tumor models treated with agents targeting both S1PR1 and PD-1. Collectively, our study suggests that RAB21+ABHD12+ sEVs derived from HNSCC cells contribute to the formation of the immunosuppressive microenvironment in the premetastatic niche and are a potential therapeutic target for enhancing the antitumor efficacy of anti–PD-1 therapy.
