未成熟骨髓和红系免疫抑制细胞存在的造血失调是肿瘤发展免疫逃逸阶段的关键特征。在此，探讨了体外生成的 B16F10 肿瘤细胞来源的细胞外囊泡 (tEV) 作为间接细胞通讯器参与肿瘤诱导的造血失调的作用。分离的 tEV 显示出尺寸范围为 100-200 nm 的小型 EV 的特征，表达常见的 EV 标记 CD63、CD9 和 Alix，并且具有带有脂质双层膜的球形形状。蛋白质组分析揭示了与 tEV 相关的显着水平的血管生成因子，特别是血管内皮生长因子 (VEGF)、骨桥蛋白和组织因子。在同基因小鼠中全身施用这些tEV可诱导脾肿大并扰乱造血功能，导致髓外造血、脾脏未成熟红系祖细胞扩张、骨髓细胞结构减少、粒细胞骨髓抑制细胞的髓质扩张以及贫血的发生。这些效应与在荷瘤小鼠中观察到的效应非常相似，并且在热灭活 tEV 后未观察到这些效应。体外研究表明，tEV 独立诱导骨髓粒细胞髓系抑制细胞和 B 细胞的扩增，同时降低红细胞生成谱系中细胞的频率。阻断 VEGF 或热灭活可显着消除 tEV 的这些作用。我们的研究结果强调了 tEV 在癌症免疫编辑的免疫逃逸阶段造血失调中的重要作用，表明它们作为解决免疫逃逸和恢复正常造血过程的目标的潜力。© 2024 作者。 《Journal of Extracellular Vesicles》由 Wiley periodicals LLC 代表国际细胞外囊泡学会出版。

Haematopoiesis dysregulation with the presence of immature myeloid and erythroid immunosuppressive cells are key characteristics of the immune escape phase of tumour development. Here, the role of in vitro generated B16F10 tumour cell-derived extracellular vesicles (tEVs) as indirect cellular communicators, participating in tumour-induced dysregulation of haematopoiesis, was explored. The isolated tEVs displayed features of small EVs with a size range of 100-200 nm, expressed the common EV markers CD63, CD9, and Alix, and had a spherical shape with a lipid bilayer membrane. Proteomic profiling revealed significant levels of angiogenic factors, particularly vascular endothelial growth factor (VEGF), osteopontin, and tissue factor, associated with the tEVs. Systemic administration of these tEVs in syngeneic mice induced splenomegaly and disrupted haematopoiesis, leading to extramedullary haematopoiesis, expansion of splenic immature erythroid progenitors, reduced bone marrow cellularity, medullary expansion of granulocytic myeloid suppressor cells, and the development of anaemia. These effects closely mirrored those observed in tumour-bearing mice and were not seen after heat inactivating the tEVs. In vitro studies demonstrated that tEVs independently induced the expansion of bone marrow granulocytic myeloid suppressor cells and B cells while reducing the frequency of cells in the erythropoietic lineage. These effects of tEVs were significantly abrogated by the blockade of VEGF or heat inactivation. Our findings underscore the important role of tEVs in dysregulating haematopoiesis during the immune escape phase of cancer immunoediting, suggesting their potential as targets for addressing immune evasion and reinstating normal hematopoietic processes.© 2024 The Author(s). Journal of Extracellular Vesicles published by Wiley Periodicals LLC on behalf of International Society for Extracellular Vesicles.