头颈鳞状细胞癌 (HNSCC) 是全球癌症负担，其 5 年总体生存率约为 50%，数十年来一直停滞不前。肿瘤诱导的免疫抑制微环境有助于 HNSCC 的进展，其中腺苷 (ADO) 途径和抑制性免疫检查点调节因子的表达上调在这方面发挥着关键作用。高中性粒细胞与淋巴细胞比率 (NLR) 与晚期肿瘤分期之间的相关性表明中性粒细胞 (NØ) 参与癌症进展。有趣的是，我们将原发性 HNSCC 样本中的高 NLR 与细胞内 PD-L1 定位增加联系起来，可能介导更具侵袭性的肿瘤特征，从而协同促进肿瘤进展。尽管如此，还需要进一步的研究来利用这些知识进行有效的治疗并克服耐药性。由于假设肿瘤微环境（TME）可能受到肿瘤（TEX）分泌的小细胞外囊泡（sEV）的影响，本研究旨在研究 HNSCC 衍生的 TEX 对 NØ 的影响和 ADO 受体的阻断作为潜在的逆转 NØ 促肿瘤表型的策略。 UMSCC47-TEX 表现出参与 ADO 信号传导的 CD73 酶活性以及免疫检查点抑制剂 PD-L1。数据显示，TEX 诱导 NØ 趋化，持续的相互作用促进向促肿瘤表型的转变，依赖于 ADO 受体 (P1R)，增加 CD170high 亚群、CD73 和 PD-L1 的表达，随后产生免疫抑制分泌组。阻断 A3R 会降低 CD73 和 PD-L1 的表达。 HNSCC 细胞的共培养实验表明，TEX 调节的 NØ 通过 Cyclin D-CDK4/6 信号传导增加 CD73/PD-L1 轴。为了支持这些发现，用 NØ 上清液处理具有原发肿瘤的 CAM 模型。此外，这些 NØ 促进了迁移、侵袭的增加，并减少了细胞死亡。将 P1R 靶向 NØ，特别是 A3R，展示了对抗 HNSCC 免疫抑制的潜在治疗策略。了解 TEX 介导的肿瘤和 NØ 之间的串扰可以为改善癌症治疗的免疫调节提供见解。© 2024 作者。 《Journal of Extracellular Vesicles》由 Wiley periodicals, LLC 代表国际细胞外囊泡学会出版。

Head and neck squamous cell carcinoma (HNSCC) is a global cancer burden with a 5-year overall survival rate of around 50%, stagnant for decades. A tumour-induced immunosuppressive microenvironment contributes to HNSCC progression, with the adenosine (ADO) pathway and an upregulated expression of inhibitory immune checkpoint regulators playing a key role in this context. The correlation between high neutrophil-to-lymphocyte ratio (NLR) with advanced tumour staging suggests involvement of neutrophils (NØ) in cancer progression. Interestingly, we associated a high NLR with an increased intracellular PD-L1 localization in primary HNSCC samples, potentially mediating more aggressive tumour characteristics and therefore synergistically favouring tumour progression. Still, further research is needed to harness this knowledge for effective treatments and overcome resistance. Since it is hypothesized that the tumour microenvironment (TME) may be influenced by small extracellular vesicles (sEVs) secreted by tumours (TEX), this study aims to investigate the impact of HNSCC-derived TEX on NØ and blockade of ADO receptors as a potential strategy to reverse the pro-tumour phenotype of NØ. UMSCC47-TEX exhibited CD73 enzymatic activity involved in ADO signalling, as well as the immune checkpoint inhibitor PD-L1. Data revealed that TEX induce chemotaxis of NØ and the sustained interaction promotes a shift into a pro-tumour phenotype, dependent on ADO receptors (P1R), increasing CD170high subpopulation, CD73 and PD-L1 expression, followed by an immunosuppressive secretome. Blocking A3R reduced CD73 and PD-L1 expression. Co-culture experiments with HNSCC cells demonstrated that TEX-modulated NØ increase the CD73/PD-L1 axis, through Cyclin D-CDK4/6 signalling. To support these findings, the CAM model with primary tumour was treated with NØ supernatant. Moreover, these NØ promoted an increase in migration, invasion, and reduced cell death. Targeting P1R on NØ, particularly A3R, exhibited potential therapeutic strategy to counteract immunosuppression in HNSCC. Understanding the TEX-mediated crosstalk between tumours and NØ offers insights into immunomodulation for improving cancer therapies.© 2024 The Authors. Journal of Extracellular Vesicles published by Wiley Periodicals, LLC on behalf of the International Society for Extracellular Vesicles.