Programmed death-ligand 1 (PD-L1) on tumor-derived small extracellular vesicles (sEVs) limits therapeutic effectiveness by interacting with the PD-1 receptor on host immune cells. Targeting the secretion of sEV PD-L1 has emerged as a promising strategy to enhance immunotherapy. However, the lack of small-molecule inhibitors poses a challenge for clinical translation. In this study, we developed a target and phenotype dual-driven high-throughput screening strategy that combined virtual screening with nanoflow-based experimental verification. We identified ibuprofen (IBP) as a novel inhibitor that effectively targeted sEV PD-L1 secretion. IBP disrupted the biogenesis and secretion of PD-L1+ sEVs in tumor cells by physically interacting with a critical regulator of sEV biogenesis, hepatocyte growth factor-regulated tyrosine kinase substrate. Notably, the mechanism of action of IBP is distinct from its commonly known targets, cyclooxygenases. Administration of IBP stimulated antitumor immunity and enhanced the efficacy of anti-PD-1 therapy in melanoma and oral squamous cell carcinoma mouse models. To address potential adverse effects, we further developed an IBP gel for topical application, which demonstrated remarkable therapeutic efficacy when combined with anti-PD-1 treatment. The discovery of this specific small inhibitor provides a promising avenue for establishing durable, systemic antitumor immunity.

中文翻译：

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高通量筛选确定布洛芬是一种用于协同癌症免疫治疗的 sEV PD-L1 抑制剂


肿瘤来源的小细胞外囊泡 （sEV） 上的程序性死亡配体 1 （PD-L1） 通过与宿主免疫细胞上的 PD-1 受体相互作用来限制治疗效果。靶向 sEV PD-L1 的分泌已成为增强免疫治疗的一种有前途的策略。然而，小分子抑制剂的缺乏对临床转化构成了挑战。在这项研究中，我们开发了一种靶标和表型双驱动高通量筛选策略，将虚拟筛选与基于纳流的实验验证相结合。我们发现布洛芬 （IBP） 是一种有效靶向 sEV PD-L1 分泌的新型抑制剂。IBP 通过与 sEV 生物发生的关键调节因子肝细胞生长因子调节的酪氨酸激酶底物物理相互作用，破坏肿瘤细胞中 PD-L1 + sEVs 的生物发生和分泌。值得注意的是，IBP 的作用机制与其通常已知的靶标环氧合酶不同。IBP 的给药刺激了抗肿瘤免疫，并增强了抗 PD-1 治疗在黑色素瘤和口腔鳞状细胞癌小鼠模型中的疗效。为了解决潜在的不良反应，我们进一步开发了一种用于局部应用的 IBP 凝胶，当与抗 PD-1 治疗联合使用时，它显示出显着的治疗效果。这种特异性小抑制剂的发现为建立持久的全身抗肿瘤免疫提供了一条有前途的途径。