PD-1/PD-L1免疫检查点抑制剂与天然产物的结合比单一疗法表现出更好的疗效。因此，本研究的目的是检查布鲁萨醇（一种源自鸦胆子的天然苦木素萜类化合物）与抗小鼠 PD-1 抗体联合使用时在小鼠头颈部鳞状细胞中的抗癌作用建立小鼠HNSCC模型和SCC-15细胞异种移植裸鼠模型，研究brusatol和抗PD-1抗体的抗癌作用。使用免疫组织化学进行机制研究。通过MTT、迁移、集落形成和跨孔侵袭测定评估细胞增殖、迁移、集落形成和侵袭。通过 qRT-PCR、流式细胞术和蛋白质印迹测定评估口腔鳞状细胞癌 (OSCC) 细胞中的 PD-L1 水平。通过 OSCC/Jurkat 共培养测定评估布鲁萨醇对 Jurkat T 细胞功能的影响。在 HNSCC 小鼠模型中，布鲁萨醇改善了抗 PD-1 抗体对肿瘤的抑制作用。机制研究表明，brusatol 可抑制肿瘤细胞生长和血管生成、诱导细胞凋亡、增加 T 淋巴细胞浸润并降低肿瘤中 PD-L1 的表达。此外，体外试验证实，brusatol 可抑制 OSCC 细胞中的 PD-L1 表达，并抑制细胞迁移、集落形成和侵袭。共培养测定表明，brusatol 的 PD-L1 抑制作用增强了 Jurkat T 细胞介导的 OSCC 细胞死亡，并逆转了 OSCC 细胞诱导的抑制作用。 Brusatol 通过靶向 PD-L1 提高了抗 PD-1 抗体的功效，表明其作为抗 PD-1 抗体的潜力。抗 PD-1 免疫疗法的佐剂。版权所有 © 2024 Elsevier Ltd. 保留所有权利。

Combing PD-1/PD-L1 immune checkpoint inhibitors with natural products has exhibited better efficacy than monotherapy. Hence, the purpose of this research was to examine the anti-cancer effects of brusatol, a natural quassinoid-terpenoid derived from Brucea javanica, when used in conjunction with an anti-mouse-PD-1 antibody in a murine head and neck squamous cell carcinoma (HNSCC) model and elucidate underlying mechanisms.A murine HNSCC model and an SCC-15 cell xenograft nude mouse model were established to investigate the anti-cancer effects of brusatol and anti-PD-1 antibody. Mechanistic studies were performed using immunohistochemistry. Cell proliferation, migration, colony formation, and invasion were evaluated by MTT, migration, colony formation, and transwell invasion assays. PD-L1 levels in oral squamous cell carcinoma (OSCC) cells were assessed through qRT-PCR, flow cytometry, and western blotting assays. The impact of brusatol on Jurkat T cell function was assessed by an OSCC/Jurkat co-culture assay.Brusatol improved tumor suppression by anti-PD-1 antibody in HNSCC mouse models. Mechanistic studies revealed brusatol inhibited tumor cell growth and angiogenesis, induced apoptosis, increased T lymphocyte infiltration, and reduced PD-L1 expression in tumors. Furthermore, in vitro assays confirmed brusatol inhibited PD-L1 expression in OSCC cells and suppressed cell migration, colony formation, and invasion. Co-culture assays indicated that brusatol's PD-L1 inhibition enhanced Jurkat T cell-mediated OSCC cell death and reversed the inhibitory effect induced by OSCC cells.Brusatol improves anti-PD-1 antibody efficacy by targeting PD-L1, suggesting its potential as an adjuvant in anti-PD-1 immunotherapy.Copyright © 2024 Elsevier Ltd. All rights reserved.