The First Affiliated Hospital of Jinan University, Guangzhou, China.
Department of Otolaryngology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
Immun Inflamm Dis. 2024 Sep;12(9):e70005. doi: 10.1002/iid3.70005.
B7-H3 protein is an important regulator of the adaptive immune response in human tumorigenesis. 4-1BB is a co-stimulatory receptor expressed on activated CD8+ T cells, and regulates T cell immunity. Here, we investigated the role of B7-H3 in the growth and invasion of nasopharyngeal carcinoma (NPC) and the effect of its interaction with 4-1BB on tumor immunity.
Short hairpin (sh) RNA was designed to knock down B7-H3 expression in NPC cells. NPC cells with stable knockdown of B7-H3 were established and injected into nude mice. The effects of B7-H3 on cell proliferation, apoptosis, and epithelial-to-mesenchymal transition (EMT) were detected by the CCK8 assay, flow cytometry, TUNEL assay, and western blot analysis. The migration and invasion abilities were determined using the Transwell assay and scratch assay. Co-immunoprecipitation (Co-IP) assays were performed to study the interaction between B7-H3 and 4-1BB. Anti-4-1BB antibody was used in a co-culture system and xenograft mice to study the effect of 4-1BB on NPC development.
NPC cells transfected with sh-B7-H3 showed a higher rate of apoptosis, slower growth rate, impaired migration, and less EMT in vitro. Xenograft mice with stable knockout of B7-H3 had lower tumor burdens, and the stripped tumors had lower rates of cell proliferation, higher rates of apoptosis, and less EMT in vivo. Additionally, decreased B7-H3 expression was positively correlated with interferon-γ, tumor necrosis factor-α, and 4-1BB+CD8+ tumor-infiltrating lymphocytes. Co-IP studies showed that B7-H3 interacts with 4-1BB. Also, the inhibitory effects of sh-B7-H3 on NPC tumor growth, invasion, and tumor immunity could be alleviated by the anti-4-1BB antibody both in vivo and in vitro.
Our findings suggest that B7-H3 may accelerate tumor growth, tumor cell invasion, and EMT, and interact with 4-1BB to produce CD8+ T cell exhaustion that inhibits tumor immunity. B7-H3 might serve as a novel target for treating NPC.
B7-H3 蛋白是人类肿瘤发生中适应性免疫反应的重要调节剂。4-1BB 是一种表达在激活的 CD8+T 细胞上的共刺激受体，调节 T 细胞免疫。在这里，我们研究了 B7-H3 在鼻咽癌（NPC）生长和侵袭中的作用及其与 4-1BB 的相互作用对肿瘤免疫的影响。
设计短发夹（sh）RNA 敲低 NPC 细胞中的 B7-H3 表达。建立稳定敲低 B7-H3 的 NPC 细胞，并将其注入裸鼠。通过 CCK8 测定、流式细胞术、TUNEL 测定和 Western blot 分析检测 B7-H3 对细胞增殖、凋亡和上皮间质转化（EMT）的影响。通过 Transwell 测定和划痕测定确定迁移和侵袭能力。通过共免疫沉淀（Co-IP）测定研究 B7-H3 与 4-1BB 的相互作用。在共培养系统和异种移植小鼠中使用抗 4-1BB 抗体研究 4-1BB 对 NPC 发展的影响。
转染 sh-B7-H3 的 NPC 细胞在体外表现出更高的凋亡率、更慢的生长速度、受损的迁移和更少的 EMT。稳定敲低 B7-H3 的异种移植小鼠的肿瘤负担较低，剥离的肿瘤在体内的细胞增殖率较低、凋亡率较高、EMT 较少。此外，B7-H3 表达的降低与干扰素-γ、肿瘤坏死因子-α和 4-1BB+CD8+肿瘤浸润淋巴细胞呈正相关。Co-IP 研究表明 B7-H3 与 4-1BB 相互作用。此外，体内和体外抗 4-1BB 抗体均可减轻 sh-B7-H3 对 NPC 肿瘤生长、侵袭和肿瘤免疫的抑制作用。
我们的研究结果表明，B7-H3 可能加速肿瘤生长、肿瘤细胞侵袭和 EMT，并与 4-1BB 相互作用产生抑制肿瘤免疫的 CD8+T 细胞耗竭。B7-H3 可能成为治疗 NPC 的新靶点。
