Cai Jiaodi, Xiao Li, Liu Jiao, Wang Dan, Zhou Yadong, Liao Zhiming, Chen Guoqun
Department of Pathology, The Affiliated Changsha Hospital of Hunan Normal University (The Fourth Hospital of Changsha), No. 70, Lushan South Road, Yuelu District, Changsha, 410006, Hunan, People's Republic of China.
Cancer Research Institute, Central South University, Changsha, 410006, Hunan, People's Republic of China.
Biochem Genet. 2025 Feb;63(1):540-556. doi: 10.1007/s10528-024-10719-3. Epub 2024 Mar 11.
Nasopharyngeal carcinoma (NPC) is one of the most common tumors of head and neck in the Southeast Asia. PD-L1-dependent immune escape plays a critical role involved in NPC development. BPIFB1 has previously reported to take tumor-suppressive actions on NPC cell proliferation and migration. Nonetheless, the function of BPIFB1 in immune escape remains largely elusive. Expression pattern on mRNA and protein levels of target genes in NPC patients' samples and cell lines were examined by qRT-PCR, western blot, and immunohistochemistry staining, respectively. The assessment of CD8 T-cell apoptosis and expression was determined by flow cytometry. Molecular interactions were verified using chromatin immunoprecipitation (ChIP) and luciferase reporter assay. BPIFB1 was downregulated in NPC tumor tissues, exhibiting a negative correlation of PD-L1. Overexpression of BPIFB1 significantly inhibited the expression of PD-L1, suppressing the apoptosis and enhancing the expression of CD8 T cells. Mechanistically, BPIFB1 was found to repress the expression of STAT1, which was identified to be an upstream activator of PD-L1. Furthermore, the EBV-encoded miR-BART4 overexpressed in NPC cells could directly target and inhibit BPIFB1. This study provided a comprehensive understanding of the molecular mechanism for the upstream and downstream pathway of BPIFB1 related with immune escape, indicating a novel approach for the treatment of NPC.
鼻咽癌(NPC)是东南亚地区最常见的头颈部肿瘤之一。PD-L1依赖性免疫逃逸在鼻咽癌的发展中起关键作用。先前有报道称BPIFB1对鼻咽癌细胞的增殖和迁移具有肿瘤抑制作用。然而,BPIFB1在免疫逃逸中的功能在很大程度上仍不清楚。分别通过qRT-PCR、蛋白质免疫印迹和免疫组织化学染色检测NPC患者样本和细胞系中靶基因的mRNA和蛋白质水平表达模式。通过流式细胞术评估CD8 T细胞凋亡和表达情况。使用染色质免疫沉淀(ChIP)和荧光素酶报告基因检测验证分子相互作用。BPIFB1在鼻咽癌肿瘤组织中表达下调,与PD-L1呈负相关。BPIFB1的过表达显著抑制PD-L1的表达,抑制细胞凋亡并增强CD8 T细胞的表达。机制上,发现BPIFB1可抑制STAT1的表达,而STAT1被确定为PD-L1的上游激活因子。此外,在NPC细胞中过表达的EBV编码的miR-BART4可直接靶向并抑制BPIFB1。本研究全面了解了BPIFB1与免疫逃逸相关的上下游途径的分子机制,为鼻咽癌的治疗指明了新方法。