Ling Huayu, Li Yuling, Wang Panjun, Zhang Zhengxiang, Yang Zhong
Department of Oncology, The First Affiliated Hospital of Wannan Medical College, Yijishan Hospital, Wuhu City, Anhui Province, 241000, China.
Department of Hematology, The Second Affiliated Hospital of Suzhou University, Suzhou City, Jiangsu Province, 215008, China.
Arch Biochem Biophys. 2025 Apr;766:110322. doi: 10.1016/j.abb.2025.110322. Epub 2025 Jan 24.
Diffuse large B-cell lymphoma (DLBCL) is a prevalent and aggressive form of non-Hodgkin's lymphoma with a complex etiology. NOP2/Sun domain 2 (NSUN2) is an RNA methyltransferase that has been linked to the regulation of gene expression in various cancers. However, the function of NSUN2 in DLBCL, specifically its contribution to exosome-driven tumor progression, remains to be thoroughly elucidated.
Quantitative real-time polymerase chain reaction was used to analyze the expression of NSUN2 and programmed death ligand 1 variant (PDL1). Western blotting assay was performed to detect the protein levels of NSUN2, PDL1 and Y-box binding protein 1 (YBX1). Cell proliferation was analyzed by cell counting kit-8 and 5-Ethynyl-2'-deoxyuridine assays. Cell apoptosis and CD206-positive cells were quantified by flow cytometry. The levels of tumor necrosis factor-alpha and interferon-γ in cell supernatant were analyzed by enzyme-linked immunosorbent assays. m6A RNA immunoprecipitation and RNA pull-down assays were performed to determine the association between NSUN2 and PDL1. An RNA immunoprecipitation assay was used to analyze the association of YBX1 and PDL1. In vitro findings were validated in a mouse model.
NSUN2 was overexpressed in DLBCL tissues and cells. DLBCL cell-derived exosomes facilitated the transfer of NSUN2 to DLBCL cells, which in turn promoted tumor cell proliferation, M2 macrophage polarization, and immune escape and inhibited cell apoptosis. In addition, NSUN2 stabilized PDL1 mRNA through an m5C-dependent mechanism and a YBX1-dependent pathway. Moreover, the suppression of PDL1 significantly mitigated the effects induced by NSUN2 within DLBCL cell-derived exosomes on cellular proliferation, apoptosis, M2 macrophage polarization, and immune evasion. Further, DLBCL cell-derived exosomal NSUN2 promoted tumor growth by regulating PDL1.
NSUN2 in DLBCL cell-derived exosomes stabilized PDL1 in a YBX1-dependent manner and thus promoted tumor immune escape and M2 macrophage polarization. These findings highlight the potential of targeting the NSUN2-PDL1 axis as a novel therapeutic strategy for DLBCL.
弥漫性大B细胞淋巴瘤（DLBCL）是一种常见且侵袭性的非霍奇金淋巴瘤，病因复杂。NOP2/太阳结构域2（NSUN2）是一种RNA甲基转移酶，与多种癌症中的基因表达调控有关。然而，NSUN2在DLBCL中的功能，特别是其对外泌体驱动的肿瘤进展的贡献，仍有待深入阐明。
采用定量实时聚合酶链反应分析NSUN2和程序性死亡配体1变体（PDL1）的表达。进行蛋白质印迹分析以检测NSUN2、PDL1和Y盒结合蛋白1（YBX1）的蛋白水平。通过细胞计数试剂盒-8和5-乙炔基-2'-脱氧尿苷测定分析细胞增殖。通过流式细胞术对细胞凋亡和CD206阳性细胞进行定量。采用酶联免疫吸附测定分析细胞上清液中肿瘤坏死因子-α和干扰素-γ的水平。进行m6A RNA免疫沉淀和RNA下拉测定以确定NSUN2与PDL1之间的关联。采用RNA免疫沉淀测定分析YBX1与PDL1的关联。体外研究结果在小鼠模型中得到验证。
NSUN2在DLBCL组织和细胞中过表达。DLBCL细胞来源的外泌体促进NSUN2向DLBCL细胞的转移，进而促进肿瘤细胞增殖、M2巨噬细胞极化和免疫逃逸，并抑制细胞凋亡。此外，NSUN2通过m5C依赖机制和YBX1依赖途径稳定PDL1 mRNA。此外，抑制PDL1可显著减轻DLBCL细胞来源的外泌体中NSUN2对细胞增殖、凋亡、M2巨噬细胞极化和免疫逃避的诱导作用。此外，DLBCL细胞来源的外泌体NSUN2通过调节PDL1促进肿瘤生长。
DLBCL细胞来源的外泌体中的NSUN2以YBX1依赖的方式稳定PDL1，从而促进肿瘤免疫逃逸和M2巨噬细胞极化。这些发现突出了靶向NSUN2-PDL1轴作为DLBCL新型治疗策略的潜力。
