Abstract：
Lymph node metastasis (LNM) is a major determinant for the poor outcome of oral squamous cell carcinoma (OSCC). Interferon regulatory factor 2 binding protein 2 (IRF2BP2) has been reported to modulate the development and progression of several types of cancers, while its role in OSCC with LNM has not been reported yet. The expression of IRF2BP2 and its association with LNM were evaluated by immunohistochemistry and qualitative reverse transcription polymerase chain reaction in clinically collected OSCC tissues. Then, loss-of-function and rescue assays were conducted to identify the role of IRF2BP2-mediated fatty acid oxidation (FAO) in the invasion, lymphoinvasion, and epithelial-mesenchymal transition (EMT) in OSCC cells. Importantly, confocal microscope, transmission electron microscope, immunofluorescence, and Western blot were applied to identify the involvement of mitochondrial fission in IRF2BP2-regulated FAO. Lastly, the in vivo models were established to evaluate the role of IRF2BP2 in OSCC. IRF2BP2 overexpression has been associated with LNM in OSCC, whose knockdown inhibited invasion, lymphoinvasion, and EMT of OSCC cells, as well as retarded FAO rate with CPT1A downregulation. And CPT1A overexpression rescued invasion, lymphoinvasion, and induced EMT in IRF2BP2-silenced OSCC cells. Mechanically, IRF2BP2 accelerated mitochondrial fission by contributing to Drp1 S616 phosphorylation and mitochondrial localization, resulting in the upregulation of CPT1A. In addition, IRF2BP2 knockdown significantly inhibited tumor growth and LNM in vivo. The highly expressed IRF2BP2 may induce the phosphorylation and mitochondrial translocation of Drp1 to activate mitochondrial fission, which upregulated CPT1A expression and FAO rate, resulting in LNM in OSCC. This highlighted a potential therapeutic vulnerability for the treatment of LNM+ OSCC via targeting IRF2BP2-FAO.
摘要：
淋巴结转移（LNM）是口腔鳞状细胞癌（OSCC）预后不良的主要决定因素。干扰素调节因子2结合蛋白2（IRF2BP2）已被报道可调节几种癌症的发生和发展。而其在OSCC伴LNM中的作用尚未报道。通过免疫组织化学和定性逆转录聚合酶链反应在临床收集的OSCC组织中评估IRF2BP2的表达及其与LNM的关联。然后，进行了功能丧失和挽救试验，以确定IRF2BP2介导的脂肪酸氧化（FAO）在入侵中的作用，淋巴侵入，OSCC细胞的上皮-间质转化（EMT）。重要的是,共聚焦显微镜,透射电子显微镜,免疫荧光，和Western印迹用于鉴定线粒体裂变在IRF2BP2调节的FAO中的参与。最后,建立体内模型以评估IRF2BP2在OSCC中的作用。IRF2BP2过表达与OSCC中的LNM相关，其击倒抑制了入侵，淋巴侵入，和OSCC细胞的EMT，以及CPT1A下调导致粮农组织费率延迟。CPT1A过表达拯救了入侵，淋巴侵入，并在IRF2BP2沉默的OSCC细胞中诱导EMT。机械上,IRF2BP2通过促进Drp1S616磷酸化和线粒体定位加速线粒体裂变，导致CPT1A上调。此外,IRF2BP2敲低在体内显著抑制肿瘤生长和LNM。高表达的IRF2BP2可能诱导Drp1的磷酸化和线粒体易位激活线粒体裂变,上调CPT1A表达和FAO速率，导致OSCC中的LNM。这突出了通过靶向IRF2BP2-FAO治疗LNM+OSCC的潜在治疗脆弱性。
