Li Zhi, Duan Yumei, Cheng Shiyue, Chen Yan, Hu Yanxin, Zhang Lu, He Jiang, Liao Qiong, Yang Lifang, Sun Lun-Quan
Center for Molecular Medicine, Xiangya Hospital, Central South University, Changsha, China 410008.
College of Veterinary Medicine, China Agricultural University, Beijing, China 100193.
Oncotarget. 2015 Sep 15;6(27):24291-303. doi: 10.18632/oncotarget.4552.
Pathogen-induced inflammation has been one of the intensive research areas in carcinogenesis. EBV encoded RNAs (EBERs) have been suggested to play roles in anti-apoptosis and growth-promotion in lymphoid and immune disorders. However, pathological roles of EBERs in solid tumors of epithelia origin remain to be elucidated. Given their characteristic dsRNA structures, recent studies provided evidences for the activation of some pattern recognition receptors (PRR) by EBERs, which is fundamental in the process of pathogenesis. Here, we show that EBERs induce inflammatory response in nasopharyngeal carcinoma (NPC) cells through Toll-like receptor 3 (TLR3), mainly featured by high level of TNFα production. Interestingly, EBERs and EBV latent membrane protein 1 (LMP1) form a positive regulatory loop with NF-κB as a key node that amplifies the inflammatory signals in EBV infected epithelial cells. We demonstrate in vivo that EBERs can interact with TLR3 and induce tumor cells to produce cytokines in B16 synergetic tumor and human NPC xenograft models, in which macrophages are recruited and activated, leading to a favorable microenvironment for solid tumor growth. Lastly, we verify a positive association between EBER and TNFα levels in NPC clinical samples and the combination of EBER and TNFα expressions provides a predictor of poor survival of NPC patients. In conclusion, EBERs play a pivotal role in inflammation-to-oncogenesis transition in NPC development.
病原体诱导的炎症一直是肿瘤发生领域的重点研究方向之一。EB病毒编码的RNA(EBERs)被认为在淋巴和免疫紊乱中的抗凋亡及促进生长过程中发挥作用。然而,EBERs在上皮来源实体瘤中的病理作用仍有待阐明。鉴于其特征性的双链RNA结构,近期研究为EBERs激活某些模式识别受体(PRR)提供了证据,这在发病机制过程中至关重要。在此,我们表明EBERs通过Toll样受体3(TLR3)在鼻咽癌(NPC)细胞中诱导炎症反应,主要特征是高水平的肿瘤坏死因子α(TNFα)产生。有趣的是,EBERs与EB病毒潜伏膜蛋白1(LMP1)形成了以核因子κB(NF-κB)为关键节点的正调控环,该环在EB病毒感染的上皮细胞中放大炎症信号。我们在体内证明,在B16协同肿瘤和人NPC异种移植模型中,EBERs可与TLR3相互作用并诱导肿瘤细胞产生细胞因子,其中巨噬细胞被募集并激活,从而为实体瘤生长创造有利的微环境。最后,我们验证了NPC临床样本中EBER与TNFα水平之间的正相关关系,且EBER和TNFα表达的联合可作为NPC患者预后不良的预测指标。总之,EBERs在NPC发生发展的炎症向肿瘤转化过程中起关键作用。