NFAT1对胶质瘤肿瘤浸润免疫细胞的调控作用及机制研究

Gliomas are the most common primary malignant tumors of the central nervous system, and the prognosis is generally poor. In our previous studies, we show the existence of tumor-infiltrating immune cells (TIICs) in the microenvironment of gliomas. Moreover, the component and proportion of TIICs are closely associated with the prognosis of glioma patients. TIICs and inflammatory mediators released by these cells influence the local immune status, result in immunosuppressive or immuno-reactive microenvironment and regulate the biological behavior of gliomas through several signaling pathways including integrin β1-ERK pathway. However, the regulatory mechanism of TIICs is still unclear. We find that the expression of nuclear factor of activated T cells-1 (NFAT1) is upregulated in high-grade glioma tissues, which affects the invasion and death of glioma cells. In addition, as a key immunomodulatory transcriptional factor, NFAT1 is widely expressed in immune cells, and controls the expression of a wide range of immune-related factors, and influence the function of immune cells. Moreover, it has been reported that, metabolic factors of tumor microenvironment, such as hypoxia and glucose-poor conditions, can affect the activity of NFAT1 signaling and in turn influence the anti-tumor immune responses. Thus, we speculate that NFAT1 signaling might play an important role in the regulation of the function and component of TIICs. In the present study, using knockout mice deficient for NFAT1 to establish animal model in combination with ex vivo and in vitro experiments, we aimed to investigate the role of NFAT1 in the regulation of TIICs in gliomas, the related molecular mechanism and signaling pathway will also be explored. The results of the study would contribute to the immunotherapy and multimodal treatment of glioma patients.

胶质瘤是最常见的原发性中枢神经系统肿瘤，预后较差。我们证实，胶质瘤微环境中存在肿瘤浸润免疫细胞（tumor infiltrating immune cell，TIIC），其成分及比例和患者预后相关。TIIC及其产生的炎症介质影响局部免疫状态，形成免疫抑制或免疫活化微环境，影响肿瘤进展。然而，TIIC的调控机制尚未明确。我们发现，活化T细胞核因子1（NFAT1）在高级别胶质瘤中表达上调，影响肿瘤侵袭和死亡。作为免疫调控转录因子，NFAT1广泛表达于免疫细胞中，调节下游基因转录，影响免疫细胞功能。文献报道，低氧、低糖微环境，通过改变NFAT1活性，影响抗肿瘤免疫应答。因此，NFAT1可能在TIIC成分和功能调控中发挥重要作用。本研究旨在通过基因敲除等方法调控NFAT1表达，建立动物模型，结合离体实验，探讨NFAT1对胶质瘤TIIC的调控作用及机制，为胶质瘤的免疫治疗及多模态治疗提供新的思路。

胶质瘤是中枢神经系统发生率最高的原发性恶性肿瘤，其中恶性程度最高的胶质母细胞瘤（Glioblastma，GBM）具有进展迅速、高度浸润、频繁复发的特点，手术与放化疗效果较差，中位生存期仅15个月，五年生存率小于5%，急需开发新的治疗方法。胶质瘤干细胞(Glioma stem cells，GSCs)是胶质瘤中一个特殊细胞亚群，具有无限增值、自我更新和多向分化等潜能，是胶质瘤放化疗耐药和频繁复发的主要原因。靶向抑制GSCs是一种极具潜力的靶向治疗手段。本项目按计划顺利进行，重点关注GSCs在肿瘤免疫微环境中的重要促癌作用和胶质瘤CD8+T细胞的浸润情况，我们得到了以下原创性研究结果：1）受EGFR途径调控的MCM8通过与DNA复制启动因子的相互作用维持GSCs的克隆形成和致瘤潜能，因此MCM8可能成为治疗胶质瘤的新靶点。2）NFAT2-HDAC1通路可能在维持GSCs恶性表型和促进MES转化中发挥重要作用，为GBMS的治疗提供了潜在的分子靶点。3）NFAT1通过调节NDEL1控制GSCs的生长和侵袭，靶向抑制NFAT1-NDEL1轴可能为治疗胶质瘤患者提供机会。4）MTBP通过MDM2依赖的p53翻译后修饰调节TP53wt GBMs的细胞存活和治疗敏感性，MTBP靶向治疗在提高患者存活率方面有潜在的用处。5）CD8+TIL水平降低可能与mGBMs的不良临床结局相关，提示局部免疫微环境对mGBMs的进展有影响。本项目所有的基础研究均使用的胶质瘤细胞均为临床阳本培育而来的原代胶质瘤细胞和GSCs细胞，因此本项研究的基础成果可能在临床水平具备极大的临床应用前景，目前正在积极推动相关临床转化的研究和应用进行，目标是建立以NFAT1-NDEL1、NFAT2-HDAC1、MTBP-MDM2、EGFRvⅢ-MCM8为靶点的靶向抑制GSCs的治疗方法，最终达到治疗患者、放化疗增敏、延长复发时间的效果。