TLR7在放疗诱导的抗肿瘤免疫反应中的作用及分子机制

For locally unresectable advanced non-small cell lung cancer, the standard treatment is radiotherapy. Beside the main machnism to caurse the DNA double-strand break, generating a strong and durable tumor-specific immune response is another main mechnism of tumor therapy recently, but the specific mechanism remains unknown. Therefore, enhancing the antitumor immune response induced by radiotherapy is an effective method to increase the treatment effectiveness.Recently,Toll-like receptors (TLRs) are a family of pattern recognition receptors that recognize highly conserved components of diverse pathogens and induce innate and adaptive immune responses. TLRs sense a variety of endogenous molecules that are released as a result of cellular or tissue damage and directly regulate cell proliferation and survival.Previous studies have proved that the ligands or agonists for TLRs and chemotherapy synergistically delayed the tumor growth and prolonged the survival of the tumor-bearing mice. The combination therapy also generated a strong and durable tumor-specific immune response. Therefore, based on the previous study, we infer that the activition of TLRs may play an immportant role in enhencing the anti-tumor activity induced by radiotherapy..Dendritic cells (DCs) are the most potent antigen-presenting cells for initiating immune responses. DCs can detect PAMPs like dying cancer cells and ligands or agonists of TLRs. Upon encounter with a PAMP, DCs undergo maturation and trigger the immune response cascade, which have been shown to be effective in producing specific anti-tumour effects both in vitro and in vivo. DCs may play an immportant role in antitumor reactions mediate by TLRs.. According to the related report and our previous study, we hypothesize that the TLRs signals can enhance the antitumor immune activity induced by radiotherapy. In order to disclose the more effects of the combinational ligands or agonists for TLRs and radiation therapy. DCs and lung adenocarcinoma cells were separated from lung caner patients and transplanted tumor model will be developed. RNA interference technique and molecular biology technique will be used to silence or activation TLRs on DCs in vivo or in vitro experiment, respectively. We then detect and compare the effects and molecular of activtion of TLRs on the antitumor immune induced by ratiotherapy by RT-PCR, Western-blot,and so on. We also compared the overall survival of transplanted tumor model between the groups. These results will be valuble to elucidate a rationale for the use of ligands or agonists of LTRs for improving anti-cancer immune activity induced by radiotherapy and provide a new method for the treatment.

放射治疗是肺癌的重要治疗策略之一，其抗肿瘤机制除直接诱导肿瘤细胞凋亡外，近来发现尚有诱导抗肿瘤免疫效应，发挥原位和远隔抗肿瘤作用，但其具体机制尚不清楚。我们研究发现，放疗后肿瘤组织TLR7表达上调，淋巴细胞增多者临床疗效较好；TLR7低表达者疗效较差，但具体机制尚不明确。基于文献报道和前期研究，提出放疗可能通过调控淋巴细胞TLR7介导的抗肿瘤免疫反应发挥原位和远隔抗肿瘤效应的假说。为验证此假说，拟构建自发性肺癌模型和细胞共培养体系，应用基因过表达、干扰等手段上调或下调TLR7的表达，应用组织病理学、免疫荧光染色、RT-PCR、Western blot等技术，体内和体外探讨放疗诱导抗肿瘤免疫的作用及机制。本研究将有助于阐明放疗诱导抗肿瘤免疫的效果及机制，为放疗和免疫联合应用提供新思路和理论依据。

放射治疗是肺癌的重要治疗策略之一，其抗肿瘤机制除直接诱导肿瘤细胞凋亡外，近来发现尚有诱导抗肿瘤免疫效应，发挥原位和远隔抗肿瘤作用，深入研究放疗诱导的抗肿瘤免疫反应发生机制并增强这种效应是发挥放疗和免疫治疗协调抗肿瘤的关键。放疗可将肿瘤细胞转变为内源性抗原而诱导机体产生抗肿瘤免疫效应，其机制可能与激活TLR7表达，降低PD-1的水平有关。该项目以解决临床具体问题为目标，以体外细胞机理研究与在体疗效观察相结合为模式，拟采用组织病理学、激光共聚焦显微镜、透射电镜、RT-PCR和Western blot等多种技术，分别从体内和体外探讨放疗诱导抗肿瘤免疫的效应以及对LTR7和PD-1的调节作用，以期阐明放疗诱导抗肿瘤免疫的作用及分子机制。（1）在体内研究中，建立肺癌动物模型及临床收集肺癌放疗患者，通过检测不同分割模式放疗诱导抗肿瘤免疫的效果、远隔效应及相关分子表达变化，分析对比放疗前后相关分子表达变化、远隔效应、病理变化等的关系，证实放疗具有诱导机体抗肿瘤免疫作用，其机制可能通过诱导表达LTR受体实现的，从而为临床应用提供理论和实验依据；（2）在体外研究中，对比检测不同放疗模式细胞株的免疫状态及相关信号通路关键分子表达变化，观察放疗模式与抗肿瘤免疫的关系，研究发现放疗能够诱导机体产生抗肿瘤免疫反应，其发生效果与放疗模式密切相关，为临床开展免疫与放疗联合抗肿瘤治疗模式提供实验依据。该项目研究成果已发表文章5篇，部分研究内容被中华医学会肿瘤专业分会组织编写的《临床路径治疗药物释义》和《胸部肿瘤放疗规范和靶区定义》一书采纳，并在全国进行推广应用，部分研究成果于2019年获批中国抗癌协会科技进步二等奖。本研究阐明了放疗诱导抗肿瘤免疫的效果及机制，为放疗和免疫联合应用提供新思路和理论依据，进一步丰富肿瘤放疗理论，为临床治疗提供一种全新的方法，具有良好的临床应用前景。