口腔癌细胞源性外泌体-lncRNAs调控NK细胞杀伤作用及机制

Exosomes are especially important in communication between cells, which could play a vital part in the regulation of tumor immunity. Tumor-derived exosomes (TDEXs) have been reported to carry biological active molecules and signaling factors (including lncRNAs, miRNAs et al.), which are able to regulate functions of immune cells. However, the detailed mechanism remains unclear, especially in NK cell-mediated anti-cancer immunity. Our previous studies indicated that exosomes derived from oral squamous cell carcinoma (OSCC) cells can enter NK cells and regulate their cytotoxic function, which was closely associated with NF-κB signaling pathway. Moreover, the functional lncRNA-ENST000000470170 and lncRNA-FR344886, which are highly up-regulated in OSCC cells, could be transferred from OSCC cells to NK cells via exosomes. According to our previous studies, we speculate that the exosomal lncRNAs derived from OSCC cells might play a unique and important role in the regulation of NK cell cytotoxic function. In this study, we mainly focus on the mechanism of immunomodulatory mediated by the TDEX-lncRNA-NF-κB axis. The feasibility of exosomal-lncRNAs as a target for the diagnosis and treatment of OSCCs will be evaluated by further studies on OSCC samples, the OSCC cell xenograft models in NOD-SCID mice and dimmunocompetent mice. In summary, the present research will provide some valuable strategies for exosome-based oral cancer therapies in the future.

外泌体（exosomes）是介导不同类型细胞间信号交流的重要载体，在肿瘤免疫中发挥重要的调控作用。肿瘤细胞来源的外泌体(Tumor-derived exosomes ，TDEXs)中包含多种调控肿瘤免疫的lncRNAs和miRNAs，但调控的方式和机制尚不明确。课题组前期研究表明，口腔鳞癌TDEXs作用NK细胞后，能显著影响其杀伤活性及NF-κB信号通路的激活；同时还发现，TDEXs能把口腔鳞癌中高表达的lncRNA-ENST000000470170和lncRNA-FR344886转运到NK细胞中，并发挥作用。由此推测，口腔鳞癌TDEX-lncRNAs在调控NK细胞方面，具有不同的作用和机制。本项目以口腔鳞癌TDEX-lncRNAs为研究对象，探究TDEXlncRNA-NF-κB轴在调控NK细胞杀伤活性方面的作用和机制。进一步通过对人口腔鳞癌组织样本、口腔鳞癌细胞系NOD-SCID鼠移植瘤模型、正常免疫小鼠荷瘤模型的研究，评估TDEX-lncRNAs作为口腔鳞癌诊治靶标的可行性。

口腔鳞癌细胞来源的外泌体中包含多种lncRNAs、miRNAs和蛋白质，它们是调控肿瘤免疫的重要分子，阐明其精细调控的方式和机制对口腔鳞癌诊治候选靶点筛选和确定具有重要意义。在国家自然科学基金项目“研究口腔癌细胞源性外泌体-lncRNAs调控NK细胞杀伤作用及机制（81874126）”资助下，取得以下研究结果。（1）发现并证实lncRNA LINC00460和lncRNA KTN1-AS1在口腔癌组织中存在异常高表达，其与口腔鳞癌的转移等恶性进展相关。LINC00460是通过结合peroxiredoxin-1促进口腔鳞癌细胞EMT表型发生。KTN1-AS1通过特异性结合miR-153-3p促进SNAI1和ZEB2的表达，进而引起口腔鳞癌细胞EMT的发生，促进转移。（2）发现并证实口腔鳞癌细胞来源的外泌体处理NK细胞短时间（24小时），NK细胞表面激活性受体NKG2D及NKp30表达出现显著上调，抑制性受体NKG2A表达下调。但随着外泌体处理NK时间的延长到7天以后，上述激活性受体NKG2D及NKp30，以及抑制性受体NKG2A的表达水平出现反转，且与高表达TGF-β1密切相关。证实了口腔鳞癌源性外泌体对NK细胞功能的调控作用与作用时间密切相关。（3）发现并证实口腔鳞癌源性外泌体中的胞外5‘-核苷酸酶（CD73）通过激活NF-κB信号通路，诱导巨噬细胞向免疫抑制表型分化；CD73诱导的巨噬细胞能够重塑引流淋巴结的免疫微环境，形成有利于癌细胞转移的转移前微环境；靶向口腔癌细胞源性外泌体-CD73能够促进PD-L1抗体的免疫治疗效果。（4）研究对口腔鳞癌微环境进行多维度的分析，还发现作为典型的微生物-组织细胞互作模型，口腔鳞癌环境中的菌群特征可能影响口腔鳞癌的发生和发展。.本课题共发表标注论文12篇，其中SCI收录9篇，获得专利授权2项；获得省部级科技成果一等奖和二等奖各1项；培养博士后和研究生7名；参加国内外会议交流报告9篇。