TIGIT抑制西妥昔单抗诱导的NK细胞ADCC的分子机制研究

自然杀伤（NK）细胞因其在免疫系统中的生物学特异性，在肿瘤免疫治疗领域具有重要意义。NK细胞介导的抗体依赖的细胞毒作用（ADCC）是西妥昔单抗治疗结直肠癌（CRC）的机制之一，而无ADCC的帕尼单抗与西妥昔单抗疗效相当，提示NK细胞介导的ADCC在西妥昔单抗治疗中被抑制，但确切机制尚不清楚。我们前期研究显示CRC患者中NK细胞活性低弱并过表达抑制型受体TIGIT，推测NK细胞通过促进TIGIT表达抑制西妥昔单抗介导的ADCC。本项目基于前期对西妥昔单抗治疗CRC的研究，拟采用电转染和CRISPR/Cas9技术构建细胞株，采用流式细胞分析、ELISA、Western Blot和活体成像等方法检测细胞活性，在细胞和动物模型水平研究TIGIT阻断在活化西妥昔单抗诱导的ADCC中的作用，阐明通过免疫检查点阻断调控NK细胞介导的ADCC的分子机制，为抗肿瘤药物的研制和CRC疗效的提升提供科学依据。

Natural killer (NK) cells have attracted much attention in the field of tumor immunotherapy due to their biological specificity in the immune system. NK cell-mediated antibody dependent cellular cytotoxicity (ADCC) is one of the mechanisms of cetuximab’s antitumor activity, however, panitumumab without ADCC activity is not less effective than cetuximab, suggesting that NK cell-mediated ADCC was inhibited in treatment with cetuximab, and the exact mechanisms are poorly defined. Our previous study showed that the cytotoxicity of NK cells in colorectal cancer (CRC) patients was low and the immunosuppressive protein TIGIT was overexpressed. Therefore, this project proposed a hypothesis that NK cells inhibited cetuximab-triggered ADCC by promoting TIGIT expression. Based on our previous research of cetuximab for the treatment of colorectal cancer, these studies not only proposed methods of reinvigorate the function of cetuximab-triggered ADCC of NK cells by immune checkpoint blockades such as anti-TIGIT from in vivo and in vitro levels, using electrotransfection and CRISPR/Cas9 technology for constructing cell lines, flow cytometry analysis techniques, ELISA, Western Blot and in vivo fluorescence imaging system for detecting cell activity, but also elucidated the molecular mechanisms of regulating NK cell-mediated ADCC through immune checkpoints blockade. The results of these studies will provide detailed theoretical support for the development of new antitumor drugs and promote the treatment effect of colorectal cancer.