NK细胞抑制性受体CD96作为肝癌checkpoint免疫治疗靶点的进一步验证

阻断抑制性受体以逆转T细胞功能耗竭的卡控点(checkpoint)免疫治疗取得肿瘤治疗历史性突破,而NK细胞功能耗竭及其卡控点研究几乎空白。申请人国际上率先在肝癌患者队列进行NK细胞抑制性受体系列研究(Hepatology 2018; Cancer Res 2018等10余篇论文)，观察到肿瘤区域抑制性受体CD96表达升高最为显著，明显伴随着NK细胞功能耗竭和疾病不良预后。拟进一步采用组合单细胞技术对肝癌区域NK细胞耗竭的细胞组学及分子谱系进行全景式分析，全面了解CD155家族分子的价值；利用各类CD155家族受/配体(CD96、TIGIT、CD226、CD155等)基因敲低或高表达的人NK细胞或人肝癌细胞或对应抗体的阻断逆转，比对CD96分子在CD155家族受/配体中主导价值；进一步建立人NK细胞重建的荷人瘤小鼠，拟在体内模型首次确证人类CD96分子作为checkpoint的治疗价值。

Checkpoint immunotherapy that targets T cell inhibitory receptors thereby reversing functional exhaustion of T cells marks the breakthrough of anticancer therapy in human history. However, researches on NK cell exhaustion and potential checkpoints targeting NK cells are very limited. Our team is among the very firsts in the world to study NK cell inhibitory receptors by using hepatocellular carcinoma (HCC) patient cohorts (Hepatology 2018; Cancer Res 2018 etc.), we observed significant elevated expression of inhibitory receptor CD96 in the intratumoral region of HCC, accompanied by NK cell functional exhaustion, and worsen disease condition and poor prognosis in HCC patients. We propose to use single cell sequencing technology combined with CyTOF to further analyze the cytogenetic and molecular signatures of NK cells in the intratumoral region of HCC, and to fully understand the value of CD155 family; to use various CD155 family receptors/ligands (CD96, TIGIT, CD226, CD155, etc.)-over-expressed or -knock-downed human NK cells or hepatoma cells or relevant blocking antibodies to compare CD96 with other CD155 family members and evaluate its significance; to establish patient-derived xenograft (PDX) model using both human HCC tumors and NK cells, and evaluate the therapeutic potential of human CD96 molecule as a checkpoint in anti-HCC immunotherapy.