靶向AFP T细胞受体(TCR)库的构建及记忆性TCR-T抗肝细胞癌研究

Liver cancer represents the third most common cause of cancer related death in china and there is no effective therapy. The TCR-T has made remarkable achievements in the solid tumor treatment. 70-80% of hepatocellular carcinoma (HCC) re-express AFP, so AFP could serve as a target for HCC adoptive transfer therapy. To obtain high specificity and diversity of T cell receptor (TCR) is the basis and difficulty of TCR-T therapy, no TCR-T products against AFP are currently approved. At present, TCR-T treatment has the following problems: 1. TCRs obtained by the traditional method have low affinity or poor diversity, therefor there are no enough candidate TCRs; 2. Difficulty to survive long-term of TCR-T leads to tumor recurrence in vivo. In previous studies, we cloned and identified 3 pairs of functional TCRs against AFP and proved TCR signaling was involved in vaccine-induced stem cell-like memory T cells which enhanced antitumor effects. In this study, murine TCRs without human self-antigen tolerance were used to construct the HLA-A24-restricted TCR library targeting human AFP; Relationship between TCR affinity and long-term anti-hepatocellular carcinoma effect of TCR-T was studied from the perspective of memory TCR-T. This study will provide the basis for guiding the TCR-T therapy targeting AFP and has important theoretical and practical significance.

肝癌是中国第三大肿瘤致死原因，尚无有效疗法。TCR-T在实体瘤治疗中取得令人瞩目的成果。70-80%的肝细胞癌（HCC）重新表达AFP，AFP可作为HCC过继细胞治疗的靶点。获得高特异性及多样性T细胞受体（TCR）是TCR-T的基础及难点，目前尚无针对AFP的TCR-T产品批准上市。目前TCR-T治疗存在以下问题：1.传统方法获得的TCR亲和力较低或者多样性较差而无足够的候选TCR；2.TCR-T体内难以长期存活导致肿瘤复发。我们以往研究克隆及鉴定3对靶向AFP功能性TCR、证明TCR信号参与疫苗诱导的记忆性干细胞样T细胞的形成从而增强抗肿瘤效应。本研究以无人类自身抗原耐受的鼠源TCR为切入点，构建靶向AFP的HLA-A24限制性TCR库并从记忆性TCR-T角度研究TCR亲和力与TCR-T长期抗肝细胞癌效应关系，为指导靶向AFP的TCR-T疗法提供依据，具有重要的理论及实际意义。

肝癌是中国第三大肿瘤致死原因，晚期肝癌尚无有效疗法。TCR-T在实体瘤治疗中取得令人瞩目的成果。70-80%的肝细胞癌（HCC）重新表达AFP，AFP可作为HCC过继细胞治疗的靶点，目前尚无针对HCC的TCR-T产品批准上市。目前HCC的TCR-T治疗存在以下问题：1.无小鼠H2限制性TCR-T治疗HCC研究模型；2.TCR-T体内难以长期存活导致肿瘤复发。本项目主要研究内容：1.克隆靶向AFP的TCR，为H2限制性TCR-T治疗HCC小鼠模型提供候选TCR；2.构建不依赖外源性IL-21的工程化TCR-T细胞从而获得具有干细胞样记忆性表型的TCR-T细胞以增强其体内外抗HCC效应。本项目利用慢病毒联合多肽疫苗免疫小鼠及单细胞转录组测序技术成功获得靶向AFP的H2限制性TCR库，由于实体瘤中T细胞面临的问题各不相同，因此本项目为TCR-T治疗HCC小鼠模型提供候选TCR，具有重要的意义；另外，本项目通过新型工程化的IL-21受体，构建自激活IL-21胞内信号的TCR-T，该工程化的IL-21受体通过STAT3信号通路刺激TCR-T，使其形成干细胞样记忆性T细胞表型并展示出更强的细胞毒T细胞功能即一种长效效应TCR-T，该TCR-T具有较好的体内外抗肿瘤效应，因此具有潜在的临床应用价值。