SMAD4促进LCK激酶调控CAR-T细胞增殖抵抗细胞衰竭的机制研究

体外和临床研究证实，CAR-T细胞治疗是新兴且有效的癌症治疗策略。但CAR-T细胞衰竭阻碍了其在实体瘤中的应用。目前CAR-T细胞衰竭发生的原因尚不清楚。LCK通过TCR信号调控T细胞活化、增殖及细胞因子的产生。预实验结果显示LCK参与CAR-T细胞与肿瘤细胞相互作用事件并影响细胞衰竭。SMAD4对T细胞免疫应答至关重要，预实验结果表明过表达SMAD4对CAR-T细胞增殖有显著促进作用，敲低SMAD4抑制CAR-T细胞增殖，且显著下调LCK表达，而敲低LCK对SMAD4表达无影响，提示SMAD4可能是LCK上游调控因子。因此我们推测，SMAD4可能通过介导LCK激酶的表达调控CAR-T细胞增殖以对抗细胞衰竭。本项目拟探究SMAD4促进LCK调控CAR-T细胞增殖对抗细胞衰竭的机制，并在此基础上优化CAR结构，以获得高增殖率、低衰竭的CAR-T细胞，促进CAR-T细胞治疗在实体瘤中的应用。

In vitro and clinical studies have confirmed that CAR-T cell therapy is a new and effective cancer treatment strategy. However, CAR-T cell exhaustion hinders its application in solid tumors. There is no unified understanding of the causes of cell exhaustion till now. LCK regulates T cell activation, proliferation and cytokine production by involving in TCR signal transduction. Our pre-experimental results showed that LCK is involved in the event that CAR-T cells engaged with tumor cells and affects CAR-T cell exhaustion. SMAD4 plays an important role in T cell immune response. Pre-experimental results showed that over-expression of SMAD4 significantly promotes the proliferation of CAR-T cells. Knockdown of SMAD4 significantly inhibits CAR-T cells proliferation, and down-regulated the expression of LCK. However, knockdown the expression of LCK shows no significant effects on the expression of SMAD4. Therefore, we speculate that SMAD4 may regulate the activation and proliferation of CAR-T cells to against cell exhaustion by mediating the expression of LCK kinase. This project aims to explore the mechanism of SMAD4 promoting LCK kinase regulating CAR-T cell proliferation against cell exhaustion. And we will optimize the CAR structure on this basis, so as to obtain CAR-T cells with high proliferation rate and low exhaustion level, which is expected to improve the application of CAR-T cell therapy in solid tumors.