The influence of co-stimulatory domains on the metabolic regulation of chimeric antigen receptor (CAR) T cell function

共刺激结构域对嵌合抗原受体（CAR）T细胞功能代谢调节的影响

• 批准号: 2444766
• 金额: --
• 依托单位: King's College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2444766
• 关键词: influence; co; stimulatory; domains; metabolic

T-cells are a vital component of the immune system and promoting/engineering T-cell responses is now at the forefront of cancer immuno-therapies. The development of chimeric antigen receptor (CAR) T-cell therapy has shown remarkable clinical responses in treating certain subsets of B cell leukemia or lymphoma. CAR's are composed of an extracellular antigen-binding region against the tumour target linked to intracellular signalling domains to signal for T- cell activation and effector function. Upon recognising antigen, clustering and immobilisation of CAR molecules occurs which induces phosphorylation of the CD3-zeta (CD3z) chain akin to signalling via the natural T cell receptor. This triggers T-cell proliferation, cytokine release, metabolic changes and cytotoxicity; the T-cell effector response. CAR T- cell therapy has been highly effective in leukemic and lymphatic cancers, however, so far, has shown disappointing results for the treatment of solid tumours. The ability of a T-cell to display full effector functions (e.g. proliferation, cytotoxicity) crucially depends on optimal cellular energy utilisation and the availability of nutrients in the environment. Tumour cells in solid tumours can counteract this immune response by manipulating the availability of nutrients in the tumour microenvironment (TME), leading to treatment failure. T-cell co-stimulation can be delivered through both CD28 and 4-1BB. CAR T cells currently in the clinic carry either costimulatory domain, termed 2nd generation CAR, and 3rd generation CAR have also been developed in which both co-stimulatory domains were placed in line as part of the CAR. Disappointingly 3rd generation CAR did not show improved performance compared to 2nd generation CAR in the clinic (1). Now, our lab has generated a parallel-CAR (pCAR) construct to optimise costimulatory signalling delivering both CD28 and 4-1BB, one as part of the CAR and one as a proximal but independent chimeric costimulatory molecule (Muliaditan, Flaherty, Maher, Schurich, manuscript under review). These pCAR T-cells have shown enhanced tumour killing capacity in vitro and in vivo compared with CAR T-cells currently in the clinic. In vitro, pCAR T-cells have shown to be more resistant to T-cell exhaustion and senescence, sustain proliferation and cytokine release. We hypothesise that the increased functionality of pCAR T-cells is due to improved T-cell metabolism and mitochondrial function. Our preliminary findings have supported this hypothesis, showing that following stimulation, pCAR T-cells have significantly higher expression of nutrient transporters, and have a higher proportion of functional mitochondria when compared to conventional CAR counterparts. The increased ability of the pCAR T-cells to take up essential nutrients like glucose and iron suggests that they can sustain a high rate metabolism, contributing to their function and proliferation. Furthermore, the enhanced functionality of their mitochondria suggests increased longevity and resistance to exhaustion, a process we have previously shown vital in chronic viral infection (2). We believe these factors will contribute to a more effective therapeutic CAR T-cell product to withstand the nutrient lacking tumour microenvironment.

T细胞是免疫系统的重要组成部分，促进/工程化T细胞应答现在处于癌症免疫疗法的最前沿。嵌合抗原受体（CAR）T细胞疗法的发展在治疗B细胞白血病或淋巴瘤的某些亚群中显示出显著的临床应答。CAR由针对肿瘤靶标的细胞外抗原结合区组成，所述细胞外抗原结合区连接至细胞内信号传导结构域以发出T细胞活化和效应子功能的信号。在识别抗原后，CAR分子的聚集和固定发生，其诱导CD 3-zeta（CD 3 z）链的磷酸化，类似于经由天然T细胞受体的信号传导。这触发T细胞增殖、细胞因子释放、代谢变化和细胞毒性; T细胞效应器应答。CAR T细胞疗法在白血病和淋巴癌中非常有效，然而，到目前为止，在治疗实体瘤方面显示出令人失望的结果。 T细胞显示全部效应子功能（例如增殖、细胞毒性）的能力关键取决于最佳的细胞能量利用和环境中营养素的可用性。实体瘤中的肿瘤细胞可以通过操纵肿瘤微环境（TME）中营养物质的可用性来抵消这种免疫反应，导致治疗失败。T细胞共刺激可以通过CD 28和4-1BB两者递送。目前在临床上的CAR T细胞携带共刺激结构域，称为第二代CAR，并且还开发了第三代CAR，其中两个共刺激结构域作为CAR的一部分排成一行。令人遗憾的是，与临床中的第二代CAR相比，第三代CAR没有显示出改善的性能（1）。现在，我们的实验室已经产生了一种平行CAR（pCAR）构建体，以优化递送CD 28和4-1BB的共刺激信号传导，一种作为CAR的一部分，另一种作为近端但独立的嵌合共刺激分子（Muliaditan，Flaherty，Maher，Schurich，正在审查的手稿）。与目前临床上的CAR T细胞相比，这些pCAR T细胞在体外和体内显示出增强的肿瘤杀伤能力。在体外，pCAR T细胞已显示出对T细胞耗竭和衰老更有抗性，维持增殖和细胞因子释放。我们假设pCAR T细胞功能的增加是由于T细胞代谢和线粒体功能的改善。我们的初步研究结果支持了这一假设，表明在刺激后，pCAR T细胞具有显著更高的营养转运蛋白表达，并且与传统CAR对应物相比具有更高比例的功能性线粒体。pCAR T细胞摄取葡萄糖和铁等必需营养素的能力增加，表明它们可以维持高速率代谢，有助于它们的功能和增殖。此外，它们线粒体功能的增强表明寿命延长和对疲劳的抵抗力增加，这是我们以前在慢性病毒感染中显示的重要过程（2）。我们相信这些因素将有助于更有效的治疗性CAR T细胞产品，以承受缺乏营养的肿瘤微环境。