嵌合抗原受体(CAR)T细胞疗法在消除B细胞恶性肿瘤方面取得了非凡的成功;然而,到目前为止,它在实体瘤的治疗中显示出有限的疗效,这被认为是由于CAR-T细胞活化不足。我们假设转录因子PU.1是先天细胞功能的主要调节因子,可能会增加促炎CART细胞的激活。T细胞用CEA特异性CAR和PU.1的组成型表达进行了工程改造。在延长的重复抗原暴露的条件下,在体外记录CAR重定向的T细胞活化的规范功能性。CART细胞中的异位PU.1表达上调共刺激受体CD40、CD80、CD86和CD70,出乎意料的是,没有增强效应子功能,但阻碍了4-1BB的上调,减少IL-2的产生,减少CART细胞增殖,并损害了它们的细胞毒性。在同源肿瘤细胞重复参与的“应激”条件下,异位PU.1的CART细胞表现出持久性降低,最终未能控制癌细胞的生长。机械上,PU.1导致CART细胞分泌IFN-β,一种已知促进CAR-T细胞磨损和凋亡的细胞因子。总的来说,PU.1可以将CART细胞的功能能力极化为先天细胞。
Chimeric antigen receptor (
CAR) T cell therapy has achieved extraordinary success in eliminating B cell malignancies; however, so far, it has shown limited efficacy in the treatment of solid tumors, which is thought to be due to insufficient
CAR T cell activation. We hypothesized that the transcription factor PU.1, a master regulator of innate cell functionality, may augment pro-inflammatory CAR T cell activation. T cells were engineered with a CEA-specific
CAR together with the constitutive expression of PU.1. CAR-redirected T cell activation was recorded for canonical functionality in vitro under conditions of prolonged repetitive antigen exposure. Ectopic PU.1 expression in CAR T cells upregulated the costimulatory receptors CD40, CD80, CD86, and CD70, which, unexpectedly, did not augment effector functions but hampered the upregulation of 4-1BB, decreased IL-2 production, reduced CAR T cell proliferation, and impaired their cytotoxic capacities. Under \"stress\" conditions of repetitive engagement of cognate tumor cells, CAR T cells with ectopic PU.1 showed reduced persistence, and finally failed to control the growth of cancer cells. Mechanistically, PU.1 caused
CAR T cells to secrete IFN-β, a cytokine known to promote
CAR T cell attrition and apoptosis. Collectively, PU.1 can polarize the functional capacities of
CAR T cells towards innate cells.