Targeting tumor and T cell DNA methylomes to improve CAR T cell therapies for diffuse midline glioma

摘要/摘要 虽然免疫疗法的进步使一些癌症的治疗方法发生了革命性的变化，但儿童脑瘤 对目前的免疫治疗特别耐药，包括免疫检查点抑制剂。今年5月 因为许多儿科脑瘤的特点是“免疫感冒”，几乎没有免疫细胞。 渗透。嵌合抗原受体(CAR)T细胞疗法对这种致命的脑瘤显示出了希望 早期临床研究认为弥漫性中线胶质瘤(DMG)。然而，在早期的研究中，患者不可避免地会屈服 这种致命的疾病。这对CAR T细胞抵抗的机制和设计提出了重要的问题 改善和延长CAR T细胞功能的策略。以表观遗传程序为靶点已被确定为 从肿瘤细胞自身和肿瘤两方面克服实体瘤免疫反应不足的策略 微环境机制。我们在DMG中已经证明，抑制DNA甲基化可以激活先天 可能刺激免疫细胞招募和活动的免疫途径(Krug等人，癌症细胞，2019年)。我们的 缺乏DNA甲基转移酶(DNMT3A)的CAR T细胞的数据显示，精疲力竭和 增强了对多种肿瘤模型的抗肿瘤活性，包括脑瘤(普林辛等人，《科学》 转化医学，2021年)。我们假设针对不同DMG的组合方法和 CAR T细胞DNA甲基化组是加强CAR T细胞治疗的合理策略。我们打算测试一下 这有两个具体目标：AIM1：确定DMG中肿瘤DNA去甲基化如何影响CAR T细胞募集 和功能。我们将检验抑制DNA甲基化诱导内源性逆转录病毒的假设 激活将增强CART细胞的激活和持久性。AIM2：确定CAR T细胞效应器功能是否 通过抑制DMG中的DNA甲基化而改善。我们将检验这样的假设：抑制DNA甲基化 在CAR中，T细胞的一种表型转化为DMG，通过防止T细胞耗尽和改善长期 效应器功能。

SUMMARY/ABSTRACT While improvements in immune therapies have revolutionized treatments in some cancers, pediatric brain tumors are especially resistant to current immunotherapy treatments, including immune check point inhibitors. This may be because many pediatric brain tumors have been characterized as “immune cold”, with little to no immune cell infiltration. Chimeric antigen receptor (CAR) T cell therapies have shown promise against fatal brain tumors such as diffuse midline glioma (DMG) in early clinical studies. However, in early studies, patients inevitably succumb to this fatal disease. This raises important questions about mechanisms of CAR T cell resistance and devising strategies to improve and prolong CAR T cell function. Targeting epigenetic programs has been identified as one strategy to overcome deficient immune responses in solid tumors through both tumor cell intrinsic and tumor microenvironment mechanisms. We have shown in DMG that inhibition of DNA methylation activates innate immune pathways that may stimulate immune cell recruitment and activity (Krug et al., Cancer Cell, 2019). Our data in CAR T cells deficient for a DNA methyl transferase (DNMT3A) displays reduced exhaustion and enhanced anti-tumor activity against multiple tumor models, including brain tumors (Prinzing et al., Science Translational Medicine, 2021). We hypothesize that combinatorial approaches that target distinct DMG and CAR T cell DNA methylomes represents a rational strategy to enhance CAR T cell therapy. We propose to test this in two specific aims: AIM1: Determine how tumor DNA demethylation in DMG impacts CAR T cell recruitment and function. We will test the hypothesis that inhibition of DNA methylation induced endogenous retroviral activation will enhance CART cell activation and persistence. AIM2: Determine if CAR T cell effector function is improved by DNA methylation inhibition in DMG. We will test the hypothesis that inhibition of DNA methylation in CAR T cells is a phenotype that translates to DMG, by preventing T cell exhaustion and improving long-term effector function.