CAR NKT Cell Immunotherapy of Neuroblastoma

摘要 尽管在治疗B细胞恶性肿瘤方面取得了显著进展，但表达嵌合抗原受体的T细胞 （汽车）在实体瘤中仍然基本无效。我们证明，与传统的T细胞和CAR-T细胞不同， V 24不变的自然杀伤T细胞（NKT）和CAR-NKT有效地运输到异种模型中的肿瘤部位 神经母细胞瘤（NB），这导致了首次在人体1期临床试验的开始，评估自体GD 2- NB儿童中的特异性CAR-NKT。这项试验的中期结果表明，治疗效果良好- 耐受并产生抗肿瘤活性，强调需要对NKT进行系统研究， 用于CAR重定向免疫疗法的替代细胞平台。我们报道了反复的抗原刺激 NKT和CAR-NKT之间的相互作用导致其效应子样分化、耗竭和抗肿瘤活性的丧失。我们 初步数据表明，Wnt信号传导，特别是转录因子LEF 1的激活，是必需的 足以维持CD 62 L+中枢记忆样NKT亚群，并与NKT相关 代谢和功能健康。这些发现为研究其作用和潜在的治疗作用提供了理论基础。 靶向CAR-NKT中的LEF 1用于癌症免疫治疗。CAR-NKT的临床前体内研究已经完成， 仅限于异种模型，其不允许评估下游先天和 适应性免疫反应为了解决这一差距，我们开发了协议，以产生和扩展高度 表达靶向人和鼠NB上表达的GD 2抗原的鼠CAR的纯鼠NKT 细胞我们还采用了同基因NB模型，忠实地概括了临床和病理 儿童高危NB的特征。我们假设1）LEF 1转录活性是必需的， 并且可以在治疗上被增强以维持CAR-NKT细胞代谢适应性、体内持久性， 持久的抗肿瘤活性;和2）CAR-NKT抗肿瘤活性取决于肿瘤细胞的直接靶向，对照 肿瘤相关的巨噬细胞，NK细胞的反式激活和肿瘤特异性T细胞的诱导。这些 假设将在以下具体目标进行测试：1）检查和治疗探索 负责维持人中枢记忆样NKT和CAR-NKT细胞的机制，和2） 探索CAR-NKT在同基因NB模型中介导抗肿瘤活性的机制。我们将使用 基因功能丧失和功能获得方法来研究LEF 1在CAR-NKT功能中的作用 分化，代谢和抗肿瘤活性，使用体外实验系统与人类细胞和 小鼠体内异种NB模型。为了研究CAR-NKT介导抗肿瘤活性的机制， 在同基因的情况下，我们将对表达GD 2的鼠NKT和T细胞进行并排比较， 特定CAR。拟议的实验将机械地剖析天然NKT细胞的贡献， TCR、肿瘤特异性CAR和治疗诱导的先天性和适应性免疫应答。结果将 为NB和其他类型癌症的下一代CAR-NKT免疫疗法的开发提供信息。

Abstract Despite remarkable progress in treating B cell malignancies, T cells expressing chimeric antigen receptors (CARs) remain largely ineffective in solid tumors. We demonstrated that unlike conventional T and CAR-T cells, V24-invariant natural killer T cells (NKTs) and CAR-NKTs effectively traffic to tumor sites in xenogeneic models of neuroblastoma (NB), which led to initiation of a first-in-human phase 1 clinical trial evaluating autologous GD2- specific CAR-NKTs in children with NB. Interim results from this trial have shown that the treatment is well- tolerated and produces antitumor activity, underscoring the need for systematic investigation of NKTs as an alternative cellular platform for CAR-redirected immunotherapy. We reported that repeated antigenic stimulation of NKTs and CAR-NKTs leads to their effector-like differentiation, exhaustion, and loss of antitumor activity. Our preliminary data demonstrate that Wnt signaling—specifically, activation of transcription factor LEF1—is required and sufficient for maintenance of the CD62L+ central memory-like NKT subset and is associated with NKT metabolic and functional fitness. These findings provide rationale for examining the role and potential therapeutic targeting of LEF1 in CAR-NKTs for cancer immunotherapy. Pre-clinical in vivo studies of CAR-NKTs have been limited to xenogeneic models, which do not allow for evaluation of the full spectrum of downstream innate and adaptive immune responses. To address this gap, we have developed protocols to generate and expand highly pure murine NKTs that express a murine CAR targeting the GD2 antigen expressed on human and murine NB cells. We have also adapted a syngeneic NB model that faithfully recapitulates the clinical and pathological characteristics of high-risk NB in children. We hypothesize that 1) LEF1 transcriptional activity is required for and can be therapeutically enhanced to maintain CAR-NKT cell metabolic fitness, in vivo persistence, and durable antitumor activity; and 2) CAR-NKT antitumor activity depends on direct targeting of tumor cells, control of tumor-associated macrophages, transactivation of NK cells and induction of tumor-specific T cells. These hypotheses will be tested in the following specific aims: 1) to examine and therapeutically explore the mechanism responsible for maintenance of human central memory-like NKT and CAR-NKT cells, and 2) to explore the mechanism by which CAR-NKTs mediate antitumor activity in a syngeneic NB model. We will use genetic loss-of-function and gain-of-function approaches to study the role of LEF1 in CAR-NKT functional differentiation, metabolism, and antitumor activity using in vitro experimental systems with human cells and in vivo xenogeneic NB models in mice. To study the mechanism by which CAR-NKTs mediate antitumor activity in the syngeneic setting, we will perform a side-by-side comparison of murine NKTs and T cells expressing a GD2- specifc CAR. The proposed experiments will mechanistically dissect the contributions of the native NKT cell TCR, the tumor-specific CAR, and therapy-induced innate and adaptive immune responses. The results will inform development of next-generation CAR-NKT immunotherapy for NB and other types of cancer.