Defining mechanisms to promote antitumor immunity by modulating one-carbon metabolism

靶向PD-1及其配体PD-L1的免疫检查点阻断（ICB）彻底改变了癌症 治疗，但只有一个子集的患者作出反应，强调迫切需要调查 抗肿瘤免疫机制，以确定新的目标，以提高ICB的效果。的 该项目的目标是确定一碳（1C）代谢的机制， 调节以改善PD-1阻断的功效。我们最近发现了1C代谢， 允许细胞利用丝氨酸或甘氨酸来产生核苷酸、NADPH的1C单位， 谷胱甘肽生物合成，作为T细胞活化过程中最受诱导的代谢途径。我们也 发现肿瘤微环境中丝氨酸和葡萄糖水平不足 （TME）。引人注目的是，通过补充甲酸盐恢复1C代谢增加了 在小鼠肿瘤模型中抗PD-1治疗和肿瘤清除的有效性。我们 假设1C代谢限制了抗肿瘤T细胞功能， 通过补充甲酸盐可以协同ICB促进抗肿瘤免疫。我们 我将在两个目标测试这一假设：目标1：确定细胞和分子机制， 所述甲酸盐补充提高了PD-1介导的肿瘤清除的功效。 我们将定义转录和表观遗传机制，1C代谢和甲酸 补充改善了CD 8 + T细胞功能并与PD-1阻断协同作用。我们将使用 创新的条件敲除模型和体内遗传扰动研究，以删除率- CD 8 + T细胞中1C代谢的限制酶，并分析其对PD-1应答的影响。 1封锁。目的2：确定补充甲酸盐的代谢机制 改善PD-1介导的肿瘤清除的功效。我们将使用细胞和体内质量 基于光谱的代谢物追踪研究和空间代谢组学，以阐明如何 甲酸补充和1C代谢的调节影响抗- 当与抗PD-1组合时，肿瘤CD 8 + T细胞。这些研究将为我们提供第一个 肿瘤中代谢和功能性免疫应答的空间和单细胞分辨率图谱 对ICB的回应。我们将确定甲酸补充剂如何改善CD 8 + T细胞 从单个CD 8 + T细胞的水平到代谢系统中的CD 8 + T细胞的反应， 异源TME这些研究的完成将通过改变范式而具有变革性 1C代谢在癌症治疗中的作用，并证明补充1C单位可以 增强抗肿瘤免疫力。我们的研究结果将为战略提供信息，并确定新的治疗方法。 改善癌症免疫治疗结果的目标。

Immune checkpoint blockade (ICB) targeting PD-1 and its ligand PD-L1 has revolutionized cancer therapy, but only a subset of patients respond, highlighting the critical need to investigate mechanisms of anti-tumor immunity to identify novel targets to enhance the effects of ICB. The goal of this project is to determine mechanisms by which one-carbon (1C) metabolism can be modulated to improve the efficacy of PD-1 blockade. We recently identified 1C metabolism, which allows cells to utilize serine or glycine to generate 1C units for nucleotides, NADPH, and glutathione biosynthesis, as the most induced metabolic pathway during T cell activation. We also discovered that there are deficits in serine and glucose levels in the tumor microenvironment (TME). Strikingly, restoring 1C metabolism by formate supplementation increases the effectiveness of anti-PD-1 treatment and tumor clearance in mouse tumor models. We hypothesize that 1C metabolism is limiting for anti-tumor T cell function and that increasing this pathway by formate supplementation can synergize with ICB to promote anti-tumor immunity. We will test this hypothesis in two aims: Aim 1: Determine cellular and molecular mechanisms by which formate supplementation improves the efficacy of PD-1 mediated tumor clearance. We will define transcriptional and epigenetic mechanisms by which 1C metabolism and formate supplementation improve CD8+ T cell function and synergize with PD-1 blockade. We will use innovative conditional knockout models and in vivo genetic perturbation studies to delete rate- limiting enzymes of 1C metabolism in CD8+ T cells, and analyze their impact on response to PD- 1 blockade. Aim 2: Determine metabolic mechanisms by which formate supplementation improves the efficacy of PD-1 mediated tumor clearance. We will use cellular and in vivo mass spectrometry-based metabolite tracing studies, and spatial metabolomics to elucidate how formate supplementation and modulation of 1C metabolism impact metabolic profiles of anti- tumor CD8+ T cells when combined with anti-PD-1. These studies will provide us with the first spatial and single cell resolution atlas of metabolic and functional immune responses in a tumor in response to ICB. We will determine how formate supplementation improves CD8+ T cell responses from the level of individual CD8+ T cells to CD8+ T cells in the metabolically heterogenous TME. Completion of these studies will be transformative by changing the paradigm of 1C metabolism in cancer treatment and demonstrating that supplementing 1C units can enhance anti-tumor immunity. Our results will inform strategies and identify novel therapeutic targets for improving cancer immunotherapy outcomes.