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

针对PD-1及其配体PD-L1的免疫检查点阻断(ICB)已使癌症发生革命性变化 治疗，但只有一小部分患者有反应，突显了调查的迫切需要 抗肿瘤免疫机制寻找新靶点增强ICB效果。这个 该项目的目标是确定一碳(1C)代谢的机制 调节以提高PD-1的阻断效果。我们最近发现了1C新陈代谢， 允许细胞利用丝氨酸或甘氨酸为核苷酸、NADPH和 谷胱甘肽的生物合成，是T细胞活化过程中诱导最多的代谢途径。我们也 发现肿瘤微环境中的丝氨酸和葡萄糖水平存在缺陷 (TME)。值得注意的是，通过补充甲酸盐来恢复1C代谢会增加 抗PD-1治疗和肿瘤清除在小鼠肿瘤模型中的有效性。我们 假设1C代谢限制了抗肿瘤T细胞的功能，并增加了这一功能 甲酸盐补充途径可与ICB协同作用，促进抗肿瘤免疫。我们 我将在两个目标中检验这一假设：目标1：通过以下方式确定细胞和分子机制 补充哪种甲酸盐可提高PD-1介导的肿瘤清除效果。 我们将定义转录和表观遗传机制，通过这些机制1C代谢和甲酸 补充剂可改善CD8+T细胞功能，并与PD-1拮抗剂协同作用。我们将使用 创新的条件性基因敲除模型和体内遗传扰动研究，以删除- CD8+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。目标2：确定补充甲酸盐的代谢机制 提高PD-1介导的肿瘤清除效率。我们将使用细胞和体内质量 基于光谱的代谢物追踪研究，以及空间代谢组学，以阐明 补充甲酸盐和调节1C代谢对抗心磷脂代谢的影响 肿瘤CD8+T细胞与抗PD-1抗体联合应用。这些研究将为我们提供第一个 肿瘤代谢和功能免疫反应的空间和单细胞分辨率图谱 作为对ICB的回应。我们将确定补充甲酸盐如何提高CD8+T细胞 代谢过程中单个CD8+T细胞对CD8+T细胞的应答 异质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。我们的结果将为策略提供参考，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.