Exploring the intersection of hypoxia and epigenetic modifiers in tumor-mediated CD8 T cell exhaustion

探索缺氧和表观遗传修饰剂在肿瘤介导的 CD8 T 细胞耗竭中的交叉作用

• 批准号: 10533919
• 负责人: Brinley Rhodes Ford
• 金额: $ 3.26万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10533919
• 关键词: Antitumor Response; Automobile Driving; CD8-Positive T-Lymphocytes; CD8B1 gene; Cell Differentiation process; Cell physiology; Cells; Chemicals; Chromatin; Chromatin Remodeling Factor; Epigenetic Process; Equilibrium; Exhibits; Functional disorder; Gene Expression; Genes; Genetic Models; Genetic Transcription; Histones; Hypoxia; Immune Response Genes; Immune response; Immunology; Immunotherapy; In Vitro; Inflammatory Response Pathway; Measures; Mediating; Methylation; Modification; Mus; Oxygen; Phenotype; Play; Regulation; Research; Resistance; Role; Signal Transduction; Supporting Cell; System; T cell differentiation; T cell response; T-Lymphocyte; Techniques; Testing; Training; Tumor Immunity; Tumor-Infiltrating Lymphocytes; anti-PD1 therapy; base; cancer immunotherapy; cytokine; cytotoxic CD8 T cells; demethylation; epigenome; exhaust; exhaustion; experience; experimental study; histone demethylase; histone methylation; histone methyltransferase; histone modification; improved; in vitro Assay; in vivo; inhibitor; innovation; neoplastic cell; novel; pluripotency; prevent; programmed cell death protein 1; receptor; response; stem cells; stem-like cell; stemness; therapeutic target; tumor; tumor hypoxia; tumor microenvironment

PROJECT SUMMARY CD8+ T cells are a fundamental component of the anti-tumor response; however, tumor-infiltrating CD8+ T cells (TIL) are rendered dysfunctional by the tumor microenvironment. CD8+ TIL display an exhausted phenotype with decreased cytokine expression and increased expression of co-inhibitory receptors (IRs), such as PD-1 and Tim-3. The acquisition of IRs marks the progression of dysfunctional TIL from progenitors (PD1lo) to terminally exhausted (PD1hiTim3+). We have described a distinct increase in bivalent genes in terminally exhausted CD8+ TIL, which are characterized by presence of both the active mark H3K4me3 and the repressive mark H3K27me3, as well as low gene expression. While this state has traditionally been found in pluripotent cells and described as a “poised” state, new research suggests that it is not specific to stem-like cells. The increase in bivalent chromatin in terminally exhausted cells suggests increased methylation in response to the tumor microenvironment. We suspect that hypoxia-mediated regulation of histone modifiers is responsible for this increase in bivalent genes and plays a critical role in mediating dysfunction. Understanding the role of bivalent genes and their regulation will provide crucial information about the regulation of exhaustion in the tumor microenvironment. This proposal seeks to use a combination of traditional immunology techniques and sequencing-based experiments to better understand the regulation of these chromatin features. We hypothesize that dysregulated chromatin modifiers of H3K27me3 drive bivalency and exhaustion in terminally exhausted T cells and can be targeted to improve anti-tumor immunity. We will test this hypothesis in two aims; we will 1) determine whether inhibition of H3K27 demethylation in hypoxia is sufficient to drive bivalency and terminal exhaustion using demethylase inhibitors and innovative in vitro assays of T cell exhaustion. We will 2) determine whether Ezh2 can be targeted to prevent bivalency in exhaustion using both inhibitors of Ezh2 activity and inducible deletion of Ezh2 in in vitro and in vivo systems, respectively. The presence of bivalent genes specific to terminally exhausted TIL supports the notion that while exhausted cells are epigenetically resistant to immunotherapy, such as anti-PD1 treatment, chromatin and transcriptional regulators can be targeted to reinvigorate exhausted TIL by increasing expression of key functional genes to improve the anti-tumor response.

项目概要 CD8+ T 细胞是抗肿瘤反应的基本组成部分；然而，肿瘤浸润性 CD8+ T 细胞 (TIL) 因肿瘤微环境而变得功能失调。 CD8+ TIL 显示耗尽表型 细胞因子表达减少，共抑制受体 (IR) 表达增加，例如 PD-1 和 蒂姆-3。 IR 的获得标志着功能失调的 TIL 从祖细胞 (PD1lo) 发展到终末期 耗尽（PD1hiTim3+）。我们已经描述了终末耗竭的 CD8+ 中二价基因的明显增加 TIL，其特征是同时存在活性标记 H3K4me3 和抑制标记 H3K27me3， 以及低基因表达。虽然传统上在多能细胞中发现并描述了这种状态 作为一种“平衡”状态，新的研究表明它并不是干细胞特有的。二价增加 最终衰竭细胞中的染色质表明对肿瘤的反应增加了甲基化 微环境。我们怀疑缺氧介导的组蛋白修饰调节是造成这种情况的原因 二价基因的增加并在介导功能障碍中发挥关键作用。了解二价的作用 基因及其调控将提供有关肿瘤耗竭调控的重要信息 微环境。该提案旨在结合传统免疫学技术和 基于测序的实验可以更好地了解这些染色质特征的调节。我们 假设 H3K27me3 的染色质修饰失调导致二价和耗竭 终末耗尽的 T 细胞，可以有针对性地提高抗肿瘤免疫力。我们将测试这个 假设有两个目标；我们将 1) 确定在缺氧情况下抑制 H3K27 去甲基化是否足够 使用去甲基酶抑制剂和创新的 T 细胞体外测定来驱动二价和末端耗尽 精疲力尽。我们将 2) 确定 Ezh2 是否可以针对使用两者来防止耗尽中的二价性 分别在体外和体内系统中 Ezh2 活性抑制剂和 Ezh2 诱导缺失。这 特异于终末耗竭 TIL 的二价基因的存在支持这样的观点：虽然耗竭细胞 表观遗传上对免疫治疗（例如抗 PD1 治疗、染色质和转录治疗）具有抗性 调节因子可以通过增加关键功能基因的表达来重新激活耗尽的 TIL 提高抗肿瘤反应。