Elucidating the Role of Tregs in Cancer Metastasis and T Cell Dysfunction

阐明 Tregs 在癌症转移和 T 细胞功能障碍中的作用

• 批准号: 10679834
• 负责人: Zoe Schmiechen
• 金额: $ 3.26万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10679834
• 关键词: Ablation; Adoptive Transfer; Antigens; Automobile Driving; Biological Response Modifiers; CD4 Positive T Lymphocytes; CD8-Positive T-Lymphocytes; CD8B1 gene; CRISPR/Cas technology; Cancer Etiology; Cancer cell line; Cell Line; Cell Separation; Cells; Cessation of life; Characteristics; Combined Modality Therapy; Cytotoxic T-Lymphocytes; DDR2 gene; Data; Detection; Development; Disease; Disseminated Malignant Neoplasm; Doctor of Philosophy; FOXP3 gene; Flow Cytometry; Functional disorder; Gene Expression Profile; Genes; Genetic Models; Goals; Grant; Histologic; Human; Immune Evasion; Immune System Diseases; Immune response; Immunocompetent; Immunologic Surveillance; Immunotherapy; Implant; Infiltration; Intrinsic factor; Invaded; Investigation; Knock-out; Knowledge; Link; Malignant Neoplasms; Malignant neoplasm of pancreas; Microscopy; Modeling; Mus; Neoplasm Metastasis; Newly Diagnosed; Organ; Pancreas; Pancreatic Diseases; Pancreatic Ductal Adenocarcinoma; Patients; Phenotype; Population; Receptor Protein-Tyrosine Kinases; Regimen; Regulatory T-Lymphocyte; Research; Research Personnel; Resistance; Role; Signal Transduction; Survival Rate; T cell differentiation; T-Cell Activation; T-Cell Depletion; T-Lymphocyte; T-Lymphocyte Subsets; Technical Expertise; Testing; Tumor Antigens; Tumor Burden; Tumor Cell Line; Variant; cancer cell; cytotoxic; cytotoxic CD8 T cells; discoidin domain receptor 2; effective therapy; exhaust; exhaustion; immune checkpoint blockade; implantation; neoantigens; novel; overexpression; pancreatic cancer patients; pancreatic ductal adenocarcinoma model; prevent; public health relevance; retroviral transduction; single-cell RNA sequencing; standard of care; therapeutic development; therapeutic target; therapy resistant; transcriptome sequencing; tumor; tumor growth; tumor microenvironment; tumor progression; tumor-immune system interactions

PROJECT ABSTRACT Pancreatic ductal adenocarcinoma (PDA) is the 4th leading cause of cancer related deaths and has a dismal 5-year survival rate of 10%. Lethality is attributed to early metastasis, late detection, and therapeutic resistance. Cytotoxic CD8 T cells are the principal mediators of immune surveillance and critical for cancer eradication. However, in PDA and other cancers, CD8 T cells progressively lose their cytotoxic function, and are thus characterized as exhausted. Immune checkpoint blockade aims to correct T cell exhaustion by blocking inhibitory signaling and has revolutionized the treatment of many malignancies. However, PDA is largely resistant. As such, this grant seeks to understand the mechanisms driving CD8 T cell exhaustion in PDA and how PDA evades an activated immune response after immunotherapy treatment. Additionally, this grant will study cancer cell-intrinsic and -extrinsic mechanisms of PDA metastasis, to develop rational therapies. My lab derived new cancer cell lines from immunotherapy resistant tumors, termed escape variants, to study mechanisms of immune evasion. I found that orthotopic implantation of escape variant cells into immunocompetent mice yields multi-organ metastatic disease, which is not seen with the immunotherapy na·1ve cell line. Thus, escape variant tumors can model metastatic disease of PDA patients. Bulk RNA sequencing identified a single gene, Ddr2, that was significantly upregulated across multiple escape variant lines compared to immunotherapy na"ive cells. Ddr2 encodes a receptor tyrosine kinase, is linked to metastasis in other malignancies, and is correlated with reduced patient survival in PDA. Investigation into the tumor microenvironment of escape variant tumors identified an accumulation of intratumoral regulatory T cells (Tregs). I found that Treg depletion significantly reduced tumor burden and metastasis and reduced the development of CD8 T cell exhaustion. I will test the central hypothesis that immunotherapy selects for metastatic cancer cells that promote intratumoral Tregs that cause CD8 T cell dysfunction. In the first Aim, I will investigate how immunotherapy escape drives Treg accumulation and metastasis. First, I will test if Treg accumulation occurs through conventional CD4 T cell differentiation within the tumor. Next, I will test if forced expression of Ddr2 drives metastasis and ablation of Ddr2 prevents metastasis. In the second Aim, I will identify the CD8 T cell subset critical for preventing PDA metastasis. First, I will determine if CD8 T cells are required for the reduction in tumor burden and abrogation of metastasis seen with Treg depletion. Next, I will use single cell RNA sequencing to identify the transcriptional signature of anti-metastatic CD8 T cells enriched with Treg depletion. Completion of the proposed research strategy will reveal mechanisms of metastasis and CD8 T cell dysfunction in PDA and identify a therapeutic target(s) in the hope of reducing PDA lethality.

项目摘要 胰腺导管腺癌 (PDA) 是癌症相关死亡的第四大原因，其 5 年生存率低至 10%，其致死率归因于早期转移、晚期发现和细胞毒性 CD8 T 细胞是主要介质。然而，在 PDA 和其他癌症中，CD8 T 细胞逐渐丧失其细胞毒性功能，因此具有免疫衰竭的特征。检查点阻断旨在通过阻断抑制性信号传导来纠正 T 细胞耗竭，并彻底改变了许多恶性肿瘤的治疗方法。然而，PDA 在很大程度上具有耐药性，因此，这项资助旨在了解 PDA 中驱动 CD8 T 细胞耗竭的机制以及 PDA 如何逃避。此外，这笔资金将研究PDA转移的癌细胞内在和外在机制，以开发来自免疫疗法耐药的新癌细胞系的合理疗法。我发现将逃逸变异细胞原位植入免疫活性小鼠体内会产生多器官转移性疾病，这是免疫治疗 na·1ve 细胞系所未见的。可以模拟 PDA 患者的转移性疾病。批量 RNA 测序鉴定出单个基因 Ddr2，与免疫治疗初始细胞相比，该基因在多个逃逸变异系中显着上调。Ddr2 编码一种受体。酪氨酸激酶与其他恶性肿瘤的转移有关，并且与 PDA 患者生存率降低有关。对逃逸变异肿瘤的肿瘤微环境的研究发现，肿瘤内调节性 T 细胞 (Treg) 的积累显着减少了肿瘤。首先，我将检验免疫疗法选择促进肿瘤内 Treg 导致 CD8 T 细胞功能障碍的转移性癌细胞的中心假设。目的是，我将测试免疫疗法逃逸如何驱动 Treg 积聚和转移，首先，我将测试肿瘤内传统 CD4 T 细胞分化是否发生 Treg 积聚，接下来，我将测试 Ddr2 的强制表达是否会驱动转移和 Ddr2 消融。在第二个目标中，我将确定对于预防 PDA 转移至关重要的 CD8 T 细胞亚群，我将确定减少肿瘤负荷和转移是否需要 CD8 T 细胞。接下来，我将使用单细胞 RNA 测序来鉴定富含 Treg 的抗转移性 CD8 T 细胞的转录特征。完成所提出的研究策略将揭示转移和 CD8 T 细胞功能障碍的机制。并确定治疗靶点以期降低 PDA 致死率。