Research Project Pancreatic Cancer

项目2(胰腺)摘要 胰腺导管腺癌(PDAC)患者的预后很差。不幸的是，试图 到目前为止，对PDAC的免疫治疗尚未取得显著的临床疗效。人们普遍认为 放射治疗(RT)可以通过释放肿瘤衍生的抗原和危险信号来启动抗肿瘤免疫， 这种免疫启动效应在多种癌症类型的RT疗效中起着至关重要的作用。相比之下，组合 采用检查点免疫治疗的RT在PDAC中普遍表现平平。目前尚不清楚这是否反映了 RT无法激活肿瘤特异性T细胞或需要额外的支持T细胞的刺激剂 引爆。树突状细胞(CDCs)是产生肿瘤抗原特异性T细胞反应的中心细胞。在动物身上 模型和人类相关研究，CDC对于检查点免疫治疗的反应性和 RT诱导肿瘤免疫。我们的假设是，RT对局部和全身肿瘤有不同的影响 通过对疾病预防控制中心的监管获得豁免。我们将直接解决这一假设，重点介绍DC和 在SOC RT过程中，T细胞反应是共形的。我们将使用scRNAseq的组合，空间解析 在人类PDAC组织和小鼠模型中进行蛋白质、代谢组谱分析，以测试以下各项。在目标1中，我们将 确定RT对CDC局部免疫启动的局部和全身影响。这些研究将使用 从SBRT患者的纵向收集的人体组织与遗传学的组合 工程化小鼠模型(GEMM)以评估RT对DC表型和功能的影响。利用我们的 机构优势，我们将在三个前瞻性和回溯性组织队列中进行这些研究 收集接受SBRT的人类PDAC患者，并使用PDAC GEMM进行机制研究。 这些研究将评估SBRT对CDC功能的局部影响。在目标2中，我们将确定 RT对PDAC患者CDC分化及系统免疫的影响我们在人类PDAC患者和 小鼠模型表明，PDAC在骨髓生成和CDC发育方面的关键差异可能会损害 肿瘤免疫。此外，我们的初步数据表明，SBRT可以改变CDC的发展和 表型。在这个目标中，我们将使用人类组织和GEMM的组合来具体研究RTS 影响全身树突状细胞的发育、表型和功能，以及这对肿瘤免疫和 RT反应中的T细胞启动。在目标3中，我们将确定RT对区域之间相互作用的影响 代谢与CDC介导的T细胞免疫。RT可以对肿瘤和间质细胞产生巨大影响 新陈代谢。同时，这些代谢变化可以调节CDC和T细胞的生存和功能。然而， 这些相互作用在完整的PDAC组织的背景下还没有得到很好的研究，在那里，区域异质性 在免疫渗入中，缺氧和间质密度是主要因素。因此，我们将使用多个正交表 包括Codex、NIMS和高级人体PDAC组织成像在内的方法在空间上解析 SBRT对细胞免疫、基质成分和代谢特征的次区域异质性的影响。

PROJECT 2 (PANCREAS) SUMMARY The prognosis for pancreatic ductal adenocarcinomas (PDAC) patients is dismal. Unfortunately, attempts at immunotherapy for PDAC to date have not achieved significant clinical benefits. It is widely accepted that radiation therapy (RT) can prime anti-tumor immunity by releasing tumor-derived antigens and danger signals, and this immune priming effect has a crucial role in RT efficacy in multiple cancer types. In contrast, combining RT with checkpoint immunotherapy has been generally underwhelming in PDAC. It is unclear if this reflects an inability of RT to prime tumor-specific T cells or a need for additional stimulants that are supportive of T-cell priming. Dendritic cells (cDCs) are central for generating tumor antigen-specific T-cell responses. In animal models and human correlative studies, cDCs are crucial for responsiveness to checkpoint immunotherapy and RT-induced tumor immunity. Our hypothesis is that RT drives divergent effects on local and systemic tumor immunities through regulation of cDCs. We will directly address this hypothesis, focusing on how DCs and T-cell responses are co-shaped during SOC RT. We will use a combination of scRNAseq, spatially resolved protein, metabolomic profiling in human PDAC tissues and mouse models to test the following. In Aim 1, we will determine the local and systemic impacts of RT on local immune priming by cDCs. These studies will use a combination of longitudinally collected human tissues from patients undergoing SBRT and genetically engineered mouse models (GEMMs) to assess the impact of RT on DC phenotype and function. Leveraging our institutional strengths, we will conduct these studies in three cohorts of prospective and retrospective tissue collections from human PDAC patients receiving SBRT and conduct mechanistic studies using PDAC GEMMs. These studies will assess the local impact of SBRT on cDC function. In Aim 2, we will determine the impact of RT on cDC differentiation and systemic immunity in PDAC patients. Our data in both human PDAC patients and mouse models demonstrated that key differences in myelopoiesis and cDC development in PDAC can impair tumor immunity. Furthermore, our preliminary data indicated that SBRT could alter cDC development and phenotype. In this aim, we will use a combination of human tissues and GEMMs to specifically study how RTs impact systemic DC development, phenotype and function, and the net impact this has on tumor immunity and T-cell priming in response to RT. In Aim 3, we will determine the impact of RT on interactions between regional metabolism and cDC-directed T-cell immunity. RT can have a dramatic impact on tumor and stromal cell metabolism. In parallel, these metabolic changes can regulate cDC and T-cell survival and function. However, these interactions have not been well studied in the context of intact PDAC tissues, where regional heterogeneity in immune infiltrate, hypoxia, and stromal density are dominant players. We will therefore use multiple orthogonal approaches including CODEX, NIMS, and advanced imaging of human PDAC tissues to spatially resolve the impact of SBRT on subregional heterogeneities in cellular immunity, stromal composition, and metabolic profiles.