Research Project Pancreatic Cancer

项目2（胰腺）总结 胰腺导管腺癌（PDAC）患者的预后很差。不幸的是， 迄今为止，PDAC免疫疗法尚未获得显著的临床益处。人们普遍认为 放射治疗（RT）可以通过释放肿瘤源性抗原和危险信号引发抗肿瘤免疫， 并且这种免疫引发效应在多种癌症类型的RT功效中具有关键作用。相反，结合 RT与检查点免疫疗法在PDAC中通常表现不佳。目前尚不清楚这是否反映了一个 RT不能引发肿瘤特异性T细胞或需要支持T细胞增殖的额外刺激物 启动树突状细胞（cDC）是产生肿瘤抗原特异性T细胞应答的中心。在动物 模型和人类相关研究中，cDC对于对检查点免疫疗法的反应性至关重要， RT诱导的肿瘤免疫。我们的假设是RT对局部和全身肿瘤的作用不同 通过监管cDC获得豁免。我们将直接讨论这一假设，重点是如何发展中国家和 T细胞应答在SOC RT期间是共形的。 在人PDAC组织和小鼠模型中进行蛋白质、代谢组学分析以测试以下内容。在目标1中，我们 确定RT对cDC的局部免疫引发的局部和全身影响。这些研究将使用 从接受SBRT的患者纵向收集的人体组织和遗传学上的 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 机构优势，我们将在前瞻性和回顾性组织的三个队列中进行这些研究 从接受SBRT的人类PDAC患者收集并使用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患者中cDC分化和全身免疫的影响。我们在人类PDAC患者和 小鼠模型表明，PDAC中骨髓生成和cDC发育的关键差异可以损害 肿瘤免疫此外，我们的初步数据表明，SBRT可以改变cDC的发育， 表型。在这个目标中，我们将使用人体组织和GEMM的组合来专门研究RT如何 影响系统性DC发育、表型和功能，以及这对肿瘤免疫的净影响， 在目标3中，我们将确定RT对区域T细胞之间相互作用的影响。 代谢和cDC导向的T细胞免疫。RT可以对肿瘤和基质细胞产生显著影响， 新陈代谢.同时，这些代谢变化可以调节cDC和T细胞的存活和功能。然而，在这方面， 这些相互作用尚未在完整的PDAC组织中得到很好的研究， 在免疫浸润中，缺氧和基质密度是主要因素。因此，我们将使用多个正交 包括CODEX、NIMS和人类PDAC组织的高级成像在内的方法， SBRT对细胞免疫、基质成分和代谢谱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.