Programmed death ligand 1 (PD-L1) cell-intrinsic signaling in pancreatic cancer – Influence on tumor metabolism, microenvironment and disease progression

胰腺导管腺癌(PDAC)是全球癌症相关死亡的主要原因之一。在过去的几年中，免疫检查点靶向治疗与几种癌症的治疗进展有关。尤其是以程序性死亡1/程序性死亡配体1(PD-1/PD-L1)轴为靶点似乎具有有益的影响。PD-L1在人胰腺癌和肿瘤微环境(TME)中均有表达，可能参与肿瘤的进展。PD-L1与T细胞结合的PD-1相互作用导致细胞毒性T细胞的耗竭和功能障碍。此外，最近的数据表明，PD-L1对肿瘤细胞和TME之间的代谢失衡有重要影响。这项建议的目的是阐明PD-L1细胞内在信号在PDAC细胞中对肿瘤代谢和T细胞反应的关键作用。我们的假设如下：1)将使用CRISPR技术生成PD-L1修饰的PDAC细胞。产生的细胞的表型变化将使用广泛的免疫学和代谢分析小组进行评估。既要进行表面培养，也要进行器官培养。2)将来自(1)的修饰细胞系原位移植到野生型小鼠体内，以模拟人类PDAC表型。将监测和比较PD-L1改变对肿瘤进展和肿瘤微环境的影响。重点将放在正电子发射断层扫描/计算机断层扫描(PET/CT)成像、存活统计以及小鼠模型的免疫学和代谢表型上。迫切需要新的PDAC治疗策略和疾病的早期诊断。该项目将为理解PD-1/PD-L1在PDAC中的内在信号转导机制做出重大贡献，并可能影响这种毁灭性疾病的多模式未来治疗。

Pancreatical ductal adenocarcinoma (PDAC) is one leading cause of cancer related deaths worldwide. In the last few years immune checkpoint targeting therapies were associated with therapeutic advances in several cancers. Especially targeting of the Programmed death 1/Programmed death ligand 1 (PD-1/PD-L1) axis seems to have a beneficial impact. PD-L1 is expressed in human pancreatic cancers and the tumor microenvironment (TME) and may be involved in tumor progression. Interaction of PD-L1 and T cell-bound PD-1 leads to exhaustion and dysfunction of cytotoxic T cells. In addition, recent data suggest that PD-L1 has a major influence on the metabolic imbalance between tumor cells and the TME. The aim of this proposal is to elucidate the key role of PD-L1 cell intrinsic signaling in PDAC cells regarding tumor metabolism and T cell response. Our hypothesis will be approached as follows: 1) PD-L1 modified PDAC cells will be generated using CRISPR technology. The altered phenotype of the generated cells will be assessed using a broad immunologic and metabolic panel of assays. Both, surface culture and organoid culture will be performed. 2) Modified cell lines from (1) will be orthotopically implanted into wildtype mice to mimic the human PDAC phenotype. The impact of PD-L1 alterations on tumor progression and the tumor micro environment will be monitored and compared. The focus will be put on positron-emission-tomography/ computed tomography (PET/CT) imaging, survival statistics and the immunologic and metabolic phenotypes of the murine model. There is an urgent need for new strategies for PDAC treatment and early diagnosis of the disease. This project will make a substantial contribution to the understanding of PD-1/PD-L1 intrinsic signaling in PDAC and potentially influence multimodal future treatment of this devastating disease.