Project 3: Impact of tumor genetics on PDAC immunobiology and responses to macrophage-targeted immunotherapy

摘要（项目3） 胰腺导管腺癌（PDAC）是一种对治疗反应较差的侵袭性恶性肿瘤， 其特征在于免疫细胞的显著浸润。特别是，巨噬细胞丰富的内 PDAC中的肿瘤微环境（TME），并有助于疾病进展和治疗抗性。 然而，影响免疫细胞（包括巨噬细胞）募集和分布的因素， PDAC在很大程度上仍然未知。最近，我们在项目1中的合作者发现， Trp 53状态表现出不同的免疫特征。我们的合作者进一步观察到， （腺泡或导管）影响肿瘤分子亚型（经典或基底样），这也是已知的 由肿瘤的免疫成分形成。我们假设癌细胞的体细胞改变， 起源类型和肿瘤分子亚型影响TME内和整个TME的免疫景观。 在PDAC进展期间的宿主。为了验证这一假设，我们将确定免疫细胞的频率， 分布，并在TME和整个主机中使用高维分析工具（CODEX 和CyTOF）在PDAC的基因工程小鼠模型（GEMM）上的应用， 和细胞来源类型（由项目1开发）。此外，我们将使用分子方法来识别 在不同基因突变的背景下调节免疫细胞募集的免疫调节因子， 细胞类型的起源，我们将使用遗传，药理学和中和抗体为基础的方法， 证实这些因素在推动PDAC进展中的功能作用。重要的是，我们将验证 在人PDAC标本和人胰腺导管细胞系中进行的这些研究的结果 细胞最后，我们最近发现模式识别受体Dectin-2在肿瘤细胞上表达， 相关的巨噬细胞（TAM）在侵袭性的，可移植的PDAC模型。值得注意的是， 天然Dectin-2配体通过重编程以T细胞依赖性方式诱导持续的PDAC消退 将免疫抑制性TAM转化为免疫刺激性抗原呈递细胞（APC）。我们假设 PDAC可以通过将Dectin-2+ TAM重编程为免疫刺激性APC来有效治疗。我们将 用Dectin-2配体治疗由项目1开发的GEMM中产生的自体肿瘤，以测试这一点 假说.此外，为了鉴定Dectin-2刺激在治疗上有效的机制， 我们将使用CODEX和CyTOF观察TME内发生的免疫景观变化， 在治疗过程中，分子方法将被用于识别免疫调节因子 负责调节治疗效果。总之，这些研究将提高我们对 免疫系统在PDAC发育过程中在基因突变、细胞凋亡和细胞凋亡的变化的背景下发生改变。 起源类型和分子亚型，以及对TAM重编程的应答。

ABSTRACT (Project 3) Pancreatic ductal adenocarcinoma (PDAC), an aggressive malignancy that is poorly responsive to treatment, is characterized by a prominent infiltration of immune cells. In particular, macrophages are abundant within the tumor microenvironment (TME) in PDAC and contribute to disease progression and treatment resistance. However, the factors affecting the recruitment and distribution of immune cells, including macrophages, in PDAC remain largely unknown. Recently, our collaborators in Project 1 found that tumors differing in their Trp53 status exhibited different immune profiles. Our collaborators further observed that the cell type of origin (acinar or ductal) influenced the tumor molecular subtype (classical or basal-like), which is also known to be shaped by the immune composition of the tumor. We postulate that somatic alterations in cancer cells, the cell type of origin, and tumor molecular subtype influence the immune landscape within the TME and throughout the host during PDAC progression. To test this hypothesis, we will determine immune cell frequency, distribution, and function in the TME and throughout the host using high-dimensional analytical tools (CODEX and CyTOF) on genetically engineered mouse models (GEMMs) of PDAC that vary in their driver mutations and cell type of origin (developed by Project 1). Additionally, we will use molecular methods to identify immunomodulatory factors regulating immune cell recruitment in the context of different genetic mutations and cell type of origin, and we will use genetic, pharmacological, and neutralizing antibody-based approaches to confirm the functional effects of these factors in driving PDAC progression. Importantly, we will validate findings from these studies in human PDAC specimens and in cell lines derived from human pancreatic ductal cells. Finally, we recently found that the pattern recognition receptor, Dectin-2, is expressed on tumor- associated macrophages (TAMs) in an aggressive, transplantable model of PDAC. Notably, administration of natural Dectin-2 ligands induces sustained PDAC regression in a T-cell dependent manner by reprogramming immunosuppressive TAMs into immunostimulatory antigen-presenting cells (APCs). We hypothesize that PDAC can be effectively treated by reprogramming Dectin-2+ TAMs into immunostimulatory APCs. We will treat autochthonous tumors arising in the GEMMs developed by Project 1 with Dectin-2 ligands to test this hypothesis. Furthermore, to identify mechanisms by which Dectin-2 stimulation is therapeutically efficacious, we will use CODEX and CyTOF to observe changes to the immune landscape occurring within the TME and throughout the host upon treatment. Molecular approaches will be used to identify immunomodulatory factors responsible for mediating therapeutic efficacy. Together, these studies will improve our understanding of how the immune system is altered during PDAC development in the context of variation in genetic mutations, cell type of origin, and molecular subtype, and in response to TAM reprogramming.