Engineering human ducts and acini from pluripotent stem cells to study cell type of origin and tumour evolution in pancreatic cancer

人类多能干细胞具有独特和无限的自我更新和增殖能力。对这些细胞的分析和科学利用大大提高了我们对多能性电路和随后发生的分化过程的理解。因此，协议已经发展到允许在我们体内几乎纯生成许多细胞类型，这反过来又为未来的体外疾病建模奠定了基础。胰腺导管腺癌（PDAC）是胰腺最具破坏性的疾病之一，尽管进行了大量的研究，但预后仍很差。具体而言，PDAC患者的5年生存率仅为4%。目前PDAC的基础研究主要限于小鼠模型，这需要新颖和创新的建模工具。在此之前，我们已经成功地从人类多能干细胞中形成了混合导管/腺泡样胰腺类器官，我们将其应用于囊性纤维化的胰腺方面建模，并筛选疾病挽救药物。然而，单独诱导腺泡或导管样结构的机会将揭示新的机会，特别是在癌症研究中。在这项赠款提案中，我们计划解决这些需求。具体来说，我们将实施控制胚胎细胞命运决定的信号，以通过排除谱系分叉处的替代命运来有效地产生所需的细胞类型。发育中的胰腺上皮从发育中的胰腺中的周围间充质和脉管系统接收旁分泌以及基于细胞-细胞的输入。细胞外基质将动态和静态机械信号传导归因于直接谱系分离，进一步证实了这种小生境-上皮通信。因此，我们还将通过基质修饰和专门的共培养技术来整合这些知识，以获得两种成熟的外分泌胰腺细胞类型，腺泡细胞和导管细胞。将人类外分泌组织异种移植到胰腺中并随后与小鼠宿主相互连接将开启体内疾病模型的新时代。我们以前的工作已经提供了概念的证明，但对移植物或宿主进行不同修饰以提高移植产量的系统测试仍然是难以捉摸的。因此，在第二个工作方案中，这一差距将通过移植物在时间和基质嵌入方面的修改以及由于损伤引起的宿主修改来弥补。这些修改和系统的阐述将有助于提高移植到小鼠胰腺宿主的PO。最后，我们将建立一个平行的努力，这些新的细胞类型，即基因未修饰的人类腺泡或导管细胞的应用平台。在此，基于人PSC的PDAC模型将根据定义的致癌事件解决关于PDAC起始、起源细胞类型、不同类型的前体病变和进展期间的PDAC传播的未决问题。

Human pluripotent stem cells harbour a unique and unlimited capacity for self-renewal and proliferation. Analysis and scientific exploitation of these cells has greatly improved our understanding of the pluripotency circuitry and subsequently occurring differentiation processes. Thereby, protocols have evolved allowing the virtually pure generation of a lot of cell types in our body, which in turn set the stage for future disease modelling in vitro. Pancreatic ductal adenocarcinoma (PDAC) is one of the most devastating diseases of the pancreas with a dismal prognosis despite intensive research efforts. Specifically, in PDAC patients the 5-year survival rate is only 4%. Current basic research in PDAC is mostly limited to mouse models underpinning the need for novel and innovative modelling tools. Previously, we have been successful in the formation of mixed ductal/acinar-like pancreatic organoids from human pluripotent stem cells that we applied for modelling pancreatic facets of cystic fibrosis and to screen for disease-rescuing drugs. However, the opportunity to separately induce either acinar or duct-like structures would unclose new opportunities particularly in cancer research. Within this grant proposal we plan to address these needs. Specifically, we will implement signals controlling embryonic cell fate decisions to efficiently yield the desired cell types through exclusion of alternate fates at lineage bifurcations. The developing pancreatic epithelium receives paracrine as well as cell-cell based input from the surrounding mesenchyme and vasculature in the developing pancreas. This niche-epithelium communication is further substantiated by extracellular matrix ascribing dynamic and static mechano-signalling to direct lineage segregation. Thus, we will also integrate this knowledge by matrix modification and specialized co-culture techniques to obtain the two mature exocrine pancreatic cell types, acinar and ductal cells. Xenotransplantation of human exocrine tissue into the pancreas and subsequent interconnection with the mouse host would launch a novel era of in vivo disease models. Our previous work has provided proof of concept but a systematic testing of different modifications either to the graft or the host to improve transplantation yield remains elusive. Therefore, in the second work programme this gap will be closed by graft modifications in terms of timing and matrix embedding and by host modifications due to injury. These modifications and systematic elaborations will help to improve engraftment of POs into the murine pancreatic host. Finally, we will set up in paralleling efforts an application platform for these novel cell types, namely genetically unmodified human acinar or ductal cells. Here, a human PSC based model for PDAC will address open questions regarding PDAC initiation, cell type of origin, different types of precursor lesions and PDAC dissemination during progression according to defined oncogenic events.