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的、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极大地提高了我们对多潜能回路和随后发生的分化过程的理解。因此，已经进化出的方案允许在我们体内产生许多几乎纯净的细胞类型，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)是胰腺疾病中最具破坏性的疾病之一，尽管有大量的研究工作，但预后很差。具体地说，PDAC患者的5年生存率仅为4%。目前对PDAC的基础研究主要局限于鼠标模型，这支持了对新颖和创新的建模工具的需求。以前，我们已经成功地从人类多能干细胞中形成了混合的导管/腺泡状胰腺器官，我们将其应用于模拟囊性纤维化的胰腺方面，并筛选疾病救治药物。然而，单独诱导腺泡或导管状结构的机会将带来新的机会，特别是在癌症研究中。在这项赠款提案中，我们计划满足这些需求。具体地说，我们将实施控制胚胎细胞命运决定的信号，通过排除世系分叉处的交替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间质和血管系统接受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的机械信号归因于直接的谱系分离，进一步证实了这种小生境-上皮细胞的沟通。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并随后与小鼠宿主相互连接将开启体内疾病模型的新纪元。我们以前的工作已经提供了概念上的证据，但对移植物或宿主的不同修改以提高移植产量的系统测试仍然难以捉摸。因此，在第二个工作方案中，这一差距将通过在时间和基质嵌入方面的移植物修改以及因受伤而进行的宿主修改来弥合。这些修饰和系统的阐述将有助于提高POS在小鼠胰腺宿主中的植入。最后，我们将为这些新的细胞类型，即未经基因改造的人腺泡细胞或导管细胞，建立一个应用平台。在这里，一个基于人类PSC的PDAC模型将解决关于PDAC的启动、细胞来源类型、不同类型的前驱病变以及根据定义的致癌事件在进展过程中PDAC扩散的未决问题。

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.