Departments of Pediatrics and Cellular and Molecular Medicine, University of California-San Diego, La Jolla, California; Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
Departments of Pediatrics and Cellular and Molecular Medicine, University of California-San Diego, La Jolla, California.
Gastroenterology. 2018 Apr;154(5):1509-1523.e5. doi: 10.1053/j.gastro.2017.12.007. Epub 2017 Dec 19.
BACKGROUND & AIMS: Intraductal papillary mucinous neoplasias (IPMNs) are precancerous cystic lesions that can develop into pancreatic ductal adenocarcinomas (PDACs). These large macroscopic lesions are frequently detected during medical imaging, but it is unclear how they form or progress to PDAC. We aimed to identify cells that form IPMNs and mutations that promote IPMN development and progression.
We generated mice with disruption of Pten specifically in ductal cells (Sox9CreER;Pten;R26R or Pten mice) and used Pten and Pten mice as controls. We also generated Kras;Pten and Kras;Pten mice. Pancreata were collected when mice were 28 weeks to 14.5 months old and analyzed by histology, immunohistochemistry, and electron microscopy. We performed multiplexed droplet digital polymerase chain reaction to detect spontaneous Kras mutations in Pten mice and study the effects of Ras pathway activation on initiation and progression of IPMNs. We obtained 2 pancreatic sections from a patient with an invasive pancreatobiliary IPMN and analyzed the regions with and without the invasive IPMN (control tissue) by immunohistochemistry.
Mice with ductal cell-specific disruption of Pten but not control mice developed sporadic, macroscopic, intraductal papillary lesions with histologic and molecular features of human IPMNs. Pten mice developed IPMNs of several subtypes. In Pten mice, 31.5% of IPMNs became invasive; invasion was associated with spontaneous mutations in Kras. Kras;Pten mice all developed invasive IPMNs within 1 month. In Kras;Pten mice, 70% developed IPMN, predominately of the pancreatobiliary subtype, and 63.3% developed PDAC. In all models, IPMNs and PDAC expressed the duct-specific lineage tracing marker yellow fluorescent protein. In immunohistochemical analyses, we found that the invasive human pancreatobiliary IPMN tissue had lower levels of PTEN and increased levels of phosphorylated (activated) ERK compared with healthy pancreatic tissue.
In analyses of mice with ductal cell-specific disruption of Pten, with or without activated Kras, we found evidence for a ductal cell origin of IPMNs. We also showed that PTEN loss and activated Kras have synergistic effects in promoting development of IPMN and progression to PDAC.
导管内乳头状黏液性肿瘤（IPMNs）是一种癌前囊性病变，可发展为胰腺导管腺癌（PDAC）。这些大型宏观病变常在医学影像学检查中发现，但尚不清楚它们是如何形成或进展为 PDAC 的。我们旨在鉴定形成 IPMN 的细胞以及促进 IPMN 发生和进展的突变。
我们生成了特异性在导管细胞中敲除 Pten 的小鼠（Sox9CreER;Pten;R26R 或 Pten 小鼠），并将 Pten 和 Pten 小鼠作为对照。我们还生成了 Kras;Pten 和 Kras;Pten 小鼠。当小鼠 28 周至 14.5 个月大时，收集胰腺并通过组织学、免疫组织化学和电子显微镜进行分析。我们通过多重数字聚合酶链反应检测 Pten 小鼠中自发的 Kras 突变，并研究 Ras 通路激活对 IPMN 起始和进展的影响。我们从一名患有侵袭性胰胆管 IPMN 的患者中获得了 2 个胰腺切片，并通过免疫组织化学分析了具有和不具有侵袭性 IPMN（对照组织）的区域。
特异性在导管细胞中敲除 Pten 的小鼠而非对照小鼠会发生散发性、宏观的、导管内乳头状病变，具有人类 IPMN 的组织学和分子特征。Pten 小鼠会发生多种亚型的 IPMN。在 Pten 小鼠中，31.5%的 IPMN 发生侵袭性；侵袭性与 Kras 中的自发突变有关。Kras;Pten 小鼠在 1 个月内均发生侵袭性 IPMN。在 Kras;Pten 小鼠中，70%发生 IPMN，主要为胰胆管型，63.3%发生 PDAC。在所有模型中，IPMN 和 PDAC 均表达导管特异性谱系追踪标记物黄色荧光蛋白。在免疫组织化学分析中，我们发现侵袭性人胰胆管 IPMN 组织与健康胰腺组织相比，PTEN 水平降低，磷酸化（激活）ERK 水平升高。
在分析特异性在导管细胞中敲除 Pten 的小鼠（有或没有激活的 Kras）时，我们发现 IPMN 来源于导管细胞。我们还表明，PTEN 缺失和激活的 Kras 在促进 IPMN 发生和进展为 PDAC 方面具有协同作用。
