The role of Prrx1 in acinar-ductal metaplasia during pancreatic tumorigenesis

项目摘要 胰腺导管腺癌（PDA）是世界上最具破坏性的癌症相关疾病之一， 美国的历史上，人们认为这些胰腺肿瘤起源于胰腺的导管室， 组织的肿瘤细胞形态的基础上。最近，这一思想流派被重新评估， 现在有确凿的证据表明腺泡细胞是起源细胞。在损伤或致癌性损伤后，腺泡 细胞经历腺泡-导管化生（ADM）过程。在组织损伤的情况下，例如胰腺炎， ADM是一种适应性反应，因为在损伤刺激停止后组织快速修复， 有趣的是，在致癌信号存在的情况下，如 突变型Kras *，ADM不能恢复，而是进展为癌前病变-最常见的 胰腺上皮内瘤变（PanIN）。在致癌刺激下ADM的进展， 标记为"致癌" ADM。该提案将研究ADM如何进展为 在Kras * 存在下的PanIN，以及研究"适应性"和"致癌性"之间的差异 Adm.我们的研究小组最近确定了配对相关的同源框1（Prrx1）转录因子作为一个转录因子。 我们以前已经表明，Prrx1表达增加， Prrx1直接与Sox 9相互作用，Sox 9是一种在ADM形成中重要的导管基因， 升级到Panin。因此，我们假设胰腺损伤后Prrx1表达上调 （胰腺炎）导致ADM的维持，并允许随后的转化， 致癌Kras *，从而促进胰腺肿瘤发生。我们将通过两个测试来验证这个假设。 相关的具体目标。目标1将确定Prrx 1对地层的要求， 胰腺损伤后ADM和PanIN损伤的维持。我们将使用组织特异性敲除 Prrx1（Ptf1aCre; Prrx1f/f）的体内表达，以确定Prrx1在 铜绿假单胞菌诱导的胰腺炎后ADM。此外，我们将在诱导型的背景下敲除Prrx1。 致癌Kras * 信号传导（iKras *; Prrx1f/f）。有了这个模型，我们可以解决是否需要Prrx1， PanIN形成和缺乏Prrx1的ADM细胞是否对Kras * 转化更具抗性。目的2 将研究"适应性"和"致癌性" ADM的调节。使用2D和3D体外试验， 我们将研究Prrx1通过促炎细胞因子和/或 分别在"适应性"和"致癌性" ADM期间的致癌Kras *。此外，我们将采取一个公正的 一种通过分离ADM细胞来鉴定"适应性"和"致癌性" ADM的额外调节的方法， iKras * 动物胰腺炎后进行RNAseq以检查差异基因表达。采取 总之，这些研究将为ADM的潜在机制提供新的见解，并阐明 促进胰腺肿瘤发生而不是组织恢复。

PROJECT SUMMARY Pancreatic ductal adenocarcinoma (PDA) is one of the most devastating cancer-related diseases in the United States. Historically, it was thought these pancreatic tumors arose from the ductal compartment of the tissue based on the morphology of the tumor cells. Recently, this school of thought has been re-evaluated and resounding evidence now points at the acinar cell as the cell of origin. Upon injury, or oncogenic insult, acinar cells undergo a process of acinar-ductal metaplasia (ADM). In the context of tissue injury, such as pancreatitis, ADM is an adaptive response as there is rapid repair of the tissue following cessation of the injury stimulus, a process we have labeled as “Adaptive” ADM. Interestingly, in the presence of oncogenic signals, such as mutant Kras*, ADM does not recover and instead progresses into precancerous lesions – the most common being pancreatic intraepithelial neoplasia (PanIN). This progression of ADM under oncogenic stimulus we have labeled as “Oncogenic” ADM. This proposal will examine the underlying mechanism of how ADM progresses to PanIN in the presence of Kras*, as well as investigate the difference between “Adaptive” and “Oncogenic” ADM. Our group has recently identified the paired-related homeobox1 (Prrx1) transcription factor as a potentially important player in ADM. We have previously shown that Prrx1 expression increases during pancreatitis, and that Prrx1 directly interacts with Sox9, a ductal gene important in the formation of ADM and progression to PanIN. Therefore, we hypothesize up-regulation of Prrx1 following pancreatic injury (pancreatitis) results in the maintenance of ADM and allows for subsequent transformation by oncogenic Kras*, thereby promoting pancreatic tumorigenesis. We will test this hypothesis through two interrelated Specific Aims. Aim 1 will determine the requirement of Prrx1 for the formation and maintenance of ADM and PanIN lesions following pancreatic injury. We will use tissue-specific knockout of Prrx1 (Ptf1aCre;Prrx1f/f) in vivo to determine the requirement of Prrx1 in the formation and maintenance of ADM following caerulein-induced pancreatitis. Additionally, we will knockout Prrx1 in the context of inducible oncogenic Kras* signaling (iKras*;Prrx1f/f). With this model, we can address whether Prrx1 is required for PanIN formation and whether ADM cells lacking Prrx1 are more resistant to transformation by Kras*. Aim 2 will investigate the regulation of “Adaptive” and “Oncogenic” ADM. Using 2D and 3D in vitro assays and tissue from Aim1, we will investigate the mechanisms of Prrx1 regulation by pro-inflammatory cytokines and/or oncogenic Kras* during “Adaptive” and “Oncogenic” ADM, respectively. Furthermore, we will take an unbiased approach to identify additional regulation of “Adaptive” and “Oncogenic” ADM by isolating ADM cells from iKras* animals following pancreatitis and performing RNAseq to examine differential gene expression. Taken together, these studies will provide new insights into the mechanisms underlying ADM and elucidate what promotes the initiation of pancreatic tumorigenesis instead of tissue recovery.