Role of nonsense mediated RNA decay in pancreatic cancer

无义介导的RNA衰变（NMD）是一种快速降解选定mRNA的机制。最近的研究 他们发现，NMD所需的UPF 1基因在超过80%的人中发生了惊人的突变和失活， 胰腺腺鳞癌（ASPC）是胰腺癌的一种特别侵袭性的形式。我们有 确定胰腺癌中UPF 1突变导致UPF 1表达降低。其他突变 最近向NMD报告的胰腺导管腺癌中发现，我们报告说， 胰腺癌中常见的许多应激抑制NMD活性。NMD抑制剂促进 转化细胞在软琼脂、皮下外植体和原位胰腺移植物中的生长 模型我们的总体目标是更好地了解NMD抑制如何增强肿瘤生长，并探索如何 我们可以利用NMD抑制来获得胰腺癌的治疗效果。 RNA稳定性筛选、RNAseq和代谢组学筛选已经将Notch信号传导和糖酵解鉴定为 NMD调节途径。Notch信号和糖酵解在胰腺癌中发挥重要作用， 一般来说，最近的胰腺癌分子分类研究表明，这两种途径是 在ASPC中特别活跃，其中NMD通常是遗传失活的。重要的是，这些途径可以 也是有针对性的。目的1：明确NMD抑制Notch的机制和意义 在胰腺癌中的激活。根据我们的初步数据，我们假设减少NMD抑制 表达稳定Notch配体和受体，Notch信号传导的激活抑制e-钙粘蛋白 表达在转移和化学抗性中起关键作用。但是我们也假设NMD 受抑制的胰腺癌对Notch抑制剂特别敏感。在目标2中，我们将确定如何 减少NMD抑制调节代谢途径，并将其用于治疗增益。基于我们 初步数据，我们假设NMD抑制稳定了选择性剪接的转录本， 线粒体呼吸系统的成员，这激活糖酵解和磷酸戊糖 分流。这些通路的激活应该使UPF 1突变的肿瘤对临床化疗更敏感。 可用的线粒体抑制剂和其他代谢抑制剂，如初步聚焦的shRNA所示， 合成致命性筛选对于这两个目标，我们将使用各种体外细胞生物学，生物化学， 分子技术我们将用独特的ASPC组织阵列以及一种新的 基因工程小鼠，我们可以暂时下调胰腺中UPF 1的表达， 因此，可以忠实地模拟ASPC中发现的UPF 1突变的后果。

Nonsense mediated RNA decay (NMD) is a mechanism to rapidly degrade select mRNAs. Recent studies have found that the UPF1 gene, required for NMD, is strikingly mutated and inactivated in >80% of adenosquamous pancreatic cancer (ASPC), a particularly aggressive form of pancreatic cancer. We have determined that UPF1 mutations in pancreatic cancer result in decreased UPF1 expression. Other mutations recently reported to inactivate NMD are found in pancreatic ductal adenocarcinoma, and we have reported that many of the stresses commonly found in pancreatic cancer repress NMD activity. NMD inhibition promotes the growth of transformed cells in soft agar, subcutaneous explants, and in an orthotopic pancreatic transplant model. Our overall goal is to better understand how NMD inhibition augments tumor growth and explore how we can exploit NMD inhibition for therapeutic gain in pancreatic cancer. RNA stability screens, RNAseq, and metabolomics screens have identified Notch signaling and Glycolysis as NMD regulated pathways. Both Notch signaling and Glycolysis play an important role in pancreatic cancer in general, and recent pancreatic cancer molecular classification studies indicate that these two pathways are particularly active in ASPC, where NMD is typically genetically inactivated. Importantly these pathways can also be targeted. In Aim 1 we will identify the mechanism and significance of NMD inhibition on Notch activation in pancreatic cancer. Based on our preliminary data we hypothesize that reduced NMD inhibition expression stabilizes Notch ligands and receptors, and the activation of Notch signaling represses e-cadherin expression to play a key role in metastases and chemo-resistance. However we also hypothesize that NMD inhibited pancreatic cancers will be particularly susceptible to Notch inhibitors. In Aim 2 we will determine how reduced NMD inhibition regulates metabolic pathways and exploit this for therapeutic gain. Based on our preliminary data, we hypothesize that NMD inhibition stabilizes alternatively spliced transcripts encoding members of the mitochondrial respiration system, and this activates glycolysis and the pentose phosphate shunt. The activation of these pathways should render tumors with UPF1 mutations more sensitive to clinically available mitochondrial inhibitors and other metabolic inhibitors, as indicated by preliminary focused shRNA synthetic lethality screens. For both Aims we will use a variety of in vitro cell biology, biochemical, and molecular techniques. We will validate our in vitro findings with unique ASPC tissue arrays, as well as a novel genetically engineered mouse in which we can temporally down-regulate UPF1 expression in pancreas, and can thus faithfully model the consequences of UPF1 mutations found in ASPC.