TBEL Project 2

项目2--摘要 胰腺囊性肿瘤(PCN)的患病率估计在20%-30%之间，并伴有导管内乳头状病变。 粘液性肿瘤(IPMN)占一半。取决于形态、位置和遗传学 IPMN可能是发展为胰腺导管腺癌(PDAC)的高危人群，因此显著 降低病人的存活率。虽然RNF43只在PDAC的一小部分中发生突变，但RNF43突变是 在IPMN中高频率流行。尽管RNF43已被确定为WNT的负调控因子 结直肠癌和包括PDAC在内的其他临床前模型中的信号转导，WNT的1期临床试验 RNF43突变实体癌(包括PDAC)患者中的抑制剂已被证明令人失望。其他 RNF43的器官特异性功能可能对IPMN的进展有很大的帮助。利用有条件的 Kras基因突变背景下的RNF43基因敲除小鼠模型我们发现RNF43基因取消了线粒体 性质和功能RNF43的缺失改善了线粒体质量控制，增加了未折叠蛋白 反应(UPR)和内质网应激。这些发现让我们假设RNF43的缺失可能会放松对 这些细胞器的串扰，以维持蛋白质平衡、代谢控制和细胞存活。 在Kras的背景下使用原地小鼠模型研究RNF43的功能丧失(生成于 Maitra博士实验室)、原代基因工程细胞系(由Lyssiotis博士实验室产生)和人类IPMN 衍生有机化合物(在Wood博士的实验室中产生；见项目3)我们建议实现以下目标： 首先，我们将研究RNF43是否调节线粒体的动力学，包括生物发生、分裂、融合 以及抑制IPMN发病的有丝分裂(目标1)。此外，我们还将调查RNF43是否会阻止IPMN 通过管理内质网线粒体动力学来限制内质网应激的发病机制(目标2)。最后，我们将 确定RNF43的丢失是否对持续的OXPHOS产生合成重要性(目标1)和 OXPHOS抑制是否/如何影响原生KRC模型中的多步进展 胰腺囊性瘤(AIM 3)。总体而言，这些研究将阐明RNF43在 线粒体质量控制、内质网线粒体动力学及其对IPMN发病机制的影响 进步。

PROJECT 2 – ABSTRACT The estimated prevalence of pancreatic cystic neoplasms (PCNs) is between 20–30% with intraductal papillary mucinous neoplasm (IPMNs) accounting for half of them. Depending on the morphology, location, and genetics IPMNs can be of high-risk developing pancreatic ductal adenocarcinoma (PDAC) and as such significantly diminishing patient’s survival. While RNF43 is only mutated in a small fraction of PDAC, RNF43 mutations are prevalent in a high frequency in IPMNs. Although RNF43 has been identified as a negative regulator of Wnt signaling in colorectal cancers and other preclinical models including PDAC, a phase 1 clinical trial of a Wnt inhibitor in patients with RNF43 mutated solid cancers (including PDAC) has been proven disappointing. Other likely organ specific functions of RNF43 might be of great advantage for IPMN progression. Utilizing a conditional knockout mouse model of RNF43 in context of Kras mutation we found that RNF43 abrogates the mitochondrial properties and functions while loss of RNF43 improved mitochondrial quality control, increased unfolded protein response (UPR) and ER stress. These findings let us hypothesize that loss of RNF43 may deregulate the crosstalk of these organelles in order to maintain proteostasis, metabolic control, and cell survival. Employing an autochthonous mouse model for functional loss of RNF43 in the context of Kras (generated in the Dr. Maitra lab), primary genetically engineered cell lines (generated in the Dr. Lyssiotis lab) and human IPMN derived organoids (generated in the Dr. Wood lab; see Project 3) we propose to pursue the following aims: First we will investigate whether RNF43 regulates mitochondrial dynamics including biogenesis, fission, fusion and mitophagy to inhibit IPMN pathogenesis (Aim 1). Further, we will investigate whether RNF43 blocks IPMN pathogenesis by limiting ER stress through management of ER-mitochondrial dynamics (Aim 2). Lastly, we will determine whether loss of RNF43 creates a synthetic essentiality for sustained OXPHOS (Aim 1) and whether/how OXPHOS inhibition impacts the multistep progression in an autochthonous KRC model of pancreatic cystic neoplasia (Aim 3). Overall, these studies will elucidate the functional role of RNF43 in mitochondria quality control, ER-mitochondrial dynamics and how this impacts IPMN pathogenesis and progression.