TBEL Project 2

项目2 -摘要 胰腺囊性肿瘤（PCNs）的估计患病率在20-30%之间， 粘液性肿瘤（IPMNs）占一半。根据形态位置和基因 IPMN可以是高风险的胰腺导管腺癌（PDAC），因此， 降低病人的生存率虽然RNF 43仅在一小部分PDAC中突变，但RNF 43突变在PDAC中的突变率很高。 在IPMN中以高频率流行。尽管RNF 43已被鉴定为Wnt的负调节因子， 在结直肠癌和其他临床前模型中的信号传导，包括PDAC，一项关于Wnt 在RNF 43突变的实体癌（包括PDAC）患者中使用这种抑制剂的结果已被证明令人失望。其他 RNF 43可能的器官特异性功能对于IPMN进展可能是非常有利的。使用条件 在Kras突变背景下的RNF 43敲除小鼠模型中，我们发现RNF 43消除了线粒体内的 RNF 43的缺失改善了线粒体的质量控制，增加了未折叠蛋白的含量， 反应（UPR）和ER应激。这些发现让我们假设RNF 43的缺失可能会使细胞内的 这些细胞器的串扰，以维持蛋白质稳态，代谢控制和细胞存活。 采用Kras背景下RNF 43功能丧失的本地小鼠模型（在实验室中产生）， 博士Maitra实验室）、原代基因工程细胞系（在Lyssiotis博士实验室中产生）和人IPMN 衍生的类器官（在伍德博士实验室产生;见项目3），我们建议追求以下目标： 首先，我们将研究RNF 43是否调节线粒体动力学，包括生物发生，分裂，融合 和线粒体自噬以抑制IPMN发病（目的1）。此外，我们将调查RNF 43是否阻止IPMN 通过管理ER-线粒体动力学限制ER应激来研究其发病机制（目的2）。最后，我们将 确定RNF 43的丧失是否产生持续OXPHOS的合成必要性（目标1），以及 OXPHOS抑制是否/如何影响本地KRC模型中的多步进展， 胰腺囊性肿瘤（Aim 3）。总的来说，这些研究将阐明RNF 43的功能作用， 线粒体质量控制，ER-线粒体动力学以及这如何影响IPMN发病机制， 进展

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.