Investigating the Role of Autophagy in Pancreatic Cancer Radiation Resistance

项目总结： 自噬在胰腺癌放射抵抗中的作用研究 胰腺导管腺癌(PDAC)是一种致命的疾病，治疗选择有限。虽然大多数人 患者死于转移性疾病，高达30%死于局部衰竭。手术只能在 少数病人。放射治疗可以用来控制原发肿瘤，但大多数患者会进步。 因此，开发使这些肿瘤对放射治疗敏感的方法可以对患者产生变革性的影响。 我们以前已经证明，抑制自噬会导致代谢功能障碍，减少PDAC的生长，以及 与放射治疗协同作用。虽然这些概念正在临床试验中进行测试，但目前的抑制剂如 羟基氯喹(HCQ)似乎不具有持久地阻断自噬的最佳效力和特异性。 针对自噬早期阶段的患者和更强大的抑制剂正在开发中。其中一个目标是 ATG4b，一种对LC3脂化和自噬小体形成至关重要的蛋白酶。在这方面，我们已经制定了 并使用ATG4b(Atg4bC74A)的显性负(DN)等位基因验证了可诱导的小鼠模型 抑制自噬，并允许我们对正在开发的ATG4b抑制剂的效果进行建模。这 新的资源使我们有机会探索抑制PDAC和正常组织中自噬的早期步骤 用于治疗效果和毒性。这将使我们能够回答几个关键问题； 包括在抑制自噬的早期和晚期的差异，正常组织毒性与强效 自噬抑制剂，以及放射增敏的最佳抑制时间。我们将通过以下方式解决这些问题 利用可诱导控制自噬的新型基因工程模型系统与 与人类疾病非常相似的PDAC的本土模型，人类原代PDAC细胞系，以及 我们开发的先进的图像引导放射治疗胰腺肿瘤的平台。 从机制上讲，这项工作建立在我们之前的研究基础上，这些研究表明自噬在PDAC新陈代谢中起着关键作用， 特别是为了减少活性氧物种(ROS)。归根结底，这些创新和严格的方法 研究将指导自噬抑制策略对患者的有效翻译，并产生重要信息 关于自噬在辐射反应中的作用。 在此背景下，我们提出了以下具体目标。 目的1.利用一种新的可诱导小鼠模型优化自噬抑制 目的2.利用自噬抑制作为放射增敏PDAC的方法。 目的3.探讨自噬依赖性代谢在PDAC辐射反应中的作用。

Project Summary: Investigating the role of autophagy in pancreatic cancer radiation resistance Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease with limited therapeutic options. While the majority of patients die from metastatic disease, up to 30% succumb to local failure. Surgery can only be performed in the minority of patients. Radiotherapy can be used to control the primary tumor, but most patients will progress. Therefore, developing ways to sensitize these tumors to radiotherapy can have a transformative impact on patients. We have previously shown that inhibition of autophagy leads to metabolic dysfunction, decreased PDAC growth, and synergizes with radiotherapy. While these concepts are being tested in clinical trials, current inhibitors such as hydroxychloroquine (HCQ) do not appear to have optimal potency and specificity to durably block autophagy in patients and more robust inhibitors are in development that target the early phases of autophagy. One such target is ATG4b, a protease that is critical for LC3 lipidation and autophagosome formation. In this regard, we have developed and validated an inducible mouse model using a dominant negative (DN) allele of ATG4b (Atg4bC74A) that potently inhibits autophagy and allows us to model the effects of the ATG4b inhibitors that are now being developed. This novel resource gives us the opportunity to explore inhibiting the early steps of autophagy in PDAC and normal tissues for therapeutic efficacy as well as toxicity. There are several critical questions that this will allow us to answer; including the differences in inhibiting the early vs. the late phases of autophagy, normal tissue toxicity with potent autophagy inhibitors, and the optimal duration of inhibition for radiosensitization. We will address these questions by exploiting this novel genetically engineered model system with inducible control of autophagy in conjunction with an autochthonous model of PDAC that closely resembles the human disease, human primary PDAC cell lines, and a platform of sophisticated image-guided delivery of radiation to pancreatic tumors that we have developed. Mechanistically, this work builds on our prior studies that has shown a critical role for autophagy in PDAC metabolism, in particular, to mitigate reactive oxygen species (ROS). Ultimately, the innovative and rigorous approach of these studies will guide the effective translation of autophagy inhibition strategies to patients and yield important information regarding the role of autophagy in the radiation response. Against this backdrop, we propose the following specific aims. Aim 1. Optimizing autophagy inhibition using a novel inducible mouse model Aim 2. Utilizing autophagy inhibition as an approach to radiosensitize PDAC. Aim 3. Investigating the role of autophagy dependent metabolism in the response of PDAC to radiation.