Investigating the Role of Autophagy in Pancreatic Cancer Radiation Resistance

项目摘要： 研究自噬在胰腺癌放射抵抗中的作用 胰腺导管腺癌（PDAC）是一种致死性疾病，治疗选择有限。虽然大多数 患者死于转移性疾病，高达30%死于局部失败。手术只能在 少数患者。放射治疗可用于控制原发肿瘤，但大多数患者会进展。 因此，开发使这些肿瘤对放疗敏感的方法可以对患者产生变革性影响。 我们先前已经表明，抑制自噬导致代谢功能障碍，PDAC生长减少， 与放疗协同作用。虽然这些概念正在临床试验中进行测试，但目前的抑制剂， 羟氯喹（HCQ）似乎不具有持久阻断自噬最佳效力和特异性， 患者和更强大的抑制剂正在开发中，目标是自噬的早期阶段。其中一个目标是 ATG 4 b，一种对LC 3脂化和自噬体形成至关重要的蛋白酶。在这方面，我们制定了 并使用ATG 4 b的显性阴性（DN）等位基因（Atg 4 bC 74 A）验证了诱导型小鼠模型， 抑制自噬，使我们能够模拟目前正在开发的ATG 4 b抑制剂的作用。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 治疗效果和毒性。这将使我们能够回答几个关键问题; 包括抑制早期与晚期自噬的差异，正常组织毒性与有效的 自噬抑制剂，以及放射增敏的最佳抑制持续时间。我们将通过以下方式解决这些问题： 利用这种新的基因工程模型系统，其具有可诱导的自噬控制， 与人类疾病非常相似的PDAC的自体模型，人类原代PDAC细胞系，以及 这是我们开发的一个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先前的研究基础上，这些研究表明自噬在PDAC代谢中起着关键作用， 特别是减少活性氧物质（ROS）。最终，这些创新和严格的方法 研究将指导自噬抑制策略有效地翻译给患者，并产生重要的信息。 关于自噬在辐射反应中的作用 在此背景下，我们提出以下具体目标。 目标1。使用新型诱导型小鼠模型优化自噬抑制 目标2.利用自噬抑制作为放射增敏PDAC的方法。 目标3：研究自噬依赖的代谢在PDAC对辐射的响应中的作用。

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.