Identifying Metabolic Dependencies of Pancreatic Cancers

项目总结： 我的研究重点一直是胰腺导管腺癌(PDAC)。这是一个 据预测，到2020年，致命肿瘤将成为美国第二大死亡原因。这种疾病是 通常在病程后期被发现，不幸的是，事实证明对大多数人来说是高度难治的 治疗方法。在过去的十年中，我们的团队一直致力于了解PDAC如何 重新连接它们的新陈代谢以支持高增殖率和细胞在营养贫乏、严酷的肿瘤中的存活 微环境。我们已经使用了新的小鼠模型来理解致癌的Kras信号是如何 PDAC中的基因突变，协调这些肿瘤的代谢重新编程，朝着更合成代谢的方向发展 州政府。事实上，这种癌基因支持胰腺癌生长的关键方式之一是通过它的作用 在肿瘤新陈代谢方面。通过对PDAC碳源利用的进一步分析，我们发现了一种新的 通过NADPH的产生对PDAC氧化还原平衡至关重要的途径。这条途径利用 谷氨酰胺碳和部分苹果酸-天冬氨酸穿梭最终以苹果酸酶转化结束 苹果酸转化为NADPH和丙酮酸。代谢途径中任何一个节点的中断都会导致氧化还原失衡 并降低了生长速度。 我们工作中出现的一个主要主题是PDAC具有惊人的新陈代谢可塑性。 这可能是一种重要的适应，以在燃料来源和氧气比例较高的环境中蓬勃发展 有限的和快速的变化。为了针对新陈代谢，了解这些适应是至关重要的。 治疗收益的脆弱性。事实上，我们已经证明，这些肿瘤可以：1)迅速地重新编程 它们对燃料来源限制的代谢途径，2)使用溶酶体清除途径来 提供必要的代谢中间体；3)通过新的代谢途径与基质细胞合作 互动。然而，这些代谢适应的整合以及这如何影响关键的代谢 PDAC在体内的依赖关系尚不清楚，了解这一点对于开发有效的 治疗方法。在这里，我们将采取综合的方法来回答这些关键问题。我们会 使用复杂的胰腺癌同基因模型来全面评估代谢依赖性 使用定制设计的小鼠CRISPR新陈代谢文库，结合代谢示踪剂研究。我们会 使用共培养系统确定肿瘤细胞和多种其他类型的细胞之间的代谢串扰 肿瘤微环境(免疫细胞、神经元、成纤维细胞群体)。使用活体模型，我们将 剖析营养物质的清除途径，并确定这些营养物质是如何利用和潜在共享的 在细胞群体之间。最后，我们将利用从这些研究中获得的知识来最大限度地发展 强大的代谢目标，将在体内使用遗传和药理学方法进行测试。

Project Summary: The focus of my research has been on the study of pancreatic ductal adenocarcinoma (PDAC). This is a deadly tumor that is predicted by 2020 to be the second leading cause of death in the U.S. The disease is typically detected late in its course and unfortunately has proven to be highly treatment refractory to most therapeutic approaches. Over the past decade, our group has been focused on understanding how PDAC rewire their metabolism to support a high proliferative rate and cell survival in a nutrient poor, austere tumor microenvironment. We have used novel mouse models to understand how oncogenic Kras, the signature genetic mutation in PDAC, orchestrates metabolic reprogramming of these tumors towards a more anabolic state. In fact, one of the critical ways that this oncogene supports pancreatic cancer growth is through its role in tumor metabolism. Through further analysis of carbon source utilization in PDAC, we identified a novel pathway that is critical for PDAC redox balance through the production of NADPH. This pathway utilizes glutamine carbon and portions of the malate-aspartate shuttle ultimately ending with malic enzyme conversion of malate to NADPH and pyruvate. Disruption at any node of this metabolic pathway results in redox imbalance and decreased growth. One of the major themes that emerged from our work is that PDAC have an amazing metabolic plasticity. This is likely an important adaptation to flourish in an environment where fuel sources and oxygen are rate limiting and rapidly shifting. Understanding these adaptations will be essential in order to target metabolic vulnerabilities for therapeutic gain. Indeed, we have shown that that these tumors can: 1) rapidly reprogram their metabolic pathways in response to fuel source limitations, 2) use lysosomal scavenging pathways to provide necessary metabolic intermediates, and 3) cooperate with stromal cells through novel metabolic interactions. However, the integration of these metabolic adaptations and how this influences key metabolic dependencies of PDAC in vivo is not yet known and will be critical to understand in order to develop effective therapeutic approaches. Here, we will take a comprehensive approach to answer these key questions. We will use sophisticated syngeneic models of pancreatic cancer to comprehensively assess metabolic dependencies using a custom designed murine CRISPR metabolism library combined with metabolic tracer studies. We will use co-culture systems to identify metabolic cross-talk between tumor cells and the multiple other cell types in the tumor micro-environment (immunocytes, neurons, fibroblast populations). Using in vivo models, we will dissect nutrient scavenging pathways and identify how these nutrients are utilized and potentially shared between cell populations. Lastly, we will utilize the knowledge gained from these studies to develop the most robust metabolic targets which will be tested in vivo using genetic and pharmacologic approaches.