Defining and Targeting Malic Enzyme Dependence in Pancreatic Cancer

胰腺癌中苹果酸酶依赖性的定义和针对

• 批准号: 9911502
• 负责人: Mengrou Shan
• 金额: $ 6.49万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-01 至 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9911502
• 关键词: Adenocarcinoma Cell; Adult; Animals; Biochemical; CELSR1 gene; Cancer Etiology; Cell Line; Cells; Cessation of life; Characteristics; Chromosomes; Clinical; Data; Dependence; Development; Disease; Drug Targeting; Enzymes; Equilibrium; Fibroblasts; Financial compensation; Flow Cytometry; Genes; Genetic; Genomics; Goals; Growth; Human; Impairment; In Vitro; Incidence; Isotopes; Knock-out; Knockout Mice; Location; MADH4 gene; Maintenance; Malignant Neoplasms; Malignant neoplasm of pancreas; Mammals; Mediating; Metabolic; Metabolic Pathway; Metabolic stress; Metabolism; Methods; Mitochondria; NADP; Nature; Nutrient; Oxidation-Reduction; Oxidative Stress; Pancreas; Pancreatic Adenocarcinoma; Pancreatic Ductal Adenocarcinoma; Pathway interactions; Patients; Pharmaceutical Preparations; Phenotype; Physiology; Protein Isoforms; Resistance; Role; Scheme; Specimen; Survival Rate; Testing; Therapeutic; Tissues; Toxic effect; Tumor Suppressor Genes; Tumor Suppressor Proteins; United States; Western Blotting; Xenograft Model; base; cancer cell; effective therapy; in vivo; inhibitor/antagonist; knock-down; malic enzyme; metabolomics; new therapeutic target; offspring; overexpression; pancreatic neoplasm; patient population; patient stratification; predictive marker; pressure; programs; targeted treatment; therapy resistant; tumor; tumor growth; tumor microenvironment

Project Summary/Abstract Pancreatic adenocarcinoma (PDA) is the most lethal major cancer, with a 5-year survival rate below 10%. This is largely due to the lack of effective treatment options. The physiology and biochemical nature of pancreatic tumors is fundamental to this therapeutic resistance. PDA cells exist in a dense, fibrotic and thus, nutrient-depleted tumor microenvironment. Predictably, metabolism is reprogrammed in PDA cells to fuel their maintenance and growth. For example, our group recently described a non-canonical pathway utilized by PDA cells to mediate oxidative stress, thereby permitting their full growth potential. More recently, my preliminary results revealed that inhibition of malic enzyme 1 (ME1), the last enzyme in this metabolic pathway, can significantly blunt tumor growth in vitro and in vivo. There are three ME isoforms in mammals, ME1-3. I identified an inverse correlation between ME1 dependence and ME2 expression in PDA cells. In other words, ME1 dependent PDA cells have low/no ME2, and ME2 expressing PDA cells are resistant to ME1 inhibition. Intriguingly, nearly 50% of PDA express low/no ME2. ME2 is in close chromosomal proximity to SMAD4, a tumor suppressor lost in PDA. Based on their genomic location, co-loss of ME2 also frequently occurs. Therefore, the loss of ME2 provides a potential context for ME1-dependent synthetic lethality and a patient stratification method for ME1 inhibitors. There is therefore a fundamental need to understand the functional roles of MEs in order to exploit this unique therapeutic vulnerability in PDA. The working hypothesis of this project is that functional redundancy exists between cytosolic ME1 and mitochondrial ME2. When ME1 is impaired, ME2 provides metabolic/redox compensatory activity. Further, loss of ME2 expression provides a context for ME1-dependent synthetic lethality. This will be tested in two parts. (Aim 1) Mechanistically, the metabolic and subcellular functions of MEs in PDA growth will be defined. The metabolic roles of MEs will be examined by steady-state metabolomics, isotope tracing and flow cytometry following alteration of ME expression. The subcellular localization and potential physical interactions of MEs will also be investigated. (Aim 2) Functionally, the compensatory effect between ME1 and ME2 on PDA growth will be examined in vitro, ex vivo and in vivo using genetic knockdown/out and overexpression. These studies will contribute to our understanding of the mechanisms that regulate metabolism in PDA and the roles of MEs. Further they will pave the way for the development of ME1-targeted drugs for PDA, while also providing a strategy for patient stratification.

项目概要/摘要 胰腺癌 (PDA) 是最致命的主要癌症，生存率为 5 年 低于10%。这很大程度上是由于缺乏有效的治疗方案。生理学和 胰腺肿瘤的生化性质是这种治疗耐药性的基础。 PDA细胞 存在于致密、纤维化且营养匮乏的肿瘤微环境中。可以预见的是， PDA 细胞中的新陈代谢被重新编程，以促进其维持和生长。例如， 我们的小组最近描述了 PDA 细胞利用的一种非常规途径来介导氧化 压力，从而充分发挥其生长潜力。最近，我的初步结果 研究表明，抑制苹果酸酶 1 (ME1)（该代谢途径中的最后一种酶）可以 在体外和体内显着抑制肿瘤生长。哺乳动物中有 3 种 ME 亚型， ME1-3。我发现 ME1 依赖性和 ME2 表达之间存在负相关性 PDA 细胞。换句话说，ME1 依赖性 PDA 细胞具有低/无 ME2，并且表达 ME2 PDA 细胞对 ME1 抑制具有抵抗力。有趣的是，近 50% 的 PDA 表达低/无 ME2。 ME2 与 SMAD4 非常接近，SMAD4 是 PDA 中丢失的肿瘤抑制因子。基于 它们的基因组位置，ME2 的共同丢失也经常发生。因此，ME2 的丢失 为 ME1 依赖性合成致死率和患者分层提供了潜在的背景 ME1抑制剂的方法。因此，有必要了解功能 ME 的作用，以利用 PDA 中这种独特的治疗脆弱性。 该项目的工作假设是细胞质之间存在功能冗余 ME1 和线粒体 ME2。当 ME1 受损时，ME2 提供代谢/氧化还原 补偿活动。此外，ME2 表达的丧失为 ME1 依赖提供了背景 综合杀伤力。这将分两部分进行测试。 （目标 1）从机制上讲，新陈代谢和 ME 在 PDA 生长中的亚细胞功能将被定义。 ME 的代谢作用将是 改变后通过稳态代谢组学、同位素示踪和流式细胞术进行检查 ME 表达。 ME 的亚细胞定位和潜在的物理相互作用将 也受到调查。 （目标2）功能上，ME1和ME2之间的补偿作用 PDA 生长将在体外、离体和体内使用基因敲除/剔除和 过度表达。这些研究将有助于我们理解这些机制 调节 PDA 的代谢和 ME 的作用。此外，他们还将为 开发针对PDA的ME1靶向药物，同时也为患者提供策略 分层。