Oxidative pentose phosphate pathway regulates AMPK homeostasis by balancing opposing LKB1 and PP2A

氧化戊糖磷酸途径通过平衡 LKB1 和 PP2A 来调节 AMPK 稳态

基本信息

批准号：
10738318
负责人：
Jing Chen
金额：
$ 1.55万
依托单位：
UNIVERSITY OF CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-04-15 至 2025-02-28
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10738318
关键词：
6-phosphogluconate A549 Acetylation Acute Acute Myelocytic Leukemia Affect Anabolism Antioxidants Binding Cell Proliferation Cells Cellular Metabolic Process Colorectal Cancer Combined Modality Therapy Complex Enzymes Focal Adhesion Kinase 1 Foundations Gene Expression Glucose-6-Phosphate Glucosephosphate Dehydrogenase Glycolysis H1299 HCT116 Cells HT29 Cells Homeostasis Human Hydrolysis In Vitro K-562 Link Lysine Malignant neoplasm of lung Metabolic Metabolic Pathway Mitochondria Molecular NADP Nucleotide Biosynthesis Oncogenic Oxidation-Reduction Pathway interactions Patients Pentosephosphate Pathway Phosphogluconate Dehydrogenase Phosphoric Monoester Hydrolases Phosphorylation Phosphotransferases Physiological Play Post-Translational Protein Processing Probability Proliferating Property Protein Phosphatase 2A Regulatory Subunit PR53 Proteins Reactive Oxygen Species Regulation Reporting Role SOD2 gene STK11 gene Series Signal Pathway Signal Transduction Signaling Molecule Testing acute myeloid leukemia cell attenuation cancer cell in vivo inhibitor knock-down leukemia lipid biosynthesis lung cancer cell macromolecule mouse model novel patient derived xenograft model programs recruit response ribulose 5-phosphate tumor growth

项目摘要

Project Summary/Abstract: The interplay between metabolic pathways and cell signaling networks that contribute to the “metabolic reprogramming” in cancer cells remains largely unknown. The oxidative pentose phosphate pathway (oxiPPP) plays a crucial role in the metabolic coordination of glycolysis, biosynthesis and redox homeostasis in cells by producing precursors for nucleotide and lipid biosynthesis, as well as antioxidant NADPH that quenches the reactive oxygen species (ROS) produced during rapid proliferation of cancer cells. There are three key enzymes along the oxiPPP. The first enzyme glucose-6-phosphate dehydrogenase (G6PD) converts glycolytic intermediate glucose-6-phosphate (G6P) to 6-phosphogluconolactone (6PGL) and produces NADPH. The second enzyme 6-phosphogluconolactonase (PGLS) converts 6PGL to 6-phosphogluconate (6PG). The third enzyme 6-phosphogluconate dehydrogenase (6PGD) converts 6PG to ribulose-5-phosphate (Ru-5-P) and also produces NADPH. We recently reported that 6PGD is commonly activated by lysine acetylation in cancer cells and activates lipogenesis through controlling its product Ru-5-P, which inhibits the LKB1-AMPK pathway by disrupting the active LKB1 complex (Shan et al., 2014 Mol Cell; Lin et al., 2015, Nat Cell Biol.). Interestingly, we found that knockdown of G6PD did not alter AMPK activation despite decreased Ru-5-P and subsequent LKB1 activation, due to enhanced activity of PP2A, the upstream phosphatase of AMPK. In contrast, knockdown of 6PGD or PGLS reduced PP2A activity. Mechanistically, knockdown of G6PD or PGLS decreased or increased 6PGL level, respectively, which enhanced the inhibitory phosphorylation of PP2A by Src. There are two forms of 6PGL, γ-6-phosphogluconolactone (γ-6PGL) is an oxiPPP byproduct with unknown function that is generated through intramolecular rearrangement of δ-6-phosphogluconolactone (δ-6GL), while δ-6PGL is the only substrate of PGLS and can undergo quick spontaneous hydrolysis. Thus, γ-6PGL is relatively stable compared to δ-6GL but does not participate in oxiPPP. Further studies revealed that γ-6PGL, but not δ-6GL, promotes Src-PP2A association, probably by binding to Src but not PP2A and enhancing PP2A recruitment. Thus, we hypothesize that G6PD, PGLS and 6PGD play differential roles in regulation of AMPK homeostasis by balancing the opposing LKB1 and PP2A, through the oxiPPP intermediate Ru-5-P and an oxiPPP “byproduct” γ-6PGL, respectively; and γ-6PGL, previously considered as a “dead end” byproduct of the oxiPPP with unknown physiological function, functions as a signaling molecule that links the metabolic oxiPPP with the Src-PP2A-AMPK signaling pathway. The specific aims are proposed: (1) To elucidate the molecular and signaling basis underlying γ-6PGL-dependent contribution to AMPK activation through inhibition of PP2A by Src; (2) To determine the differential effects of G6PD and PGLS on AMPK activation, redox homeostasis and tumor growth; and (3) To evaluate combined therapy with oxiPPP inhibitors and AMPK activator in the treatment of human leukemia and lung cancer cells in vitro and in vivo.

项目摘要/摘要：代谢途径与细胞信号网络之间的相互作用，有助于“代谢癌细胞中的重新编程”仍然在很大程度上未知。在细胞中糖酵解，生物合成和氧化还原稳态的代谢配位中起着至关重要的作用产生用于核苷酸和脂质生物合成的前体，以及抗氧化剂NADPH，它淬灭在癌细胞快速增殖过程中产生的活性氧（ROS）。有三种关键酶沿着Oxippp。第一个酶-6-磷酸脱氢酶（G6PD）转化糖酵解中间葡萄糖-6-磷酸（G6P）至6-磷酸葡萄糖醛酮（6pgl），并产生NADPH。这第二酶6-磷酸葡萄糖酸糖苷酸酯酶（PGLS）将6PGL转换为6-磷酸葡萄糖酸酯（6pg）。第三酶6-磷酸葡萄糖酸脱氢酶（6pgd）将6pg转换为5-磷酸盐（RU-5-P），也将其转换为产生NADPH。我们最近报道，癌细胞中通常通过赖氨酸乙酰化激活6pGD 并通过控制其产物RU-5-P激活脂肪生成，从而抑制LKB1-AMPK途径破坏活性LKB1复合物（Shan等，2014 Mol Cell; Lin等，2015，Nat Cell Biol。）。有趣的是，我们发现G6PD的敲低不会改变AMPK激活目的地降低RU-5-P，随后的LKB1 由于PP2A的活性增强，AMPK上游磷酸酶的活性增强。相反，敲除 6PGD或PGL降低了PP2A活性。从机械上讲，G6PD或PGL的敲低减少或增加 6PGL水平分别增强了SRC对PP2A的抑制磷酸化。有两种形式 6PGL，γ-6-磷酸葡萄糖酮（γ-6PGL）是具有未知功能的OXIPPP副产品通过分子内重排的Δ-6-磷酸葡萄糖酮（δ-6GL），而δ-6PGL是唯一的 PGL的底物可以快速进行赞助水解。那是γ-6PGL相对稳定到δ-6GL，但不参与OXIPPP。进一步的研究表明，γ-6PGL而不是δ-6GL促进 SRC-PP2A关联，可能是通过与SRC结合，但不结合PP2A并增强PP2A的募集。这是我们假设G6PD，PGL和6PGD在AMPK调节中起鉴别作用通过OXIPPP中级RU-5-P平衡相对的LKB1和PP2A，稳态 OXIPPP“副产品”γ-6PGL；和γ-6PGL，以前被认为是具有未知身体功能的OXIPPP，起作用的信号分子，与代谢OXIPPP联系起来带有SRC-PP2A-AMPK信号通路。提出了具体目的：（1）阐明分子和信号基础通过SRC抑制PP2A对AMPK激活产生的γ-6PGL依赖性贡献；（2）确定G6PD和PGL对AMPK激活，氧化还原稳态和肿瘤的差异影响生长; （3）评估与OXIPPP抑制剂和AMPK激活剂的合并治疗人白血病和肺癌细胞体外和体内。