Signaling and Targeting of 6-Phosphogluconate Dehydrogenase in Human Cancers

人类癌症中 6-磷酸葡萄糖酸脱氢酶的信号传导和靶向

• 批准号: 8838743
• 负责人: Jing Chen
• 金额: $ 32.96万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-15 至 2019-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8838743
• 关键词: 5' -AMP-activated protein kinase; 6-phosphogluconate; Acetyl-CoA Carboxylase; Acetylation; Anabolism; Attenuated; B-Cell Acute Lymphoblastic Leukemia; Back; Binding; Bioenergetics; Bone Marrow Transplantation; Cancer cell line; Cell Proliferation; Cell Survival; Cells; Cervical Intraepithelial Neoplasia; Clinical Treatment; Colorectal Cancer; Complex; DNA biosynthesis; Data; Development; Enzymes; Evaluation; H1299; Health; Homeostasis; Human; In Vitro; K-562; Laboratories; Link; Lysine; Malignant Neoplasms; Malignant neoplasm of lung; Metabolic; Metabolic Pathway; Metabolism; Modeling; Mus; NADP; Normal Cell; Nucleotide Biosynthesis; Nude Mice; Oxidation-Reduction; Pathogenesis; Pathway interactions; Patients; Pentosephosphate Pathway; Pharmaceutical Preparations; Phosphogluconate Dehydrogenase; Phosphorylation; Phosphorylation Inhibition; Production; Protein Kinase Inhibitors; RNA; RNA biosynthesis; Reducing Agents; Regulation; Reporting; Resistance; Role; STK11 gene; Signal Transduction; Signaling Molecule; Testing; Tissues; Toxic effect; Xenograft procedure; base; cancer cell; in vivo; inhibitor/antagonist; leukemia; lipid biosynthesis; mimetics; mutant; next generation; novel; protein kinase inhibitor; ribulose 5-phosphate; small hairpin RNA; small molecule; therapeutic target; thyroid neoplasm; tumor; tumor growth; tumor metabolism

DESCRIPTION (provided by applicant): How cancer cells coordinate anabolic biosynthesis and redox homeostasis remains largely unknown. In normal cells, 6-phosphogluconate dehydrogenase (6PGD), an enzyme in the oxidative pentose phosphate pathway (PPP), converts 6-phosphogluconate (6-PG) to ribulose 5-phosphate (Ru-5-P) and produces NADPH. Upregulated 6PGD activity has been reported in several cancer tissues including colorectal cancers, cervical intraepithelial neoplasia and thyroid tumors, as well as leukemia (our unpublished data). However, how 6PGD is activated in human cancers and whether 6PGD activity is important in pathogenesis and tumor development remain unknown. We found that acetylation at K76 and K294 enhances 6PGD activation and is commonly observed in diverse human cancer cells. Stable knockdown of 6PGD in cancer cells results in reduced oxidative PPP flux and RNA/DNA biosynthesis. Surprisingly, 6PGD knockdown also causes decreased NADPH/NADP+ ratio, suggesting an important role for 6PGD in NADPH production that cannot be compensated by other NADPH-producing enzymes. Moreover, cancer cells with 6PGD knockdown show elevated ROS levels and aberrant biosynthesis, leading to reduced cell proliferation and tumor growth in xenograft nude mice. We next screened and identified Physcion as a novel, selective small molecule 6PGD inhibitor. Treatment with Physcion or its derivative S3 effectively inhibits cell proliferation in diverse human cancer cells with no off-taret effect. Physcion and S3 also effectively inhibit cell viability and proliferation of primary leukema cells from human patients with minimal toxicity. Furthermore, S3 significantly reduces tumor growth in xenograft nude mice subcutaneously injected with human H1299 lung cancer or K562 leukemia cells with minimal toxicity in vivo. Thus, we hypothesize that lysine acetylation enhances 6PGD activation, which promotes cancer cell proliferation and tumor growth; 6PGD thus represents a novel anti-cancer target in clinical treatment. Intriguingly, we also found that knockdown of 6PGD results in decreased intracellular levels of Ru-5-P (6PGD product), leading to activation of AMP-activated protein kinase (AMPK), which subsequently inhibits acetyl-CoA carboxylase 1 (ACC1) and consequently lipogenesis. Thus, in addition to the well-established connection between PPP and nucleotide biosynthesis, 6PGD provides a novel link between PPP, AMPK signaling and lipogenesis, which, along with the surprisingly crucial role for 6PGD in NADPH production and redox homeostasis, is important for cancer metabolism and tumor growth. We will test these hypotheses using human lung cancer and leukemias (CML, AML and B-ALL) as platforms. Three Specific Aims were proposed (1) To examine whether lysine acetylation is important for 6PGD activation and promotion of cancer cell metabolism and tumor growth; (2) To explore how 6PGD links PPP, AMPK signaling and lipogenesis to coordinate with redox regulation in promoting cancer cell metabolism and tumor growth; and (3) To validate 6PGD as an anti-leukemia target in treatment of human leukemia cells in vitro and in vivo using 6PGD small molecule inhibitors developed in our laboratory.

描述（由申请人提供）：癌细胞如何协调合成代谢生物合成和氧化还原稳态仍然很大程度上未知。在正常细胞中，6-磷酸葡萄糖酸脱氢酶 (6PGD)（氧化戊糖磷酸途径 (PPP) 中的一种酶）将 6-磷酸葡萄糖酸 (6-PG) 转化为 5-磷酸核酮糖 (Ru-5-P) 并产生 NADPH。据报道，多种癌症组织中 6PGD 活性上调，包括结直肠癌、宫颈上皮内瘤变和甲状腺肿瘤以及白血病（我们未发表的数据）。然而，6PGD 在人类癌症中如何被激活以及 6PGD 活性在发病机制和肿瘤发展中是否重要仍不清楚。我们发现 K76 和 K294 处的乙酰化可增强 6PGD 激活，并且在多种人类癌细胞中常见。癌细胞中 6PGD 的稳定敲低会导致氧化 PPP 通量和 RNA/DNA 生物合成减少。令人惊讶的是，6PGD 敲低还会导致 NADPH/NADP+ 比率降低，这表明 6PGD 在 NADPH 产生中发挥着重要作用，而其他 NADPH 产生酶无法弥补这一作用。此外，6PGD敲低的癌细胞表现出ROS水平升高和生物合成异常，导致异种移植裸鼠中的细胞增殖和肿瘤生长减少。接下来我们筛选并鉴定大黄素甲醚是一种新型选择性小分子 6PGD 抑制剂。大黄素甲醚或其衍生物 S3 处理可有效抑制多种人类癌细胞的细胞增殖，且无偏离塔塔效应。大黄素甲醚和 S3 还能有效抑制人类患者原发性白血病细胞的细胞活力和增殖，且毒性极小。此外，S3可显着减少皮下注射人H1299肺癌或K562白血病细胞的异种移植裸鼠的肿瘤生长，且体内毒性极小。因此，我们假设赖氨酸乙酰化增强了 6PGD 的激活，从而促进癌细胞增殖和肿瘤生长；因此，6PGD代表了临床治疗中的一个新的抗癌靶点。有趣的是，我们还发现 6PGD 的敲除会导致细胞内 Ru-5-P（6PGD 产物）水平降低，从而导致 AMP 激活蛋白激酶 (AMPK) 的激活，随后抑制乙酰辅酶 A 羧化酶 1 (ACC1) 和因此脂肪生成。因此，除了 PPP 和核苷酸生物合成之间已建立的联系之外，6PGD 还提供了 PPP、AMPK 信号传导和脂肪生成之间的新联系，这与 6PGD 在 NADPH 产生和氧化还原稳态中令人惊讶的关键作用一起，对于癌症非常重要代谢和肿瘤生长。我们将使用人类肺癌和白血病（CML、AML 和 B-ALL）作为平台来测试这些假设。提出了三个具体目标（1）研究赖氨酸乙酰化对于6PGD激活以及促进癌细胞代谢和肿瘤生长是否重要； （2）探讨6PGD如何连接PPP、AMPK信号和脂肪生成，协调氧化还原调节，促进癌细胞代谢和肿瘤生长； (3) 使用我们实验室开发的6PGD小分子抑制剂在体外和体内验证6PGD作为抗白血病靶点治疗人类白血病细胞。