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tissues including colorectal cancers, cervical intraepithelial neoplasia and thyroid tumors, as well as leukemia (our unpublished data).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是未知的。在正常细胞中，6-磷酸葡萄糖酸脱氢酶（6-PGD），一种氧化戊糖磷酸途径（PPP）中的酶，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。在包括结肠直肠癌、宫颈上皮内瘤变和甲状腺肿瘤以及白血病在内的几种癌组织中已经报道了上调的6PGD活性（我们未发表的数据）。然而，6PGD如何在人类癌症中被激活以及6PGD活性在发病机制和肿瘤发展中是否重要仍然未知。我们发现K76和K294的乙酰化增强了6PGD的活化，并且在多种人类癌细胞中常见。癌细胞中6PGD的稳定敲除导致氧化PPP通量和RNA/DNA生物合成减少。令人惊讶的是，6 PGD敲除也会导致NADPH/NADP+比率下降，这表明6 PGD在NADPH产生中发挥着重要作用，而其他产生NADPH的酶无法补偿这种作用。此外，具有6PGD敲低的癌细胞显示升高的ROS水平和异常的生物合成，导致异种移植物裸鼠中细胞增殖和肿瘤生长减少。我们接下来筛选并鉴定了Physcion作为一种新型的选择性小分子6PGD抑制剂。用大黄素甲醚或其衍生物S3处理有效地抑制多种人类癌细胞中的细胞增殖，而没有脱靶效应。大黄素甲醚和S3还有效地抑制来自人类患者的原代白血病细胞的细胞活力和增殖，毒性最小。此外，S3显著降低皮下注射人H1299肺癌或K562白血病细胞的异种移植裸鼠的肿瘤生长，体内毒性最小。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; 6PGD因此代表了临床治疗中的新抗癌靶点。有趣的是，我们还发现6PGD的敲低导致Ru-5-P（6PGD产物）的细胞内水平降低，导致AMP活化蛋白激酶（AMPK）的活化，其随后抑制乙酰辅酶A羧化酶1（ACC 1）并因此抑制脂肪生成。因此，除了PPP和核苷酸生物合成之间的良好建立的联系之外，6PGD还提供了PPP、AMPK信号传导和脂肪生成之间的新联系，其沿着6PGD在NADPH产生和氧化还原稳态中令人惊讶的关键作用，对于癌症代谢和肿瘤生长是重要的。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。本研究的目的有三：（1）研究赖氨酸乙酰化是否在6PGD的激活、促进肿瘤细胞代谢和肿瘤生长中起重要作用;（2）研究6PGD如何将PPP、AMPK信号和脂肪生成联系起来，协同氧化还原调节，促进肿瘤细胞代谢和肿瘤生长;（3）利用本实验室开发的6-PGD小分子抑制剂，在体外和体内验证6-PGD作为抗白血病靶点对人白血病细胞的治疗作用。