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

基本信息

批准号：
8630691
负责人：
Jing Chen
金额：
$ 33.52万
依托单位：
EMORY UNIVERSITY
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 2019-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8630691
关键词：
5&apos -AMP-activated protein kinase 6-phosphogluconate Acetyl-CoA Carboxylase Acetylation Acetylcysteine 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 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 public health relevance ribulose 5-phosphate small hairpin RNA small molecule therapeutic target thyroid neoplasm tumor tumor growth tumor metabolism

项目摘要

Abstract: 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tissues including colorectal cancers, cervical intraepithelial neoplasia and thyroid tumors, as well as leukemia (our unpublished data).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-target effect. Physcion and S3 also effectively inhibit cell viability and proliferation of primary leukemia 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.

抽象的：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。正常情况下细胞，6-磷酸葡萄糖酸脱氢酶 (6PGD)，氧化戊糖磷酸途径中的一种酶 (PPP)，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、宫颈癌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 是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 处的乙酰化增强了 6PGD 的激活，并且通常在多种人类癌细胞中观察到。癌细胞中 6PGD 的稳定敲低导致氧化减少 PPP 通量和 RNA/DNA 生物合成。令人惊讶的是，6PGD 敲除也会导致 NADPH/NADP+ 降低比率，表明 6PGD 在 NADPH 产生中发挥着重要作用，而其他作用无法弥补产生 NADPH 的酶。此外，6PGD 敲低的癌细胞显示出 ROS 水平升高，并且生物合成异常，导致异种移植裸鼠细胞增殖和肿瘤生长减少。我们接下来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。大黄素甲醚治疗或其衍生物S3可有效抑制多种人类癌细胞的细胞增殖，且无脱靶效应。大黄素甲醚和 S3 还可以有效抑制人原发性白血病细胞的细胞活力和增殖。患者的毒性最小。此外，S3 显着降低异种移植裸鼠的肿瘤生长皮下注射人H1299肺癌或K562白血病细胞，体内毒性极小。因此，我们假设赖氨酸乙酰化增强 6PGD 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 的敲低会导致细胞内 Ru-5-P（6PGD 产品）水平降低，从而导致激活 AMP 激活蛋白激酶 (AMPK)，随后抑制乙酰辅酶 A 羧化酶 1 (ACC1) 以及随后的脂肪生成。因此，除了 PPP 和 PPP 之间建立良好的联系外，核苷酸生物合成，6PGD 提供了 PPP、AMPK 信号传导和脂肪生成之间的新联系， 6PGD 在 NADPH 产生和氧化还原稳态中发挥着令人惊讶的关键作用，对于癌症代谢和肿瘤生长。我们将使用人类肺癌和白血病来测试这些假设（CML、AML 和 B-ALL）作为平台。提出了三个具体目标（1）检查赖氨酸是否乙酰化对于6PGD激活、促进癌细胞代谢和肿瘤生长很重要； (2) 至探索 6PGD 如何连接 PPP、AMPK 信号传导和脂肪生成，以协调氧化还原调节，促进癌细胞代谢和肿瘤生长； (3) 验证 6PGD 作为抗白血病靶点治疗使用我们实验室开发的 6PGD 小分子抑制剂对人类白血病细胞进行体外和体内研究。