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Zimmer AD, Walbrecq G, Kozar I, Behrmann I, Haan C. Phosphorylation of the pyruvate dehydrogenase complex precedes HIF-1-mediated effects and pyruvate dehydrogenase kinase 1 upregulation during the first hours of hypoxic treatment in hepatocellular carcinoma cells. HYPOXIA 2016; 4:135-145. [PMID: 27800515 PMCID: PMC5085306 DOI: 10.2147/hp.s99044] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The pyruvate dehydrogenase complex (PDC) is an important gatekeeper enzyme connecting glycolysis to the tricarboxylic acid (TCA) cycle and oxidative phosphorylation (OXPHOS). Thereby, it has a strong impact on the glycolytic flux as well as the metabolic phenotype of a cell. PDC activity is regulated via reversible phosphorylation of three serine residues on the pyruvate dehydrogenase (PDH) E1α subunit. Phosphorylation of any of these residues by the PDH kinases (PDKs) leads to a strong decrease in PDC activity. Under hypoxia, the inactivation of the PDC has been described to be dependent on the hypoxia-inducible factor 1 (HIF-1)-induced PDK1 protein upregulation. In this study, we show in two hepatocellular carcinoma cell lines (HepG2 and JHH-4) that, during the adaptation to hypoxia, PDH is already phosphorylated at time points preceding HIF-1-mediated transcriptional events and PDK1 protein upregulation. Using siRNAs and small molecule inhibitor approaches, we show that this inactivation of PDC is independent of HIF-1α expression but that the PDKs need to be expressed and active. Furthermore, we show that reactive oxygen species might be important for the induction of this PDH phosphorylation since it correlates with the appearance of an altered redox state in the mitochondria and is also inducible by H2O2 treatment under normoxic conditions. Overall, these results show that neither HIF-1 expression nor PDK1 upregulation is necessary for the phosphorylation of PDH during the first hours of the adaptation to hypoxia.
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Affiliation(s)
| | - Geoffroy Walbrecq
- Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Ines Kozar
- Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Iris Behrmann
- Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Claude Haan
- Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
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152
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Rauckhorst AJ, Taylor EB. Mitochondrial pyruvate carrier function and cancer metabolism. Curr Opin Genet Dev 2016; 38:102-109. [PMID: 27269731 DOI: 10.1016/j.gde.2016.05.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 04/29/2016] [Accepted: 05/12/2016] [Indexed: 12/12/2022]
Abstract
Metabolic reprogramming in cancer supports the increased biosynthesis required for unchecked proliferation. Increased glucose utilization is a defining feature of many cancers that is accompanied by altered pyruvate partitioning and mitochondrial metabolism. Cancer cells also require mitochondrial tricarboxylic acid cycle activity and electron transport chain function for biosynthetic competency and proliferation. Recent evidence demonstrates that mitochondrial pyruvate carrier (MPC) function is abnormal in some cancers and that increasing MPC activity may decrease cancer proliferation. Here we examine recent findings on MPC function and cancer metabolism. Special emphasis is placed on the compartmentalization of pyruvate metabolism and the alternative routes of metabolism that maintain the cellular biosynthetic pools required for unrestrained proliferation in cancer.
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Affiliation(s)
- Adam J Rauckhorst
- Department of Biochemistry, Fraternal Order of the Eagles Diabetes Research Center, Abboud Cardiovascular Research Center, Holden Comprehensive Cancer Center, and Pappajohn Biomedical Institute, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Eric B Taylor
- Department of Biochemistry, Fraternal Order of the Eagles Diabetes Research Center, Abboud Cardiovascular Research Center, Holden Comprehensive Cancer Center, and Pappajohn Biomedical Institute, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.
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153
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Computational Study on New Natural Compound Inhibitors of Pyruvate Dehydrogenase Kinases. Int J Mol Sci 2016; 17:340. [PMID: 26959013 PMCID: PMC4813202 DOI: 10.3390/ijms17030340] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 02/27/2016] [Accepted: 03/01/2016] [Indexed: 01/04/2023] Open
Abstract
Pyruvate dehydrogenase kinases (PDKs) are key enzymes in glucose metabolism, negatively regulating pyruvate dehyrogenase complex (PDC) activity through phosphorylation. Inhibiting PDKs could upregulate PDC activity and drive cells into more aerobic metabolism. Therefore, PDKs are potential targets for metabolism related diseases, such as cancers and diabetes. In this study, a series of computer-aided virtual screening techniques were utilized to discover potential inhibitors of PDKs. Structure-based screening using Libdock was carried out following by ADME (adsorption, distribution, metabolism, excretion) and toxicity prediction. Molecular docking was used to analyze the binding mechanism between these compounds and PDKs. Molecular dynamic simulation was utilized to confirm the stability of potential compound binding. From the computational results, two novel natural coumarins compounds (ZINC12296427 and ZINC12389251) from the ZINC database were found binding to PDKs with favorable interaction energy and predicted to be non-toxic. Our study provide valuable information of PDK-coumarins binding mechanisms in PDK inhibitor-based drug discovery.
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154
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Tang H, Luo X, Li J, Zhou Y, Li Y, Song L, Zhang X, Chen T. Pyruvate dehydrogenase B promoted the growth and migration of the nasopharyngeal carcinoma cells. Tumour Biol 2016; 37:10563-9. [DOI: 10.1007/s13277-016-4922-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 01/27/2016] [Indexed: 02/04/2023] Open
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155
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Caino MC, Altieri DC. Molecular Pathways: Mitochondrial Reprogramming in Tumor Progression and Therapy. Clin Cancer Res 2015; 22:540-5. [PMID: 26660517 DOI: 10.1158/1078-0432.ccr-15-0460] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 11/19/2015] [Indexed: 01/22/2023]
Abstract
Small-molecule inhibitors of the phosphoinositide 3-kinase (PI3K), Akt, and mTOR pathway currently in the clinic produce a paradoxical reactivation of the pathway they are intended to suppress. Furthermore, fresh experimental evidence with PI3K antagonists in melanoma, glioblastoma, and prostate cancer shows that mitochondrial metabolism drives an elaborate process of tumor adaptation culminating with drug resistance and metastatic competency. This is centered on reprogramming of mitochondrial functions to promote improved cell survival and to fuel the machinery of cell motility and invasion. Key players in these responses are molecular chaperones of the Hsp90 family compartmentalized in mitochondria, which suppress apoptosis via phosphorylation of the pore component, Cyclophilin D, and enable the subcellular repositioning of active mitochondria to membrane protrusions implicated in cell motility. An inhibitor of mitochondrial Hsp90s in preclinical development (gamitrinib) prevents adaptive mitochondrial reprogramming and shows potent antitumor activity in vitro and in vivo. Other therapeutic strategies to target mitochondria for cancer therapy include small-molecule inhibitors of mutant isocitrate dehydrogenase (IDH) IDH1 (AG-120) and IDH2 (AG-221), which opened new therapeutic prospects for patients with high-risk acute myelogenous leukemia (AML). A second approach of mitochondrial therapeutics focuses on agents that elevate toxic ROS levels from a leaky electron transport chain; nevertheless, the clinical experience with these compounds, including a quinone derivative, ARQ 501, and a copper chelator, elesclomol (STA-4783) is limited. In light of this evidence, we discuss how best to target a resurgence of mitochondrial bioenergetics for cancer therapy.
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Affiliation(s)
- M Cecilia Caino
- Prostate Cancer Discovery and Development Program, Tumor Microenvironment and Metastasis Program, The Wistar Institute, Philadelphia, Pennsylvania
| | - Dario C Altieri
- Prostate Cancer Discovery and Development Program, Tumor Microenvironment and Metastasis Program, The Wistar Institute, Philadelphia, Pennsylvania.
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156
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Jochmanová I, Zhuang Z, Pacak K. Pheochromocytoma: Gasping for Air. Discov Oncol 2015; 6:191-205. [PMID: 26138106 DOI: 10.1007/s12672-015-0231-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 06/19/2015] [Indexed: 02/06/2023] Open
Abstract
There has been increasing evidence that pseudohypoxia--a phenomenon that we refer to as "gasping for air"--along with mitochondrial enzyme dysregulation play a crucial role in tumorigenesis, particularly in several hereditary pheochromocytomas (PHEOs) and paragangliomas (PGLs). Alterations in key tricarboxylic acids (TCA) cycle enzymes (SDH, FH, MDH2) have been shown to induce pseudohypoxia via activation of the hypoxia-inducible transcription factor (HIF) signaling pathway that is involved in tumorigenesis, invasiveness, and metastatic spread, including an association with resistance to various cancer therapies and worse prognosis. This review outlines the ongoing story of the pathogenesis of hereditary PHEOs/PGLs, showing the unique and most updated evidence of TCA cycle dysregulation that is tightly linked to hypoxia signaling.
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Affiliation(s)
- Ivana Jochmanová
- Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver NICHD, National Institutes of Health, Building 10, CRC, 1-East, Room 1E-3140, 10 Center Drive, MSC-1109, Bethesda, MD, 20892-1109, USA.,1st Department of Internal Medicine, Medical Faculty, P. J. Šafárik University in Košice, Trieda SNP 1, 04011, Košice, Slovakia
| | - Zhengping Zhuang
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Karel Pacak
- Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver NICHD, National Institutes of Health, Building 10, CRC, 1-East, Room 1E-3140, 10 Center Drive, MSC-1109, Bethesda, MD, 20892-1109, USA.
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157
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Mordhorst BR, Murphy SL, Ross RM, Samuel MS, Salazar SR, Ji T, Behura SK, Wells KD, Green JA, Prather RS. Obstructive jaundice and carcinoma of the gallbladder. Cell Reprogram 1969; 20:38-48. [PMID: 29412741 PMCID: PMC5804098 DOI: 10.1089/cell.2017.0040] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The Warburg effect is a metabolic phenomenon characterized by increased glycolytic activity, decreased mitochondrial oxidative phosphorylation, and the production of lactate. This metabolic phenotype is characterized in rapidly proliferative cell types such as cancerous cells and embryonic stem cells. We hypothesized that a Warburg-like metabolism could be achieved in other cell types by treatment with pharmacological agents, which might, in turn, facilitate nuclear reprogramming. The aim of this study was to treat fibroblasts with CPI-613 and PS48 to induce a Warburg-like metabolic state. We demonstrate that treatment with both drugs altered the expression of 69 genes and changed the level of 21 metabolites in conditioned culture media, but did not induce higher proliferation compared to the control treatment. These results support a role for the reverse Warburg effect, whereby cancer cells induce cancer-associated fibroblast cells in the surrounding stroma to exhibit the metabolically characterized Warburg effect. Cancer-associated fibroblasts then produce and secrete metabolites such as pyruvate to supply the cancerous cells, thereby supporting tumor growth and metastasis. While anticipating an increase in the production of lactate and increased cellular proliferation, both hallmarks of the Warburg effect, we instead observed increased secretion of pyruvate without changes in proliferation.
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Affiliation(s)
| | | | - Renee M. Ross
- Department of Animal Sciences, University of Missouri, Columbia, Missouri
| | - Melissa S. Samuel
- Department of Animal Sciences, University of Missouri, Columbia, Missouri
| | | | - Tieming Ji
- Department of Statistics, University of Missouri, Columbia, Missouri
| | - Susanta K. Behura
- Department of Animal Sciences, University of Missouri, Columbia, Missouri
| | - Kevin D. Wells
- Department of Animal Sciences, University of Missouri, Columbia, Missouri
| | - Jonathan A. Green
- Department of Animal Sciences, University of Missouri, Columbia, Missouri
| | - Randall S. Prather
- Department of Animal Sciences, University of Missouri, Columbia, Missouri
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