Pyruvate Dehydrogenase Kinase Inhibitor Research Articles

PDK inhibition promotes glucose utilization, reduces hepatic lipid deposition, and improves oxidative stress in largemouth bass (Micropterus salmoides) by increasing pyruvate oxidative phosphorylation.

In omnivorous fish, the pyruvate dehydrogenase kinases (PDKs)-pyruvate dehydrogenase E1α subunit (PDHE1α) axis is essential in the regulation of carbohydrate oxidative catabolism. Among the existing research, the role of the PDKs-PDHE1α axis in carnivorous fish with poor glucose utilization is unclear. In the present study, we determined the effects of PDK inhibition on the liver glycolipid metabolism of largemouth bass (Micropterus salmoides). DCA is a PDK-specific inhibitor that inhibits PDK by binding the allosteric sites. A total of 160 juvenile largemouth bass were randomly divided into two groups, with four replicates of 20 fish each, fed a control diet and a control diet supplemented with dichloroacetate (DCA) for 8 weeks. The present results showed that DCA supplementation significantly decreased the hepatosomatic index, triglycerides in liver and serum, and total liver lipids of largemouth bass compared with the control group. In addition, compared with the control group, DCA treatment significantly down-regulated gene expression associated with lipogenesis. Furthermore, DCA supplementation significantly decreased the mRNA expression of pdk3a and increased PDHE1α activity. In addition, DCA supplementation improved glucose oxidative catabolism and pyruvate oxidative phosphorylation (OXPHOS) in the liver, as evidenced by low pyruvate content in the liver and up-regulated expressions of glycolysis-related and TCA cycle/OXPHOS-related genes. Moreover, DCA consumption decreased hepatic malondialdehyde (MDA) content, enhanced the activities of superoxide dismutase (SOD), and increased transforming growth factor beta (tgf-β), glutathione S-transferase (gst), and superoxide dismutase 1 (sod1) gene expression compared with the control diet. This study demonstrated that inhibition of PDKs by DCA promoted glucose utilization, reduced hepatic lipid deposition, and improved oxidative stress in largemouth bass by increasing pyruvate OXPHOS. Our findings contribute to the understanding of the underlying mechanism of the PDKs-PDHE1α axis in glucose metabolism and improve the utilization of dietary carbohydrates in farmed carnivorous fish.

Dichloroacetate as a novel pharmaceutical treatment for cancer-related fatigue in melanoma.

Cancer-related fatigue (CRF) is one of the most common complications in patients with multiple cancer types and severely affects patients' quality of life. However, there have only been single symptom-relieving adjuvant therapies but no effective pharmaceutical treatment for the CRF syndrome. Dichloroacetate (DCA), a small molecule inhibitor of pyruvate dehydrogenase kinase, has been tested as a potential therapy to slow tumor growth, based largely on its effects in vitro to halt cell division. We found that although DCA did not affect rates of tumor growth or the efficacy of standard cancer treatment (immunotherapy and chemotherapy) in two murine cancer models, DCA preserved physical function in mice with late-stage tumors by reducing circulating lactate concentrations. In vivo liquid chromatography-mass spectrometry/mass spectrometry studies suggest that DCA treatment may preserve membrane potential, postpone proteolysis, and relieve oxidative stress in muscles of tumor-bearing mice. In all, this study provides evidence for DCA as a novel pharmaceutical treatment to maintain physical function and motivation in murine models of CRF.NEW & NOTEWORTHY We identify a new metabolic target for cancer-related fatigue, dichloroacetate (DCA). They demonstrate that in mice, DCA preserves physical function and protects against the detrimental effects of cancer treatment by reducing cancer-induced increases in circulating lactate. As DCA is already FDA approved for another indication, these results could be rapidly translated to clinical trials for this condition for which no pharmaceutical therapies exist beyond symptom management.

Inhibition of Pyruvate Dehydrogenase Kinase 4 Attenuates Myocardial and Mitochondrial Injury in Sepsis-Induced Cardiomyopathy.

Sepsis-induced cardiomyopathy (SIC) is a cardiac dysfunction caused by sepsis, with mitochondrial dysfunction being a critical contributor. Pyruvate dehydrogenase kinase 4 (PDK4) is a kinase of pyruvate dehydrogenase with multifaceted actions in mitochondrial metabolism. However, its role in SIC remains unknown. Serum PDK4 levels were measured and analyzed in 27 children with SIC, 30 children with sepsis, and 29 healthy children. In addition, for mice exhibiting SIC, the effects of PDK4 knockdown or inhibition on the function and structure of the myocardium and mitochondria were assessed. The findings from the analysis of children with SIC revealed that PDK4 was significantly elevated and correlated with disease severity and organ injury. Nonsurvivors displayed higher serum PDK4 levels than survivors. Furthermore, mice with SIC benefited from PDK4 knockdown or inhibition, showing improved myocardial contractile function, reduced myocardial injury, and decreased mitochondrial structural injury and dysfunction. In addition, inhibition of PDK4 decreased the inhibitory phosphorylation of PDHE1α (pyruvate dehydrogenase complex E1 subunit α) and improved abnormal pyruvate metabolism and mitochondrial dysfunction. PDK4 is a potential biomarker for the diagnosis and prognosis of SIC. In experimental SIC, PDK4 promoted mitochondrial dysfunction with increased phosphorylation of PDHE1α and abnormal pyruvate metabolism.

Inhibition of pyruvate dehydrogenase kinase 4 ameliorates kidney ischemia-reperfusion injury by reducing succinate accumulation during ischemia and preserving mitochondrial function during reperfusion

Ischemia-reperfusion (IR) injury, a leading cause of acute kidney injury (AKI), is still without effective therapies. Succinate accumulation during ischemia followed by its oxidation during reperfusion leads to excessive reactive oxygen species (ROS) and severe kidney damage. Consequently, the targeting of succinate accumulation may represent a rational approach to the prevention of IR-induced kidney injury. Since ROS are generated primarily in mitochondria, which are abundant in the proximal tubule of the kidney, we explored the role of pyruvate dehydrogenase kinase 4 (PDK4), a mitochondrial enzyme, in IR-induced kidney injury using proximal tubule cell-specific Pdk4 knockout (Pdk4ptKO) mice. Knockout or pharmacological inhibition of PDK4 ameliorated IR-induced kidney damage. Succinate accumulation during ischemia, which is responsible for mitochondrial ROS production during reperfusion, was reduced by PDK4 inhibition. PDK4 deficiency established conditions prior to ischemia resulting in less succinate accumulation, possibly because of a reduction in electron flow reversal in complex II, which provides electrons for the reduction of fumarate to succinate by succinate dehydrogenase during ischemia. The administration of dimethyl succinate a cell-permeable form of the Complex II inhibitor malonate, attenuated the beneficial effects of PDK4 deficiency, suggesting that the kidney-protective effect is succinate-dependent. Finally, genetic or pharmacological inhibition of PDK4 prevented IR-induced mitochondrial damage in mice and normalized mitochondrial function in an in vitro model of IR injury. Thus, inhibition of PDK4 represents a novel means of preventing IR-induced kidney injury, and involves the inhibition of ROS-induced kidney-toxicity through reduction in succinate accumulation and mitochondrial dysfunction.

Metabolic rewiring controlled by c-Fos governs cartilage integrity in osteoarthritis

ObjectivesThe activator protein-1 (AP-1) transcription factor component c-Fos regulates chondrocyte proliferation and differentiation, but its involvement in osteoarthritis (OA) has not been functionally assessed.Methodsc-Fos expression was evaluated by immunohistochemistry on...

All-in-One Pyruvate Dehydrogenase Kinase Inhibitor for Tracking, Targeting, and Enhanced Efficacy.

The metabolic preference of cells toward glycolysis often indicates a diseased state ranging from cancer to other dysfunctions. When a particular cell type utilizes glycolysis as a major energy production pathway, their mitochondria become impaired resulting a cascade of events which eventually contributes to resistance toward therapies to tackle such diseases. In abnormal tissues such as seen in the tumor microenvironment, when cancer cells utilize glycolysis, other cell types such as the immune cells switch their metabolism and prefer such glycolysis. As a result, utilization of therapies to destroy glycolytic preferences by cancer cells results in destruction of immune cells contributing toward an immunosuppressive phenotype. Thus, development of targeted, trackable, comparatively stable glycolysis inhibitors is urgently needed to manage diseases where glycolysis is preferred for disease progression. No glycolysis inhibitor exists which can be tracked and packaged in a delivery vehicle for efficient targeted deployment. Here, we report synthesis, characterization, and formulation of an all-in-one glycolysis inhibitor and document the therapeutic potential along with trackability and glycolysis inhibition of this inhibitor by utilizing an in vivo breast cancer model.

Temporal changes in glucose metabolism reflect polarization in resident and monocyte-derived macrophages after myocardial infarction.

Metabolic reprogramming from glycolysis to the mitochondrial tricarboxylic acid (TCA) cycle and oxidative phosphorylation may mediate macrophage polarization from the pro-inflammatory M1 to the anti-inflammatory M2 phenotype. We hypothesized that changes in cardiac macrophage glucose metabolism would reflect polarization status after myocardial infarction (MI), ranging from the early inflammatory phase to the later wound healing phase. MI was induced by permanent ligation of the left coronary artery in adult male C57BL/6J mice for 1 (D1), 3 (D3), or 7 (D7) days. Infarct macrophages were subjected to metabolic flux analysis or gene expression analysis. Monocyte versus resident cardiac macrophage metabolism was assessed using mice lacking the Ccr2 gene (CCR2 KO). By flow cytometry and RT-PCR, D1 macrophages exhibited an M1 phenotype while D7 macrophages exhibited an M2 phenotype. Macrophage glycolysis (extracellular acidification rate) was increased at D1 and D3, returning to basal levels at D7. Glucose oxidation (oxygen consumption rate) was decreased at D3, returning to basal levels at D7. At D1, glycolytic genes were elevated (Gapdh, Ldha, Pkm2), while TCA cycle genes were elevated at D3 (Idh1 and Idh2) and D7 (Pdha1, Idh1/2, Sdha/b). Surprisingly, Slc2a1 and Hk1/2 were increased at D7, as well as pentose phosphate pathway (PPP) genes (G6pdx, G6pd2, Pgd, Rpia, Taldo1), indicating increased PPP activity. Macrophages from CCR2 KO mice showed decreased glycolysis and increased glucose oxidation at D3, and decreases in Ldha and Pkm2 expression. Administration of dichloroacetate, a pyruvate dehydrogenase kinase inhibitor, robustly decreased pyruvate dehydrogenase phosphorylation in the non-infarcted remote zone, but did not affect macrophage phenotype or metabolism in the infarct zone. Our results indicate that changes in glucose metabolism and the PPP underlie macrophage polarization following MI, and that metabolic reprogramming is a key feature of monocyte-derived but not resident macrophages.

Structural Manipulations of Marine Natural Products Inspire a New Library of 3-Amino-1,2,4-Triazine PDK Inhibitors Endowed with Antitumor Activity in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the main aggressive types of cancer, characterized by late prognosis and drug resistance. Among the main factors sustaining PDAC progression, the alteration of cell metabolism has emerged to have a key role in PDAC cell proliferation, invasion, and resistance to standard chemotherapeutic agents. Taking into account all these factors and the urgency in evaluating novel options to treat PDAC, in the present work we reported the synthesis of a new series of indolyl-7-azaindolyl triazine compounds inspired by marine bis-indolyl alkaloids. We first assessed the ability of the new triazine compounds to inhibit the enzymatic activity of pyruvate dehydrogenase kinases (PDKs). The results showed that most of derivatives totally inhibit PDK1 and PDK4. Molecular docking analysis was executed to predict the possible binding mode of these derivatives using ligand-based homology modeling technique. Evaluation of the capability of new triazines to inhibit the cell growth in 2D and 3D KRAS-wild-type (BxPC-3) and KRAS-mutant (PSN-1) PDAC cell line, was carried out. The results showed the capacity of the new derivatives to reduce cell growth with a major selectivity against KRAS-mutant PDAC PSN-1 on both cell models. These data demonstrated that the new triazine derivatives target PDK1 enzymatic activity and exhibit cytotoxic effects on 2D and 3D PDAC cell models, thus encouraging further structure manipulation for analogs development against PDAC.

Dichloroacetic acid and rapamycin synergistically inhibit tumor progression.

Mammalian target of rapamycin (mTOR) controls cellular anabolism, and mTOR signaling is hyperactive in most cancer cells. As a result, inhibition of mTOR signaling benefits cancer patients. Rapamycin is a US Food and Drug Administration (FDA)-approved drug, a specific mTOR complex 1 (mTORC1) inhibitor, for the treatment of several different types of cancer. However, rapamycin is reported to inhibit cancer growth rather than induce apoptosis. Pyruvate dehydrogenase complex (PDHc) is the gatekeeper for mitochondrial pyruvate oxidation. PDHc inactivation has been observed in a number of cancer cells, and this alteration protects cancer cells from senescence and nicotinamide adenine dinucleotide (NAD+‍) exhaustion. In this paper, we describe our finding that rapamycin treatment promotes pyruvate dehydrogenase E1 subunit alpha 1 (PDHA1) phosphorylation and leads to PDHc inactivation dependent on mTOR signaling inhibition in cells. This inactivation reduces the sensitivity of cancer cells' response to rapamycin. As a result, rebooting PDHc activity with dichloroacetic acid (DCA), a pyruvate dehydrogenase kinase (PDK) inhibitor, promotes cancer cells' susceptibility to rapamycin treatment in vitro and in vivo.

Pyruvate dehydrogenase kinase inhibitor dichloroacetate augments autophagy mediated constraining the replication of Mycobacteroides massiliense in macrophages

Increasing evidence indicates a strong interaction between cellular metabolism and innate macrophage immunity. Here, we show that the intracellular replication of Mycobacteroides massiliense in macrophages depends on host pyruvate dehydrogenase kinase (PDK) activity. Infection with M. massiliense induced a metabolic switch in macrophages by increasing glycolysis and decreasing oxidative phosphorylation. Treatment with dichloroacetate (DCA), a PDK inhibitor, converts this switch in M. massiliense-infected macrophages and restricts intracellular bacterial replication. Mechanistically, DCA resulted in AMPKα1 activation via increased AMP/ATP ratio, consequently inducing autophagy to constrain bacterial proliferation in the phagolysosome. This study suggests that the pharmacological inhibition of PDK could be a strategy for host-directed therapy to control virulent M. massiliense infections.

Abstract 1371: Tumor treating fields exposure causes an imbalance of reactive oxygen homeostasis likely through the cytosolic function of the fanconi′s anemia genes

Abstract The use of Tumor Treating Fields (TTFields) has been shown to significantly benefit patients with non-resectable locally advanced or metastatic glioblastoma and malignant pleural mesothelioma. Although the disruption of mitosis that was initially attributed as the mechanism of tumor cell killing, in subsequent studies, it has been shown that TTFields inhibits DNA damage repair by downregulating DNA repair genes and proteins, including those associated with Fanconi's Anemia (FA). As a result, radiation-induced DNA damage repair is reduced and DNA replication fork protection is impaired, leading to replication stress and replication fork collapse. As the FA genes play a critical role in multiple repair pathways, TTFields is likely to increase susceptibility to other chemo agents besides radiation that cause DNA damage which is repaired by FA-dependent DNA repair and replication fork maintenance pathways in nuclei. In addition to their nuclear role, the FA proteins also regulate mitophagy in the cytosol. Using a panel of non-small cell lung cancer cell lines, it was found that TTFields exposure disrupted the clearance of damaged mitochondria despite the presence of a well-defined membrane markers for autophagosomal destruction of damaged mitochondria, that being PINK1 and parkin. Analysis of electron micrographs revealed disrupted mitochondrial cristae, while radical oxygen metabolism studies identified an imbalance leading to the production of reactive oxygen species (ROS) and ultimately, cell death. The downregulation of key mitochondrial genes including DAPIT, OSCP1, ATP5S, ATP5B and COXIV that are related to electron transport and mitochondrial integrity was confirmed by gene expression analysis. The small molecule dichloroacetate (DCA), an inhibitor of pyruvate dehydrogenase kinase, changes the metabolic state of cancer cells from cytoplasmic glycolysis to mitochondrial glucose oxidation, resulting in a decrease in mitochondrial membrane potential and an increase in ROS production in cancer cells. A combination of DCA with TTFields is therefore being investigated as a means of exploiting mitochondrial dysfunction caused by TTFields. The inhibition of mitophagy suggests a new mechanism of action for TTFields exposure tied to the downregulation of the FA pathway genes, the result being both nuclear and cytosolic perturbations in cell homeostasis. This study offers an evidence-based rationale for combining TTFields with various chemotherapy agents that may cause DNA damage, induce replication stress, and expose cells to radical oxygen byproducts of disrupting electron transport chains and the disruption of mitochondrial integrity. Citation Format: Narasimha Kumar Karanam, Michael Story. Tumor treating fields exposure causes an imbalance of reactive oxygen homeostasis likely through the cytosolic function of the fanconi′s anemia genes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1371.

Dichloroacetophenone biphenylsulfone ethers as anticancer pyruvate dehydrogenase kinase inhibitors in non-small cell lung cancer models

Pyruvate dehydrogenase kinase 1 (PDK1) is an important metabolic enzyme which is often overexpressed in many types of cancers, including non-small-cell lung cancers (NSCLC). Targeting PDK1 appears to be an attractive anticancer strategy. Based on a previously reported moderate potent anticancer PDK1 inhibitor, 64, we developed three dichloroacetophenone biphenylsulfone ethers, 30, 31 and 32, which showed strong PDK1 inhibitions of 74%, 83% and 72% at 10 μM, respectively. Then we investigated the anticancer effects of 31 in two NSCLC cell lines, namely, NCI–H1299 and NCI–H1975. It was found that 31 exhibited sub-micromolar cancer cell IC50s, suppressed colony formation, induced mitochondrial membrane potential depolarization, triggered apoptosis, altered cellular glucose metabolism, with concomitant reductions in extracellular lactate levels and enhanced the generation of reactive oxygen species in NSCLC cells. Moreover, 31 significantly suppressed the tumor growth in an NCI–H1975 mouse xenograft model, outperforming the anticancer effects of 64. Taken together our results suggested that inhibition of PDK1 via dichloroacetophenone biphenylsulfone ethers may provide a novel direction leading to an alternative treatment option in NSCLC therapy.

LCZ696 (sacubitril/valsartan) inhibits pulmonary hypertension induced right ventricular remodeling by targeting pyruvate dehydrogenase kinase 4

BackgroundRight ventricular (RV) function is a major prognostic factor in patients with cardiopulmonary disease. Effective medical therapies are available for left heart failure, but they are usually less effective or even ineffective in right heart failure. Here, we tested the hypothesis that LCZ696 (sacubitril/valsartan) can attenuate pressure overload-induced RV remodeling by inhibiting pyruvate dehydrogenase kinase 4 (PDK4). MethodsAdult male C57 mice were subjected to transverse aortic constriction (TAC), pulmonary artery constriction (PAC), or sham surgery. Bioinformatics analysis was used to screen for common differentially expressed genes (DEGs) between TAC and PAC. Chemical compounds targeting DEGs were predicted by molecular docking analysis. Effects of LCZ696 on PAC-induced RV remodeling and the associated PDK4-related mechanisms were investigated. ResultsWe found 60 common DEGs between PAC and TAC, and Pdk4 was one of the downregulated DEGs. From 47 chemical compounds with potential cardiovascular activity and PDK4 protein binding ability, we selected LCZ696 to treat PAC-induced RV remodeling because of its high docking score for binding PDK4. Compared with vehicle-treated PAC mice, LCZ696-treated mice had significantly smaller RV wall thickness and RV diameters, less myocardial fibrosis, lower expression of PDK4 protein, and less phosphorylation of glycogen synthase kinase-3β (p-GSK3β). In PAC mice, overexpression of Pdk4 blocked the inhibitory effect of LCZ696 on RV remodeling, whereas conditional knockout of Pdk4 attenuated PAC-induced RV remodeling. ConclusionsPdk4 is a common therapeutic target for pressure overload-induced left ventricular and RV remodeling, and LCZ696 attenuates RV remodeling by downregulating Pdk4 and inhibiting PDK4/p-GSK3β signal.

Pyruvate dehydrogenase kinase regulates vascular inflammation in atherosclerosis and increases cardiovascular risk.

Recent studies have revealed a close connection between cellular metabolism and the chronic inflammatory process of atherosclerosis. While the link between systemic metabolism and atherosclerosis is well established, the implications of altered metabolism in the artery wall are less understood. Pyruvate dehydrogenase kinase (PDK)-dependent inhibition of pyruvate dehydrogenase (PDH) has been identified as a major metabolic step regulating inflammation. Whether the PDK/PDH axis plays a role in vascular inflammation and atherosclerotic cardiovascular disease remains unclear. Gene profiling of human atherosclerotic plaques revealed a strong correlation between PDK1 and PDK4 transcript levels and the expression of pro-inflammatory and destabilizing genes. Remarkably, the PDK1 and PDK4 expression correlated with a more vulnerable plaque phenotype, and PDK1 expression was found to predict future major adverse cardiovascular events. Using the small-molecule PDK inhibitor dichloroacetate (DCA) that restores arterial PDH activity, we demonstrated that the PDK/PDH axis is a major immunometabolic pathway, regulating immune cell polarization, plaque development, and fibrous cap formation in Apoe-/- mice. Surprisingly, we discovered that DCA regulates succinate release and mitigates its GPR91-dependent signals promoting NLRP3 inflammasome activation and IL-1β secretion by macrophages in the plaque. We have demonstrated for the first time that the PDK/PDH axis is associated with vascular inflammation in humans and particularly that the PDK1 isozyme is associated with more severe disease and could predict secondary cardiovascular events. Moreover, we demonstrate that targeting the PDK/PDH axis with DCA skews the immune system, inhibits vascular inflammation and atherogenesis, and promotes plaque stability features in Apoe-/- mice. These results point toward a promising treatment to combat atherosclerosis.

Design, Synthesis, and Evaluation of Novel Pyruvate Dehydrogenase Kinase Inhibitors.

The present work describes the synthesis and the biological evaluation of novel compounds acting as pyruvate dehydrogenase kinase (PDK) inhibitors. These drugs should become a new therapeutic approach for the treatment of pathologies improved by the control of the blood lactate level. Four series of compounds belonging to N-(4-(N-alkyl/aralkylsulfamoyl)phenyl)-2- methylpropanamides and 1,2,4-benzothiadiazine 1,1-dioxides were prepared and evaluated as PDK inhibitors. The newly synthesized N-(4-(N-alkyl/aralkylsulfamoyl)phenyl)-2-methylpropanamides structurally related to previously reported reference compounds 4 and 5 were found to be potent PDK inhibitors (i.e. 10d: IC50 = 41 nM). 1,2,4-Benzothiadiazine 1,1-dioxides carrying a (methyl/ trifluoromethyl)-propanamide moiety at the 6-position were also designed as conformationally restricted ring-closed analogues of N-(4-(N-alkyl/aralkylsulfamoyl)phenyl)-2-hydroxy-2-methylpropanamides. Most of them were found to be less potent than their ring-opened analogues. Interestingly, the best choice of hydrocarbon side chain at the 4-position was the benzyl chain, providing 11c (IC50 = 3.6 μM) belonging to "unsaturated" 1,2,4-benzothiadiazine 1,1-dioxides, and 12c (IC50 = 0.5 μM) belonging to "saturated' 1,2,4-benzothiadiazine 1,1-dioxides. This work showed that ring-closed analogues of N-(4-(N-alkyl/aralkylsulfamoyl) phenyl)- 2-hydroxy-2-methylpropanamides were less active as PDK inhibitors than their corresponding ring-opened analogues. However, the introduction of a bulkier substituent at the 4-position of the 1,2,4-benzothiadiazine 1,1-dioxide core structure, such as a benzyl or a phenethyl side chain, was allowed, opening the way to the design of new inhibitors with improved PDK inhibitory activity.

Bovine tumor necrosis factor-alpha Increases IL-6, IL-8, and PGE2 in bovine fibroblast-like synoviocytes by metabolic reprogramming

Lameness is a common condition in dairy cattle caused by infectious or noninfectious agents. Joint lesions are the second most common cause of lameness and can be diagnosed in association with the presentation of digit injuries. Fibroblast-like synoviocyte (FLS) are predominant cells of synovia and play a key role in the pathophysiology of joint diseases, thus increasing the expression of proinflammatory mediators. Tumor necrosis factor-alpha (TNF-α) is a potent proinflammatory cytokine involved in cyclooxygenase 2 (COX-2) and proinflammatory cytokine expression in FLS. Previously, TNF-α was demonstrated to increase hypoxia-inducible Factor 1 (HIF-1), a transcription factor that rewires cellular metabolism and increases the expression of interleukin (IL)-6 in bovine FLS (bFLS). Despite this, the proinflammatory effects of TNF-α in bFLS on metabolic reprogramming have been poorly studied. We hypothesized that TNF-α increases glycolysis and in this way controls the expression of IL-6, IL-8, and COX-2 in bFLS. Results first, gas chromatography/mass spectrometry (GC/MS)-based untargeted metabolomics revealed that bTNF-α altered the metabolism of bFLS, increasing glucose, isoleucine, leucine, methionine, valine, tyrosine, and lysine and decreasing malate, fumarate, α-ketoglutarate, stearate, palmitate, laurate, aspartate, and alanine. In addition, metabolic flux analysis using D-glucose-13C6 demonstrated an increase of pyruvate and a reduction in malate and citrate levels, suggesting a decreased flux toward the tricarboxylic acid cycle after bTNF-α stimulation. However, bTNF-α increased lactate dehydrogenase subunit A (LDHA), IL-6, IL-8, IL-1β and COX-2 expression, which was dependent on glycolysis and the PI3K/Akt pathway. The use of FX11 and dichloroacetate (DCA), an inhibitor of LDHA and pyruvate dehydrogenase kinase (PDK) respectively, partially reduced the expression of IL-6. Our results suggest that bTNF-α induces metabolic reprogramming that favors glycolysis in bFLS and increases IL-6, IL-8, IL-1β and COX-2/PGE2.

Andrographolide suppresses aerobic glycolysis and induces apoptotic cell death by inhibiting pyruvate dehydrogenase kinase 1 expression.

Metabolic disorder is a major characteristic of cancer cells, and controlling genes involved in metabolic shifts can be an effective strategy for cancer treatment. Andrographolide (AG), a diterpenoid lactone, is widely recognized as a natural anticancer drug due to its ability to inhibit cancer growth. The present study aimed to investigate the mechanism underlying the mitochondrial‑mediated anticancer effect of AG by inhibiting pyruvate dehydrogenase kinase 1 (PDK1) expression in lung cancer cells. Cells were treated with AG and PDK1 mRNA and protein expression was determined using reverse transcription‑quantitative PCR and western blotting, respectively. As a result, AG significantly inhibited the viability of human lung cancer cells and suppressed aerobic glycolysis by decreasing lactate generation. AG further decreased the PDK1 protein and mRNA levels in a dose‑dependent manner. AG‑induced cell death was assessed by flow cytometry and fluorescence microscopy. AG induced apoptotic cell death that was associated with the cleavage of poly (ADP ribose) polymerase, activation of caspase‑3, and mitochondrial damage, which was associated with an increase in reactive oxygen species and loss of mitochondrial membrane potential. AG‑induced cell death was partially suppressed via PDK1 overexpression in lung cancer cells. Therefore, the anticancer effects of AG on human lung cancer cells may negatively regulate the expression of PDK1.

1,2,4-Amino-triazine derivatives as pyruvate dehydrogenase kinase inhibitors: Synthesis and pharmacological evaluation

Among the different hallmarks of cancer, deregulation of cellular metabolism turned out to be an essential mechanism in promoting cancer resistance and progression. The pyruvate dehydrogenase kinases (PDKs) are well known as key regulators in cells metabolic process and their activity was found to be overexpressed in different metabolic alerted types of cancer, including the high aggressive pancreatic ductal adenocarcinoma (PDAC). To date few PDK inhibitors have been reported, and the different molecules developed are characterized by structural chemical diversity. In an attempt to find novel classes of potential PDK inhibitors, the molecular hybridization approach, which combine two or more active scaffolds in a single structure, was employed. Herein we report the synthesis and the pharmacological evaluation of the novel hybrid molecules, characterized by the fusion of three different pharmacophoric sub-units such as 1,2,4-amino triazines, 7-azaindoles and indoles, in a single structure. The synthesized derivatives demonstrated a promising ability in hampering the enzymatic activity of PDK1 and 4, further confirmed by docking studies. Interestingly, these derivatives retained a strong antiproliferative activity against pancreatic cancer cells either in 2D and 3D models. Mechanistic studies in highly aggressive PDAC cells confirmed their ability to hamper PDK axis and to induce cancer cell death by apoptosis. Moreover, in vivo translational studies in a murine syngeneic solid tumor model confirmed the ability of the most representative compounds to target the PDK system and highlight the ability to reduce the tumor growth without inducing substantial body weight changes in the treated mice.

Synthesis of N‐(2‐(tert‐Butylamino)‐2‐oxoethyl)‐2,2‐dichloro‐N‐aryl(alkyl)acetamides as Anticancer Agents: Molecular Modeling and Biological Evaluations

AbstractDichloroacetate (DCA) is considered as a highly bioavailable and small anticancer agent which reduces tumor growth through inhibition of pyruvate dehydrogenase kinases. Various DCA derivatives were designed, synthesized and eluated by FT‐IR, 1HNMR, 13CNMR and Mass spectrum. Biological evaluations of the synthesized compounds were evaluated against three human cancer cell lines, A549 (lung), MCF‐7 (breast), and MDA‐MB‐231 (breast), as well as a non‐tumorigenic breast cell line (MCF‐10A). Among synthesized compounds, N‐(2‐(tert‐butylamino)‐1‐(4‐nitrophenyl)‐2‐oxoethyl)‐2,2‐dichloro‐N‐(2‐fluorophenyl)acetamide (A5) had a promising cytotoxic effect with IC50 values of 11.94, 15.57, and 16.54 μM against MCF‐7, MDA‐MB‐231, and A549 cells, respectively. It can also induce apoptosis in MCF‐7 cell line. Molecular docking and molecular dynamic simulation studies were also carried out show binding sites and energies to the PDKs isoenzymes. All of the compounds demonstrated appropriate selectivity between cancerous and non‐cancerous cell lines. These results provide valuable insight for the additional development of novel dichloroacetate‐containing compounds.

Pyruvate dehydrogenase kinase supports macrophage NLRP3 inflammasome activation during acute inflammation

Activating the macrophage NLRP3 inflammasome can promote excessive inflammation with severe cell and tissue damage and organ dysfunction. Here, we show that pharmacological or genetic inhibition of pyruvate dehydrogenase kinase (PDHK) significantly attenuates NLRP3 inflammasome activation in murine and human macrophages and septic mice by lowering caspase-1 cleavage and interleukin-1β (IL-1β) secretion. Inhibiting PDHK reverses NLRP3 inflammasome-induced metabolic reprogramming, enhances autophagy, promotes mitochondrial fusion over fission, preserves crista ultrastructure, and attenuates mitochondrial reactive oxygen species (ROS) production. The suppressive effect of PDHK inhibition on the NLRP3 inflammasome is independent of its canonical role as a pyruvate dehydrogenase regulator. Our study suggests a non-canonical role of mitochondrial PDHK in promoting mitochondrial stress and supporting NLRP3 inflammasome activation during acute inflammation.