Dichloroacetate Treatment Research Articles

Dichloroacetate, a pyruvate dehydrogenase activator, alleviates high-fat-induced impairment of myogenic differentiation in skeletal muscles.

Obesity-induced impairment of myogenic differentiation leads to muscle loss and sarcopenia. Pyruvate dehydrogenase (PDH) plays a crucial role in glucose metabolism and is associated with muscle differentiation. However, the effect of dichloroacetate (DCA), a PDH activator, on obesity-induced impairment of myogenic differentiation remains unknown. Here, we evaluated the effects of DCA treatment on high-fat intake-induced impairment of myogenic differentiation in C2C12 cells and C57BL/6 mice. In C2C12 cells, DCA treatment improved PDH activity that was reduced by palmitate (PAL) and decreased the lactate concentrations in the media. Additionally, DCA reversed PAL- and high-fat diet (HFD)-induced decrease in the expression of myoblast determination protein 1 (MyoD), myogenin (MyoG) and myosin heavy chain (MyHC) in C2C12 cells and C57BL/6 mice. To explore the possible mechanism, DCA treatment restored the levels of p-Akt, p-FoxO1, p-FoxO3a and p-p38 MAPK levels in PAL-treated C2C12 cells. Moreover, the protective effects of DCA were reversed by treatment with the Akt inhibitor MK2206 in C2C12 cells. In summary, DCA treatment alleviated high-fat intake-induced impairment of myogenic differentiation via Akt signalling, suggesting its potential in treating obesity-associated muscle loss and sarcopenia.

8071 Prevention Of Acute Kidney Injury By Reducing Mitochondrial Dysfunction In Diabetic Mice

Abstract Disclosure: M. Kim: None. C. Oh: None. A. Khang: None. J. Jeon: None. I. Lee: None. Background: Acute Kidney Injury (AKI) significantly contributes to the pathogenesis of diabetic kidney disease, often exacerbating chronic kidney disease (CKD) and accelerating the need for dialysis. Mitochondrial dysfunction, induced by an increase in reactive Oxygen Species (ROS) and inflammation, plays a crucial role in AKI. This study investigates the prevention of AKI by reducing mitochondrial dysfunction through pyruvate dehydrogenase kinase (PDK) inhibition in an ischemia-reperfusion (IR)-induced AKI model using streptozotocin (STZ)-induced diabetic mice. Methods: We utilized an IR-induced AKI model in STZ-induced diabetic C57BL6/J mice, subjecting them to IR by clamping both renal pedicles. Mitochondrial function tests, cellular apoptosis, and inflammatory markers were evaluated in NRK-52E cells and mouse primary tubular cells after hypoxia and reoxygenation using a hypoxia workstation. Results: In diabetic mice experiencing AKI following IR injury, there was a significant increase in pyruvate dehydrogenase E1α (PDHE1α) phosphorylation. This correlated with a notable increase in mitochondrial damage - TEM images of mice with IR-induced kidney injury revealed distension, loss of cristae, and fragmentation of the mitochondria. We also observed a decrease in oxygen consumption rate (OCR) accompanied by increased ROS, as well as increased production of inflammatory markers. Remarkably, the pan-PDK inhibitor, sodium dichloroacetate (DCA), mitigated apoptosis, attributable to the reduction of PDHE1α phosphorylation levels as well as normalized mitochondrial morphology and function. DCA treatment lessened oxidative stress and decreased the production of inflammatory markers following IR-induced AKI or hypoxia-reoxygenation injury. Conclusion: Restoration of mitochondrial function by DCA effectively alleviated renal injury by decreasing ROS production and inflammation, highlighting its critical role in IR-mediated damage. These results suggest another potential target for renal protection during AKI; therefore, the prevention of acute kidney injury through the inhibition of PDK could be a promising therapeutic approach for treating Diabetic Kidney Disease (DKD). Presentation: 6/1/2024

Pharmacological activation of pyruvate dehydrogenase by dichloroacetate protects against obesity-induced muscle atrophy in vitro and in vivo

Obesity-induced muscle atrophy leads to physical impairment and metabolic dysfunction, which are risky for older adults. The activity of pyruvate dehydrogenase (PDH), a critical regulator of glucose metabolism, is reduced in obesity. Additionally, PDH activator dichloroacetate (DCA) improves metabolic dysfunction. However, the effects of PDH activation on skeletal muscles in obesity remain unclear. Thus, this study aimed to evaluate the effects of PDH activation by DCA treatment on obesity-induced muscle atrophy in vitro and in vivo and elucidate the possible underlying mechanisms. Results showed that PDH activation by DCA treatment ameliorated muscle loss, decreased the cross-sectional area, and reduced grip strength in C57BL/6 mice fed a high-fat diet (HFD). Elevation of muscle atrophic factors atrogin-1 and muscle RING-finger protein-1 (MuRF-1) and autophagy factors LC3BII and p62 were abrogated by DCA treatment in palmitate-treated C2C12 myotubes and in the skeletal muscles of HFD-fed mice. Moreover, p-Akt, p-FoxO1, and p-FoxO3 protein levels were reduced and p-NF-κB p65 and p-p38 MAPK protein levels were elevated in palmitate-treated C2C12 myotubes, which were restored by DCA treatment. However, the protective effects of DCA treatment against myotube atrophy were reversed by treatment with Akt inhibitor MK2206. Taken together, our study demonstrated that PDH activation by DCA treatment can alleviate obesity-induced muscle atrophy. It may serve as a basis for developing novel strategies to prevent obesity-associated muscle loss.

Abstract 7155: Dichloroacetate reverses cisplatin resistance in ovarian cancer through promoting ROS production

Abstract Chemotherapy resistance and the high rate of ovarian cancer relapse pose major challenges in the treatment of ovarian cancer. The development of chemoresistance contributes to poor overall prognosis associated with ovarian cancer and high cancer-related mortality in women worldwide. Herein, we found that Dichloroacetate (DCA), a pan-pyruvate dehydrogenase kinase (PDK) inhibitor, is a potent agent to overcome Cisplatin (CP) resistance in ovarian cancer treatment. Firstly, we elucidated that phosphorylation of pyruvate dehydrogenase (pPDH) was elevated in CP-resistant ovarian cancer cells. Then, blockage of pPDH by DCA treatment significantly inhibited cell migratory and invasive capacity in CP-resistant ovarian cancer cells through the transition of motile mesenchymal phenotypes into epithelial characteristics. DCA markedly decreased the number of sphere formations and attenuated the stem cell-like properties in CP-resistant ovarian cancer cells. In combination with CP treatment, DCA effectively inhibited cell proliferation in chemoresistant ovarian cancer cells by triggering apoptosis. Collectively, we suggested that DCA is a promising drug to reverse CP resistance for ovarian cancer treatment. We further tested the underlying mechanisms of DCA to restore CP sensitivity in ovarian cancer. We found that CP treatment promoted reactive oxygen species (ROS) production to induce cell death in CP-sensitive ovarian cancer. However, CP-resistant ovarian cancer cells exhibited higher basal levels of ROS compared with sensitive cancer cells, and CP treatment failed to generate ROS production. That means ovarian cancer cells steadily adapted to elevated ROS levels, then becoming ROS-adapted ovarian cancer cells to survive. Interestingly, DCA treatment results in the buildup of ROS production, causing cell death in CP-resistant ovarian cancer. Therefore, our study suggests that ROS production can be an attractive target in DCA treatment to restore CP sensitivity in ovarian cancer. Citation Format: Yen Thi Do, Seungmee Lee, Changmin Shin, Hyewon Chung, Jin Young Kim, Eunyoung Ha, Sojin Shin, Ji Hae Seo. Dichloroacetate reverses cisplatin resistance in ovarian cancer through promoting ROS production [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7155.

Reducing Oxidative Stress and Inflammation by Pyruvate Dehydrogenase Kinase 4 Inhibition Is Important in Prevention of Renal Ischemia-Reperfusion Injury in Diabetic Mice.

Reactive oxygen species (ROS) and inflammation are reported to have a fundamental role in the pathogenesis of ischemia-reperfusion (IR) injury, a leading cause of acute kidney injury. The present study investigated the role of pyruvate dehydrogenase kinase 4 (PDK4) in ROS production and inflammation following IR injury. We used a streptozotocin-induced diabetic C57BL6/J mouse model, which was subjected to IR by clamping both renal pedicles. Cellular apoptosis and inflammatory markers were evaluated in NRK-52E cells and mouse primary tubular cells after hypoxia and reoxygenation using a hypoxia work station. Following IR injury in diabetic mice, the expression of PDK4, rather than the other PDK isoforms, was induced with a marked increase in pyruvate dehydrogenase E1α (PDHE1α) phosphorylation. This was accompanied by a pronounced ROS activation, as well as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and monocyte chemoattractant protein-1 (MCP-1) production. Notably, sodium dichloroacetate (DCA) attenuated renal IR injury-induced apoptosis which can be attributed to reducing PDK4 expression and PDHE1α phosphorylation levels. DCA or shPdk4 treatment reduced oxidative stress and decreased TNF-α, IL-6, IL-1β, and MCP-1 production after IR or hypoxia-reoxygenation injury. PDK4 inhibition alleviated renal injury with decreased ROS production and inflammation, supporting a critical role for PDK4 in IR mediated damage. This result indicates another potential target for reno-protection during IR injury; accordingly, the role of PDK4 inhibition needs to be comprehensively elucidated in terms of mitochondrial function during renal IR injury.

Management of ulcerative colitis by dichloroacetate: Impact on NFATC1/NLRP3/IL1B signaling based on bioinformatics analysis combined with in vivo experimental verification

The inflammatory response in ulcerative colitis (UC) could be relieved by the conventional immunomodulatory agents; 5-aminosalicylic acid, corticosteroids, or azathioprine. However, the low remission rates and the intolerance to these agents necessitate investigation of gene expression signature in UC that could influence the therapeutic efficacy of drugs, as well as the interference with persistence genes by novel therapeutic option. Three microarray datasets (GSE66407, GSE38713 and GSE14580) from the NCBI-GEO database were utilized. Differentially expressed genes between samples of patients with UC and healthy ones were analyzed using R software. In addition, in vivo study using oxazolone-induced UC in BALB/c mice was carried out to investigate the proposed therapeutic efficacy of dichloroacetate (DCA). The bioinformatics analysis revealed the persistence of NLRP3, NFATC1, and IL1B in UC despite treatment with common therapeutic agents. DCA administration to oxazolone-treated mice showed remarkable interference with those persistence genes. Western blotting analysis for NLRP3, NFATC1, nuclear/total NF-κB, and cleaved caspase-1 revealed the ability of DCA to reduce the expression levels of these proteins in oxazolone-treated mice. Additionally, the inflammatory cytokines IL-1β and IL-13 were reduced in colonic tissue by DCA treatment. The therapeutic efficacy of DCA was further confirmed by the apparent reduction in histopathological scoring, disease activity index, and the normalization of colon length. Therefore, DCA could be suggested as a novel and promising therapeutic option in UC based on its ability to interfere with the persistence of NFATC1/NLRP3/IL1B signaling. That merits further safety/toxicological pre-clinical assessment and update of bioavailability/metabolism data prior to clinical investigation.

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.

In-vivo magnetic resonance spectroscopy of lactate as a non-invasive biomarker of dichloroacetate activity in cancer and non-cancer central nervous system disorders.

The adverse effects of lactic acidosis in the cancer microenvironment have been increasingly recognized. Dichloroacetate (DCA) is an orally bioavailable, blood brain barrier penetrable drug that has been extensively studied in the treatment of mitochondrial neurologic conditions to reduce lactate production. Due to its effect reversing aerobic glycolysis (i.e., Warburg-effect) and thus lactic acidosis, DCA became a drug of interest in cancer as well. Magnetic resonance spectroscopy (MRS) is a well-established, non-invasive technique that allows detection of prominent metabolic changes, such as shifts in lactate or glutamate levels. Thus, MRS is a potential radiographic biomarker to allow spatial and temporal mapping of DCA treatment. In this systematic literature review, we gathered the available evidence on the use of various MRS techniques to track metabolic changes after DCA administration in neurologic and oncologic disorders. We included in vitro, animal, and human studies. Evidence confirms that DCA has substantial effects on lactate and glutamate levels in neurologic and oncologic disease, which are detectable by both experimental and routine clinical MRS approaches. Data from mitochondrial diseases show slower lactate changes in the central nervous system (CNS) that correlate better with clinical function compared to blood. This difference is most striking in focal impairments of lactate metabolism suggesting that MRS might provide data not captured by solely monitoring blood. In summary, our findings corroborate the feasibility of MRS as a pharmacokinetic/pharmacodynamic biomarker of DCA delivery in the CNS, that is ready to be integrated into currently ongoing and future human clinical trials using DCA.

Physiology of PNS axons relies on glycolytic metabolism in myelinating Schwann cells.

While lactate shuttle theory states that glial cells metabolize glucose into lactate to shuttle it to neurons, how glial cells support axonal metabolism and function remains unclear. Lactate production is a common occurrence following anaerobic glycolysis in muscles. However, several other cell types, including some stem cells, activated macrophages and tumor cells, can produce lactate in presence of oxygen and cellular respiration, using Pyruvate Kinase 2 (PKM2) to divert pyruvate to lactate dehydrogenase. We show here that PKM2 is also upregulated in myelinating Schwann cells (mSC) of mature mouse sciatic nerve versus postnatal immature nerve. Deletion of this isoform in PLP-expressing cells in mice leads to a deficit of lactate in mSC and in peripheral nerves. While the structure of myelin sheath was preserved, mutant mice developed a peripheral neuropathy. Peripheral nerve axons of mutant mice failed to maintain lactate homeostasis upon activity, resulting in an impaired production of mitochondrial ATP. Action potential propagation was not altered but axonal mitochondria transport was slowed down, muscle axon terminals retracted and motor neurons displayed cellular stress. Additional reduction of lactate availability through dichloroacetate treatment, which diverts pyruvate to mitochondrial oxidative phosphorylation, further aggravated motor dysfunction in mutant mice. Thus, lactate production through PKM2 enzyme and aerobic glycolysis is essential in mSC for the long-term maintenance of peripheral nerve axon physiology and function.

Glycolytic Inhibitors Potentiated the Activity of Paclitaxel and Their Nanoencapsulation Increased Their Delivery in a Lung Cancer Model.

Antiglycolytic agents inhibit cell metabolism and modify the tumor’s microenvironment, affecting chemotherapy resistance mechanisms. In this work, we studied the effect of the glycolytic inhibitors 3-bromopyruvate (3BP), dichloroacetate (DCA) and 2-deoxyglucose (2DG) on cancer cell properties and on the multidrug resistance phenotype, using lung cancer cells as a model. All compounds led to the loss of cell viability, with different effects on the cell metabolism, migration and proliferation, depending on the drug and cell line assayed. DCA was the most promising compound, presenting the highest inhibitory effect on cell metabolism and proliferation. DCA treatment led to decreased glucose consumption and ATP and lactate production in both A549 and NCI-H460 cell lines. Furthermore, the DCA pretreatment sensitized the cancer cells to Paclitaxel (PTX), a conventional chemotherapeutic drug, with a 2.7-fold and a 10-fold decrease in PTX IC50 values in A549 and NCI-H460 cell lines, respectively. To increase the intracellular concentration of DCA, thereby potentiating its effect, DCA-loaded poly(lactic-co-glycolic acid) nanoparticles were produced. At higher DCA concentrations, encapsulation was found to increase its toxicity. These results may help find a new treatment strategy through combined therapy, which could open doors to new treatment approaches.

The Comparative Experimental Study of Sodium and Magnesium Dichloroacetate Effects on Pediatric PBT24 and SF8628 Cell Glioblastoma Tumors Using a Chicken Embryo Chorioallantoic Membrane Model and on Cells In Vitro.

In this study, pyruvate dehydrogenase kinase-1 inhibition with dichloroacetate (DCA) was explored as an alternative cancer therapy. The study’s aim was to compare the effectiveness of NaDCA and MgDCA on pediatric glioblastoma PBT24 and SF8628 tumors and cells. The treatment effects were evaluated on xenografts growth on a chicken embryo chorioallantoic membrane. The PCNA, EZH2, p53, survivin expression in tumor, and the SLC12A2, SLC12A5, SLC5A8, CDH1, and CDH2 expression in cells were studied. The tumor groups were: control, cells treated with 10 mM and 5 mM of NaDCA, and 5 mM and 2.5 mM of MgDCA. The cells were also treated with 3 mM DCA. Both the 10 mM DCA preparations significantly reduced PBT24 and SF8624 tumor invasion rates, while 5 mM NaDCA reduced it only in the SF8628 tumors. The 5 mM MgDCA inhibited tumor-associated neoangiogenesis in PBT24; both doses of NaDCA inhibited tumor-associated neoangiogenesis in SF8628. The 10 mM DCA inhibited the expression of markers tested in PBT24 and SF8628 tumors, but the 5 mM DCA affect on their expression depended on the cation. The DCA treatment did not affect the SLC12A2, SLC12A5, and SLC5A8 expression in cells but increased CDH1 expression in SF8628. The tumor response to DCA at different doses indicated that a contrast between NaDCA and MgDCA effectiveness reflects the differences in the tested cells’ biologies.

Sepsis, pyruvate, and mitochondria energy supply chain shortage.

Balancing high energy-consuming danger resistance and low energy supply of disease tolerance is a universal survival principle that often fails during sepsis. Our research supports the concept that sepsis phosphorylates and deactivates mitochondrial pyruvate dehydrogenase complex control over the tricarboxylic cycle and the electron transport chain. StimulatIng mitochondrial energetics in septic mice and human sepsis cell models can be achieved by inhibiting pyruvate dehydrogenase kinases with the pyruvate structural analog dichloroacetate. Stimulating the pyruvate dehydrogenase complex by dichloroacetate reverses a disruption in the tricarboxylic cycle that induces itaconate, a key mediator of the disease tolerance pathway. Dichloroacetate treatment increases mitochondrial respiration and ATP synthesis, decreases oxidant stress, overcomes metabolic paralysis, regenerates tissue, organ, and innate and adaptive immune cells, and doubles the survival rate in a murine model of sepsis.

Abstract 6163: Targeting glucose metabolism through inhibition of pyruvate dehydrogenase kinase to improve response to immune-checkpoint inhibition in melanoma

Abstract Immune-checkpoint inhibitors have improved survival of patients with advanced melanoma, however, 40-50% of patients do not benefit sufficiently. Melanoma tumor lesions have high glucose uptake due to metabolic reprogramming, which supports tumor cell growth and is partially mediated through elevated expression of mitochondrial pyruvate dehydrogenase kinases (PDK1-4). Resultant decreased glucose levels and low pH in the tumor microenvironment are detrimental to antitumor immune cell function. Here, we aimed to reverse metabolic reprogramming in melanoma through PDK inhibition, thereby inhibiting tumor cell growth while maintaining or potentially enhancing antitumor immunity. We used a panel of four melanoma cell lines with genetic backgrounds similar to those most frequently found in patients, namely the BRAF-mutant A375 and S-MEL-28 cell lines, the NRAS-mutant SK-MEL-2 cell line and the BRAF/NRAS wild-type MeWo cell line. These were then treated with PDK inhibitor dichloroacetate (DCA) to determine effects on viability and metabolic phenotype. Furthermore, we investigated whether DCA synergized with treatment with the glutaminase inhibitor CB-839. Finally, we determined the effect of DCA on viability, interferon-γ (IFN-γ) secretion and antitumor activity of CD8+ T cells. MeWo cells were most sensitive to DCA, while SK-MEL-2 was the least sensitive, with IC50 values ranging from 13.3 to 27.0 mM. DCA led to an up to 6-fold increase in oxygen consumption rate:extracellular acidification rate (OCR:ECAR) ratio in all cell lines. SK-MEL-28 cells were not sensitive to CB-839, while the IC50 values in the other cell lines ranged from 7.9 nM in MeWo to 139.2 nM in SK-MEL-2 cells. DCA synergized with CB-839 in 2D and 3D culture, ranging from 2-fold sensitization compared to either drug alone in MeWo up to 5-fold sensitization in SK-MEL-2. In activated CD8+ T cells, viability was not affected by DCA treatment of up to 21 mM, whereas proliferation was only mildly inhibited. These cells also showed a 2.5-fold increase in OCR:ECAR ratio after DCA treatment. Interestingly, IFN-γ secretion by CD8+ T cells was increased 2.8-fold after DCA treatment and tumor cell killing by CD8+ T cells in a coculture with A375 cells was not impaired by DCA or CB-839 treatment. We conclude that DCA can indeed reprogram cellular metabolism in melanoma and synergizes with other metabolically targeted drugs in antitumor activity, while keeping the antitumor reactivity of CD8+ T cells intact. Supported by the Dutch Cancer Foundation (10913/2017-1). Citation Format: Jiske F. Tiersma, Bernardus Evers, Barbara M. Bakker, Steven de Jong, Mathilde Jalving. Targeting glucose metabolism through inhibition of pyruvate dehydrogenase kinase to improve response to immune-checkpoint inhibition in melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6163.

Comparison Between Dichloroacetate and Phenylbutyrate Treatment for Pyruvate Dehydrogenase Deficiency.

Pyruvate dehydrogenase (PDH) deficiency is caused by a number of pathogenic variants and the most common are found in the PDHA1 gene. The PDHA1 gene encodes one of the subunits of the PDH enzyme found in a carbohydrate metabolism pathway involved in energy production. Pathogenic variants of PDHA1 gene usually impact the α-subunit of PDH causing energy reduction. It potentially leads to increased mortality in sufferers. Potential treatments for this disease include dichloroacetate and phenylbutyrate, previously used for other diseases such as cancer and maple syrup urine disease. However, not much is known about their efficacy in treating PDH deficiency. Effective treatment for PDH deficiency is crucial as carbohydrate is needed in a healthy diet and rice is the staple food for a large portion of the Asian population. This review analysed the efficacy of dichloroacetate and phenylbutyrate as potential treatments for PDH deficiency caused by PDHA1 pathogenic variants. Based on the findings of this review, dichloroacetate will have an effect on most PDHA1 pathogenic variant and can act as a temporary treatment to reduce the lactic acidosis, a common symptom of PDH deficiency. Phenylbutyrate can only be used on patients with certain pathogenic variants (p.P221L, p.R234G, p.G249R, p.R349C, p.R349H) on the PDH protein. It is hoped that the review would provide an insight into these treatments and improve the quality of lives for patients with PDH deficiency.

Concentration-dependent effects of dichloroacetate in type 2 diabetic hearts assessed by hyperpolarized [1-13 C]-pyruvate magnetic resonance imaging.

Personalized medicine or individualized therapy promises a paradigm shift in healthcare. This is particularly true in complex and multifactorial diseases such as diabetes and the multitude of related pathophysiological complications. Diabetic cardiomyopathy represents an emerging condition that could be effectively treated if better diagnostic and, in particular, better therapeutic monitoring tools were available. In this study, we investigate the ability to differentiate low and high doses of metabolically targeted therapy in an obese type 2 diabetic rat model. Low-dose dichloroacetate (DCA) treatment was associated with increased lactate production, while no or little change was seen in bicarbonate production. High-dose DCA treatment was associated with a significant metabolic switch towards increased bicarbonate production. These findings support further studies using hyperpolarized [1-13 C]-pyruvate magnetic resonance imaging to differentiate treatment effects and thus allow for personalized titration of therapeutics.

Dichloroacetate reactivates pyruvate-supported peroxide removal by liver mitochondria and prevents NAFLD aggravation in NAD(P)+ transhydrogenase-null mice consuming a high-fat diet

The mechanisms by which a high-fat diet (HFD) promotes non-alcoholic fatty liver disease (NAFLD) appear to involve liver mitochondrial dysfunction and redox imbalance. The functional loss of the enzyme NAD(P)+ transhydrogenase, a main source of mitochondrial NADPH, results in impaired mitochondrial peroxide removal, pyruvate dehydrogenase inhibition by phosphorylation, and progression of NAFLD in HFD-fed mice. The present study aimed to investigate whether pharmacological reactivation of pyruvate dehydrogenase by dichloroacetate attenuates the mitochondrial redox dysfunction and the development of NAFLD in NAD(P)+ transhydrogenase-null (Nnt−/−) mice fed an HFD (60% of total calories from fat). For this purpose, Nnt−/− mice and their congenic controls (Nnt+/+) were fed chow or an HFD for 20 weeks and received sodium dichloroacetate or NaCl in the final 12 weeks via drinking water. The results showed that HFD reduced the ability of isolated liver mitochondria from Nnt−/− mice to remove peroxide, which was prevented by the dichloroacetate treatment. HFD-fed mice of both Nnt genotypes exhibited increased body and liver mass, as well as a higher content of hepatic triglycerides, but dichloroacetate treatment attenuated these abnormalities only in Nnt−/− mice. Notably, dichloroacetate treatment decreased liver pyruvate dehydrogenase phosphorylation levels and prevented the aggravation of NAFLD in HFD-fed Nnt−/− mice. Conversely, dichloroacetate treatment elicited moderate hepatocyte ballooning in chow-fed mice, suggesting potentially toxic effects. We conclude that the protection against HFD-induced NAFLD by dichloroacetate is associated with its role in reactivating pyruvate dehydrogenase and reestablishing the pyruvate-supported liver mitochondrial capacity to handle peroxide in Nnt−/− mice.

Sodium dichloroacetate stimulates cardiac mitochondrial metabolism and improves cardiac conduction in the ovine fetus during labor.

Previous studies in our laboratory have suggested that the increase in stillbirth in pregnancies complicated by chronic maternal stress or hypercortisolemia is associated with cardiac dysfunction in late stages of labor and delivery. Transcriptomics analysis of the overly represented differentially expressed genes in the fetal heart of hypercortisolemic ewes indicated involvement of mitochondrial function. Sodium dichloroacetate (DCA) has been used to improve mitochondrial function in several disease states. We hypothesized that administration of DCA to laboring ewes would improve both cardiac mitochondrial activity and cardiac function in their fetuses. Four groups of ewes and their fetuses were studied: control, cortisol-infused (1 g/kg/day from 115 to term; CORT), DCA-treated (over 24 h), and DCA+CORT-treated; oxytocin was delivered starting 48 h before the DCA treatment. DCA significantly decreased cardiac lactate, alanine, and glucose/glucose-6-phosphate and increased acetylcarnitine/isobutyryl-carnitine. DCA increased mitochondrial activity, increasing oxidative phosphorylation (PCI, PCI+II) per tissue weight or per unit of citrate synthase. DCA also decreased the duration of the QRS, attenuating the prolongation of the QRS observed in CORT fetuses. The effect to reduce QRS duration with DCA treatment correlated with increased glycerophosphocholine and serine and decreased phosphorylcholine after DCA treatment. There were negative correlations of acetylcarnitine/isobutyryl-carnitine to both heart rate (HR) and mean arterial pressure (MAP). These results suggest that improvements in mitochondrial respiration with DCA produced changes in the cardiac lipid metabolism that favor improved conduction in the heart. DCA may therefore be an effective treatment of fetal cardiac metabolic disturbances in labor that can contribute to impairments of fetal cardiac conduction.

Abstract 11800: Inhibition of Pyruvate Dehydrogenase Kinase Does Not Improve Cardiac Abnormalities in a Mouse Model of Human Barth Syndrome

Introduction/Hypothesis: Heart failure presents as the leading cause of infant mortality in individuals with the rare genetic disease, Barth Syndrome (BTHS). The causative mutation underlying the BTHS phenotype has been mapped to the tafazzin ( TAZ) g ene, which encodes for a phospholipid transacylase critical for the remodelling of the mitochondrial phospholipid, cardiolipin. Perturbations in myocardial energy metabolism may contribute to the development and progression of cardiomyopathy in BTHS. Given that cardiac glucose oxidation is impaired in a mouse model of human BTHS, we hypothesized that pharmacological enhancement of glucose oxidation through dichloroacetate (DCA) treatment could mitigate BTHS-related cardiac dysfunction. Methods: DCA was added to the drinking water (84 mM) of 6-week-old mice with experimental BTHS (doxycycline-inducible Taz knockdown (TazKD) mice) for 6-weeks. In vivo cardiac function was assessed via ultrasound echocardiography prior to and following the DCA treatment period. Hearts were extracted from TazKD mice and their wild-type (WT) littermates for protein expression profiling and enzyme activity assessment at the end of the treatment protocol. Results: Prior to treatment at 4-5 weeks of age, TazKD mice exhibited hypertrophic cardiomyopathy as demonstrated by an increase in the ratio between left ventricular (LV) anterior and posterior wall thickness during diastole in relation to lean body mass (0.042±0.003 vs 0.062±0.008 mm/g; 0.049±0.002 vs 0.069±0.005 mm/g). TazKD mice also exhibited impaired LV systolic and diastolic volumes. Treatment with DCA decreased inhibitory phosphorylation of pyruvate dehydrogenase, the rate-limiting enzyme of glucose oxidation, and trended to increase its activity ( p =0.19) in ventricular extracts from TazKD mice compared to their WT littermates, thus suggestive of increased myocardial glucose oxidation. However, despite a potential improvement of cardiac energy metabolism, treatment with DCA did not improve cardiac structural and functional parameters in TazKD mice. Conclusions: Our findings suggest that optimization of cardiac glucose oxidation may not be a feasible strategy for alleviating BTHS-associated cardiomyopathy.

Metformin and Dichloroacetate Suppress Proliferation of Liver Cancer Cells by Inhibiting mTOR Complex 1.

The Warburg effect is important for cancer cell proliferation. This phenomenon can be flexible by interaction between glycolysis and mitochondrial oxidation for energy production. We aimed to investigate the anticancer effects of the pyruvate dehydrogenase kinase inhibitor, dichloroacetate (DCA) and the mitochondrial respiratory complex I inhibitor metformin in liver cancer cells. The anticancer effect of DCA and/or metformin on HepG2, PLC/PRF5 human liver cancer cell lines, MH-134 murine hepatoma cell lines, and primary normal hepatocytes using MTT assay. Inhibition of lactate/ATP production and intracellular reactive oxygen species generation by DCA and metformin was investigated. Inhibition of PI3K/Akt/mTOR complex I was evaluated to see whether it occurred through AMPK signaling. Anticancer effects of a combination treatment of DCA and metformin were evaluated in HCC murine model. The results showed that metformin and DCA effectively induced apoptosis in liver cancer cells. A combination treatment of metformin and DCA did not affect viability of primary normal hepatocytes. Metformin upregulated glycolysis in liver cancer cells, thereby increasing sensitivity to the DCA treatment. Metformin and DCA inhibited mTOR complex I signaling through upregulated AMPK-independent REDD1. In addition, metformin and DCA increased reactive oxygen species levels in liver cancer cells, which induced apoptosis. A combination treatment of metformin and DCA significantly suppressed the tumor growth of liver cancer cells using in vivo xenograft model. Taken together, the combined treatment of metformin and DCA suppressed the growth of liver cancer cells. This strategy may be effective for patients with advanced liver cancer.