Succinate Metabolism Research Articles

OR30-2 Targeting Succinate Metabolism in Endocrine Therapy Resistant, ER Positive, Breast Cancer Cells

Abstract Estrogen receptor positive (ER+) breast cancer is the most common subtype among all breast cancers and is responsible for most breast cancer related deaths. Endocrine therapies, such as selective estrogen receptor modulators (SERM) and aromatase inhibitors (AI), often given in combination with cyclin-dependent kinase 4/6 (CDK4/6) inhibitors, are initially effective but the majority of advanced ER+ breast cancers eventually become refractory to endocrine therapies. Therefore, understanding the underlying molecular mechanisms that enable or promote resistance to endocrine therapies may lead to novel therapeutic targets.Cancer cells have a high energy demand and as a result consume greater quantities of glucose to meet their energy and anabolic demands to support cell growth and proliferation. In this study, we used breast cancer cell models that are endocrine therapy sensitive and resistant and investigated the metabolic flux of glucose by growing the cells in the presence of the stable glucose isotope, UC13-Glucose. We measured the C13-labelled metabolites of glycolysis and the TCA cycle. Glucose consumption was higher in endocrine therapy resistant MCF7/LCC9 (LCC9) cells compared with parental MCF7 (MCF7) and estrogen independent, endocrine therapy sensitive MCF7/LCC1 (LCC1) cells. Notably, in LCC9 cells the m+4 and m+6 isotopomer of C-13 labelled citrate was absent. Further, in LCC9 cells, C-13 labelled fumarate was very low while the succinate: fumarate ratio was markedly higher. These results suggest that the TCA cycle is impaired in LCC9 cells and the conversion of succinate to fumarate is dysregulated. Succinate dehydrogenase (SDH) enzyme is responsible for catalytic conversion of succinate to fumarate. SDH is a multimeric protein comprised of four different subunits and SDH assembly factor 2 (SDHAF2), which is a tumor suppressor gene. Our study further showed that SDHAF2 protein was under expressed in LCC9 cells compared with LCC1 cells, likely contributing to lower SDH activity. Intriguingly, when SDH activity was inhibited using dimethylmalonate, the LCC9 were re-sensitized to both Fulvestrant and 4-hydroxytamoxifen. Data analysis of clinical samples shows that poor relapse free survival in ER+ breast cancer patients is correlated with lower expression levels of SDHAF2. Overall, this study suggests that targeting succinate metabolism may help to restore sensitivity to Fulvestrant and tamoxifen in endocrine therapy resistance in ER+ breast cancer cells. Presentation: Tuesday, June 14, 2022 10:00 a.m. - 10:15 a.m.

Combined Transcriptome and Metabolome Analysis of a New Species of Microalgae from the Tibetan Plateau and Its Response to Sewage Treatment

Microalgae are pivotal in maintaining water quality in the lakes and rivers of Qinghai-Tibet plateau. The optimum sewage treatment conditions for Desmodesmus sp. Are, temperature: 20–25 °C, light intensity: 3000–8000 lx, and pH: 7.0–7.5, identified based on orthogonal experiments. The maximum removal rate of total nitrogen, total phosphorus, and chemical oxygen demand was more than 95% in the actual sewage treatment. The sewage treatment capacity of Desmodesmus sp. From plateau is higher than that from plains under the same treatment conditions. To identify the differentially expressed genes and metabolites in Desmodesmus sp. In response to sewage treatment, a combination of metabolomics and transcriptomics was employed to the microalgae with and without sewage treatment. The results showed that the oxidative phosphorylation, photosynthesis, and propanoate metabolism pathways were the most significantly enriched pathways in sewage treatment. Furthermore, the metabolism of adenosine diphosphate, 2-oxobutanoate, and succinate were significantly upregulated, downregulated, and both upregulated and downregulated, respectively, as shown by the combined transcriptome and metabolome analysis. Additionally, we found that sewage treatment could also induce numerous changes in the primary metabolism, such as carbohydrate, fatty acid biosynthesis, and amino acid metabolism when compared with control. Overall, our results should improve fundamental knowledge of molecular responses to Desmodesmus sp. in sewage treatment and contribute to the design of strategies in microalgae response to sewage treatment.

Docosahexaenoic Acid Alleviates Brain Damage by Promoting Mitophagy in Mice with Ischaemic Stroke.

Mitophagy, the selective removal of damaged mitochondria through autophagy, is crucial for mitochondrial turnover and quality control. Docosahexaenoic acid (DHA), an essential omega-3 fatty acid, protects mitochondria in various diseases. This study aimed to investigate the neuroprotective role of DHA in ischaemic stroke models in vitro and in vivo and its involvement in mitophagy and mitochondrial dysfunction. A mouse model of ischaemic stroke was established through middle cerebral artery occlusion (MCAO). To simulate ischaemic stroke in vitro, PC12 cells were subjected to oxygen–glucose deprivation (OGD). Immunofluorescence analysis, western blotting (WB), electron microscopy (EM), functional behavioural tests, and Seahorse assay were used for analysis. DHA treatment significantly alleviated the brain infarction volume, neuronal apoptosis, and behavioural dysfunction in mice with ischaemic stroke. In addition, DHA enhanced mitophagy by significantly increasing the number of autophagosomes and LC3-positive mitochondria in neurons. The Seahorse assay revealed that DHA increased glutamate and succinate metabolism in neurons after ischaemic stroke. JC-1 and MitoSox staining, and evaluation of ATP levels indicated that DHA-induced mitophagy alleviated reactive oxygen species (ROS) accumulation and mitochondrial injury. Mechanistically, DHA improved mitochondrial dynamics by increasing the expression of dynamin-related protein 1 (Drp1), LC3, and the mitophagy clearance protein Pink1/Parkin. Mdivi-1, a specific mitophagy inhibitor, abrogated the neuroprotective effects of DHA, indicating that DHA protected neurons by enhancing mitophagy. Therefore, DHA can protect against neuronal apoptosis after stroke by clearing the damaged mitochondria through Pink1/Parkin-mediated mitophagy and by alleviating mitochondrial dysfunction.

An overview about the approaches used in the production of alpha-ketoglutaric acid with their applications

Abstract Alpha ketoglutaric acid is a biological compound found naturally in the human body. It plays an important role in the cell metabolism and has a role in various metabolic pathways including Kreb’s cycle, protein metabolism and so on. Keto glutaric acid is chemically prepared from succinic acid and oxalic acid. It is a direct precursor of glutamic acid and triazines. It can be produced by oxidative decarboxylation of isocitrate by isocitrate dehydrogenase. The yeast Yarrowia lipolytica is used as a prospective producer of alpha ketoglutaric acid from ethanol. The capability to synthesize Keto glutaric acid has so far been investigated for many microorganisms such as Pseudomonas fluoroscens , Bacillus subtilis etc. P. fluoroscens have the ability to synthesize a huge amount of alpha ketoglutaric acid in a glycerol medium supplemented with manganese (Mn). The Mangnese has a significant impact on glycerol metabolism resulting in the buildup of alpha ketoglutaric acid. The metabolism of succinate may result in the production of alpha ketoglutarate. Despite its importance in TCA cycle, alpha ketoglutaric acid buildup as an intermediate product of bacterial glucose oxidation. Along with chemical synthesis and microbial fermentation, enzymatic transformation can also be used to produce alpha ketoglutaric acid. Biodiesel waste is considered as cheap and renewable carbon source for the development of alpha ketoglutaric acid. Alpha ketoglutarate is used for kidney disease, intestinal and stomach disorders and many other conditions. It also plays an important role in the food industry as food and nutrient enhancers. The review is covering all the aspects related with the Alpha ketoglutaric acid production, utilization and product recovery.

Succinate metabolism in cardiovascular diseases

Cardiovascular disease (CVD) refers to a class of diseases related to the heart or blood vessels that have high global incidence. Succinate is generally considered an important intermediate product of the tricarboxylic acid cycle. Recent studies have shown that succinate is related to the pathophysiology of CVD, such as atherosclerosis, acute aortic dissection, hypertension, myocardial ischemia-reperfusion injury, and heart failure. It may represent a potential target or biomarker for CVD. It has been demonstrated that succinate not only participates in various energy metabolic pathways but also plays an important role in various pathophysiological activities as a signaling molecule. Given the significance of metabolism in CVD, it is important to focus on the metabolic regulation mechanism of succinate in CVD. This review outlines the latest evidence pointing to the potential role of succinate in CVD, along with its mechanisms, and updates the current understanding on the role of succinate in CVD. Further studies may focus on identifying succinate, its receptor, and its downstream signaling molecules as new targets for the prevention and treatment of CVD.

Genetic impairment of succinate metabolism disrupts bioenergetic sensing in adrenal neuroendocrine cancer.

Metabolic dysfunction mutations can impair energy sensing and cause cancer. Loss of function of the mitochondrial tricarboxylic acid (TCA) cycle enzyme subunit succinate dehydrogenase B (SDHB) results in various forms of cancer typified by pheochromocytoma (PC). Here we delineate a signaling cascade where the loss of SDHB induces the Warburg effect, triggers dysregulation of [Ca2+]i, and aberrantly activates calpain and protein kinase Cdk5, through conversion of its cofactor from p35 to p25. Consequently, aberrant Cdk5 initiates a phospho-signaling cascade where GSK3 inhibition inactivates energy sensing by AMP kinase through dephosphorylation of the AMP kinase γ subunit, PRKAG2. Overexpression of p25-GFP in mouse adrenal chromaffin cells also elicits this phosphorylation signaling and causes PC. A potent Cdk5 inhibitor, MRT3-007, reverses this phospho-cascade, invoking a senescence-like phenotype. This therapeutic approach halted tumor progression invivo. Thus, we reveal an important mechanistic feature of metabolic sensing and demonstrate that its dysregulation underlies tumor progression in PC and likely other cancers.

Succinate metabolism in the retinal pigment epithelium uncouples respiration from ATP synthesis.

SUMMARYFumarate can be a surrogate for O2 as a terminal electron acceptor in the electron transport chain. Reduction of fumarate produces succinate, which can be exported. It is debated whether intact tissues can import and oxidize succinate produced by other tissues. In a previous report, we showed that mitochondria in retinal pigment epithelium (RPE)-choroid preparations can use succinate to reduce O2 to H2O. However, cells in that preparation could have been disrupted during tissue isolation. We now use multiple strategies to quantify intactness of the isolated RPE-choroid tissue. We find that exogenous 13C4-succinate is oxidized by intact cells then exported as fumarate or malate. Unexpectedly, we also find that oxidation of succinate is different from oxidation of other substrates because it uncouples electron transport from ATP synthesis. Retinas produce and export succinate. Our findings imply that retina succinate may substantially increase O2 consumption by uncoupling adjacent RPE mitochondria.

Cold or Not So Cold?-Static Organ Preservation at 10 °C May Prolong Organ Preservation and Facilitate Transplant Logistics.

Cold or Not So Cold?-Static Organ Preservation at 10 °C May Prolong Organ Preservation and Facilitate Transplant Logistics.

In silico analysis of bacterial metabolism of glutamate and GABA in the gut in a rat model of obesity and type 2 diabetes.

Dysbiosis of gut microbiota has adverse effects on host health. This study aimed to determine the effects of changes of faecal microbiota in obese and diabetic rats on the imputed production of enzymes involved in the metabolism of glutamate, gamma-aminobutyric acid (GABA), and succinate. The levels of glutamate decarboxylase, GABA transaminase, succinate-semialdehyde dehydrogenase, and methylisocitrate lyase were reduced or absent in diabetic rats compared with controls and obese rats. Glutamate decarboxylase (GAD) was significantly reduced in obese rats compared with control rats, while the other enzymes were unaltered; different bacterial taxa are suggested to be involved. Levels of bacterial enzymes were inversely correlated with the blood glucose level. These findings suggest that the absence of GABA and reduced succinate metabolism from gut microbiota contribute to the diabetic state in rats.

Genetic Impairment of Succinate Metabolism Disrupts Bioenergetic Sensing in Adrenal Neuroendocrine Cancer

Genetic Impairment of Succinate Metabolism Disrupts Bioenergetic Sensing in Adrenal Neuroendocrine Cancer

Glucocorticoids coordinate macrophage metabolism through the regulation of the tricarboxylic acid cycle

ObjectivesGlucocorticoids (GCs) are one of the most widely prescribed anti-inflammatory drugs. By acting through their cognate receptor, the glucocorticoid receptor (GR), GCs downregulate the expression of pro-inflammatory genes and upregulate the expression of anti-inflammatory genes. Metabolic pathways have recently been identified as key parts of both the inflammatory activation and anti-inflammatory polarization of macrophages, immune cells responsible for acute inflammation and tissue repair. It is currently unknown whether GCs control macrophage metabolism, and if so, to what extent metabolic regulation by GCs confers anti-inflammatory activity. MethodsUsing transcriptomic and metabolomic profiling of macrophages, we identified GC-controlled pathways involved in metabolism, especially in mitochondrial function. ResultsMetabolic analyses revealed that GCs repress glycolysis in inflammatory myeloid cells and promote tricarboxylic acid (TCA) cycle flux, promoting succinate metabolism and preventing intracellular accumulation of succinate. Inhibition of ATP synthase attenuated GC-induced transcriptional changes, likely through stalling of TCA cycle anaplerosis. We further identified a glycolytic regulatory transcription factor, HIF1α, as regulated by GCs, and as a key regulator of GC responsiveness during inflammatory challenge. ConclusionsOur findings link metabolism to gene regulation by GCs in macrophages.

Stable Isotope-Resolved Metabolomics Studies on Corticosteroid-Induced PC12 Cells: A Strategy for Evaluating Glucose Catabolism in an in Vitro Model of Depression.

Depression is a common psychopathological state or mood disorder syndrome. The serious risks to human life and the inadequacy of the existing antidepressant drugs have driven us to understand the pathogenesis of depression from a new perspective. Our research group has found disturbances in glucose catabolism in both depression and nephrotic syndrome. What are the specific metabolic pathways and specificities of glucose catabolism disorders caused by depression? To address the above scientific questions, we creatively combined traditional metabolomics technology with stable isotope-resolved metabolomics to research the glucose catabolism of the corticosterone-induced PC12 cell damage model and the adriamycin-induced glomerular podocyte damage model. The results showed an increased flux of pyruvate metabolism in depression. The increased flux of pyruvate metabolism led to an activation of gluconeogenesis in depression. The disturbed upstream metabolism of succinate caused the tricarboxylic acid cycle (TCA cycle) to be blocked in depression. In addition, there were metabolic disturbances in the purine metabolism and pentose phosphate pathways in depression. Compared with nephrotic syndrome, pyruvate metabolism, the TCA cycle, and gluconeogenesis metabolism in depression were specific. The metabolic pathways researched above are likely to be important targets for the efficacy of antidepressants.

Mitochondrial Succinate Metabolism and Reactive Oxygen Species Are Important but Not Essential for Eliciting Carotid Body and Ventilatory Responses to Hypoxia in the Rat.

Reflex increases in breathing in response to acute hypoxia are dependent on activation of the carotid body (CB)—A specialised peripheral chemoreceptor. Central to CB O2-sensing is their unique mitochondria but the link between mitochondrial inhibition and cellular stimulation is unresolved. The objective of this study was to evaluate if ex vivo intact CB nerve activity and in vivo whole body ventilatory responses to hypoxia were modified by alterations in succinate metabolism and mitochondrial ROS (mitoROS) generation in the rat. Application of diethyl succinate (DESucc) caused concentration-dependent increases in chemoafferent frequency measuring approximately 10–30% of that induced by severe hypoxia. Inhibition of mitochondrial succinate metabolism by dimethyl malonate (DMM) evoked basal excitation and attenuated the rise in chemoafferent activity in hypoxia. However, approximately 50% of the response to hypoxia was preserved. MitoTEMPO (MitoT) and 10-(6′-plastoquinonyl) decyltriphenylphosphonium (SKQ1) (mitochondrial antioxidants) decreased chemoafferent activity in hypoxia by approximately 20–50%. In awake animals, MitoT and SKQ1 attenuated the rise in respiratory frequency during hypoxia, and SKQ1 also significantly blunted the overall hypoxic ventilatory response (HVR) by approximately 20%. Thus, whilst the data support a role for succinate and mitoROS in CB and whole body O2-sensing in the rat, they are not the sole mediators. Treatment of the CB with mitochondrial selective antioxidants may offer a new approach for treating CB-related cardiovascular–respiratory disorders.

Aronia berry polyphenols have matrix-dependent effects on the gut microbiota

The objective of this study was to determine the extent that the aronia berry matrix affects gut microbiota composition, fecal short chain fatty acids (SCFAs), and colonic anthocyanins in healthy mice. C57BL/6J mice were fed AIN-93 M control diet (C) or C with whole aronia berry (AB), aronia extract (AE), or polyphenol-depleted AB (D) at the expense of cornstarch. After one week of feeding, AB and D increased fecal anthocyanins more than AE. Diets differentially affected SCFA and microbiota. AB fecal SCFA was associated with increased metabolism of succinate and pyruvate to butyrate. D increased acetic acid production, was associated with increased abundance of predicted genes for fermentation of carbohydrates to acetyl-coA. AB and D also increased predicted abundance of microbial catechol metabolism pathway I relative to C, which was attributed to enrichment of Lachnospiraceae. Therefore, the berry matrix impacts how aronia polyphenols interact with the gut microbiota in healthy mice.

Succinate Pathway in Head and Neck Squamous Cell Carcinoma: Potential as a Diagnostic and Prognostic Marker.

Simple SummaryEmerging evidence points to succinate as an important oncometabolite in cancer development; however, the contribution of the succinate-SUCNR1 axis to cancer progression remains unclear. Head and neck squamous cell carcinoma (HNSCC) is associated with disease and treatment-related morbidity so there is an urgent need for innovation in treatment and diagnosis practices. Our aim was to evaluate the potential of the succinate-related pathway as a diagnostic and prognostic biomarker in HNSCC. The circulating succinate levels are increased in HNSCC, being a potential noninvasive biomarker for HNSCC diagnosis. Moreover, the succinate receptor (SUCNR1) and genes related to succinate metabolism, which are predominantly expressed in the tumoral mucosa as compared with healthy tissue, are positively associated with plasma succinate. Remarkably, we found that SUCNR1 and SDHA expression levels predict prognosis.Head and neck squamous cell carcinoma (HNSCC) is characterized by high rates of mortality and treatment-related morbidity, underscoring the urgent need for innovative and safe treatment strategies and diagnosis practices. Mitochondrial dysfunction is a hallmark of cancer and can lead to the accumulation of tricarboxylic acid cycle intermediates, such as succinate, which function as oncometabolites. In addition to its role in cancer development through epigenetic events, succinate is an extracellular signal transducer that modulates immune response, angiogenesis and cell invasion by activating its cognate receptor SUCNR1. Here, we explored the potential value of the circulating succinate and related genes in HNSCC diagnosis and prognosis. We determined the succinate levels in the serum of 66 pathologically confirmed, untreated patients with HNSCC and 20 healthy controls. We also surveyed the expression of the genes related to succinate metabolism and signaling in tumoral and nontumoral adjacent tissue and in normal mucosa from 50 patients. Finally, we performed immunohistochemical analysis of SUCNR1 in mucosal samples. The results showed that the circulating levels of succinate were higher in patients with HNSCC than in the healthy controls. Additionally, the expression of SUCNR1, HIF-1α, succinate dehydrogenase (SDH) A, and SDHB was higher in the tumor tissue than in the matched normal mucosa. Consistent with this, immunohistochemical analysis revealed an increase in SUCNR1 protein expression in tumoral and nontumoral adjacent tissue. High SUCNR1 and SDHA expression levels were associated with poor locoregional control, and the locoregional recurrence-free survival rate was significantly lower in patients with high SUCNR1 and SDHA expression than in their peers with lower levels (77.1% [95% CI: 48.9–100.0] vs. 16.7% [95% CI: 0.0–44.4], p = 0.018). Thus, the circulating succinate levels are elevated in HNSCC and high SUCNR1/SDHA expression predicts poor locoregional disease-free survival, identifying this oncometabolite as a potentially valuable noninvasive biomarker for HNSCC diagnosis and prognosis.

Targeting alveolar-specific succinate dehydrogenase A attenuates pulmonary inflammation during acute lung injury.

Acute lung injury (ALI) is an inflammatory lung disease, which manifests itself in patients as acute respiratory distress syndrome (ARDS). Previous studies have implicated alveolar‐epithelial succinate in ALI protection. Therefore, we hypothesized that targeting alveolar succinate dehydrogenase SDH A would result in elevated succinate levels and concomitant lung protection. Wild‐type (WT) mice or transgenic mice with targeted alveolar‐epithelial Sdha or hypoxia‐inducible transcription factor Hif1a deletion were exposed to ALI induced by mechanical ventilation. Succinate metabolism was assessed in alveolar‐epithelial via mass spectrometry as well as redox measurements and evaluation of lung injury. In WT mice, ALI induced by mechanical ventilation decreased SDHA activity and increased succinate in alveolar‐epithelial. In vitro, cell‐permeable succinate decreased epithelial inflammation during stretch injury. Mice with inducible alveolar‐epithelial Sdha deletion (Sdhaloxp/loxp SPC‐CreER mice) revealed reduced lung inflammation, improved alveolar barrier function, and attenuated histologic injury. Consistent with a functional role of succinate to stabilize HIF, Sdhaloxp/loxp SPC‐CreER experienced enhanced Hif1a levels during hypoxia or ALI. Conversely, Hif1aloxp/loxp SPC‐CreER showed increased inflammation with ALI induced by mechanical ventilation. Finally, wild‐type mice treated with intra‐tracheal dimethlysuccinate were protected during ALI. These data suggest that targeting alveolar‐epithelial SDHA dampens ALI via succinate‐mediated stabilization of HIF1A. Translational extensions of our studies implicate succinate treatment in attenuating alveolar inflammation in patients suffering from ARDS.

Succinate Metabolism in the Retinal Pigment Epithelium Uncouples Respiration from ATP Synthesis

Succinate Metabolism in the Retinal Pigment Epithelium Uncouples Respiration from ATP Synthesis

Botrytis cinerea methyl isocitrate lyase mediates oxidative stress tolerance and programmed cell death by modulating cellular succinate levels

Fungi lack the entire animal core apoptotic machinery. Nevertheless, regulated cell death with apoptotic markers occurs in multicellular as well as in unicellular fungi and is essential for proper fungal development and stress adaptation. The discrepancy between appearance of an apoptotic-like regulated cell death (RCD) in the absence of core apoptotic machinery is further complicated by the fact that heterologous expression of animal apoptotic genes in fungi affects fungal RCD. Here we describe the role of BcMcl, a methyl isocitrate lyase from the plant pathogenic fungus Botrytis cinerea, in succinate metabolism, and the connection of succinate with stress responses and cell death. Over expression of bcmcl resulted in elevated tolerance to oxidative stress and reduced levels of RCD, which were associated with accumulation of elevated levels of succinate. Deletion of bcmcl had almost no effect on fungal development or stress sensitivity, and succinate levels were unchanged in the deletion strain. Gene expression experiments showed co-regulation of bcmcl and bcicl (isocitrate lyase); expression of the bcicl gene was enhanced in bcmcl deletion and suppressed in bcmcl over expression strains. External addition of succinate reproduced the phenotypes of the bcmcl over expression strains, including developmental defects, reduced virulence, and improved oxidative stress tolerance. Collectively, our results implicate mitochondria metabolic pathways, and in particular succinate metabolism, in regulation of fungal stress tolerance, and highlight the role of this onco-metabolite as potential mediator of fungal RCD.

Hypothermic oxygenated perfusion protects from mitochondrial injury before liver transplantation.

BackgroundMitochondrial succinate accumulation has been suggested as key event for ischemia reperfusion injury in mice. No specific data are however available on behavior of liver mitochondria during ex situ machine perfusion in clinical transplant models.MethodsWe investigated mitochondrial metabolism of isolated perfused rat livers before transplantation. Livers were exposed to warm and cold ischemia to simulate donation after circulatory death (DCD) and organ transport. Subsequently, livers were perfused with oxygenated Belzer-MPS for 1h, at hypothermic or normothermic conditions. Various experiments were performed with supplemented succinate and/or mitochondrial inhibitors. The perfusate, liver tissues, and isolated mitochondria were analyzed by mass-spectroscopy and fluorimetry. Additionally, rat DCD livers were transplanted after 1h hypothermic or normothermic oxygenated perfusion. In parallel, perfusate samples were analysed during HOPE-treatment of human DCD livers before transplantation.FindingsSuccinate exposure during rat liver perfusion triggered a dose-dependent release of mitochondrial Flavin-Mononucleotide (FMN) and NADH in perfusates under normothermic conditions. In contrast, perfusate FMN was 3-8 fold lower under hypothermic conditions, suggesting less mitochondrial injury during cold re-oxygenation compared to normothermic conditions. HOPE-treatment induced a mitochondrial reprogramming with uploading of the nucleotide pool and effective succinate metabolism. This resulted in a clear superiority after liver transplantation compared to normothermic perfusion. Finally, the degree of mitochondrial injury during HOPE of human DCD livers, quantified by perfusate FMN and NADH, was predictive for liver function.InterpretationMitochondrial injury determines outcome of transplanted rodent and human livers. Hypothermic oxygenated perfusion improves mitochondrial function, and allows viability assessment of liver grafts before implantation.Fundingdetailed information can be found in Acknowledgments.

EGFR-upregulated LIFR promotes SUCLG2-dependent castration resistance and neuroendocrine differentiation of prostate cancer.

Neuroendocrine (NE) differentiation is a well-recognized phenotypic change of prostate cancer after androgen deprivation therapy (ADT), and it ultimately develops into an aggressive subset of this disease. However, the contribution of signaling pathways that lead to metabolic disorders and NE differentiation of prostate cancer remains unclear. In this study, we identified that ADT induced upregulation of the succinate-CoA ligase GDP-forming beta subunit (SUCLG2), which regulates succinate metabolism and NE differentiation of prostate cancer. We demonstrated a connection that upregulation of epidermal growth factor receptor (EGFR)-leukemia inhibitory factor receptor (LIFR) signaling induced SUCLG2 expression in prostate cancer cells. The LIFR is upregulated by nuclear EGFR, which acts as a transcriptional regulator, directly binds to the LIFR promoter, and drives NE differentiation and glycolysis of prostate cancer. LIFR upregulation is associated with SUCLG2, which increased succinate synthesis and enzymatic activities of mitochondrial nucleoside diphosphate kinase (NDPK) in prostate cancer cells. Knockdown of SUCLG2 suppressed NE differentiation in cultured cells and reduced prostate tumor growth in a xenograft model. Analysis of prostate tissue samples showed increased intensity of nuclear EGFR associated with the LIFR and SUCLG2 in castration-resistant prostate cancer tumors. Our study provides a mechanism whereby ADT upregulates EGFR-LIFR signaling that activates SUCLG2, which subsequently stimulates the metabolic changes associated with NE differentiation and aggressive prostate cancer phenotype.