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Author(s): Kim Vriens [sup.1] [sup.2] , Stefan Christen [sup.1] [sup.2] , Sweta Parik [sup.1] [sup.2] [sup.3] [sup.4] , Dorien Broekaert [sup.1] [sup.2] , Kazuaki Yoshinaga [sup.5] [sup.6] , Ali Talebi [...], Most tumours have an aberrantly activated lipid metabolism.sup.1,2 that enables them to synthesize, elongate and desaturate fatty acids to support proliferation. However, only particular subsets of cancer cells are sensitive to approaches that target fatty acid metabolism and, in particular, fatty acid desaturation.sup.3. This suggests that many cancer cells contain an unexplored plasticity in their fatty acid metabolism. Here we show that some cancer cells can exploit an alternative fatty acid desaturation pathway. We identify various cancer cell lines, mouse hepatocellular carcinomas, and primary human liver and lung carcinomas that desaturate palmitate to the unusual fatty acid sapienate to support membrane biosynthesis during proliferation. Accordingly, we found that sapienate biosynthesis enables cancer cells to bypass the known fatty acid desaturation pathway that is dependent on stearoyl-CoA desaturase. Thus, only by targeting both desaturation pathways is the in vitro and in vivo proliferation of cancer cells that synthesize sapienate impaired. Our discovery explains metabolic plasticity in fatty acid desaturation and constitutes an unexplored metabolic rewiring in cancers. In several human and mouse cancer cell lines and carcinomas, a sapienate biosynthesis pathway underpins metabolic plasticity by allowing these cells to bypass stearoyl-CoA desaturase-dependent fatty acid desaturation.

Acquired tracheo-oesophageal fistulas (TEFs) are rare and challenging complications in the course of oesophageal cancer. While surgery is the only curative treatment option for TEFs many patients are not eligible for surgery. Endoscopic treatment approaches such as tracheal-and/or oesophageal-stenting are available, but associated with complications like the development of new fistulas and mucus retention. Offlabel- use of cardiac amplatzer occluder devices to close TEFs has been reported in few case-reports with inconsistent short-term outcomes. We report a case of successful closure of two adjacent TEFs with two partially overlapping cardiac amplatzer occluder devices. The insertion of a 12 mm and a 9 mm device was successful and without complications. The patient tolerated the cardiac amplatzer-devices well and could resume oral food uptake after 2 months. Two years after closure, the patient remained free of symptoms suggesting complete sealing of the fistulas. [ABSTRACT FROM AUTHOR]

Angiogenesis relies on the proliferation and migration of endothelial cells (1). The importance of endothelial cell proliferation for expansive growth of the vascular network has long been recognized (2). While [...], The metabolism of endothelial cells during vessel sprouting remains poorly studied. Here we report that endothelial loss of CPT1A, a rate-limiting enzyme of fatty acid oxidation (FAO), causes vascular sprouting defects due to impaired proliferation, not migration, of human and murine endothelial cells. Reduction of FAO in endothelial cells did not cause energy depletion or disturb redox homeostasis, but impaired de novo nucleotide synthesis for DNA replication. Isotope labelling studies in control endothelial cells showed that fatty acid carbons substantially replenished the Krebs cycle, and were incorporated into aspartate (a nucleotide precursor), uridine monophosphate (a precursor of pyrimidine nucleoside triphosphates) and DNA. CPT1A silencing reduced these processes and depleted endothelial cell stores of aspartate and deoxyribonucleoside triphosphates. Acetate (metabolized to acetyl-CoA, thereby substituting for the depleted FAO-derived acetyl-CoA) or a nucleoside mix rescued the phenotype of CPT1A-silenced endothelial cells. Finally, CPT1 blockade inhibited pathological ocular angiogenesis in mice, suggesting a novel strategy for blocking angiogenesis.

Aims: Elderly patients with sinus node dysfunction (SND) are at increased risk of falls with possible injuries. However, the incidence of these adverse events and its reduction after permanent pacemaker (PPM) implantation are not known.Methods and Results: Eighty-seven patients (mean [SD] age 75.4 [8.3] years, 51% women) with SND and an indication for cardiac pacing were included and were examined by a standardized interview targeting fall history. The incidence and total number of falls, falls with injury, falls requiring treatment, and falls resulting in a fracture were assessed for the time period of 12 months before (retrospectively) and after PPM implantation (prospectively). Furthermore, symptoms such as syncope, dizziness, and dyspnea were evaluated before and after PPM implantation. The implantation of a PPM was associated with a reduced proportion of patients experiencing at least one fall by 71% (from 53 to 15%, P < 0.001) and a reduction of the absolute number of falls by 90% (from 127 to 13, P < 0.001) during the 12 months before vs. after PPM implant. Falls with injury (28 vs. 10%, P = 0.005), falls requiring medical attention (31 vs. 8%, P < 0.001), and falls leading to fracture (8 vs. 0%, P = 0.013) were similarly reduced. Notably, fewer patients had syncope (4 vs. 45%, P < 0.001) and dizziness after PPM implantation (12 vs. 45%, P < 0.001).Conclusion: Falls, fall-related injuries, and fall-related fractures are frequent in SND patients. Permanent pacemaker implantation is associated with a significantly reduced risk of these adverse events, although no causal relationship could be established due to the study design. [ABSTRACT FROM AUTHOR]

Summary Cellular proliferation depends on refilling the tricarboxylic acid (TCA) cycle to support biomass production (anaplerosis). The two major anaplerotic pathways in cells are pyruvate conversion to oxaloacetate via pyruvate carboxylase (PC) and glutamine conversion to α-ketoglutarate. Cancers often show an organ-specific reliance on either pathway. However, it remains unknown whether they adapt their mode of anaplerosis when metastasizing to a distant organ. We measured PC-dependent anaplerosis in breast-cancer-derived lung metastases compared to their primary cancers using in vivo 13 C tracer analysis. We discovered that lung metastases have higher PC-dependent anaplerosis compared to primary breast cancers. Based on in vitro analysis and a mathematical model for the determination of compartment-specific metabolite concentrations, we found that mitochondrial pyruvate concentrations can promote PC-dependent anaplerosis via enzyme kinetics. In conclusion, we show that breast cancer cells proliferating as lung metastases activate PC-dependent anaplerosis in response to the lung microenvironment. [ABSTRACT FROM AUTHOR]

Cancer cells reprogram their metabolism to promote growth and proliferation. The genetic evidence pointing to the importance of the amino acid serine in tumorigenesis is striking. The gene encoding the enzyme 3-phosphoglycerate dehydrogenase (PHGDH), which catalyzes the first committed step of serine biosynthesis, is overexpressed in tumors and cancer cell lines via focal amplification and nuclear factor erythroid-2-related factor 2 (NRF2)-mediated up-regulation. PHGDH-overexpressing cells are exquisitely sensitive to genetic ablation of the pathway. Here, we report the discovery of a selective small molecule inhibitor of PHGDH, CBR-5884, identified by screening a library of 800,000 drug-like compounds. CBR-5884 inhibited de novo serine synthesis in cancer cells and was selectively toxic to cancer cell lines with high serine biosynthetic activity. Biochemical characterization of the inhibitor revealed that it was a noncompetitive inhibitor that showed a time-dependent onset of inhibition and disrupted the oligomerization state of PHGDH. The identification of a small molecule inhibitor of PHGDH not only enables thorough preclinical evaluation of PHGDH as a target in cancers, but also provides a tool with which to study serine metabolism. [ABSTRACT FROM AUTHOR]

Metabolic alterations have emerged as an important hallmark in the development of various diseases. Thus, understanding the complex interplay of metabolism with other cellular processes such as cell signalling is critical to rationally control and modulate cellular physiology. Here, we review in the context of mammalian target of rapamycin, AMP-activated protein kinase and p53, the orchestrated interplay between metabolism and cellular signalling as well as transcriptional regulation. Moreover, we discuss recent discoveries in auto-regulation of metabolism ( i.e. how metabolic parameters such as metabolite levels activate or inhibit enzymes and thus metabolic pathways). Finally, we review functional consequences of post-translational modification on metabolic enzyme abundance and/or activities. [ABSTRACT FROM AUTHOR]

Key distinguishing characteristics of yeast glucose metabolism are the relative proportions of fermentation and respiration. Crabtree-positive yeast species exhibit a respirofermentative metabolism, whereas aerobic species respire fully without secretion of fermentation byproducts. Physiological data suggest a gradual transition in different species between these two states. Here, we investigate whether this gradual transition also occurs at the intracellular level by quantifying the intracellular metabolism of Saccharomyces cerevisiae, Saccharomyces bayanus, Saccharomyces exiguus, Kluyveromyces thermotolerans, Yarrowia lipolytica, Pichia angusta and Candida rugosa by C-flux analysis and metabolomics. Different from the extracellular physiology, the intracellular fluxes through the tricarboxylic acid cycle fall into two classes where the aerobic species exhibit much higher respiratory fluxes at otherwise similar glycolytic fluxes. More generally, we found the intracellular metabolite concentrations to be primarily species-specific. The sole exception of a metabolite-flux correlation in a species-overarching manner was found for fructose-1,6-bisphosphate and dihydroxyacetone-phosphate, indicating a conservation of the functional properties around these two metabolites. [ABSTRACT FROM AUTHOR]

Nicotinamide adenine dinucleotide (NAD+) and its reduced form (NADH) are coenzymes employed in hundreds of metabolic reactions. NAD+ also serves as a substrate for enzymes such as sirtuins, poly(ADP-ribose) polymerases (PARPs) and ADP-ribosyl cyclases. Given the pivotal role of NAD(H) in health and disease, studying NAD+ metabolism has become essential to monitor genetic- and/or drug-induced perturbations related to metabolic status and diseases (such as ageing, cancer or obesity), and its possible therapies. Here, we present a strategy based on liquid chromatography-tandem mass spectrometry (LC-MS/MS), for the analysis of the NAD+ metabolome in biological samples. In this method, hydrophilic interaction chromatography (HILIC) was used to separate a total of 18 metabolites belonging to pathways leading to NAD+ biosynthesis, including precursors, intermediates and catabolites. As redox cofactors are known for their instability, a sample preparation procedure was developed to handle a variety of biological matrices: cell models, rodent tissues and biofluids, as well as human biofluids (urine, plasma, serum, whole blood). For clinical applications, quantitative LC-MS/MS for a subset of metabolites was demonstrated for the analysis of the human whole blood of nine volunteers. Using this developed workflow, our methodology allows studying NAD+ biology from mechanistic to clinical applications. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to an article related to the mutations in genes in a previous issue.

Metastases are the leading cause of mortality in patients with cancer. Metastasis formation requires cancer cells to adapt their cellular phenotype. However, how metabolism supports this adaptation of cancer cells is poorly defined. We use 2D versus 3D cultivation to induce a shift in the cellular phenotype of breast cancer cells. We discover that proline catabolism via proline dehydrogenase (Prodh) supports growth of breast cancer cells in 3D culture. Subsequently, we link proline catabolism to in vivo metastasis formation. In particular, we find that PRODH expression and proline catabolism is increased in metastases compared to primary breast cancers of patients and mice. Moreover, inhibiting Prodh is sufficient to impair formation of lung metastases in the orthotopic 4T1 and EMT6.5 mouse models, without adverse effects on healthy tissue and organ function. In conclusion, we discover that Prodh is a potential drug target for inhibiting metastasis formation. [ABSTRACT FROM AUTHOR]

A correction is presented to the article "Fatty Acid Carbon Is Essential for dNTP Synthesis in Endothelial Cells" by Sandra Schoors, Gitte Borgers, Ilaria Elia, and others in volume 520 of the journal, noting a possible confusion regarding the Krebs cycle and anaplerosis.

Abstract: Objective: Secondary prevention for coronary heart disease is achieved by pharmaceutical control of risk factors and patients’ own self management behaviour. To comply with longterm treatment patients need sufficient knowledge of their condition and should be satisfied with acute care. Therefore a questionnaire measuring both issues was constructed. Methods and results: Latent class analysis applied in a sample of over 2000 patients suffering from acute coronary syndrome revealed 4 configurative patterns of knowledge and 5 distinct patterns of (dis-)satisfaction. Nearly 50% of all patients displayed insufficient knowledge upon discharge. Deficits clustered around misinformation on necessary lifestyle changes versus dysfunctional strategies for future emergency situations. Satisfaction and disease specific knowledge were interrelated in complex patterns. Conclusions: Disease specific knowledge and satisfaction with treatment proved to be psychometrically valid indicators of the quality of the treatment process that might also have an impact on outcome. Practice implications: A validated questionnaire is ready for routine administration after discharge of patients with acute coronary syndrome from acute hospital care. Patient education efforts and quality improvement in treatment centres might be effectively monitored using this questionnaire. [Copyright &y& Elsevier]

SLC25A32 is a member of the solute carrier 25 family of mitochondrial transporters. SLC25A32 transports tetrahydrofolate (THF) as well as FAD into mitochondria and regulates mitochondrial one-carbon metabolism and redox balance. While it is known that cancer cells require one-carbon and FAD-dependent mitochondrial metabolism to sustain cell proliferation, the role of SLC25A32 in cancer cell growth remains unexplored. Our results indicate that the SLC25A32 gene is highly amplified in different tumors and that amplification correlates with increased mRNA expression and reduced patients´ survival. siRNA-mediated knock-down and CRISPR-mediated knock-out of SLC25A32 in cancer cells of different origins, resulted in the identification of cell lines sensitive and resistant to SLC25A32 inhibition. Mechanistically, tracing of deuterated serine revealed that SLC25A32 knock-down does not affect the mitochondrial/cytosolic folate flux as measured by Liquid Chromatography coupled Mass Spectrometry (LC-MS). Instead, SLC25A32 inhibition results in a respiratory chain dysfunction at the FAD-dependent complex II enzyme, induction of Reactive Oxygen Species (ROS) and depletion of reduced glutathione (GSH), which impairs cancer cell proliferation. Moreover, buthionine sulfoximine (BSO) treatment further sensitizes cells to ROS-mediated inhibition of cell proliferation upon SLC25A32 knock-down. Treatment of cells with the FAD precursor riboflavin and with GSH rescues cancer cell proliferation upon SLC25A32 down-regulation. Our results indicate that the reduction of mitochondrial FAD concentrations by targeting SLC25A32 has potential clinical applications as a single agent or in combination with approved cancer drugs that lead to increased oxidative stress and reduced tumor growth., Competing Interests: CONFLICTS OF INTEREST The authors have declared no conflicts of interest., (Copyright: © 2020 Santoro et al.)

Glutamine metabolism provides synergistic support for macrophage activation and elicitation of desirable immune responses; however, the underlying mechanisms regulated by glutamine metabolism to orchestrate macrophage activation remain unclear. Here we show that the production of α-ketoglutarate (αKG) via glutaminolysis is important for alternative (M2) activation of macrophages, including engagement of fatty acid oxidation (FAO) and Jmjd3-dependent epigenetic reprogramming of M2 genes. This M2-promoting mechanism is further modulated by a high αKG/succinate ratio, whereas a low ratio strengthens the proinflammatory phenotype in classically activated (M1) macrophages. As such, αKG contributes to endotoxin tolerance after M1 activation. This study reveals new mechanistic regulations by which glutamine metabolism tailors the immune responses of macrophages through metabolic and epigenetic reprogramming.

Aims: Elderly patients with sinus node dysfunction (SND) are at increased risk of falls with possible injuries. However, the incidence of these adverse events and its reduction after permanent pacemaker (PPM) implantation are not known., Methods and Results: Eighty-seven patients (mean [SD] age 75.4 [8.3] years, 51% women) with SND and an indication for cardiac pacing were included and were examined by a standardized interview targeting fall history. The incidence and total number of falls, falls with injury, falls requiring treatment, and falls resulting in a fracture were assessed for the time period of 12 months before (retrospectively) and after PPM implantation (prospectively). Furthermore, symptoms such as syncope, dizziness, and dyspnea were evaluated before and after PPM implantation. The implantation of a PPM was associated with a reduced proportion of patients experiencing at least one fall by 71% (from 53 to 15%, P < 0.001) and a reduction of the absolute number of falls by 90% (from 127 to 13, P < 0.001) during the 12 months before vs. after PPM implant. Falls with injury (28 vs. 10%, P = 0.005), falls requiring medical attention (31 vs. 8%, P < 0.001), and falls leading to fracture (8 vs. 0%, P = 0.013) were similarly reduced. Notably, fewer patients had syncope (4 vs. 45%, P < 0.001) and dizziness after PPM implantation (12 vs. 45%, P < 0.001)., Conclusion: Falls, fall-related injuries, and fall-related fractures are frequent in SND patients. Permanent pacemaker implantation is associated with a significantly reduced risk of these adverse events, although no causal relationship could be established due to the study design., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.)

The regulation of gene expression in response to nutrient availability is fundamental to the genotype-phenotype relationship. The metabolic-genetic make-up of the cell, as reflected in auxotrophy, is hence likely to be a determinant of gene expression. Here, we address the importance of the metabolic-genetic background by monitoring transcriptome, proteome and metabolome in a repertoire of 16 Saccharomyces cerevisiae laboratory backgrounds, combinatorially perturbed in histidine, leucine, methionine and uracil biosynthesis. The metabolic background affected up to 85% of the coding genome. Suggesting widespread confounding, these transcriptional changes show, on average, 83% overlap between unrelated auxotrophs and 35% with previously published transcriptomes generated for non-metabolic gene knockouts. Background-dependent gene expression correlated with metabolic flux and acted, predominantly through masking or suppression, on 88% of transcriptional interactions epistatically. As a consequence, the deletion of the same metabolic gene in a different background could provoke an entirely different transcriptional response. Propagating to the proteome and scaling up at the metabolome, metabolic background dependencies reveal the prevalence of metabolism-dependent epistasis at all regulatory levels. Urging a fundamental change of the prevailing laboratory practice of using auxotrophs and nutrient supplemented media, these results reveal epistatic intertwining of metabolism with gene expression on the genomic scale., Competing Interests: The authors declare no competitive interests.

Targeting cancer metabolism has the potential to lead to major advances in tumor therapy. Numerous promising metabolic drug targets have been identified. Yet, it has emerged that there is no singular metabolism that defines the oncogenic state of the cell. Rather, the metabolism of cancer cells is a function of the requirements of a tumor. Hence, the tissue of origin, the (epi)genetic drivers, the aberrant signaling, and the microenvironment all together define these metabolic requirements. In this chapter we discuss in light of (epi)genetic, signaling, and environmental factors the diversity in cancer metabolism based on triple-negative and estrogen receptor-positive breast cancer, early- and late-stage prostate cancer, and liver cancer. These types of cancer all display distinct and partially opposing metabolic behaviors (e.g., Warburg versus reverse Warburg metabolism). Yet, for each of the cancers, their distinct metabolism supports the oncogenic phenotype. Finally, we will assess the therapeutic potential of metabolism based on the concepts of metabolic normalization and metabolic depletion.

Metabolite exchange among co-growing cells is frequent by nature, however, is not necessarily occurring at growth-relevant quantities indicative of non-cell-autonomous metabolic function. Complementary auxotrophs of Saccharomyces cerevisiae amino acid and nucleotide metabolism regularly fail to compensate for each other's deficiencies upon co-culturing, a situation which implied the absence of growth-relevant metabolite exchange interactions. Contrastingly, we find that yeast colonies maintain a rich exometabolome and that cells prefer the uptake of extracellular metabolites over self-synthesis, indicators of ongoing metabolite exchange. We conceived a system that circumvents co-culturing and begins with a self-supporting cell that grows autonomously into a heterogeneous community, only able to survive by exchanging histidine, leucine, uracil, and methionine. Compensating for the progressive loss of prototrophy, self-establishing communities successfully obtained an auxotrophic composition in a nutrition-dependent manner, maintaining a wild-type like exometabolome, growth parameters, and cell viability. Yeast, as a eukaryotic model, thus possesses extensive capacity for growth-relevant metabolite exchange and readily cooperates in metabolism within progressively establishing communities.

Objective: We investigated the prevalence of bronchial asthma in patients with Tako-Tsubo Syndrome (TTS)., Design: This retrospective case-series study was conducted in a primary care hospital in Zurich, Switzerland. Data of all patients with newly diagnosed TTS (2002 - 2012) were assessed electronically by the use of ICD-10. Asthma prevalence was compared to published epidemiologic data., Setting: Bronchial asthma is characterized by airway inflammation and, during attack, release of endogenous catecholamines. Sympathomimetic drugs are the mainstay of treatment for asthma patients. Likewise, catecholamine mediated diffuse microvascular myocardial dysfunction seems to be of critical importance for the development of TTS., Results: 20 cases of TTS were identified. 90% were female, showed a median age of 70±13y [25y - 90y], an apical and/or midventricular ballooning pattern with preserved basal function and a median initial LVEF of 34±9% [25% - 55%]. 65% of patients underwent coronary angiography to rule out significant coronary artery disease. Hypertension was present in 45% of patients, 35% were smokers, none was suffering from diabetes. Prevalence of asthma in patients with TTS was significantly higher compared to the normal population (25% vs. 7%, p=0.012). In 30% of the TTS patients an iatrogenic cause for development of TTS was identified., Conclusion: Prevalence of asthma was significantly higher in patients with TTS compared to epidemiologic data from an age-matched population. Phenotypes of patients developing obstructive ventilatory disease and TTS might share common pathogenic mechanisms beyond the use of bronchodilatators. In addition, we identified other iatrogenic etiologies in patients with TTS.

Aneuploidy, a chromosome content that is not a multiple of the haploid karyotype, is associated with reduced fitness in all organisms analyzed to date. In budding yeast aneuploidy causes cell proliferation defects, with many different aneuploid strains exhibiting a delay in G1, a cell cycle stage governed by extracellular cues, growth rate, and cell cycle events. Here we characterize this G1 delay. We show that 10 of 14 aneuploid yeast strains exhibit a growth defect during G1. Furthermore, 10 of 14 aneuploid strains display a cell cycle entry delay that correlates with the size of the additional chromosome. This cell cycle entry delay is due to a delayed accumulation of G1 cyclins that can be suppressed by supplying cells with high levels of a G1 cyclin. Our results indicate that aneuploidy frequently interferes with the ability of cells to grow and, as with many other cellular stresses, entry into the cell cycle.