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Enzymes that catalyse CpG methylation in DNA, including the DNA methyltransferases 1 (DNMT1), 3A (DNMT3A) and 3B (DNMT3B), are indispensable for mammalian tissue development and homeostasis1-4. They are also implicated in human developmental disorders and cancers5-8, supporting the critical role of DNA methylation in the specification and maintenance of cell fate. Previous studies have suggested that post-translational modifications of histones are involved in specifying patterns of DNA methyltransferase localization and DNA methylation at promoters and actively transcribed gene bodies9-11. However, the mechanisms that control the establishment and maintenance of intergenic DNA methylation remain poorly understood. Tatton-Brown-Rahman syndrome (TBRS) is a childhood overgrowth disorder that is defined by germline mutations in DNMT3A. TBRS shares clinical features with Sotos syndrome (which is caused by haploinsufficiency of NSD1, a histone methyltransferase that catalyses the dimethylation of histone H3 at K36 (H3K36me2)8,12,13), which suggests that there is a mechanistic link between these two diseases. Here we report that NSD1-mediated H3K36me2 is required for the recruitment of DNMT3A and maintenance of DNA methylation at intergenic regions. Genome-wide analysis shows that the binding and activity of DNMT3A colocalize with H3K36me2 at non-coding regions of euchromatin. Genetic ablation of Nsd1 and its paralogue Nsd2 in mouse cells results in a redistribution of DNMT3A to H3K36me3-modified gene bodies and a reduction in the methylation of intergenic DNA. Blood samples from patients with Sotos syndrome and NSD1-mutant tumours also exhibit hypomethylation of intergenic DNA. The PWWP domain of DNMT3A shows dual recognition of H3K36me2 and H3K36me3 in vitro, with a higher binding affinity towards H3K36me2 that is abrogated by TBRS-derived missense mutations. Together, our study reveals a trans-chromatin regulatory pathway that connects aberrant intergenic CpG methylation to human neoplastic and developmental overgrowth.
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DNA (Citosina-5-)-Metiltransferases/metabolismo , Metilação de DNA , DNA Intergênico/metabolismo , Histonas/metabolismo , Animais , Linhagem Celular , DNA Metiltransferase 3A , Estudo de Associação Genômica Ampla , Transtornos do Crescimento/genética , Transtornos do Crescimento/fisiopatologia , Humanos , Camundongos , Ligação Proteica , Domínios Proteicos , Transporte Proteico , Síndrome de Sotos/genética , Síndrome de Sotos/fisiopatologiaRESUMO
Hotspot histone H3 mutations have emerged as drivers of oncogenesis in cancers of multiple lineages. Specifically, H3 lysine 36 to methionine (H3K36M) mutations are recurrently identified in chondroblastomas, undifferentiated sarcomas, and head and neck cancers. While the mutation reduces global levels of both H3K36 dimethylation (H3K36me2) and trimethylation (H3K36me3) by dominantly inhibiting their respective specific methyltransferases, the relative contribution of these methylation states to the chromatin and phenotypic changes associated with H3K36M remains unclear. Here, we specifically deplete H3K36me2 or H3K36me3 in mesenchymal cells, using CRISPR-Cas9 to separately knock out the corresponding methyltransferases NSD1/2 or SETD2. By profiling and comparing the epigenomic and transcriptomic landscapes of these cells with cells expressing the H3.3K36M oncohistone, we find that the loss of H3K36me2 could largely recapitulate H3.3K36M's effect on redistribution of H3K27 trimethylation (H3K27me3) and gene expression. Consistently, knockout of Nsd1/2, but not Setd2, phenocopies the differentiation blockade and hypersensitivity to the DNA-hypomethylating agent induced by H3K36M. Together, our results support a functional divergence between H3K36me2 and H3K36me3 and their nonredundant roles in H3K36M-driven oncogenesis.
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Carcinogênese/genética , Epigênese Genética , Histonas/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias/metabolismo , Processamento de Proteína Pós-Traducional , Animais , Antimetabólitos Antineoplásicos/farmacologia , Sistemas CRISPR-Cas , Linhagem Celular , Cromatina/química , Cromatina/metabolismo , Citarabina/farmacologia , Decitabina/farmacologia , Edição de Genes , Histona-Lisina N-Metiltransferase/deficiência , Histona-Lisina N-Metiltransferase/genética , Histonas/genética , Humanos , Lisina/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Metilação/efeitos dos fármacos , Camundongos , Mutação , Proteínas de Neoplasias/genética , Neoplasias/genética , Neoplasias/patologia , Fenótipo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Repressoras/deficiência , Proteínas Repressoras/genética , Transcriptoma/efeitos dos fármacosRESUMO
BACKGROUND: Obesity is a risk factor for pneumonia and acute respiratory distress syndrome. OBJECTIVE: To determine whether obesity is associated with intubation or death, inflammation, cardiac injury, or fibrinolysis in coronavirus disease 2019 (COVID-19). DESIGN: Retrospective cohort study. SETTING: A quaternary academic medical center and community hospital in New York City. PARTICIPANTS: 2466 adults hospitalized with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection over a 45-day period with at least 47 days of in-hospital observation. MEASUREMENTS: Body mass index (BMI), admission biomarkers of inflammation (C-reactive protein [CRP] level and erythrocyte sedimentation rate [ESR]), cardiac injury (troponin level), and fibrinolysis (D-dimer level). The primary end point was a composite of intubation or death in time-to-event analysis. RESULTS: Over a median hospital length of stay of 7 days (interquartile range, 3 to 14 days), 533 patients (22%) were intubated, 627 (25%) died, and 59 (2%) remained hospitalized. Compared with overweight patients, patients with obesity had higher risk for intubation or death, with the highest risk among those with class 3 obesity (hazard ratio, 1.6 [95% CI, 1.1 to 2.1]). This association was primarily observed among patients younger than 65 years and not in older patients (P for interaction by age = 0.042). Body mass index was not associated with admission levels of biomarkers of inflammation, cardiac injury, or fibrinolysis. LIMITATIONS: Body mass index was missing for 28% of patients. The primary analyses were conducted with multiple imputation for missing BMI. Upper bounding factor analysis suggested that the results are robust to possible selection bias. CONCLUSION: Obesity is associated with increased risk for intubation or death from COVID-19 in adults younger than 65 years, but not in adults aged 65 years or older. PRIMARY FUNDING SOURCE: National Institutes of Health.
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Betacoronavirus , Índice de Massa Corporal , Infecções por Coronavirus/epidemiologia , Intubação Intratraqueal/estatística & dados numéricos , Obesidade/epidemiologia , Pneumonia Viral/epidemiologia , Centros Médicos Acadêmicos , Fatores Etários , Idoso , Biomarcadores/sangue , Sedimentação Sanguínea , Proteína C-Reativa/análise , COVID-19 , Estudos de Coortes , Feminino , Produtos de Degradação da Fibrina e do Fibrinogênio/análise , Hospitalização , Hospitais Comunitários , Humanos , Tempo de Internação/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Cidade de Nova Iorque/epidemiologia , Pandemias , Modelos de Riscos Proporcionais , Estudos Retrospectivos , SARS-CoV-2 , Troponina/sangueRESUMO
Cryptococcus neoformans infective endocarditis is rarely reported. In this report, we present a case of infective endocarditis secondary to Cryptococcus neoformans in a lung-transplant recipient and review the relevant literature. A 65-year-old man was hospitalized with hypoxemic respiratory failure and underwent left-sided single lung transplantation. In the setting of worsening hypoxemia, blood cultures were drawn, which grew C. neoformans. Lumbar puncture was performed, and CSF PCR was also positive for Cryptococcus. Further exposure history revealed that he had raised chickens while living in Peru. Transesophageal echocardiography showed an aortic valve vegetation, and he was diagnosed with cryptococcal infective endocarditis. He received liposomal amphotericin B and flucytosine for two weeks and was later transitioned to fluconazole. This case highlights the need for thorough social history prior to lung transplantation, as pulmonary colonization with C. neoformans may result in infective endocarditis after immunosuppression.
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Fumarate hydratase (FH) is an enzyme of the tricarboxylic acid cycle (TCA cycle) that catalyses the hydration of fumarate into malate. Germline mutations of FH are responsible for hereditary leiomyomatosis and renal-cell cancer (HLRCC). It has previously been demonstrated that the absence of FH leads to the accumulation of fumarate, which activates hypoxia-inducible factors (HIFs) at normal oxygen tensions. However, so far no mechanism that explains the ability of cells to survive without a functional TCA cycle has been provided. Here we use newly characterized genetically modified kidney mouse cells in which Fh1 has been deleted, and apply a newly developed computer model of the metabolism of these cells to predict and experimentally validate a linear metabolic pathway beginning with glutamine uptake and ending with bilirubin excretion from Fh1-deficient cells. This pathway, which involves the biosynthesis and degradation of haem, enables Fh1-deficient cells to use the accumulated TCA cycle metabolites and permits partial mitochondrial NADH production. We predicted and confirmed that targeting this pathway would render Fh1-deficient cells non-viable, while sparing wild-type Fh1-containing cells. This work goes beyond identifying a metabolic pathway that is induced in Fh1-deficient cells to demonstrate that inhibition of haem oxygenation is synthetically lethal when combined with Fh1 deficiency, providing a new potential target for treating HLRCC patients.
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Fumarato Hidratase/genética , Fumarato Hidratase/metabolismo , Genes Letais/genética , Genes Supressores de Tumor , Heme Oxigenase (Desciclizante)/genética , Heme Oxigenase (Desciclizante)/metabolismo , Mutação/genética , Animais , Bilirrubina/metabolismo , Linhagem Celular , Células Cultivadas , Ciclo do Ácido Cítrico , Simulação por Computador , Fumarato Hidratase/deficiência , Fumaratos/metabolismo , Glutamina/metabolismo , Heme/metabolismo , Heme Oxigenase (Desciclizante)/antagonistas & inibidores , Neoplasias Renais/tratamento farmacológico , Neoplasias Renais/enzimologia , Neoplasias Renais/genética , Neoplasias Renais/metabolismo , Leiomiomatose/congênito , Leiomiomatose/tratamento farmacológico , Leiomiomatose/enzimologia , Leiomiomatose/genética , Leiomiomatose/metabolismo , Camundongos , Mitocôndrias/metabolismo , NAD/metabolismo , Síndromes Neoplásicas Hereditárias , Neoplasias Cutâneas , Neoplasias UterinasRESUMO
RATIONALE: Establishment of a functional vasculature requires the interconnection and remodeling of nascent blood vessels. Precise regulation of factors that influence endothelial cell migration and function is essential for these stereotypical vascular patterning events. The secreted Slit ligands and their Robo receptors constitute a critical signaling pathway controlling the directed migration of both neurons and vascular endothelial cells during embryonic development, but the mechanisms of their regulation are incompletely understood. OBJECTIVE: To identify microRNAs regulating aspects of the Slit-Robo pathway and vascular patterning. METHODS AND RESULTS: Here, we provide evidence that microRNA (miR)-218, which is encoded by an intron of the Slit genes, inhibits the expression of Robo1 and Robo2 and multiple components of the heparan sulfate biosynthetic pathway. Using in vitro and in vivo approaches, we demonstrate that miR-218 directly represses the expression of Robo1, Robo2, and glucuronyl C5-epimerase (GLCE), and that an intact miR-218-Slit-Robo regulatory network is essential for normal vascularization of the retina. Knockdown of miR-218 results in aberrant regulation of this signaling axis, abnormal endothelial cell migration, and reduced complexity of the retinal vasculature. CONCLUSIONS: Our findings link Slit gene expression to the posttranscriptional regulation of Robo receptors and heparan sulfate biosynthetic enzymes, allowing for precise control over vascular guidance cues influencing the organization of blood vessels during development.
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Glicoproteínas/antagonistas & inibidores , MicroRNAs/fisiologia , Proteínas do Tecido Nervoso/antagonistas & inibidores , Receptores Imunológicos/antagonistas & inibidores , Vasos Retinianos/embriologia , Transdução de Sinais/genética , Animais , Sequência de Bases , Células COS , Células Cultivadas , Chlorocebus aethiops , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Glicoproteínas/fisiologia , Heparitina Sulfato/antagonistas & inibidores , Heparitina Sulfato/biossíntese , Heparitina Sulfato/genética , Peptídeos e Proteínas de Sinalização Intercelular/genética , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/genética , Camundongos , MicroRNAs/antagonistas & inibidores , MicroRNAs/genética , Dados de Sequência Molecular , Neovascularização Fisiológica/genética , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/fisiologia , Receptores Imunológicos/genética , Vasos Retinianos/fisiologia , Transcrição Gênica , Proteínas RoundaboutRESUMO
BACKGROUNDAlthough convalescent plasma has been widely used to treat severe coronavirus disease 2019 (COVID-19), data from randomized controlled trials that support its efficacy are limited.METHODSWe conducted a randomized, double-blind, controlled trial among adults hospitalized with severe and critical COVID-19 at 5 sites in New York City (USA) and Rio de Janeiro (Brazil). Patients were randomized 2:1 to receive a single transfusion of either convalescent plasma or normal control plasma. The primary outcome was clinical status at 28 days following randomization, measured using an ordinal scale and analyzed using a proportional odds model in the intention-to-treat population.RESULTSOf 223 participants enrolled, 150 were randomized to receive convalescent plasma and 73 to receive normal control plasma. At 28 days, no significant improvement in the clinical scale was observed in participants randomized to convalescent plasma (OR 1.50, 95% confidence interval [CI] 0.83-2.68, P = 0.180). However, 28-day mortality was significantly lower in participants randomized to convalescent plasma versus control plasma (19/150 [12.6%] versus 18/73 [24.6%], OR 0.44, 95% CI 0.22-0.91, P = 0.034). The median titer of anti-SARS-CoV-2 neutralizing antibody in infused convalescent plasma units was 1:160 (IQR 1:80-1:320). In a subset of nasopharyngeal swab samples from Brazil that underwent genomic sequencing, no evidence of neutralization-escape mutants was detected.CONCLUSIONIn adults hospitalized with severe COVID-19, use of convalescent plasma was not associated with significant improvement in day 28 clinical status. However, convalescent plasma was associated with significantly improved survival. A possible explanation is that survivors remained hospitalized at their baseline clinical status.TRIAL REGISTRATIONClinicalTrials.gov, NCT04359810.FUNDINGAmazon Foundation, Skoll Foundation.
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COVID-19/terapia , SARS-CoV-2 , Adulto , Idoso , Idoso de 80 Anos ou mais , Brasil/epidemiologia , COVID-19/imunologia , COVID-19/mortalidade , Método Duplo-Cego , Feminino , Humanos , Imunização Passiva , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Cidade de Nova Iorque/epidemiologia , Pandemias , SARS-CoV-2/imunologia , Índice de Gravidade de Doença , Resultado do Tratamento , Soroterapia para COVID-19RESUMO
An amendment to this paper has been published and can be accessed via the original article.
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An amendment to this paper has been published and can be accessed via the original article.
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OBJECTIVES: The aim of this study is to evaluate the efficacy and safety of human anti-SARS-CoV-2 convalescent plasma in hospitalized adults with severe SARS-CoV-2 infection. TRIAL DESIGN: This is a prospective, single-center, phase 2, randomized, controlled trial that is blinded to participants and clinical outcome assessor. PARTICIPANTS: Eligible participants include adults (≥ 18 years) with evidence of SARS-CoV-2 infection by PCR test of nasopharyngeal or oropharyngeal swab within 14 days of randomization, evidence of infiltrates on chest radiography, peripheral capillary oxygen saturation (SpO2) ≤ 94% on room air, and/or need for supplemental oxygen, non-invasive mechanical ventilation, or invasive mechanical ventilation, who are willing and able to provide written informed consent prior to performing study procedures or who have a legally authorized representative available to do so. Exclusion criteria include participation in another clinical trial of anti-viral agent(s)* for coronavirus disease-2019 (COVID-19), receipt of any anti-viral agent(s)* with possible activity against SARS-CoV-2 <24 hours prior to plasma infusion, mechanical ventilation (including extracorporeal membrane oxygenation [ECMO]) for ≥ 5 days, severe multi-organ failure, history of allergic reactions to transfused blood products per NHSN/CDC criteria, known IgA deficiency, and pregnancy. Included participants will be hospitalized at the time of randomization and plasma infusion. *Use of remdesivir as treatment for COVID-19 is permitted. The study will be undertaken at Columbia University Irving Medical Center in New York, USA. INTERVENTION AND COMPARATOR: The investigational treatment is anti-SARS-CoV-2 human convalescent plasma. To procure the investigational treatment, volunteers who recovered from COVID-19 will undergo testing to confirm the presence of anti-SARS-CoV-2 antibody to the spike trimer at a 1:400 dilution. Donors will also be screened for transfusion-transmitted infections (e.g. HIV, HBV, HCV, WNV, HTLV-I/II, T. cruzi, ZIKV). If donors have experienced COVID-19 symptoms within 28 days, they will be screened with a nasopharyngeal swab to confirm they are SARS-CoV-2 PCR-negative. Plasma will be collected using standard apheresis technology by the New York Blood Center. Study participants will be randomized in a 2:1 ratio to receive one unit (200 - 250 mL) of anti-SARS-CoV-2 plasma versus one unit (200 - 250 mL) of the earliest available control plasma. The control plasma cannot be tested for presence of anti-SARS-CoV-2 antibody prior to the transfusion, but will be tested for anti- SARS-CoV-2 antibody after the transfusion to allow for a retrospective per-protocol analysis. MAIN OUTCOMES: The primary endpoint is time to clinical improvement. This is defined as time from randomization to either discharge from the hospital or improvement by one point on the following seven-point ordinal scale, whichever occurs first. 1. Not hospitalized with resumption of normal activities 2. Not hospitalized, but unable to resume normal activities 3. Hospitalized, not requiring supplemental oxygen 4. Hospitalized, requiring supplemental oxygen 5. Hospitalized, requiring high-flow oxygen therapy or non-invasive mechanical ventilation 6. Hospitalized, requiring ECMO, invasive mechanical ventilation, or both 7. Death This scale, designed to assess clinical status over time, was based on that recommended by the World Health Organization for use in determining efficacy end-points in clinical trials in hospitalized patients with COVID-19. A recent clinical trial evaluating the efficacy and safety of lopinavir- ritonavir for patients hospitalized with severe COVID-19 used a similar ordinal scale, as have recent clinical trials of novel therapeutics for severe influenza, including a post-hoc analysis of a trial evaluating immune plasma. The primary safety endpoints are cumulative incidence of grade 3 and 4 adverse events and cumulative incidence of serious adverse events during the study period. RANDOMIZATION: Study participants will be randomized in a 2:1 ratio to receive anti-SARS-CoV-2 plasma versus control plasma using a web-based randomization platform. Treatment assignments will be generated using randomly permuted blocks of different sizes to minimize imbalance while also minimizing predictability. BLINDING (MASKING): The study participants and the clinicians who will evaluate post-treatment outcomes will be blinded to group assignment. The blood bank and the clinical research team will not be blinded to group assignment. NUMBERS TO BE RANDOMIZED (SAMPLE SIZE): We plan to enroll 129 participants, with 86 in the anti-SARS-CoV-2 arm, and 43 in the control arm. Among the participants, we expect ~70% or n = 72 will achieve clinical improvement. This will yield an 80% power for a one-sided Wald test at 0.15 level of significance under the proportional hazards model with a hazard ratio of 1.5. TRIAL STATUS: Protocol AAAS9924, Version 17APR2020, 4/17/2020 Start of recruitment: April 20, 2020 Recruitment is ongoing. TRIAL REGISTRATION: ClinicalTrials.gov: NCT04359810 Date of trial registration: April 24, 2020 Retrospectively registered FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest of expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.
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Betacoronavirus/imunologia , Infecções por Coronavirus/terapia , Pneumonia Viral/terapia , Ensaios Clínicos Controlados Aleatórios como Assunto , Adulto , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , COVID-19 , Ensaios Clínicos Fase II como Assunto , Humanos , Imunização Passiva/efeitos adversos , Imunização Passiva/métodos , Pandemias , Estudos Prospectivos , SARS-CoV-2 , Soroterapia para COVID-19RESUMO
BACKGROUND: Pyruvate dehydrogenase (PDH) occupies a central node of intermediary metabolism, converting pyruvate to acetyl-CoA, thus committing carbon derived from glucose to an aerobic fate rather than an anaerobic one. Rapidly proliferating tissues, including human tumors, use PDH to generate energy and macromolecular precursors. However, evidence supports the benefits of constraining maximal PDH activity under certain contexts, including hypoxia and oncogene-induced cell growth. Although PDH is one of the most widely studied enzyme complexes in mammals, its requirement for cell growth is unknown. In this study, we directly addressed whether PDH is required for mammalian cells to proliferate. RESULTS: We genetically suppressed expression of the PDHA1 gene encoding an essential subunit of the PDH complex and characterized the effects on intermediary metabolism and cell proliferation using a combination of stable isotope tracing and growth assays. Surprisingly, rapidly dividing cells tolerated loss of PDH activity without major effects on proliferative rates in complete medium. PDH suppression increased reliance on extracellular lipids, and in some cell lines, reducing lipid availability uncovered a modest growth defect that could be completely reversed by providing exogenous-free fatty acids. PDH suppression also shifted the source of lipogenic acetyl-CoA from glucose to glutamine, and this compensatory pathway required a net reductive isocitrate dehydrogenase (IDH) flux to produce a source of glutamine-derived acetyl-CoA for fatty acids. By deleting the cytosolic isoform of IDH (IDH1), the enhanced contribution of glutamine to the lipogenic acetyl-CoA pool during PDHA1 suppression was eliminated, and growth was modestly suppressed. CONCLUSIONS: Although PDH suppression substantially alters central carbon metabolism, the data indicate that rapid cell proliferation occurs independently of PDH activity. Our findings reveal that this central enzyme is essentially dispensable for growth and proliferation of both primary cells and established cell lines. We also identify the compensatory mechanisms that are activated under PDH deficiency, namely scavenging of extracellular lipids and lipogenic acetyl-CoA production from reductive glutamine metabolism through IDH1.
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Dysregulated metabolism is a hallmark of cancer cell lines, but little is known about the fate of glucose and other nutrients in tumors growing in their native microenvironment. To study tumor metabolism in vivo, we used an orthotopic mouse model of primary human glioblastoma (GBM). We infused (13)C-labeled nutrients into mice bearing three independent GBM lines, each with a distinct set of mutations. All three lines displayed glycolysis, as expected for aggressive tumors. They also displayed unexpected metabolic complexity, oxidizing glucose via pyruvate dehydrogenase and the citric acid cycle, and using glucose to supply anaplerosis and other biosynthetic activities. Comparing the tumors to surrounding brain revealed obvious metabolic differences, notably the accumulation of a large glutamine pool within the tumors. Many of these same activities were conserved in cells cultured ex vivo from the tumors. Thus GBM cells utilize mitochondrial glucose oxidation during aggressive tumor growth in vivo.
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Neoplasias Encefálicas/metabolismo , Glioblastoma/metabolismo , Glucose/metabolismo , Mitocôndrias/metabolismo , Animais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Glioblastoma/genética , Glioblastoma/patologia , Gluconeogênese , Glutamato-Amônia Ligase/metabolismo , Ácido Glutâmico/metabolismo , Glutaminase/metabolismo , Glutamina/metabolismo , Glicólise , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Transplante de Neoplasias , Neostriado/metabolismo , Neostriado/patologia , Oxirredução , Fenótipo , Piruvato Carboxilase/metabolismo , Estatísticas não Paramétricas , Células Tumorais CultivadasRESUMO
Metabolic imaging has great clinical potential in cancer because perturbations of metabolism are common hallmarks of malignant cellular transformation. Novel imaging strategies focused on glutamine could provide a valuable complement to (18)F-FDG PET, because glutamine complements glucose in the metabolic platforms that support tumor growth at the cellular level. Furthermore, recent work has demonstrated that distinct aspects of glutamine metabolism are under the control of oncogenes and tumor suppressors. It is plausible that imaging glutamine metabolism could predict both the presence of specific transforming mutations in the tumor and the sensitivity to therapeutic agents designed to target glutamine use. Here, we review the essential aspects of glutamine metabolism in cancer cells and discuss opportunities for imaging in cancer patients.