Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 70
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Cell ; 168(5): 890-903.e15, 2017 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-28162770

RESUMO

The genetic dependencies of human cancers widely vary. Here, we catalog this heterogeneity and use it to identify functional gene interactions and genotype-dependent liabilities in cancer. By using genome-wide CRISPR-based screens, we generate a gene essentiality dataset across 14 human acute myeloid leukemia (AML) cell lines. Sets of genes with correlated patterns of essentiality across the lines reveal new gene relationships, the essential substrates of enzymes, and the molecular functions of uncharacterized proteins. Comparisons of differentially essential genes between Ras-dependent and -independent lines uncover synthetic lethal partners of oncogenic Ras. Screens in both human AML and engineered mouse pro-B cells converge on a surprisingly small number of genes in the Ras processing and MAPK pathways and pinpoint PREX1 as an AML-specific activator of MAPK signaling. Our findings suggest general strategies for defining mammalian gene networks and synthetic lethal interactions by exploiting the natural genetic and epigenetic diversity of human cancer cells.


Assuntos
Redes Reguladoras de Genes , Leucemia Mieloide Aguda/genética , Animais , Proteínas de Transporte , Linhagem Celular Tumoral , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Epigênese Genética , Genes Essenciais , Humanos , Sistema de Sinalização das MAP Quinases , Camundongos , Proteínas Mitocondriais , Processamento de Proteína Pós-Traducional , Proteínas ras/genética
2.
Cell ; 171(3): 642-654.e12, 2017 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-29053970

RESUMO

The mTORC1 kinase is a master growth regulator that senses many environmental cues, including amino acids. Activation of mTORC1 by arginine requires SLC38A9, a poorly understood lysosomal membrane protein with homology to amino acid transporters. Here, we validate that SLC38A9 is an arginine sensor for the mTORC1 pathway, and we uncover an unexpectedly central role for SLC38A9 in amino acid homeostasis. SLC38A9 mediates the transport, in an arginine-regulated fashion, of many essential amino acids out of lysosomes, including leucine, which mTORC1 senses through the cytosolic Sestrin proteins. SLC38A9 is necessary for leucine generated via lysosomal proteolysis to exit lysosomes and activate mTORC1. Pancreatic cancer cells, which use macropinocytosed protein as a nutrient source, require SLC38A9 to form tumors. Thus, through SLC38A9, arginine serves as a lysosomal messenger that couples mTORC1 activation to the release from lysosomes of the essential amino acids needed to drive cell growth.


Assuntos
Sistemas de Transporte de Aminoácidos/metabolismo , Aminoácidos Essenciais/metabolismo , Lisossomos/metabolismo , Complexos Multiproteicos/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Sequência de Aminoácidos , Sistemas de Transporte de Aminoácidos/química , Sistemas de Transporte de Aminoácidos/genética , Animais , Arginina/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Humanos , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina , Camundongos , Camundongos Endogâmicos C57BL , Alinhamento de Sequência
3.
Cell ; 166(5): 1324-1337.e11, 2016 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-27565352

RESUMO

Mitochondria house metabolic pathways that impact most aspects of cellular physiology. While metabolite profiling by mass spectrometry is widely applied at the whole-cell level, it is not routinely possible to measure the concentrations of small molecules in mammalian organelles. We describe a method for the rapid and specific isolation of mitochondria and use it in tandem with a database of predicted mitochondrial metabolites ("MITObolome") to measure the matrix concentrations of more than 100 metabolites across various states of respiratory chain (RC) function. Disruption of the RC reveals extensive compartmentalization of mitochondrial metabolism and signatures unique to the inhibition of each RC complex. Pyruvate enables the proliferation of RC-deficient cells but has surprisingly limited effects on matrix contents. Interestingly, despite failing to restore matrix NADH/NAD balance, pyruvate does increase aspartate, likely through the exchange of matrix glutamate for cytosolic aspartate. We demonstrate the value of mitochondrial metabolite profiling and describe a strategy applicable to other organelles.


Assuntos
Redes e Vias Metabólicas , Metaboloma , Mitocôndrias/metabolismo , Transporte de Elétrons/genética , Células HeLa , Humanos , Ácido Pirúvico/metabolismo , Ácido Pirúvico/farmacologia
4.
Cell ; 162(3): 540-51, 2015 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-26232224

RESUMO

The mitochondrial electron transport chain (ETC) enables many metabolic processes, but why its inhibition suppresses cell proliferation is unclear. It is also not well understood why pyruvate supplementation allows cells lacking ETC function to proliferate. We used a CRISPR-based genetic screen to identify genes whose loss sensitizes human cells to phenformin, a complex I inhibitor. The screen yielded GOT1, the cytosolic aspartate aminotransferase, loss of which kills cells upon ETC inhibition. GOT1 normally consumes aspartate to transfer electrons into mitochondria, but, upon ETC inhibition, it reverses to generate aspartate in the cytosol, which partially compensates for the loss of mitochondrial aspartate synthesis. Pyruvate stimulates aspartate synthesis in a GOT1-dependent fashion, which is required for pyruvate to rescue proliferation of cells with ETC dysfunction. Aspartate supplementation or overexpression of an aspartate transporter allows cells without ETC activity to proliferate. Thus, enabling aspartate synthesis is an essential role of the ETC in cell proliferation.


Assuntos
Ácido Aspártico/biossíntese , Proliferação de Células , Transporte de Elétrons , Mitocôndrias/metabolismo , Aspartato Aminotransferase Citoplasmática/metabolismo , Ácido Aspártico/metabolismo , DNA Mitocondrial/genética , Humanos , Células Jurkat , Mutação , Fenformin/farmacologia , Ácido Pirúvico/metabolismo
5.
Cell ; 158(5): 1094-1109, 2014 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-25171410

RESUMO

It is increasingly appreciated that oncogenic transformation alters cellular metabolism to facilitate cell proliferation, but less is known about the metabolic changes that promote cancer cell aggressiveness. Here, we analyzed metabolic gene expression in cancer cell lines and found that a set of high-grade carcinoma lines expressing mesenchymal markers share a unique 44 gene signature, designated the "mesenchymal metabolic signature" (MMS). A FACS-based shRNA screen identified several MMS genes as essential for the epithelial-mesenchymal transition (EMT), but not for cell proliferation. Dihydropyrimidine dehydrogenase (DPYD), a pyrimidine-degrading enzyme, was highly expressed upon EMT induction and was necessary for cells to acquire mesenchymal characteristics in vitro and for tumorigenic cells to extravasate into the mouse lung. This role of DPYD was mediated through its catalytic activity and enzymatic products, the dihydropyrimidines. Thus, we identify metabolic processes essential for the EMT, a program associated with the acquisition of metastatic and aggressive cancer cell traits.


Assuntos
Transição Epitelial-Mesenquimal , Pirimidinas/metabolismo , Animais , Carcinoma/metabolismo , Linhagem Celular Tumoral , Di-Hidrouracila Desidrogenase (NADP)/genética , Citometria de Fluxo , Perfilação da Expressão Gênica , Humanos , Mesoderma/citologia , Mesoderma/metabolismo , Camundongos , RNA Interferente Pequeno/metabolismo
6.
Nephrology (Carlton) ; 29(6): 311-324, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38403867

RESUMO

Hyperkalaemia is an electrolyte imbalance that impairs muscle function and myocardial excitability, and can potentially lead to fatal arrhythmias and sudden cardiac death. The prevalence of hyperkalaemia is estimated to be 6%-7% worldwide and 7%-10% in Asia. Hyperkalaemia frequently affects patients with chronic kidney disease, heart failure, and diabetes mellitus, particularly those receiving treatment with renin-angiotensin-aldosterone system (RAAS) inhibitors. Both hyperkalaemia and interruption of RAAS inhibitor therapy are associated with increased risks for cardiovascular events, hospitalisations, and death, highlighting a clinical dilemma in high-risk patients. Conventional potassium-binding resins are widely used for the treatment of hyperkalaemia; however, caveats such as the unpalatable taste and the risk of gastrointestinal side effects limit their chronic use. Recent evidence suggests that, with a rapid onset of action and improved gastrointestinal tolerability, novel oral potassium binders (e.g., patiromer and sodium zirconium cyclosilicate) are alternative treatment options for both acute and chronic hyperkalaemia. To optimise the care for patients with hyperkalaemia in the Asia-Pacific region, a multidisciplinary expert panel was convened to review published literature, share clinical experiences, and ultimately formulate 25 consensus statements, covering three clinical areas: (i) risk factors of hyperkalaemia and risk stratification in susceptible patients; (ii) prevention of hyperkalaemia for at-risk individuals; and (iii) correction of hyperkalaemia for at-risk individuals with cardiorenal disease. These statements were expected to serve as useful guidance in the management of hyperkalaemia for health care providers in the region.


Assuntos
Consenso , Hiperpotassemia , Humanos , Hiperpotassemia/epidemiologia , Hiperpotassemia/terapia , Hiperpotassemia/diagnóstico , Ásia/epidemiologia , Fatores de Risco , Potássio/sangue , Silicatos/uso terapêutico , Silicatos/efeitos adversos
7.
Platelets ; 33(8): 1139-1145, 2022 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-35316151

RESUMO

The use of mean platelet diameter (MPD) to classify inherited thrombocytopenia (IT) has been demonstrated in several studies. Alternatively, the mean platelet volume (MPV) may be used, but in macrothrombocytopenia this may not be available. We hypothesized that platelet forward scatter (FSC) measurements using flow cytometry may be used for the size-based classification of IT. The study aimed to assess the ability of platelet FSC to measure platelet size and whether it could be used as an alternative to the MPD or MPV.Blood samples were obtained from individuals undergoing investigation for inherited platelet function disorders (IPFD, n = 40) or platelet number disorders (IPND, n = 46). A hematology analyzer was used to obtain MPV and platelet counts, flow cytometry to measure platelet FSC and ImageJ software to measure MPD from stained blood smears. The International Society of Thrombosis and Hemostasis (ISTH) Bleeding Assessment Tool (BAT) was used to calculate bleeding scores.Twenty-nine(63%) of IPND patients had an MPV that could not be reported. A significant correlation to platelet FSC was found to the MPD (p < .0001) and MPV (p < .0001) and an inverse correlation with platelet count (p < .0001). No significant correlation was found between FSC and bleeding history. In conclusion, platelet FSC is an alternative to MPV and may be used in macrothrombocytopenia where the MPV is not recorded.


Assuntos
Transtornos Plaquetários , Trombocitopenia , Plaquetas , Citometria de Fluxo , Hemorragia , Humanos , Volume Plaquetário Médio , Contagem de Plaquetas , Trombocitopenia/diagnóstico
8.
Platelets ; 33(3): 432-442, 2022 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-34223798

RESUMO

Variants of the Diaphanous-Related Formin 1 (DIAPH-1) gene have recently been reported causing inherited macrothrombocytopenia. The essential/"diagnostic" characteristics associated with the disorder are emerging; however, robust and complete criteria are not established. Here, we report the first cases of DIAPH1-related disorder in Australia caused by the autosomal dominant gain-of-function DIAPH1 R1213X variant formed by truncation of the protein within the diaphanous auto-regulatory domain (DAD) with loss of regulatory motifs responsible for autoinhibitory interactions within the DIAPH1 protein. We affirm phenotypic changes induced by the DIAPH1 R1213X variant to include macrothrombocytopenia, early-onset progressive sensorineural hearing loss, and mild asymptomatic neutropenia. High-resolution microscopy confirms perturbations of cytoskeletal dynamics caused by the DIAPH1 variant and we extend the repertoire of changes generated by this variant to include alteration of procoagulant platelet formation and possible dental anomalies.


Assuntos
Plaquetas/metabolismo , Surdez/genética , Forminas/efeitos adversos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Surdez/patologia , Humanos , Fenótipo
9.
Proc Natl Acad Sci U S A ; 116(1): 303-312, 2019 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-30541894

RESUMO

Mitochondria are metabolic organelles that are essential for mammalian life, but the dynamics of mitochondrial metabolism within mammalian tissues in vivo remains incompletely understood. While whole-tissue metabolite profiling has been useful for studying metabolism in vivo, such an approach lacks resolution at the cellular and subcellular level. In vivo methods for interrogating organellar metabolites in specific cell types within mammalian tissues have been limited. To address this, we built on prior work in which we exploited a mitochondrially localized 3XHA epitope tag (MITO-Tag) for the fast isolation of mitochondria from cultured cells to generate MITO-Tag Mice. Affording spatiotemporal control over MITO-Tag expression, these transgenic animals enable the rapid, cell-type-specific immunoisolation of mitochondria from tissues, which we verified using a combination of proteomic and metabolomic approaches. Using MITO-Tag Mice and targeted and untargeted metabolite profiling, we identified changes during fasted and refed conditions in a diverse array of mitochondrial metabolites in hepatocytes and found metabolites that behaved differently at the mitochondrial versus whole-tissue level. MITO-Tag Mice should have utility for studying mitochondrial physiology, and our strategy should be generally applicable for studying other mammalian organelles in specific cell types in vivo.


Assuntos
Epitopos/imunologia , Mitocôndrias/imunologia , Animais , Hepatócitos/metabolismo , Immunoblotting , Lipídeos/fisiologia , Masculino , Metabolômica/métodos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mitocôndrias/química , Mitocôndrias/metabolismo , Mitocôndrias/fisiologia , Mitocôndrias Hepáticas/química , Mitocôndrias Hepáticas/imunologia , Mitocôndrias Hepáticas/metabolismo , Mitocôndrias Hepáticas/fisiologia , Proteômica/métodos
10.
Nature ; 520(7547): 363-7, 2015 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-25855294

RESUMO

Cancer cells adapt their metabolic processes to support rapid proliferation, but less is known about how cancer cells alter metabolism to promote cell survival in a poorly vascularized tumour microenvironment. Here we identify a key role for serine and glycine metabolism in the survival of brain cancer cells within the ischaemic zones of gliomas. In human glioblastoma multiforme, mitochondrial serine hydroxymethyltransferase (SHMT2) and glycine decarboxylase (GLDC) are highly expressed in the pseudopalisading cells that surround necrotic foci. We find that SHMT2 activity limits that of pyruvate kinase (PKM2) and reduces oxygen consumption, eliciting a metabolic state that confers a profound survival advantage to cells in poorly vascularized tumour regions. GLDC inhibition impairs cells with high SHMT2 levels as the excess glycine not metabolized by GLDC can be converted to the toxic molecules aminoacetone and methylglyoxal. Thus, SHMT2 is required for cancer cells to adapt to the tumour environment, but also renders these cells sensitive to glycine cleavage system inhibition.


Assuntos
Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Glioblastoma/metabolismo , Glioblastoma/patologia , Glicina Hidroximetiltransferase/metabolismo , Glicina/metabolismo , Isquemia/metabolismo , Acetona/análogos & derivados , Acetona/metabolismo , Acetona/toxicidade , Animais , Neoplasias Encefálicas/irrigação sanguínea , Neoplasias Encefálicas/enzimologia , Hipóxia Celular , Linhagem Celular Tumoral , Sobrevivência Celular , Feminino , Glioblastoma/irrigação sanguínea , Glioblastoma/enzimologia , Glicina Desidrogenase (Descarboxilante)/antagonistas & inibidores , Glicina Desidrogenase (Descarboxilante)/metabolismo , Humanos , Isquemia/enzimologia , Isquemia/patologia , Camundongos , Necrose , Consumo de Oxigênio , Aldeído Pirúvico/metabolismo , Aldeído Pirúvico/toxicidade , Piruvato Quinase/metabolismo , Microambiente Tumoral , Ensaios Antitumorais Modelo de Xenoenxerto
11.
Environ Res ; 197: 111087, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33798514

RESUMO

Soil erosion can present a major threat to agriculture due to loss of soil, nutrients, and organic carbon. Therefore, soil erosion modelling is one of the steps used to plan suitable soil protection measures and detect erosion hotspots. A bibliometric analysis of this topic can reveal research patterns and soil erosion modelling characteristics that can help identify steps needed to enhance the research conducted in this field. Therefore, a detailed bibliometric analysis, including investigation of collaboration networks and citation patterns, should be conducted. The updated version of the Global Applications of Soil Erosion Modelling Tracker (GASEMT) database contains information about citation characteristics and publication type. Here, we investigated the impact of the number of authors, the publication type and the selected journal on the number of citations. Generalized boosted regression tree (BRT) modelling was used to evaluate the most relevant variables related to soil erosion modelling. Additionally, bibliometric networks were analysed and visualized. This study revealed that the selection of the soil erosion model has the largest impact on the number of publication citations, followed by the modelling scale and the publication's CiteScore. Some of the other GASEMT database attributes such as model calibration and validation have negligible influence on the number of citations according to the BRT model. Although it is true that studies that conduct calibration, on average, received around 30% more citations, than studies where calibration was not performed. Moreover, the bibliographic coupling and citation networks show a clear continental pattern, although the co-authorship network does not show the same characteristics. Therefore, soil erosion modellers should conduct even more comprehensive review of past studies and focus not just on the research conducted in the same country or continent. Moreover, when evaluating soil erosion models, an additional focus should be given to field measurements, model calibration, performance assessment and uncertainty of modelling results. The results of this study indicate that these GASEMT database attributes had smaller impact on the number of citations, according to the BRT model, than anticipated, which could suggest that these attributes should be given additional attention by the soil erosion modelling community. This study provides a kind of bibliographic benchmark for soil erosion modelling research papers as modellers can estimate the influence of their paper.


Assuntos
Bibliometria , Erosão do Solo , Agricultura , Publicações , Solo
12.
Nature ; 508(7494): 108-12, 2014 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-24670634

RESUMO

As the concentrations of highly consumed nutrients, particularly glucose, are generally lower in tumours than in normal tissues, cancer cells must adapt their metabolism to the tumour microenvironment. A better understanding of these adaptations might reveal cancer cell liabilities that can be exploited for therapeutic benefit. Here we developed a continuous-flow culture apparatus (Nutrostat) for maintaining proliferating cells in low-nutrient media for long periods of time, and used it to undertake competitive proliferation assays on a pooled collection of barcoded cancer cell lines cultured in low-glucose conditions. Sensitivity to low glucose varies amongst cell lines, and an RNA interference (RNAi) screen pinpointed mitochondrial oxidative phosphorylation (OXPHOS) as the major pathway required for optimal proliferation in low glucose. We found that cell lines most sensitive to low glucose are defective in the OXPHOS upregulation that is normally caused by glucose limitation as a result of either mitochondrial DNA (mtDNA) mutations in complex I genes or impaired glucose utilization. These defects predict sensitivity to biguanides, antidiabetic drugs that inhibit OXPHOS, when cancer cells are grown in low glucose or as tumour xenografts. Notably, the biguanide sensitivity of cancer cells with mtDNA mutations was reversed by ectopic expression of yeast NDI1, a ubiquinone oxidoreductase that allows bypass of complex I function. Thus, we conclude that mtDNA mutations and impaired glucose utilization are potential biomarkers for identifying tumours with increased sensitivity to OXPHOS inhibitors.


Assuntos
Biguanidas/farmacologia , Meios de Cultura/metabolismo , Meios de Cultura/farmacologia , Glucose/deficiência , Neoplasias/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Técnicas de Cultura de Células/instrumentação , Técnicas de Cultura de Células/métodos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Meios de Cultura/química , DNA Mitocondrial/genética , Complexo I de Transporte de Elétrons/deficiência , Complexo I de Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/metabolismo , Glucose/metabolismo , Glucose/farmacologia , Humanos , Hipoglicemiantes/farmacologia , Masculino , Camundongos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Tipagem Molecular , Mutação , Transplante de Neoplasias , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Fosforilação Oxidativa/efeitos dos fármacos , Fenformin/farmacologia , Interferência de RNA , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
13.
Intern Med J ; 49 Suppl 1: 5-8, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30815979

RESUMO

BACKGROUND: Recently, new evidence from large scale trials and updated guidelines have emerged on the risks and benefits of extended dual antiplatelet therapy (DAPT) for patients with acute coronary syndrome (ACS). AIMS: To discuss, clarify and advise on the application of the evidences and guidelines on individual patient selection for extended DAPT, with regard to balancing risk factors, particularly in Asian populations. METHODS: A total of 14 local cardiologists from Hong Kong with extensive experience in cardiology and cardiac interventions convened in a series of 3 advisory board meetings from October 2016 to September 2017, which included reviews of new evidence in the literature and discussions of the latest clinical trends, using an anonymous, electronic voting system for arriving at consensuses. RESULTS: Recommendations were produced for the following nine risk factors: old age (>65), chronic kidney disease (CKD), diabetes mellitus (DM), recurrent myocardial infarction (MI), multi-vessel disease (MVD), multiple stents, bioresorbable vascular scaffold (BVS) stent, left main stenting and peripheral artery disease (PAD). Strong ischaemic risk factors include DM, recurrent MI, MVD and/or >3 stents; less-strong ischaemic factors include CKD, left main stenting, BVS stent and PAD. Old age can be an unclear risk factor due to variations in physical fitness even among patients of identical age. DISCUSSION: The strengths and limitations of the results were acknowledged. CONCLUSION: ACS patients with ischaemic risk factors could be considered for extended DAPT beyond 12 months, while balancing the risk of bleeding.


Assuntos
Síndrome Coronariana Aguda/terapia , Stents Farmacológicos/efeitos adversos , Inibidores da Agregação Plaquetária/administração & dosagem , Guias de Prática Clínica como Assunto , Síndrome Coronariana Aguda/diagnóstico , Comitês Consultivos , Esquema de Medicação , Quimioterapia Combinada , Hemorragia/induzido quimicamente , Hemorragia/prevenção & controle , Hong Kong , Humanos , Infarto do Miocárdio/etiologia , Inibidores da Agregação Plaquetária/efeitos adversos , Antagonistas do Receptor Purinérgico P2Y/administração & dosagem , Antagonistas do Receptor Purinérgico P2Y/efeitos adversos , Fatores de Risco , Trombose/etiologia , Trombose/prevenção & controle
14.
Nat Chem Biol ; 12(6): 452-8, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27110680

RESUMO

Serine is both a proteinogenic amino acid and the source of one-carbon units essential for de novo purine and deoxythymidine synthesis. In the canonical pathway of glucose-derived serine synthesis, Homo sapiens phosphoglycerate dehydrogenase (PHGDH) catalyzes the first, rate-limiting step. Genetic loss of PHGDH is toxic toward PHGDH-overexpressing breast cancer cell lines even in the presence of exogenous serine. Here, we used a quantitative high-throughput screen to identify small-molecule PHGDH inhibitors. These compounds reduce the production of glucose-derived serine in cells and suppress the growth of PHGDH-dependent cancer cells in culture and in orthotopic xenograft tumors. Surprisingly, PHGDH inhibition reduced the incorporation into nucleotides of one-carbon units from glucose-derived and exogenous serine. We conclude that glycolytic serine synthesis coordinates the use of one-carbon units from endogenous and exogenous serine in nucleotide synthesis, and we suggest that one-carbon unit wasting thus may contribute to the efficacy of PHGDH inhibitors in vitro and in vivo.


Assuntos
Carbono/metabolismo , Inibidores Enzimáticos/farmacologia , Fosfoglicerato Desidrogenase/antagonistas & inibidores , Serina/biossíntese , Bibliotecas de Moléculas Pequenas/farmacologia , Animais , Carbono/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/química , Feminino , Glicólise/efeitos dos fármacos , Humanos , Neoplasias Mamárias Experimentais/tratamento farmacológico , Neoplasias Mamárias Experimentais/enzimologia , Neoplasias Mamárias Experimentais/metabolismo , Neoplasias Mamárias Experimentais/patologia , Camundongos , Estrutura Molecular , Fosfoglicerato Desidrogenase/metabolismo , Purinas/biossíntese , Serina/química , Bibliotecas de Moléculas Pequenas/química , Relação Estrutura-Atividade , Timidina/biossíntese , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
15.
Nature ; 476(7360): 346-50, 2011 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-21760589

RESUMO

Cancer cells adapt their metabolic processes to drive macromolecular biosynthesis for rapid cell growth and proliferation. RNA interference (RNAi)-based loss-of-function screening has proven powerful for the identification of new and interesting cancer targets, and recent studies have used this technology in vivo to identify novel tumour suppressor genes. Here we developed a method for identifying novel cancer targets via negative-selection RNAi screening using a human breast cancer xenograft model at an orthotopic site in the mouse. Using this method, we screened a set of metabolic genes associated with aggressive breast cancer and stemness to identify those required for in vivo tumorigenesis. Among the genes identified, phosphoglycerate dehydrogenase (PHGDH) is in a genomic region of recurrent copy number gain in breast cancer and PHGDH protein levels are elevated in 70% of oestrogen receptor (ER)-negative breast cancers. PHGDH catalyses the first step in the serine biosynthesis pathway, and breast cancer cells with high PHGDH expression have increased serine synthesis flux. Suppression of PHGDH in cell lines with elevated PHGDH expression, but not in those without, causes a strong decrease in cell proliferation and a reduction in serine synthesis. We find that PHGDH suppression does not affect intracellular serine levels, but causes a drop in the levels of α-ketoglutarate, another output of the pathway and a tricarboxylic acid (TCA) cycle intermediate. In cells with high PHGDH expression, the serine synthesis pathway contributes approximately 50% of the total anaplerotic flux of glutamine into the TCA cycle. These results reveal that certain breast cancers are dependent upon increased serine pathway flux caused by PHGDH overexpression and demonstrate the utility of in vivo negative-selection RNAi screens for finding potential anticancer targets.


Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Genômica , Serina/biossíntese , Animais , Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/enzimologia , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proliferação de Células , Ciclo do Ácido Cítrico/fisiologia , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Ácido Glutâmico/metabolismo , Humanos , Ácidos Cetoglutáricos/metabolismo , Melanoma/enzimologia , Melanoma/genética , Camundongos , Transplante de Neoplasias , Fosfoglicerato Desidrogenase/genética , Fosfoglicerato Desidrogenase/metabolismo , Interferência de RNA
16.
Diabetologia ; 58(1): 79-86, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25335440

RESUMO

AIMS/HYPOTHESIS: This study compared the incidence rate of type 1 diabetes in children diagnosed with enterovirus (EV) infections with that in age- and sex-matched children without EV infection in a population-based cohort. In addition, we examined whether the direction or magnitude of the association between EV infection and type 1 diabetes differs according to atopic disease status in children. METHODS: We used insurance claims data from Taiwan's National Health Insurance Research Database to derive type 1 diabetes incidence in children aged up to 18 years with or without a diagnosis of EV infection during 2000-2008. Incidence rate ratios and HRs of type 1 diabetes for EV infection were estimated by Poisson regression and Cox's proportional hazard regression model. RESULTS: Overall incidence of type 1 diabetes was higher in the EV than in the non-EV infection cohort (5.73 vs 3.89 per 100,000 person-years; incidence rate ratio 1.48 [95% CI 1.19, 1.83]), with an adjusted HR of 1.48 (95% CI 1.19, 1.83). Among children without EV, incidence increased with age at diagnosis of EV infection, except in those aged 5-10 years. The HRs of type 1 diabetes in children with allergic rhinitis, bronchial asthma or either one of these atopic diseases showed more variation than in those children without these diseases. CONCLUSIONS/INTERPRETATION: This nationwide retrospective cohort study found a positive correlation between type 1 diabetes and EV infection. The results suggest that a preventive strategy, such as an effective vaccine against EV infection, may lessen the incidence of type 1 diabetes in Taiwan.


Assuntos
Diabetes Mellitus Tipo 1/epidemiologia , Infecções por Enterovirus/epidemiologia , Adolescente , Criança , Pré-Escolar , Estudos de Coortes , Bases de Dados Factuais , Feminino , Humanos , Incidência , Lactente , Masculino , Fatores de Risco , Taiwan/epidemiologia
17.
Artigo em Inglês | MEDLINE | ID: mdl-39284668

RESUMO

It is increasingly appreciated that cancer cells adapt their metabolic pathways to support rapid growth and proliferation as well as survival, often even under the poor nutrient conditions that characterize some tumors. Cancer cells can also rewire their metabolism to circumvent chemotherapeutics that inhibit core metabolic pathways, such as nucleotide synthesis. A critical approach to the study of cancer metabolism is metabolite profiling (metabolomics), the set of technologies, usually based on mass spectrometry, that allow for the detection and quantification of metabolites in cancer cells and their environments. Metabolomics is a burgeoning field, driven by technological innovations in mass spectrometers, as well as novel approaches to isolate cells, subcellular compartments, and rare fluids, such as the interstitial fluid of tumors. Here, we discuss three emerging metabolomic technologies: spatial metabolomics, single-cell metabolomics, and organellar metabolomics. The use of these technologies along with more established profiling methods, like single-cell transcriptomics and proteomics, is likely to underlie new discoveries and questions in cancer research.

18.
Semin Thromb Hemost ; 39(1): 25-32, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23329646

RESUMO

Hyperactivation and aggregation of platelets play a major role in thrombosis and hemostasis. The aims of this study were to investigate the effects of omega-3 polyunsaturated fatty acids (PUFAs) on platelet function. Light transmission aggregometry and flow cytometric analyses of platelet activation and platelet-leukocyte aggregates were determined at baseline and after 4 weeks of omega-3 (docosahexaenoic acid 520 mg and eicosapentaenoic acid 120 mg) supplementation. In total, 40 healthy subjects and 16 patients with a history of cardiovascular disease (CVD) completed the study. In healthy subjects, omega-3 PUFA significantly reduced adenosine diphosphate (ADP)-induced (maximum amplitude, 77.0% ± 3.2% vs. 71.6% ± 3.4%, p = 0.036; maximum slope, 86.3 ± 1.8 vs. 80.7 ± 2.1, p = 0.014) and adrenaline-induced platelet aggregation (maximum slope, 42.8 ± 2.7 vs. 37.4 ± 3.0, p = 0.013; lag time, 00:21 ± 00:02 vs. 00:31 ± 00:03 s, p = 0.002). Omega-3 PUFA also reduced P-selectin expression (40.5% ± 2.9% vs. 34.4% ± 2.4%, p = 0.049) on platelets and platelet-monocyte aggregates (38.5% ± 2.6% vs. 31.4% ± 2.5%, p = 0.022) after activation with ADP 0.5 µM. There were fewer changes in platelet aggregation and activation found in subjects with CVD. Nevertheless, there was a reduction in the slope of arachidonic acid-induced platelet aggregation (13.21 ± 6.41 vs. 4.88 ± 3.01, p = 0.009) and increased lag time for U46619 (00:16 ± 00:00 vs. 00:29 ± 00:07 s, p = 0.018) induced platelet aggregation. Thus, 4-week supplementation of 640 mg omega-3 PUFA reduced measures of platelet aggregation and activation in healthy subjects but effects were less evident in patients with existing CVD. Our findings support the recommendation that the omega-3 PUFA dose be higher in CVD than among healthy subjects.


Assuntos
Plaquetas/efeitos dos fármacos , Doenças Cardiovasculares/sangue , Suplementos Nutricionais , Ácidos Graxos Ômega-3/farmacologia , Difosfato de Adenosina/farmacologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Plaquetas/fisiologia , Ácidos Docosa-Hexaenoicos/administração & dosagem , Ácidos Docosa-Hexaenoicos/farmacologia , Relação Dose-Resposta a Droga , Esquema de Medicação , Ácido Eicosapentaenoico/administração & dosagem , Ácido Eicosapentaenoico/farmacologia , Epinefrina/farmacologia , Ácidos Graxos Ômega-3/administração & dosagem , Humanos , Pessoa de Meia-Idade , Ativação Plaquetária/efeitos dos fármacos , Agregação Plaquetária/efeitos dos fármacos , Adulto Jovem
20.
J Comp Eff Res ; 12(1): e220164, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36264113

RESUMO

WHAT IS THIS SUMMARY ABOUT?: This is a summary of a research survey called ACTION Teens. In our survey, 12,987 people from 10 countries answered questions about obesity. They were: 5275 teenagers with obesity, 5389 caregivers of teenagers with obesity, and 2323 doctors who provide medical care for teenagers with obesity. WHAT WERE THE MAIN RESULTS OF THE SURVEY?: Most teenagers with obesity were worried about their weight and thought that losing weight was their responsibility. Many teenagers had already tried to lose weight. For teenagers, wanting to be more fit or in better shape was the top reason for wanting to lose weight. Some caregivers did not realize how worried their teenager was about their own weight. There were also some caregivers who were not aware of their teenager's recent attempts to lose weight. As a group, the doctors did not know the main reasons why teenagers want to lose weight. They also did not know the main reasons preventing teenagers from losing weight. WHAT DO THE RESULTS OF THE SURVEY MEAN?: Teenagers with obesity will be better supported and understood if there is better communication between teenagers, caregivers, and doctors. Clinical Trial Registration: NCT05013359 (ClinicalTrials.gov).


Assuntos
Cuidadores , Obesidade , Humanos , Adolescente , Obesidade/epidemiologia , Obesidade/terapia , Idioma , Redução de Peso , Atenção à Saúde
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA