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1.
Nat Rev Mol Cell Biol ; 16(7): 393-405, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26122615

RESUMEN

The function of p53 as a tumour suppressor has been attributed to its ability to promote cell death or permanently inhibit cell proliferation. However, in recent years, it has become clear that p53 can also contribute to cell survival. p53 regulates various metabolic pathways, helping to balance glycolysis and oxidative phosphorylation, limiting the production of reactive oxygen species, and contributing to the ability of cells to adapt to and survive mild metabolic stresses. Although these activities may be integrated into the tumour suppressive functions of p53, deregulation of some elements of the p53-induced response might also provide tumours with a survival advantage.


Asunto(s)
Muerte Celular , Supervivencia Celular , Proteína p53 Supresora de Tumor/metabolismo , Animales , Humanos
2.
Mol Cell ; 61(2): 210-21, 2016 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-26774282

RESUMEN

Crosstalk between cellular metabolism and the epigenome regulates epigenetic and metabolic homeostasis and normal cell behavior. Changes in cancer cell metabolism can directly impact epigenetic regulation and promote transformation. Here we analyzed the contribution of methionine and serine metabolism to methylation of DNA and RNA. Serine can contribute to this pathway by providing one-carbon units to regenerate methionine from homocysteine. While we observed this contribution under methionine-depleted conditions, unexpectedly, we found that serine supported the methionine cycle in the presence and absence of methionine through de novo ATP synthesis. Serine starvation increased the methionine/S-adenosyl methionine ratio, decreasing the transfer of methyl groups to DNA and RNA. While serine starvation dramatically decreased ATP levels, this was accompanied by lower AMP and did not activate AMPK. This work highlights the difference between ATP turnover and new ATP synthesis and defines a vital function of nucleotide synthesis beyond making nucleic acids.


Asunto(s)
Adenosina Trifosfato/biosíntesis , Metilación de ADN , Metionina/metabolismo , Neoplasias/metabolismo , Serina/metabolismo , Adenosina Monofosfato/metabolismo , Línea Celular Tumoral , Neoplasias Colorrectales/metabolismo , Metilación de ADN/efectos de los fármacos , Homocisteína/farmacología , Humanos , ARN/metabolismo , S-Adenosilmetionina/metabolismo , Estrés Fisiológico/efectos de los fármacos
3.
Nature ; 544(7650): 372-376, 2017 04 19.
Artículo en Inglés | MEDLINE | ID: mdl-28425994

RESUMEN

The non-essential amino acids serine and glycine are used in multiple anabolic processes that support cancer cell growth and proliferation (reviewed in ref. 1). While some cancer cells upregulate de novo serine synthesis, many others rely on exogenous serine for optimal growth. Restriction of dietary serine and glycine can reduce tumour growth in xenograft and allograft models. Here we show that this observation translates into more clinically relevant autochthonous tumours in genetically engineered mouse models of intestinal cancer (driven by Apc inactivation) or lymphoma (driven by Myc activation). The increased survival following dietary restriction of serine and glycine in these models was further improved by antagonizing the anti-oxidant response. Disruption of mitochondrial oxidative phosphorylation (using biguanides) led to a complex response that could improve or impede the anti-tumour effect of serine and glycine starvation. Notably, Kras-driven mouse models of pancreatic and intestinal cancers were less responsive to depletion of serine and glycine, reflecting an ability of activated Kras to increase the expression of enzymes that are part of the serine synthesis pathway and thus promote de novo serine synthesis.


Asunto(s)
Glicina/deficiencia , Neoplasias Intestinales/dietoterapia , Neoplasias Intestinales/metabolismo , Linfoma/dietoterapia , Linfoma/metabolismo , Serina/deficiencia , Animales , Antioxidantes/metabolismo , Biguanidas/farmacología , Línea Celular Tumoral , Dieta , Modelos Animales de Enfermedad , Femenino , Privación de Alimentos , Glicina/metabolismo , Humanos , Neoplasias Intestinales/genética , Neoplasias Intestinales/patología , Linfoma/patología , Masculino , Ratones , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Estado Nutricional , Fosforilación Oxidativa/efectos de los fármacos , Neoplasias Pancreáticas/dietoterapia , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Proteínas Proto-Oncogénicas p21(ras)/genética , Serina/biosíntesis , Serina/metabolismo , Serina/farmacología , Tasa de Supervivencia
5.
Mol Cell ; 55(2): 158-60, 2014 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-25038411

RESUMEN

In this issue of Molecular Cell, Lewis et al. (2014) describe a new method to determine where in the cell NADPH is produced, contributing to a growing appreciation that the THF cycle is an important source of mitochondrial NADPH.


Asunto(s)
Citosol/metabolismo , Mitocondrias/metabolismo , NADP/metabolismo , Humanos
6.
Sci Adv ; 9(36): eadh2023, 2023 09 08.
Artículo en Inglés | MEDLINE | ID: mdl-37672588

RESUMEN

Previous studies have revealed a role for proline metabolism in supporting cancer development and metastasis. In this study, we show that many cancer cells respond to loss of attachment by accumulating and secreting proline. Detached cells display reduced proliferation accompanied by a general decrease in overall protein production and de novo amino acid synthesis compared to attached cells. However, proline synthesis was maintained under detached conditions. Furthermore, while overall proline incorporation into proteins was lower in detached cells compared to other amino acids, there was an increased production of the proline-rich protein collagen. The increased excretion of proline from detached cells was also shown to be used by macrophages, an abundant and important component of the tumor microenvironment. Our study suggests that detachment induced accumulation and secretion of proline may contribute to tumor progression by supporting increased production of extracellular matrix and providing proline to surrounding stromal cells.


Asunto(s)
Neoplasias , Prolina , Aminoácidos , Transporte Biológico , Matriz Extracelular , Macrófagos
7.
Cell Rep ; 42(6): 112562, 2023 06 27.
Artículo en Inglés | MEDLINE | ID: mdl-37245210

RESUMEN

Mitochondrial 10-formyltetrahydrofolate (10-formyl-THF) is utilized by three mitochondrial enzymes to produce formate for nucleotide synthesis, NADPH for antioxidant defense, and formyl-methionine (fMet) to initiate mitochondrial mRNA translation. One of these enzymes-aldehyde dehydrogenase 1 family member 2 (ALDH1L2)-produces NADPH by catabolizing 10-formyl-THF into CO2 and THF. Using breast cancer cell lines, we show that reduction of ALDH1L2 expression increases ROS levels and the production of both formate and fMet. Both depletion of ALDH1L2 and direct exposure to formate result in enhanced cancer cell migration that is dependent on the expression of the formyl-peptide receptor (FPR). In various tumor models, increased ALDH1L2 expression lowers formate and fMet accumulation and limits metastatic capacity, while human breast cancer samples show a consistent reduction of ALDH1L2 expression in metastases. Together, our data suggest that loss of ALDH1L2 can support metastatic progression by promoting formate and fMet production, resulting in enhanced FPR-dependent signaling.


Asunto(s)
Neoplasias de la Mama , Formiatos , Oxidorreductasas actuantes sobre Donantes de Grupo CH-NH , Femenino , Humanos , Neoplasias de la Mama/metabolismo , Formiatos/metabolismo , Metionina , NADP , Especies Reactivas de Oxígeno , Oxidorreductasas actuantes sobre Donantes de Grupo CH-NH/metabolismo
8.
Nat Commun ; 12(1): 6176, 2021 10 26.
Artículo en Inglés | MEDLINE | ID: mdl-34702840

RESUMEN

Serine is a non-essential amino acid that is critical for tumour proliferation and depletion of circulating serine results in reduced tumour growth and increased survival in various cancer models. While many cancer cells cultured in a standard tissue culture medium depend on exogenous serine for optimal growth, here we report that these cells are less sensitive to serine/glycine depletion in medium containing physiological levels of metabolites. The lower requirement for exogenous serine under these culture conditions reflects both increased de novo serine synthesis and the use of hypoxanthine (not present in the standard medium) to support purine synthesis. Limiting serine availability leads to increased uptake of extracellular hypoxanthine, sparing available serine for other pathways such as glutathione synthesis. Taken together these results improve our understanding of serine metabolism in physiologically relevant nutrient conditions and allow us to predict interventions that may enhance the therapeutic response to dietary serine/glycine limitation.


Asunto(s)
Neoplasias/metabolismo , Serina/metabolismo , Vías Biosintéticas , Línea Celular Tumoral , Proliferación Celular , Medios de Cultivo/química , Medios de Cultivo/metabolismo , Glicina/análisis , Glicina/metabolismo , Humanos , Hipoxantina/análisis , Hipoxantina/metabolismo , Neoplasias/dietoterapia , Neoplasias/patología , Purinas/biosíntesis , Serina/análisis , Regulación hacia Arriba
9.
Cancer Cell ; 37(2): 168-182.e4, 2020 02 10.
Artículo en Inglés | MEDLINE | ID: mdl-31983610

RESUMEN

The TIGAR protein has antioxidant activity that supports intestinal tissue repair and adenoma development. Using a pancreatic ductal adenocarcinoma (PDAC) model, we show that reactive oxygen species (ROS) regulation by TIGAR supports premalignant tumor initiation while restricting metastasis. Increased ROS in PDAC cells drives a phenotypic switch that increases migration, invasion, and metastatic capacity. This switch is dependent on increased activation of MAPK signaling and can be reverted by antioxidant treatment. In mouse and human, TIGAR expression is modulated during PDAC development, with higher TIGAR levels in premalignant lesions and lower TIGAR levels in metastasizing tumors. Our study indicates that temporal, dynamic control of ROS underpins full malignant progression and helps to rationalize conflicting reports of pro- and anti-tumor effects of antioxidant treatment.


Asunto(s)
Proteínas Reguladoras de la Apoptosis/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Neoplasias Pancreáticas/genética , Monoéster Fosfórico Hidrolasas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Proteínas Reguladoras de la Apoptosis/genética , Carcinoma Ductal Pancreático/patología , Proliferación Celular/genética , Regulación Neoplásica de la Expresión Génica/genética , Humanos , Monoéster Fosfórico Hidrolasas/genética , Neoplasias Pancreáticas
10.
Cell Metab ; 30(4): 720-734.e5, 2019 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-31447323

RESUMEN

Cancer metastasis depends on cell survival following loss of extracellular matrix attachment and dissemination through the circulation. The metastatic spread can be enhanced by the clustering of detached cancer cells and increased antioxidant defense. Here, we link these responses by describing how cell clustering limits reactive oxygen species (ROS). Loss of attachment causes mitochondrial perturbations and increased ROS production. The formation of cell clusters induces a hypoxic environment that drives hypoxia-inducible factor 1-alpha (Hif1α)-mediated mitophagy, clearing damaged mitochondria and limiting ROS. However, hypoxia and reduced mitochondrial capacity promote dependence on glycolysis for ATP production that is supported by cytosolic reductive metabolism. Preventing this metabolic adaptation or disruption of cell clusters results in ROS accumulation, cell death, and a reduction of metastatic capacity in vivo. Our results provide a mechanistic explanation for the role of cell clustering in supporting survival during extracellular matrix detachment and metastatic spread and may point to targetable vulnerabilities.


Asunto(s)
Mitocondrias/metabolismo , Metástasis de la Neoplasia/patología , Células Neoplásicas Circulantes/metabolismo , Células Neoplásicas Circulantes/patología , Especies Reactivas de Oxígeno/metabolismo , Animales , Hipoxia de la Célula , Movimiento Celular , Supervivencia Celular , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Desnudos , Mitofagia
11.
Methods Mol Biol ; 1928: 55-67, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30725450

RESUMEN

Tracing the fate of carbon-13 (13C) labeled metabolites within cells by liquid chromatography mass spectrometry (LCMS) is a powerful analytical technique used for many years in the study of cell metabolism. Conventional experiments using LCMS and labeled nutrients tend to track the incorporation of 13C from exogenous nutrients (such as amino acids) into other, relatively proximal, cellular metabolites. Several labs have extended this technique to track transfer of 13C from the metabolite pool onto macromolecules, such as DNA, where methylation acts as an important functional modification. Here we describe a complete method that integrates previously established techniques to simultaneously track the use of 13C-serine or 13C-methionine into metabolite pools of the methionine cycle and into methylation of DNA and RNA. Given the ability to track methyl-transfer in a time-dependent way, this technique can provide temporal information about active methyl-transfer as well as quantification of total DNA/RNA methylation levels.


Asunto(s)
Isótopos de Carbono/metabolismo , Epigénesis Genética , Metionina/metabolismo , Neoplasias/genética , Neoplasias/metabolismo , Isótopos de Nitrógeno/metabolismo , Serina/metabolismo , Línea Celular Tumoral , Cromatografía Liquida , Metilación de ADN , Epigenómica/métodos , Humanos , Hidrólisis , ARN/genética , ARN/metabolismo , Espectrometría de Masas en Tándem
12.
Methods Mol Biol ; 1862: 109-119, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30315463

RESUMEN

Heavy isotope labeled metabolites are readily detected by mass spectrometry and are commonly used to analyze the rates of metabolic reactions in cultured cells. The ability to detect labeled metabolites-and infer fluxes-is influenced by a number of factors that can confound simplistic comparative assays. The accumulation of labeled metabolites is strongly influenced by the pool size of the metabolite of interest and also by changes in downstream reactions, which are not always fully perceived. Here, we describe a method that overcomes some of these limitations and allows simple calculation of reaction rates under low nutrient, rapid reaction rate conditions. Acutely increasing the pool of the metabolite of interest (by adding a pulse of excess unlabeled nutrient to the cells) rapidly increases accumulation of labeled metabolite, facilitating a more accurate assessment of reaction rate.


Asunto(s)
Técnicas de Cultivo de Célula/métodos , Marcaje Isotópico/métodos , Análisis de Flujos Metabólicos/métodos , Metabolómica/métodos , Isótopos de Carbono/química , Técnicas de Cultivo de Célula/instrumentación , Medios de Cultivo/química , Células HCT116 , Humanos , Marcaje Isotópico/instrumentación , Análisis de Flujos Metabólicos/instrumentación , Redes y Vías Metabólicas/efectos de los fármacos , Metabolómica/instrumentación , Isótopos de Nitrógeno/química , Nutrientes/metabolismo , Serina/farmacología
13.
Biochim Biophys Acta Rev Cancer ; 1870(1): 32-42, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-29883595

RESUMEN

p53 is an important tumour suppressor gene, with loss of p53 contributing to the development of most human cancers. However, the activation of p53 in response to stress signals underpins a role for p53 in diverse aspects of health and disease. Activities of p53 that regulate metabolism can play a role in maintaining homeostasis and protecting cells from damage - so preventing disease development. By contrast, either loss or over-activation of p53 can contribute to numerous metabolic pathologies, including aging, obesity and diabetes.


Asunto(s)
Proteína p53 Supresora de Tumor/metabolismo , Adipocitos/metabolismo , Envejecimiento , Animales , Muerte Celular , Supervivencia Celular , Senescencia Celular , Diabetes Mellitus/metabolismo , Humanos , Hígado/metabolismo , Ratones , Neoplasias/metabolismo , Obesidad/metabolismo , Páncreas/metabolismo , Estrés Fisiológico
14.
Cell Metab ; 28(5): 721-736.e6, 2018 11 06.
Artículo en Inglés | MEDLINE | ID: mdl-30122553

RESUMEN

Numerous mechanisms to support cells under conditions of transient nutrient starvation have been described. Several functions of the tumor-suppressor protein p53 can contribute to the adaptation of cells to metabolic stress and help cancer cell survival under nutrient-limiting conditions. We show here that p53 promotes the expression of SLC1A3, an aspartate/glutamate transporter that allows the utilization of aspartate to support cells in the absence of extracellular glutamine. Under glutamine deprivation, SLC1A3 expression maintains electron transport chain and tricarboxylic acid cycle activity, promoting de novo glutamate, glutamine, and nucleotide synthesis to rescue cell viability. Tumor cells with high levels of SLC1A3 expression are resistant to glutamine starvation, and SLC1A3 depletion retards the growth of these cells in vitro and in vivo, suggesting a therapeutic potential for SLC1A3 inhibition.


Asunto(s)
Transportador 1 de Aminoácidos Excitadores/metabolismo , Glutamina/metabolismo , Neoplasias/metabolismo , Inanición/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Adaptación Fisiológica , Animales , Línea Celular Tumoral , Supervivencia Celular , Ciclo del Ácido Cítrico , Femenino , Humanos , Ratones Endogámicos BALB C
15.
Cell Rep ; 7(4): 1248-58, 2014 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-24813884

RESUMEN

Previous work has shown that some cancer cells are highly dependent on serine/glycine uptake for proliferation. Although serine and glycine can be interconverted and either might be used for nucleotide synthesis and one-carbon metabolism, we show that exogenous glycine cannot replace serine to support cancer cell proliferation. Cancer cells selectively consumed exogenous serine, which was converted to intracellular glycine and one-carbon units for building nucleotides. Restriction of exogenous glycine or depletion of the glycine cleavage system did not impede proliferation. In the absence of serine, uptake of exogenous glycine was unable to support nucleotide synthesis. Indeed, higher concentrations of glycine inhibited proliferation. Under these conditions, glycine was converted to serine, a reaction that would deplete the one-carbon pool. Providing one-carbon units by adding formate rescued nucleotide synthesis and growth of glycine-fed cells. We conclude that nucleotide synthesis and cancer cell proliferation are supported by serine--rather than glycine--consumption.


Asunto(s)
Carbono/metabolismo , Glicina/metabolismo , Neoplasias/metabolismo , Serina/metabolismo , Procesos de Crecimiento Celular/fisiología , Glicina/administración & dosificación , Glicina/farmacocinética , Células HCT116 , Humanos , Células MCF-7 , Redes y Vías Metabólicas , Neoplasias/patología , Serina/administración & dosificación , Serina/farmacocinética
16.
Ageing Res Rev ; 12(4): 918-30, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24080227

RESUMEN

Accumulation of oxidative damage has been proposed to be causal to aging as defined by the Free radical Theory of Aging, which has been subject to recent debate. However, a major hurdle in understanding the biological roles of reactive oxygen species (ROS) signaling and their oxidative damage has been the widely recognized methodological difficulties to measure oxidative damage and ROS in vivo. In this review we describe the various novel approaches that have recently been developed to overcome this challenge in the nematode Caenorhabditis elegans, which is a paradigm invertebrate model organism for studying aging and age-related disease given its short lifespan, easy genetics and transparency. In addition, we also discuss these methods in other important model organisms of aging, including the budding yeast Saccharomyces cerevisiae, the fruitfly Drosophila melanogaster and the mouse Mus musculus. After an introduction on the various ROS that can be encountered, we discuss approaches for the detection and quantification of ROS and ROS damage of DNA, lipids and proteins, highlighting examples from literature to demonstrate the applicability and caveats of each method. As will become clear, combinations of approaches have now become possible and will prove essential for thoroughly understanding the involvement of ROS and ROS damage in the biology of aging and disease.


Asunto(s)
Envejecimiento/metabolismo , Caenorhabditis elegans/metabolismo , Modelos Animales , Estrés Oxidativo/fisiología , Especies Reactivas de Oxígeno/metabolismo , Envejecimiento/genética , Animales , Caenorhabditis elegans/genética , Radicales Libres/análisis , Radicales Libres/metabolismo , Humanos , Especies Reactivas de Oxígeno/análisis
17.
PLoS One ; 8(11): e80935, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24244726

RESUMEN

Cellular systems are essential model systems to study reactive oxygen species and oxidative damage but there are widely accepted technical difficulties with available methods for quantifying endogenous oxidative damage in these systems. Here we present a stable isotope dilution UPLC-MS/MS protocol for measuring F2-isoprostanes as accurate markers for endogenous oxidative damage in cellular systems. F2-isoprostanes are chemically stable prostaglandin-like lipid peroxidation products of arachidonic acid, the predominant polyunsaturated fatty acid in mammalian cells. This approach is rapid and highly sensitive, allowing for the absolute quantification of endogenous lipid peroxidation in as little as ten thousand cells as well as damage originating from multiple ROS sources. Furthermore, differences in the endogenous cellular redox state induced by transcriptional regulation of ROS scavenging enzymes were detected by following this protocol. Finally we showed that the F2-isoprostane 5-iPF2α-VI is a metabolically stable end product, which is excreted from cells. Overall, this protocol enables accurate, specific and sensitive quantification of endogenous lipid peroxidation in cellular systems.


Asunto(s)
F2-Isoprostanos/análisis , Ácido Araquidónico/análisis , Ácido Araquidónico/química , Ácido Araquidónico/metabolismo , Cromatografía Líquida de Alta Presión , F2-Isoprostanos/química , F2-Isoprostanos/metabolismo , Células Hep G2 , Humanos , Peroxidación de Lípido/fisiología , Espectrometría de Masas en Tándem
18.
Aging Cell ; 12(2): 214-23, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23279719

RESUMEN

Oxidative damage is thought to be a major cause in development of pathologies and aging. However, quantification of oxidative damage is methodologically difficult. Here, we present a robust liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach for accurate, sensitive, and linear in vivo quantification of endogenous oxidative damage in the nematode Caenorhabditis elegans, based on F3-isoprostanes. F3-isoprostanes are prostaglandin-like markers of oxidative damage derived from lipid peroxidation by Reactive Oxygen Species (ROS). Oxidative damage was quantified in whole animals and in multiple cellular compartments, including mitochondria and peroxisomes. Mutants of the mitochondrial electron transport proteins mev-1 and clk-1 showed increased oxidative damage levels. Furthermore, analysis of Superoxide Dismutase (sod) and Catalase (ctl) mutants uncovered that oxidative damage levels cannot be inferred from the phenotype of resistance to pro-oxidants alone and revealed high oxidative damage in a small group of chemosensory neurons. Longitudinal analysis of aging nematodes revealed that oxidative damage increased specifically with postreproductive age. Remarkably, aging of the stress-resistant and long-lived daf-2 insulin/IGF-1 receptor mutant involved distinct daf-16-dependent phases of oxidative damage including a temporal increase at young adulthood. These observations are consistent with a hormetic response to ROS.


Asunto(s)
Envejecimiento/metabolismo , Caenorhabditis elegans/metabolismo , Isoprostanos/metabolismo , Mitocondrias/metabolismo , Peroxisomas/metabolismo , Envejecimiento/genética , Animales , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Catalasa/genética , Catalasa/metabolismo , Citocromos b , Factores de Transcripción Forkhead , Expresión Génica , Insulina/genética , Insulina/metabolismo , Isoprostanos/análisis , Mutación , Oxidación-Reducción , Especies Reactivas de Oxígeno/metabolismo , Receptor IGF Tipo 1/genética , Receptor IGF Tipo 1/metabolismo , Receptor de Insulina/genética , Receptor de Insulina/metabolismo , Células Receptoras Sensoriales , Succinato Deshidrogenasa/genética , Succinato Deshidrogenasa/metabolismo , Superóxido Dismutasa/genética , Superóxido Dismutasa/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
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