RESUMO
Oncogenes can alter metabolism by changing the balance between anabolic and catabolic processes. However, how oncogenes regulate tumor cell biomass remains poorly understood. Using isogenic MCF10A cells transformed with nine different oncogenes, we show that specific oncogenes reduce the biomass of cancer cells by promoting extracellular vesicle (EV) release. While MYC and AURKB elicited the highest number of EVs, each oncogene selectively altered the protein composition of released EVs. Likewise, oncogenes alter secreted miRNAs. MYC-overexpressing cells require ceramide, whereas AURKB requires ESCRT to release high levels of EVs. We identify an inverse relationship between MYC upregulation and activation of the RAS/MEK/ERK signaling pathway for regulating EV release in some tumor cells. Finally, lysosome genes and activity are downregulated in the context of MYC and AURKB, suggesting that cellular contents, instead of being degraded, were released via EVs. Thus, oncogene-mediated biomass regulation via differential EV release is a new metabolic phenotype.
Assuntos
Aurora Quinase B/genética , Vesículas Extracelulares/metabolismo , Oncogenes/genética , Proteínas Proto-Oncogênicas c-myc/genética , Metabolismo Energético/genética , Vesículas Extracelulares/genética , Regulação Neoplásica da Expressão Gênica , Genes ras/genética , Humanos , Lisossomos/genética , MAP Quinase Quinase Quinases/genética , Sistema de Sinalização das MAP Quinases/genética , Metabolismo/genética , Transdução de Sinais/genéticaRESUMO
How MYC reprograms metabolism in primary tumors remains poorly understood. Using integrated gene expression and metabolite profiling, we identify six pathways that are coordinately deregulated in primary MYC-driven liver tumors: glutathione metabolism; glycine, serine, and threonine metabolism; aminoacyl-tRNA biosynthesis; cysteine and methionine metabolism; ABC transporters; and mineral absorption. We then focus our attention on glutathione (GSH) and glutathione disulfide (GSSG), as they are markedly decreased in MYC-driven tumors. We find that fewer glutamine-derived carbons are incorporated into GSH in tumor tissue relative to non-tumor tissue. Expression of GCLC, the rate-limiting enzyme of GSH synthesis, is attenuated by the MYC-induced microRNA miR-18a. Inhibition of miR-18a in vivo leads to increased GCLC protein expression and GSH abundance in tumor tissue. Finally, MYC-driven liver tumors exhibit increased sensitivity to acute oxidative stress. In summary, MYC-dependent attenuation of GCLC by miR-18a contributes to GSH depletion in vivo, and low GSH corresponds with increased sensitivity to oxidative stress in tumors. Our results identify new metabolic pathways deregulated in primary MYC tumors and implicate a role for MYC in regulating a major antioxidant pathway downstream of glutamine.
Assuntos
Glutamato-Cisteína Ligase/antagonistas & inibidores , Glutationa/metabolismo , Neoplasias Hepáticas/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Animais , Linhagem Celular Tumoral , Análise por Conglomerados , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Glutamato-Cisteína Ligase/genética , Glutamato-Cisteína Ligase/metabolismo , Glutamina/metabolismo , Humanos , Neoplasias Hepáticas/genética , Redes e Vias Metabólicas/genética , Metaboloma , Metabolômica/métodos , Camundongos , Camundongos Transgênicos , MicroRNAs/genética , Estresse Oxidativo , Proteínas Proto-Oncogênicas c-myc/genética , Interferência de RNARESUMO
Many mechanisms have been proposed for how heightened aerobic glycolytic metabolism fuels cancer pathogenicity, but there are still many unexplored pathways. Here, we have performed metabolomic profiling to map glucose incorporation into metabolic pathways upon transformation of mammary epithelial cells by 11 commonly mutated human oncogenes. We show that transformation of mammary epithelial cells by oncogenic stimuli commonly shunts glucose-derived carbons into synthesis of sialic acid, a hexosamine pathway metabolite that is converted to CMP-sialic acid by cytidine monophosphate N-acetylneuraminic acid synthase (CMAS) as a precursor to glycoprotein and glycolipid sialylation. We show that CMAS knockdown leads to elevations in intracellular sialic acid levels, a depletion of cellular sialylation, and alterations in the expression of many cancer-relevant genes to impair breast cancer pathogenicity. Our study reveals the heretofore unrecognized role of sialic acid metabolism and protein sialylation in regulating the expression of genes that maintain breast cancer pathogenicity.
Assuntos
Neoplasias da Mama/metabolismo , Regulação Neoplásica da Expressão Gênica , Ácido N-Acetilneuramínico/metabolismo , Proteínas de Neoplasias/metabolismo , Animais , Neoplasias da Mama/enzimologia , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Feminino , Técnicas de Silenciamento de Genes , Xenoenxertos , Humanos , Metabolômica , Camundongos SCID , N-Acilneuraminato Citidililtransferase/genética , N-Acilneuraminato Citidililtransferase/metabolismo , TranscriptomaRESUMO
Expression of the oncogenic transcription factor MYC is disproportionately elevated in triple-negative breast cancer (TNBC), as compared to estrogen receptor-, progesterone receptor- or human epidermal growth factor 2 receptor-positive (RP) breast cancer. We and others have shown that MYC alters metabolism during tumorigenesis. However, the role of MYC in TNBC metabolism remains mostly unexplored. We hypothesized that MYC-dependent metabolic dysregulation is essential for the growth of MYC-overexpressing TNBC cells and may identify new therapeutic targets for this clinically challenging subset of breast cancer. Using a targeted metabolomics approach, we identified fatty acid oxidation (FAO) intermediates as being dramatically upregulated in a MYC-driven model of TNBC. We also identified a lipid metabolism gene signature in patients with TNBC that were identified from The Cancer Genome Atlas database and from multiple other clinical data sets, implicating FAO as a dysregulated pathway that is critical for TNBC cell metabolism. We found that pharmacologic inhibition of FAO catastrophically decreased energy metabolism in MYC-overexpressing TNBC cells and blocked tumor growth in a MYC-driven transgenic TNBC model and in a MYC-overexpressing TNBC patient-derived xenograft. These findings demonstrate that MYC-overexpressing TNBC shows an increased bioenergetic reliance on FAO and identify the inhibition of FAO as a potential therapeutic strategy for this subset of breast cancer.
Assuntos
Carcinogênese/genética , Metabolismo Energético/genética , Ácidos Graxos/metabolismo , Proteínas Proto-Oncogênicas c-myc/biossíntese , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/genética , Metabolismo Energético/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Metabolismo dos Lipídeos/genética , Oxirredução , Proteínas Proto-Oncogênicas c-myc/genética , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Mitochondrial dysfunction affects cellular energy metabolism, but less is known about the consequences for cytoplasmic biosynthetic reactions. We report that mtDNA replication disorders caused by TWINKLE mutations-mitochondrial myopathy (MM) and infantile onset spinocerebellar ataxia (IOSCA)-remodel cellular dNTP pools in mice. MM muscle shows tissue-specific induction of the mitochondrial folate cycle, purine metabolism, and imbalanced and increased dNTP pools, consistent with progressive mtDNA mutagenesis. IOSCA-TWINKLE is predicted to hydrolyze dNTPs, consistent with low dNTP pools and mtDNA depletion in the disease. MM muscle also modifies the cytoplasmic one-carbon cycle, transsulfuration, and methylation, as well as increases glucose uptake and its utilization for de novo serine and glutathione biosynthesis. Our evidence indicates that the mitochondrial replication machinery communicates with cytoplasmic dNTP pools and that upregulation of glutathione synthesis through glucose-driven de novo serine biosynthesis contributes to the metabolic stress response. These results are important for disorders with primary or secondary mtDNA instability and offer targets for metabolic therapy.
Assuntos
DNA Mitocondrial/metabolismo , Mitocôndrias/metabolismo , Miopatias Mitocondriais/metabolismo , Nucleotídeos/metabolismo , Degenerações Espinocerebelares/metabolismo , Adulto , Animais , Carbono/metabolismo , DNA Helicases/genética , DNA Helicases/metabolismo , Replicação do DNA , DNA Mitocondrial/genética , Feminino , Ácido Fólico/metabolismo , Glucose/metabolismo , Glutationa/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/genética , Mitocôndrias/patologia , Miopatias Mitocondriais/genética , Miopatias Mitocondriais/patologia , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Modelos Moleculares , Mutação , Serina/metabolismo , Degenerações Espinocerebelares/genética , Degenerações Espinocerebelares/patologiaRESUMO
Targeting dysregulated metabolic pathways is a promising therapeutic strategy for eradicating cancer. Understanding how frequently altered oncogenes regulate metabolic enzyme targets would be useful in identifying both broad-spectrum and targeted metabolic therapies for cancer. Here, we used activity-based protein profiling to identify serine hydrolase activities that were consistently upregulated by various human oncogenes. Through this profiling effort, we found oncogenic regulatory mechanisms for several cancer-relevant serine hydrolases and discovered that platelet activating factor acetylhydrolase 1B2 and 1B3 (PAFAH1B2 and PAFAH1B3) activities were consistently upregulated by several oncogenes, alongside previously discovered cancer-relevant hydrolases fatty acid synthase and monoacylglycerol lipase. While we previously showed that PAFAH1B2 and 1B3 were important in breast cancer, our most recent profiling studies have revealed that these enzymes may be dysregulated broadly across many types of cancers. Here, we find that pharmacological blockade of both enzymes impairs cancer pathogenicity across multiple different types of cancer cells, including breast, ovarian, melanoma, and prostate cancer. We also show that pharmacological blockade of PAFAH1B2 and 1B3 causes unique changes in lipid metabolism, including heightened levels of tumor-suppressing lipids. Our results reveal oncogenic regulatory mechanisms of several cancer-relevant serine hydrolases using activity-based protein profiling, and we show that PAFAH1B2 and 1B3 are important in maintaining cancer pathogenicity across a wide spectrum of cancer types.
Assuntos
1-Alquil-2-acetilglicerofosfocolina Esterase/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , 1-Alquil-2-acetilglicerofosfocolina Esterase/antagonistas & inibidores , Linhagem Celular Tumoral , Humanos , Metabolismo dos Lipídeos/efeitos dos fármacos , Metaboloma/efeitos dos fármacos , Proteínas Associadas aos Microtúbulos/antagonistas & inibidores , Neoplasias/tratamento farmacológicoRESUMO
Cancer cells possess fundamentally altered metabolism that supports their pathogenic features, which includes a heightened reliance on aerobic glycolysis to provide precursors for synthesis of biomass. We show here that inositol polyphosphate phosphatase 1 (INPP1) is highly expressed in aggressive human cancer cells and primary high-grade human tumors. Inactivation of INPP1 leads to a reduction in glycolytic intermediates that feed into the synthesis of the oncogenic signaling lipid lysophosphatidic acid (LPA), which in turn impairs LPA signaling and further attenuates glycolytic metabolism in a feed-forward mechanism to impair cancer cell motility, invasiveness, and tumorigenicity. Taken together these findings reveal a novel mode of glycolytic control in cancer cells that can serve to promote key oncogenic lipid signaling pathways that drive cancer pathogenicity.
Assuntos
Carcinoma Papilar/patologia , Cistadenocarcinoma Seroso/patologia , Glicólise/efeitos dos fármacos , Fosfatos de Inositol/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Neoplasias Ovarianas/patologia , Monoéster Fosfórico Hidrolases/metabolismo , Animais , Apoptose/efeitos dos fármacos , Western Blotting , Carcinoma Papilar/tratamento farmacológico , Carcinoma Papilar/metabolismo , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Cistadenocarcinoma Seroso/tratamento farmacológico , Cistadenocarcinoma Seroso/metabolismo , Feminino , Humanos , Metaboloma/efeitos dos fármacos , Camundongos , Camundongos SCID , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Neoplasias/patologia , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/metabolismo , Monoéster Fosfórico Hidrolases/antagonistas & inibidores , Monoéster Fosfórico Hidrolases/genética , RNA Interferente Pequeno/genética , Transdução de Sinais/efeitos dos fármacos , Células Tumorais CultivadasRESUMO
The endocannabinoid system, most popularly known as the target of the psychoactive component of marijuana, Δ(9)-tetrahydrocannabinol (THC), is a signaling network that modulates a diverse range of physiological processes including nociception, behavior, cognitive function, appetite, metabolism, motor control, memory formation, and inflammation. While THC and its derivatives have garnered notoriety in the eyes of the public, the endocannabinoid system consists of two endogenous signaling lipids, 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (anandamide), which activate cannabinoid receptors CB1 and CB2 in the nervous system and peripheral tissues. This review will focus on the recent efforts to chemically manipulate 2-AG signaling through the development of inhibitors of the 2-AG-synthesizing enzyme diacylglycerol lipase (DAGL) or the 2-AG-degrading enzyme monoacylglycerol lipase (MAGL), and assessing the therapeutic potential of DAGL and MAGL inhibitors in pain, inflammation, degenerative diseases, tissue injury, and cancer.
Assuntos
Ácidos Araquidônicos/metabolismo , Eicosanoides/metabolismo , Endocanabinoides/metabolismo , Glicerídeos/metabolismo , Animais , Ácidos Araquidônicos/química , Dronabinol/química , Dronabinol/farmacologia , Dronabinol/uso terapêutico , Endocanabinoides/química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/uso terapêutico , Glicerídeos/química , Humanos , Lipase Lipoproteica/antagonistas & inibidores , Lipase Lipoproteica/metabolismo , Monoacilglicerol Lipases/antagonistas & inibidores , Monoacilglicerol Lipases/genética , Monoacilglicerol Lipases/metabolismo , Transtornos do Humor/tratamento farmacológico , Transtornos do Humor/metabolismo , Transtornos do Humor/patologia , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Neoplasias/patologia , Doenças Neurodegenerativas/tratamento farmacológico , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Dor/tratamento farmacológico , Dor/metabolismo , Dor/patologia , Transdução de Sinais/efeitos dos fármacosRESUMO
Adenosine monophosphate-activated protein kinase (AMPK) is a conserved sensor of intracellular energy activated in response to low nutrient availability and environmental stress. In a screen for conserved substrates of AMPK, we identified ULK1 and ULK2, mammalian orthologs of the yeast protein kinase Atg1, which is required for autophagy. Genetic analysis of AMPK or ULK1 in mammalian liver and Caenorhabditis elegans revealed a requirement for these kinases in autophagy. In mammals, loss of AMPK or ULK1 resulted in aberrant accumulation of the autophagy adaptor p62 and defective mitophagy. Reconstitution of ULK1-deficient cells with a mutant ULK1 that cannot be phosphorylated by AMPK revealed that such phosphorylation is required for mitochondrial homeostasis and cell survival during starvation. These findings uncover a conserved biochemical mechanism coupling nutrient status with autophagy and cell survival.