RESUMO
Under certain stress conditions, astrocytes operate in aerobic glycolysis, a process controlled by pyruvate dehydrogenase (PDH) inhibition through its E1 α subunit (Pda1) phosphorylation. This supplies lactate to neurons, which save glucose to obtain NADPH to, among other roles, counteract reactive oxygen species. A failure in this metabolic cooperation causes severe damage to neurons. In this work, using humanized Saccharomyces cerevisiae cells in which its endogenous Cu/Zn Superoxide Dismutase (SOD1) was replaced by human ortholog, we investigated the role of human SOD1 (hSOD1) in aerobic glycolysis regulation and its implications to amyotrophic lateral sclerosis (ALS), a neurodegenerative disease. Yeast cells ferment glucose even in the presence of oxygen and switch to respiratory metabolism after glucose exhaustion. However, like cells of SOD1-knockout strain, cells expressing A4V mutant of hSOD1 growing on glucose showed a respiratory phenotype, i.e., low glucose and high oxygen consumptions and low intracellular oxidation levels in response to peroxide stress, contrary to cells expressing wild-type (WT) SOD1 (yeast or human). The A4V mutation in hSOD1 is linked to ALS. In contrast to WT SOD1 strains, PDH activity of both sod1Δ and A4V hSOD1 cells did not change in response to a metabolic shift toward oxidative metabolism, which was associated to lower Pda1 phosphorylation levels under growth on glucose. Taken together, our results suggest that A4V mutant cannot regulate aerobic glycolysis via Pda1 phosphorylation the same way WT hSOD1, which might be linked to problems observed in the motor neurons of ALS patients with the SOD1 A4V mutation.
Assuntos
Esclerose Lateral Amiotrófica , Glicólise , Saccharomyces cerevisiae , Superóxido Dismutase-1 , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/patologia , Humanos , Superóxido Dismutase-1/genética , Superóxido Dismutase-1/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Glucose/metabolismo , MutaçãoRESUMO
Methylglyoxal (MG) is considered a classical biomarker of diabetes mellitus and its comorbidities. However, a role for this compound in exacerbated immune responses, such as septicemia, is being increasingly observed and requires clarification, particularly in the context of neuroinflammatory responses. Herein, we used two different approaches (in vivo and acute hippocampal slice models) to investigate MG as a biomarker of neuroinflammation and the neuroimmunometabolic shift to glycolysis in lipopolysaccharide (LPS) inflammation models. Our data reinforce the hypothesis that LPS-induced neuroinflammation stimulates the cerebral innate immune response by increasing IL-1ß, a classical pro-inflammatory cytokine, and the astrocyte reactive response, via elevating S100B secretion and GFAP levels. Acute neuroinflammation promotes an early neuroimmunometabolic shift to glycolysis by elevating glucose uptake, lactate release, PFK1, and PK activities. We observed high serum and cerebral MG levels, in association with a reduction in glyoxalase 1 detoxification activity, and a close correlation between serum and hippocampus MG levels with the systemic and neuroinflammatory responses to LPS. Findings strongly suggest a role for MG in immune responses.
Assuntos
Biomarcadores , Hipocampo , Lipopolissacarídeos , Doenças Neuroinflamatórias , Aldeído Pirúvico , Aldeído Pirúvico/metabolismo , Lipopolissacarídeos/farmacologia , Animais , Doenças Neuroinflamatórias/metabolismo , Doenças Neuroinflamatórias/induzido quimicamente , Biomarcadores/metabolismo , Masculino , Hipocampo/metabolismo , Hipocampo/efeitos dos fármacos , Ratos Wistar , Subunidade beta da Proteína Ligante de Cálcio S100/metabolismo , Glicólise/efeitos dos fármacos , Interleucina-1beta/metabolismo , Inflamação/metabolismo , Inflamação/induzido quimicamente , Proteína Glial Fibrilar Ácida/metabolismo , Lactoilglutationa Liase/metabolismo , Ratos , Astrócitos/metabolismo , Astrócitos/efeitos dos fármacosRESUMO
Modulation of autophagy as an anticancer strategy has been widely studied and evaluated in several cell models. However, little attention has been paid to the metabolic changes that occur in a cancer cell when autophagy is inhibited or induced. In this review, we describe how the expression and regulation of various autophagy-related (ATGs) genes and proteins are associated with cancer progression and cancer plasticity. We present a comprehensive review of how deregulation of ATGs affects cancer cell metabolism, where inhibition of autophagy is mainly reflected in the enhancement of the Warburg effect. The importance of metabolic changes, which largely depend on the cancer type and form part of a cancer cell's escape strategy after autophagy modulation, is emphasized. Consequently, pharmacological strategies based on a dual inhibition of metabolic and autophagy pathways emerged and are reviewed critically here.
Assuntos
Glicólise , Neoplasias , Humanos , Proteínas Relacionadas à Autofagia/metabolismo , Neoplasias/metabolismo , Estresse OxidativoRESUMO
Introduction: This study provides evidence of how Th1 cell metabolism is modulated by the purinergic receptor P2X7 (P2RX7), a cation cannel activated by high extracellular concentrations of adenosine triphosphate (ATP). Methods: In vivo analysis was performed in the Plasmodium chabaudi model of malaria in view of the great relevance of this infectious disease for human health, as well as the availability of data concerning Th1/Tfh differentiation. Results: We show that P2RX7 induces T-bet expression and aerobic glycolysis in splenic CD4+ T cells that respond to malaria, at a time prior to Th1/Tfh polarization. Cell-intrinsic P2RX7 signaling sustains the glycolytic pathway and causes bioenergetic mitochondrial stress in activated CD4+ T cells. We also show in vitro the phenotypic similarities of Th1-conditioned CD4+ T cells that do not express P2RX7 and those in which the glycolytic pathway is pharmacologically inhibited. In addition, in vitro ATP synthase blockade and the consequent inhibition of oxidative phosphorylation, which drives cellular metabolism for aerobic glycolysis, is sufficient to promote rapid CD4+ T cell proliferation and polarization to the Th1 profile in the absence of P2RX7. Conclusion: These data demonstrate that P2RX7-mediated metabolic reprograming for aerobic glycolysis is a key event for Th1 differentiation and suggest that ATP synthase inhibition is a downstream effect of P2RX7 signaling that potentiates the Th1 response.
Assuntos
Glicólise , Malária , Receptores Purinérgicos P2X7 , Células Th1 , Animais , Camundongos , Camundongos Endogâmicos C57BL , Receptores Purinérgicos P2X7/metabolismo , Células Th1/citologia , Células Th1/metabolismo , Diferenciação Celular , Plasmodium chabaudi , Malária/imunologia , Trifosfato de Adenosina , Adenosina Trifosfatases , Mitocôndrias/metabolismo , Proteínas com Domínio T/metabolismo , Fosforilação Oxidativa , Transdução de Sinais , Células CultivadasRESUMO
Abstract Oral potentially malignant disorders (OPMD) are associated with an increased risk of oral squamous cell carcinoma (OSCC). OSCC has an aggressive profile and is the most prevalent among different head and neck malignancies. Most OSCC patients are diagnosed with advanced stage tumors and have a poor prognosis. Cancer cells are able to reprogram their metabolism, even in the presence of oxygen, enhancing the conversion of glucose to lactate via the glycolytic pathway, a phenomenon mainly regulated by hypoxia-inducible factor (HIF) signaling. Thus, several glycometabolism-related biomarkers are upregulated. Objectives This study aimed to evaluate the immunoexpression of the HIF targets GLUT1, GLUT3, HK2, PFKL, PKM2, pPDH, LDHA, MCT4, and CAIX in OPMD and OSCC samples, in order to identify potential correlations between biomarkers' immunoexpression, clinicopathological features, and prognostic parameters. Methodology OSCC and OPMD samples from 21 and 34 patients (respectively) were retrospectively collected and stained for the different biomarkers by immunohistochemistry. Results CAIX and MCT4 expressions were significantly higher in OSCC samples when compared with OPMD samples, while the rest were also expressed by OPMD. GLUT3 and PKM2 alone, and the concomitant expression of more than four glycometabolism-related biomarkers were significantly correlated with the presence of dysplasia in OPMD. When considering OSCC cases, a trend toward increased expression of biomarkers and poor clinicopathological features was observed, and the differences regarding HK2, PFKL, LDHA and MCT4 expression were significant. Moreover, HK2 and CAIX were correlated with low survival rates. GLUT1 and GLUT3 were significantly associated with poor outcome when their expression was observed in the hypoxic region of malignant lesions. Conclusion OPMD and OSCC cells overexpress glycolysis-related proteins, which is associated with aggressive features and poor patient outcome. Further research is needed to deeply understand the glycolic phenotype in the process of oral carcinogenesis.
RESUMO
Cancer-related metabolic features are in part maintained by hexokinase 2 upregulation, which leads to high levels of glucose-6-phosphate (G6P) and is needed to provide energy and biomass to support rapid proliferation. Using a humanized model of the yeast Saccharomyces cerevisiae, we explored how human hexokinase 2 (HK2) behaves under different nutritional conditions. At high glucose levels, yeast presents aerobic glycolysis through a regulatory mechanism known as catabolic repression, which exerts a metabolic adaptation like the Warburg effect. At high glucose concentrations, HK2 did not translocate into the nucleus and was not able to shift the metabolism toward a highly glycolytic state, in contrast to the effect of yeast hexokinase 2 (Hxk2), which is a crucial protein for the control of aerobic glycolysis in S. cerevisiae. During the stationary phase, when glucose is exhausted, Hxk2 is shuttled out of the nucleus, ceasing catabolic repression. Cells harvested at this condition display low glucose consumption rates. However, glucose-starved cells expressing HK2 had an increased capacity to consume glucose. In those cells, HK2 localized to mitochondria, becoming insensitive to G6P inhibition. We also found that the sugar trehalose-6-phosphate (T6P) is a human HK2 inhibitor, like yeast Hxk2, but was not able to inhibit human HK1, the isoform that is ubiquitously expressed in almost all mammalian tissues. In contrast to G6P, T6P inhibited HK2 even when HK2 was associated with mitochondria. The binding of HK2 to mitochondria is crucial for cancer survival and proliferation. T6P was able to reduce the cell viability of tumor cells, although its toxicity was not impressive. This was expected as cell absorption of phosphorylated sugars is low, which might be counteracted using nanotechnology. Altogether, these data suggest that T6P may offer a new paradigm for cancer treatment based on specific inhibition of HK2.
Assuntos
Hexoquinase , Fosfatos Açúcares , Animais , Humanos , Hexoquinase/metabolismo , Saccharomyces cerevisiae/metabolismo , Glicólise , Glucose/metabolismo , MamíferosRESUMO
Epithelial-to-mesenchymal transition (EMT) confers the most lethal characteristics to cancer cells i.e., metastasis and resistance to chemo-and-radio-therapy, and therefore exhibit an appealing target in the field of oncology. Research in the past decade has demonstrated the crucial role of aerobic glycolysis in EMT, which is generally credited as the glucose metabolism for the creation of biomass such as fatty acids, amino acids, and nucleotides thereby providing building blocks for limitless proliferation. In the present review, apart from discussing EMT's evident role in the metastatic process and cancer stemness, we also talked about the vital role of glycolytic enzymes viz. GLUTs, HKs, PGI, PFK-1, aldolase, enolase, PK, LDHA, etc. in the induction of the EMT process in cancerous cells.
Assuntos
Transição Epitelial-Mesenquimal , Neoplasias , Carcinogênese , Glicólise , Humanos , Células-Tronco NeoplásicasRESUMO
INTRODUCTION AND OBJECTIVES: Warburg effect is attracting increasing attention as it is important for cancer progression. However, how cancer cells regulate glucose metabolism through glycolysis is still unknown. Here, we demonstrated the regulatory role of Ras related GTP binding D (RRAGD) in human hepatocellular carcinoma (HCC) cells. PATIENTS OR MATERIALS AND METHODS: Kaplan-Meier's analysis was used to analyze the correlation between RRAGD expression levels and prognosis of HCC patients from the Cancer Genome Atlas database. Two stable RRAGD knockdown HCC cell lines were created using shRNAs to investigate cancer progression and aerobic glycolysis. Western blot and quantitative reverse transcription polymerase chain reaction were performed to detect the expression levels of RRAGD and MYC. RESULTS: RRAGD expression was elevated in HCC patients with poor prognosis. RRAGD knockdown could inhibit the proliferation, invasion and migration of Huh-7 and HepG2 cells. Interestingly, silence RRAGD was able to reduce the glucose uptake, lactate production and extracellular acidification rate of HCC. RRAGD expression level was up-regulated by oncogene MYC in HCC cells. CONCLUSION: This study highlights RRAGD as an important cancer-promoting factor for cancer progression and aerobic glycolysis, and thereby it is a potential therapeutic target for HCC intervention.
Assuntos
Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Proteínas Monoméricas de Ligação ao GTP/genética , Efeito Warburg em Oncologia , Carcinoma Hepatocelular/metabolismo , Técnicas de Cultura de Células , Linhagem Celular Tumoral , Bases de Dados Factuais , Humanos , Neoplasias Hepáticas/metabolismo , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Prognóstico , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , RNA Mensageiro/metabolismoRESUMO
Lactate, the product of aerobic glycolysis, plays a dual role as fuel and intercellular signal in inflammation, immune evasion, and tumor progression. The production of lactate by macrophages has been associated with their polarization and function. Here we describe imaging protocols to characterize the metabolism of cultured human macrophages using a genetically encoded fluorescent sensor-specific for lactate. By superfusing cultures with increasing lactate concentrations and pharmacological inhibitors, it is possible to estimate the kinetic parameters of monocarboxylate transporter 4 (MCT4) and lactate production. Practical advice is given regarding sensor expression, imaging, and data analysis. The spatiotemporal resolution of this technique is amenable to the study of fast events at the single-cell level in different immune and other cell types.
Assuntos
Ácido Láctico/metabolismo , Macrófagos/metabolismo , Transporte Biológico/fisiologia , Linhagem Celular , Corantes Fluorescentes/metabolismo , Humanos , Cinética , Transportadores de Ácidos Monocarboxílicos/metabolismo , Células THP-1/metabolismoRESUMO
Protein kinase CK2 (formerly known as casein kinase 2) is abnormally elevated in many cancers. This may increase tumor aggressiveness through CK2-dependent phosphorylation of key proteins in several signaling pathways. In this work, we have compiled evidence from the literature to suggest that CK2 also modulates a metabolic switch characteristic of cancer cells that enhances resistance to death, due to either drugs or to a microenvironment deficient in oxygen or nutrients. Concurrently, CK2 may help to preserve mitochondrial activity in a PTEN-dependent manner. PTEN, widely recognized as a tumor suppressor, is another CK2 substrate in the PI3K/Akt signaling pathway that promotes cancer viability and aerobic glycolysis. Given that CK2 can regulate Akt as well as two of its main effectors, namely mTORC1 and ß-catenin, we comprehensively describe how CK2 may modulate cancer energetics by regulating expression of key targets and downstream processes, such as HIF-1 and autophagy, respectively. Thus, the specific inhibition of CK2 may lead to a catastrophic death of cancer cells, which could become a feasible therapeutic strategy to beat this devastating disease. In fact, ATP-competitive inhibitors, synthetic peptides and antisense oligonucleotides have been designed as CK2 inhibitors, some of them used in preclinical models of cancer, of which TBB and silmitasertib are widely known. We will finish by discussing a hypothetical scenario in which cancer cells are "addicted" to CK2; i.e., in which many proteins that regulate signaling pathways and metabolism-linked processes are highly dependent on this kinase.