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Breast cancer treatments are limited by the cancer subtype and its selectivity towards tumor cells, hence the importance of finding compounds that increase the survival of healthy cells and target any subtype. Incomptine A (IA) is a sesquiterpene lactone with demonstrated cytotoxic activity. In this study, through in vitro assays, it was observed that IA has similar cytotoxic activity between the subtypes triple negative, HER2+, and luminal A of the breast cancer cell lines. IA cytotoxic activity is higher in cancer than in nontumorigenic cells, and its selectivity index for cancer cells is more than that of the drug doxorubicin. Molecular docking and its in silico comparison with the 2-Deoxyglucose inhibitor suggest that IA could bind to Hexokinase II (HKII), decreasing its expression. Since we did not find changes in the expression of the glycolytic pathway, we suppose that IA could affect the antiapoptotic function of HKII in cancer cells. The IA-HKII union would activate the voltage-gated anion channel 1 (VDAC1), resuming apoptosis. Therefore, we suggest that IA could be used against almost any subtype and that its cytotoxic effect could be due to the reactivation of apoptosis in breast cancer cells.

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Cyclin/cyclin-dependent kinase (CDK) heterodimers have multiple phosphorylation targets and may alter the activity of these targets. Proteins from different metabolic processes are among the phosphorylation targets, that is, enzymes of central carbon metabolism. This work explores the interaction of Cyc/CDK complex members with the glycolytic enzymes hexokinase 7 (HXK7) and glyceraldehyde-3-phosphate dehydrogenase (GAP). Both enzymes interacted steadily with CycD2;2, CycB2;1 and CDKA;1 but not with CDKB1;1. However, Cyc/CDKB1;1 complexes phosphorylated both enzymes, decreasing their activities. Treatment with a CDK-specific inhibitor (RO-3306) or with lambda phosphatase after kinase assay restored total HXK7 activity, but not GAP activity. In enzymatic assays, increasing concentrations of CDKB1;1, but not of CycD2;2, CycB2;1 or CycD2;2/CDKB1;1 complex, decreased GAP activity. Cell cycle regulators may modulate carbon channeling in glycolysis by two different mechanisms: Cyc/CDK-mediated phosphorylation of targets (e.g., HXK7; canonical mechanism) or by direct and transient interaction of the metabolic enzyme (e.g., GAP) with CDKB1;1 without a Cyc partner (alternative mechanism).

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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.

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La medición de glucosa en caninos es un procedimiento habitual en la clínica diaria, actualmente este valor se puede obtener mediante dispositivos portátiles y pruebas laboratoriales. Se realizó esta investigación con el fin de aportar mayor conocimiento sobre la importancia de la medición de glucosa, ya que en los últimos años ha perdido valor entre las pruebas hematológicas a considerar debido a que solo se relaciona con determinadas patologías como la diabetes u otras enfermedades metabólicas. El presente trabajo tiene como objetivo comparar los valores de glucosa en caninos obtenidos mediante un glucómetro portátil de uso humano (Accu-chek® Active, Roche Diagnostic, Mannheim, Alemania); veterinario (aLcose® Vet Glu, jjPlus Corporation, New Taipei, Taiwán) y la prueba estándar de laboratorio, esto nos indicará la fiabilidad de los resultados obtenidos mediante estos métodos. Se realizó la toma de muestras de sangre de 50 caninos clínicamente sanos, de los cuales se obtuvo el resultado de glucemia mediante estos tres métodos. Los resultados de nuestra investigación evidenciaron que las tres formas de evaluación de la glucosa sanguínea en perros brindaban resultados estadísticamente diferentes (p < 0.05). Se obtuvo valores de glucosa diferentes entre los tres métodos de medición, teniendo como promedios finales 84.14 mg/dL, 101.12 mg/dL y 91.12 mg/dL correspondientes al glucómetro portátil de uso humano, veterinario y a la prueba estándar de laboratorio respectivamente. En conclusión, los glucómetros portátiles de uso humano subestiman los valores reales de glucosa, mientras que los de uso veterinario lo sobreestiman, comparados con la prueba estándar de laboratorio.

A medição de glicose nos cães é um procedimento habitual realizado no atendimento clínico. Atualmente este valor pode ser obtido por meio de dispositivos portáteis e testes laboratoriais. Esta pesquisa foi realizada com a finalidade de destacar a importância da medição de glicose, visto que nos últimos anos esta avaliação não tem sido muito valorada entre os testes hematológicos, sendo considerada relevante apenas em relação a patologias como a diabetes e outras doenças metabólicas. O presente estudo teve como objetivo comparar os valores de glicose em cães obtidos com glicômetro portátil de uso humano; veterinário e o teste padrão de laboratório. Esta comparação poderá indicar a confiabilidade dos resultados obtidos mediante os métodos avaliados. Foi realizada a amostragem do sangue de 50 caninos clinicamente sadios os quais foram submetidos a avaliação de glicose mediante os três métodos. Os resultados de nossa investigação evidenciaram que as três formas de avaliação da glicose sanguínea têm resultados estatisticamente diferentes (p < 0,05). Os valores de glicose tiveram medias finais de 84,14 mg/dL, 101,12 mg/dL e 91,12 mg/dL para o glicômetro portátil de uso humano (Accu-chek® Active, Roche Diagnostic, Mannheim, Alemanha), veterinário (aLcose® Vet Glu, jjPlus Corporation, Nova Taipei, Taiwan) e o teste padrão de laboratório, respectivamente. Ao concluir, os glicômetros portáteis de uso humano subestimam os valores reais de glicose e os de uso veterinário os superestimam quando comparados com o teste padrão de laboratório.

The measurement of glucose in canines is a common procedure in daily clinical practice. Currently this value can be obtained by use of portable devices and laboratory tests. This research was carried out in order to provide more knowledge about the importance of glucose measurement, since in recent years it has lost value among the hematological tests to be considered because it is only related to certain pathologies such as diabetes or other metabolic diseases. The present study aimed to compare the glucose values in dogs obtained with a portable glucometer for human use, veterinarian use, and the standard laboratory test. This comparison may indicate the reliability of the results obtained through the evaluated methods. A blood sampling of 50 clinically healthy canines was taken and submitted to glucose evaluation using the three methods. Our investigation showed that the three ways of assessing blood glucose have statistically different results (p < 0.05). Glucose values had final averages of 84.14 mg/dL, 101.12 mg/dL, and 91.12 mg/dL for the portable glucometer for human use (Accu-chek® Active, Roche Diagnostic, Mannheim, Germany), veterinary (aLcose® Vet Glu, jjPlus Corporation, New Taipei, Taiwan) and the standard laboratory test, respectively. In conclusion, portable glucometers for human use underestimate the glucose values, and those for veterinary use overestimate them compared to the standard laboratory test.

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Chronic Myeloid Leukemia is a neoplastic disease characterized by the abnormal expansion of hematopoietic cells with compromised functions. Leukemic cells often display a multidrug resistance phenotype, enabling them to evade a number of structurally unrelated cytotoxic compounds. One of those mechanisms relies on the high expression of efflux transporters, such as the ABC proteins, whose activity depends on the hydrolysis of ATP to reduce intracellular drug accumulation. In the present work, we employed a well-known erythroleukemia cell line, K562, and a multidrug resistant derivative cell, FEPS, to evaluate how hexokinase II, a key regulator for the rate-limiting step glycolysis, contributes to the establishment of the multidrug resistance phenotype. We found that multidrug resistant cells primarily resort to glycolysis to generate ATP. Clotrimazole reduced the expression of mitochondrial hexokinase II, which destabilized bioenergetic parameters such as reactive oxygen species production, ATP, and glutathione levels on multidrug resistant cells. This impaired the activity of ABCC1, leading to increased drug accumulation and cell death. In summary, we propose that decoupling of hexokinase II from the mitochondria emerges as a promising strategy to generate collateral sensitivity and aid in the management of chronic myeloid leukemia in chemotherapy-refractory patients.

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Water deficit currently acts as one of the largest limiting factors for agricultural productivity worldwide. Additionally, limitation by water scarcity is projected to continue in the future with the further onset of effects of global climate change. As a result, it is critical to develop or breed for crops that have increased water use efficiency and that are more capable of coping with water scarce conditions. However, increased intrinsic water use efficiency (iWUE) typically brings a trade-off with CO2 assimilation as all gas exchange is mediated by stomata, through which CO2 enters the leaf while water vapor exits. Previously, promising results were shown using guard-cell-targeted overexpression of hexokinase to increase iWUE without incurring a penalty in photosynthetic rates or biomass production. Here, two homozygous transgenic tobacco (Nicotiana tabacum) lines expressing Arabidopsis Hexokinase 1 (AtHXK1) constitutively (35SHXK2 and 35SHXK5) and a line that had guard-cell-targeted overexpression of AtHXK1 (GCHXK2) were evaluated relative to wild type for traits related to photosynthesis and yield. In this study, iWUE was significantly higher in GCHXK2 compared with wild type without negatively impacting CO2 assimilation, although results were dependent upon leaf age and proximity of precipitation event to gas exchange measurement.

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Glucose and oxygen (O2) are vital to the brain. Glucose metabolism and mitochondria play a pivotal role in this process, culminating in the increase of reactive O2 species. Hexokinase (HK) is a key enzyme on glucose metabolism and is coupled to the brain mitochondrial redox modulation by recycling ADP for oxidative phosphorylation (OXPHOS). GABA shunt is an alternative pathway to GABA metabolism that increases succinate levels, a Krebs cycle intermediate. Although glucose and GABA metabolisms are intrinsically connected, their interplay coordinating mitochondrial function is poorly understood. Here, we hypothesize that the HK and the GABA shunt interact to control mitochondrial metabolism differently in the cortex and the hypothalamus. The GABA shunt stimulated mitochondrial O2 consumption and H2O2 production higher in hypothalamic synaptosomes (HSy) than cortical synaptosomes (CSy). The GABA shunt increased the HK coupled to OXPHOS activity in both population of synaptosomes, but the rate of activation was higher in HSy than CSy. Significantly, malonate and vigabatrin blocked the effects of the GABA shunt in the HK activity coupled to OXPHOS. It indicates that the glucose phosphorylation is linked to GABA and Krebs cycle reactions. Together, these data shed light on the HK and SDH role on the metabolism of each region fed by GABA turnover, which depends on the neurons' metabolic route.

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Moonlighting proteins are defined as proteins with two or more functions that are unrelated and independent to each other, so that inactivation of one of them should not affect the second one and vice versa. Intriguingly, all the glycolytic enzymes are described as moonlighting proteins in some organisms. Hexokinase (HXK) is a critical enzyme in the glycolytic pathway and displays a wide range of functions in different organisms such as fungi, parasites, mammals, and plants. This review discusses HXKs moonlighting functions in depth since they have a profound impact on the responses to nutritional, environmental, and disease challenges. HXKs' activities can be as diverse as performing metabolic activities, as a gene repressor complexing with other proteins, as protein kinase, as immune receptor and regulating processes like autophagy, programmed cell death or immune system responses. However, most of those functions are particular for some organisms while the most common moonlighting HXK function in several kingdoms is being a glucose sensor. In this review, we also analyze how different regulation mechanisms cause HXK to change its subcellular localization, oligomeric or conformational state, the response to substrate and product concentration, and its interactions with membrane, proteins, or RNA, all of which might impact the HXK moonlighting functions.

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Diabetic retinopathy is thought to be trigger by glucose- induced oxidative stress which leads to an increase of the mitochondrial permeability through opening the permeability transition pore (MTP). In several cell types, hexokinases interact with the mitochondria regulating MTP opening, avoiding cytochrome c release. We studied HK I mitochondrial proportion in control and streptozotocin-induced diabetic rat retinas. In the normal retina, 50% of HK I was linked to mitochondria, proportion that did not change up to 60 days of diabetes. Mitochondria from normal and diabetic rat retinas showed a limited swelling, and similar cytochrome c levels. G-6-P and glycogen content increased 3-6-fold in diabetic rat retinas, while lactate content did not vary. Results suggest that mitochondrial bound HK produce G-6-P and drove it to glycogen synthesis, controlling ROS production and lactate toxicity.

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Methyl jasmonate (MeJA), common in the plant kingdom, is capable of reducing articular and hepatic inflammation and oxidative stress in adjuvant-induced arthritic rats. This study investigated the actions of orally administered MeJA (75-300 mg/kg) on inflammation, oxidative stress and selected enzyme activities in the brain of Holtzman rats with adjuvant-induced arthritis. MeJA prevented the arthritis-induced increased levels of nitrites, nitrates, lipid peroxides, protein carbonyls and reactive oxygen species (ROS). It also prevented the enhanced activities of myeloperoxidase and xanthine oxidase. Conversely, the diminished catalase and superoxide dismutase activities and glutathione (GSH) levels caused by arthritis were totally or partially prevented. Furthermore, MeJA increased the activity of the mitochondrial isocitrate dehydrogenase, which helps to supply NADPH for the mitochondrial glutathione cycle, possibly contributing to the partial recovery of the GSH/oxidized glutathione (GSSG) ratio. These positive actions on the antioxidant defenses may counterbalance the effects of MeJA as enhancer of ROS production in the mitochondrial respiratory chain. A negative effect of MeJA is the detachment of hexokinase from the mitochondria, which can potentially impair glucose phosphorylation and metabolism. In overall terms, however, it can be concluded that MeJA attenuates to a considerable extent the negative effects caused by arthritis in terms of inflammation and oxidative stress.

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Blood and liver from curimbata (Prochilodus lineatus) acclimated at pH 4.5, 7.0 and 8.0 and at 20 and 30 °C were exposed in vitro to different concentrations of copper (Cu): 98 ± 0.8 µg Cu L-1 at pH 4.5 and 16 ± 0.2 µg Cu L-1 at pH 8.0 at 20 °C; 88 ± 0.8 µg Cu L-1 at pH 4.5 and 14 ± 0.5 µg Cu L-1 at pH 8.0 at 30 °C and in 29 µg Cu L-1 at pH 7.0 at 20 and 30 °C for 2 h. The pH affected the levels of glucose and glycogen and in vitro exposure to Cu increased glucose levels and decreased glycogen at 20 and 30 °C. Exposures to acid water and Cu in vitro also resulted in an increase in enzyme activity in the blood, hexokinase (HK), pyruvate kinase (PK) and at pH 8.0 decreased the HK activity and increased PK and lactate dehydrogenase (LDH) activities at 20 °C. Cu caused an increase in the activities of HK (at pH 4.5) and PK in both pH, 4.5 and 8.0 at 30 °C. At 20 °C, HK (pH 8.0) and glycose-6-phosphate dehydrogenase (G6PDH) (pH 4.5) activities increased and PK (pHs 4.5 and 8.0) and LDH decreased (pH 4.5) in the liver. In vitro, exposure to Cu increased HK and G6PDH at pH 8.0 and PK activity increased in both pH values and LDH increased in pH 7.0. Cu exposure in vitro at 30 °C, phosphofructokinase (PFK) and PK activities decreased and LDH activity increased in all pH values when compared to fish from the water from its respective pH values. Interactions occurred in blood and liver between the temperature, pH and exposure to copper in vitro. The in vitro tests may constitute an interesting biological model for experimental and applied toxicology, especially in the case of environmental pollution.

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The adult brain is a high-glucose and oxygen-dependent organ, with an extremely organized network of cells and large energy-consuming synapses. To reach this level of organization, early stages in development must include an efficient control of cellular events and regulation of intracellular signaling molecules and ions such as hydrogen peroxide (H2 O2 ) and calcium (Ca2+ ), but in cerebral tissue, these mechanisms of regulation are still poorly understood. Hexokinase (HK) is the first enzyme in the metabolism of glucose and, when bound to mitochondria (mtHK), it has been proposed to have a role in modulation of mitochondrial H2 O2  generation and Ca2+ handling. Here, we have investigated how mtHK modulates these signals in the mitochondrial context during postnatal development of the mouse brain. Using high-resolution respirometry, western blot analysis, spectrometry and resorufin, and Calcium Green fluorescence assays with brain mitochondria purified postnatally from day 1 to day 60, we demonstrate that brain HK increases its coupling to mitochondria and to oxidative phosphorylation to induce a cycle of ADP entry/ATP exit of the mitochondrial matrix that leads to efficient control over H2 O2 generation and Ca2+ uptake during development until reaching plateau at day 21. This contrasts sharply with the antioxidant enzymes, which do not increase as mitochondrial H2 O2 generation escalates. These results suggest that, as its use of glucose increases, the brain couples HK to mitochondria to improve glucose metabolism, redox balance and Ca2+ signaling during development, positioning mitochondria-bound hexokinase as a hub for intracellular signaling control.

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BACKGROUND: Seed germination is a crucial process in the plant life cycle when a dramatic variation of type and sugar content occurs just as the seed is hydrated. The production of hexose 6 phosphate is a key node in different pathways that are required for a successful germination. Hexokinase (HXK) is the only plant enzyme that phosphorylates glucose (Glc), so it is key to fueling several metabolic pathways depending on their substrate specificity, metabolite regulatory responses and subcellular localization. In maize, the HXK family is composed of nine genes, but only six of them (ZmHXK4-9) putatively encode catalytically active enzymes. Here, we cloned and functionally characterized putative catalytic enzymes to analyze their metabolic contribution during germination process. RESULTS: From the six HXKs analyzed here, only ZmHXK9 has minimal hexose phosphorylating activity even though enzymatic function of all isoforms (ZmHXK4-9) was confirmed using a yeast complementation approach. The kinetic parameters of recombinant proteins showed that ZmHXK4-7 have high catalytic efficiency for Glc, fructose (Fru) and mannose (Man), ZmHXK7 has a lower Km for ATP, and together with ZmHXK8 they have lower sensitivity to inhibition by ADP, G6P and N-acetylglucosamine than ZmHXK4-6 and ZmHXK9. Additionally, we demonstrated that ZmHXK4-6 and ZmHXK9 are located in the mitochondria and their location relies on the first 30 amino acids of the N-terminal domain. Otherwise, ZmHXK7-8 are constitutively located in the cytosol. HXK activity was detected in cytosolic and mitochondrial fractions and high Glc and Fru phosphorylating activities were found in imbibed embryos. CONCLUSIONS: Considering the biochemical characteristics, location and the expression of ZmHXK4 at onset of germination, we suggest that it is the main contributor to mitochondrial activity at early germination times, at 24 h other ZmHXKs also contribute to the total activity. While in the cytosol, ZmHXK7 could be responsible for the activity at the onset of germination, although later, ZmHXK8 also contributes to the total HXK activity. Our observations suggest that the HXKs may be redundant proteins with specific roles depending on carbon and ATP availability, metabolic needs, or sensor requirements. Further investigation is necessary to understand their specific or redundant physiological roles.

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Hexokinases play a critical role in the cellular uptake and utilization of glucose. As such, they are of fundamental importance to all cells. By catalyzing glucose to produce glucose-6-phosphate, hexokinases control the first irreversible step of glucose metabolism and initiate all major pathways of glucose consumption. Our objective was to develop and validate highly sensitive and selective high-performance liquid chromatography with photodiode array detector (HPLC-PDA) assays allowing the determination of adenosine diphosphate, which was used for the determination of hexokinase activity. Samples were analyzed by HPLC-PDA using a C18 analytical column (250 × 4.6 mm) for chromatographic separation. Optimal detection was achieved based on isocratic elution with a mobile phase consisting of a mixture of sodium phosphate monobasic buffer and methanol. This method met all of the requirements of specificity, sensitivity, linearity, precision, accuracy and stability generally accepted in bioanalytical chemistry and was successfully applied to a study of hexokinase activity in an alloxan-induced diabetic rat model. Determination of hexokinase activity will permit characterization of cellular metabolic state in many diseases, such as cancer and diabetes.

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Glucokinase from pathogenic protozoa of the genus Leishmania is a potential drug target for the chemotherapeutic treatment against leishmaniasis because this enzyme is located at a nodal point between two critically important metabolic pathways, glycolysis and the pentose phosphate pathway (PPP). L. braziliensis glucokinase (LbGlcK) was evaluated for its structural characterization and enzymatic performance. The enzyme catalyzes the phosphorylation of d-glucose with co-substrate ATP to yield the products G6P and ADP. LbGlcK had KM values determined as 6.61 ± 2.63 mM and 0.338 ± 0.080 mM for d-glucose and ATP, respectively. The 1.85 Å resolution X-ray crystal structure of the apo form of LbGlcK was determined and a homodimer was revealed where each subunit (both in open conformations) included the typical small and large domains. Structural comparisons were assessed in relationship to Homo sapiens hexokinase IV and Trypanosoma cruzi glucokinase. Comparisons revealed that all residues important for making hydrogen bonding interactions with d-glucose in the active site and catalysis were strictly conserved. LbGlcK was screened against four glucosamine analogue inhibitors and the stronger inhibitor of the series, HPOP-GlcN, had a Ki value of 56.9 ± 16.6 µM that exhibited competitive inhibition. For the purpose of future structure-based drug design experimentation, L. braziliensis glucokinase was observed to be very similar to T. cruzi glucokinase even though there was a 44% protein sequence identity between the two enzymes.

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The reduced expression of solute carrier family 2, facilitated glucose transporter member 4 (GLUT4) and hexokinase-2 (HK2) in skeletal muscle participates in insulin resistance of diabetes mellitus (DM). MicroRNAs (miRNAs) have emerged as important modulators of mRNA/protein expression, but their role in DM is unclear. We investigated miRNAs hypothetically involved in GLUT4/HK2 expression in soleus muscle of type 1 diabetes-like rats. In silico analysis revealed 651 miRNAs predicted to regulate solute carrier family 2 member 4 (Slc2a4) mRNA, several of them also predicted to regulate Hk2 mRNA, and 16 miRNAs were selected for quantification. Diabetes reduced Slc2a4/GLUT4 and Hk2/HK2 expression (50-77%), upregulated miR-29b-3p and miR-29c-3p (50-100%), and downregulated miR-93-5p, miR-150-5p, miR-199a-5p, miR-345-3p, and miR-532-3p (~30%) expression. Besides, GLUT4 and HK2 proteins correlated (P < 0.05) negatively with miR-29b-3p and miR-29c-3p and positively with miR-199a-5p and miR-532-3p, suggesting that these miRNAs could be markers of alterations in GLUT4 and HK2 expression. Additionally, diabetes increased the nuclear factor kappa B subunit 1 protein (p50) expression, a repressor of Slc2a4, which was also predicted as a target for miR-199a-5p and miR-532-3p. Correlations were also detected between these miRNAs and blood glucose, 24-h glycosuria and plasma fructosamine, and insulin therapy reversed most of the alterations. In sum, we report that diabetes altered miR-29b-3p, miR-29c-3p, miR-199a-5p and miR-532-3p expression in muscle of male rats, where their predicted targets Slc2a4/GLUT4 and Hk2/HK2 are repressed. These data shed light on these miRNAs as a markers of impaired skeletal muscle glucose disposal, and, consequently, glycemic control in diabetes.

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Among all the adaptations of cancer cells, their ability to change metabolism from the oxidative to the glycolytic phenotype is a hallmark called the Warburg effect. Studies on tumor metabolism show that improved glycolysis and glutaminolysis are necessary to maintain rapid cell proliferation, tumor progression, and resistance to cell death. Thyroid neoplasms are common endocrine tumors that are more prevalent in women and elderly individuals. The incidence of thyroid cancer has increased in the Past decades, and recent findings describing the metabolic profiles of thyroid tumors have emerged. Currently, several drugs are in development or clinical trials that target the altered metabolic pathways of tumors are undergoing. We present a review of the metabolic reprogramming in cancerous thyroid tissues with a focus on the factors that promote enhanced glycolysis and the possible identification of promising metabolic targets in thyroid cancer.

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Glucose and oxygen are vital for the brain, as these molecules provide energy and metabolic intermediates that are necessary for cell function. The glycolysis pathway and mitochondria play a pivotal role in cell energy metabolism, which is closely related to reactive oxygen species (ROS) production. Hexokinase (HK) is a key enzyme involved in glucose metabolism that modulates the level of brain mitochondrial ROS by recycling ADP for oxidative phosphorylation (OxPhos). Here, we hypothesize that the control of mitochondrial metabolism by hexokinase differs in distinct areas of the brain, such as the cortex and hypothalamus, in which ROS might function as signaling molecules. Thus, we investigated mitochondrial metabolism of synaptosomes derived from both brain regions. Cortical synaptosomes (CSy) show a predominance of glutamatergic synapses, while in the hypothalamic synaptosomes (HSy), the GABAergic synapses predominate. Significant differences of oxygen consumption and ROS production were related to higher mitochondrial complex II activity (succinate dehydrogenase-SDH) in CSy rather than to mitochondrial number. Mitochondrial HK (mt-HK) activity was higher in CSy than in HSy regardless the substrate added. Mitochondrial O2 consumption related to mt-HK activation by 2-deoxyglucose was also higher in CSy. In the presence of substrate for complex II, the activation of synaptosomal mt-HK promoted depuration of ROS in both HSy and CSy, while ROS depuration did not occur in HSy when substrate for complex I was used. The impact of the mt-HK inhibition by glucose-6-phosphate (G6P) was the same in synaptosomes from both areas. Together, the differences found between CSy and HSy indicate specific roles of mt-HK and SDH on the metabolism of each brain region, what probably depends on the main metabolic route that is used by the neurons.

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Hexokinase (HK) is the first enzyme in the glycolytic pathway and is responsible for glucose phosphorylation and fixation into the cell. HK (HK-II) is expressed in skeletal muscle and can be found in the cytosol or bound mitochondria, where it can protect cells against insults such as oxidative stress. 4-Phenyl butyric acid (4-PBA) is a chemical chaperone that inhibits endoplasmic reticulum stress and contributes to the restoring of glucose homeostasis. AIMS: Here, we decided to investigate whether HK activity and its interaction with mitochondria could be a target of 4-PBA action. MAIN METHODS: L6 myotubes were treated with 1mM 4-PBA for 24, 48 or 72h. We evaluated HK activity, glucose and oxygen consumption, gene and protein expression. KEY FINDINGS: We found that L6 myotubes treated with 4-PBA presented more HK activity in the particulate fraction, increased glucose consumption and augmented Glut4, Hk2 and Vdac1 mRNA expression. Moreover, 4-PBA prevented the deleterious effect of antimycin-A on HK particulate activity. SIGNIFICANCE: Together, these results suggest a new role of 4-PBA in glucose metabolism that includes HK as a potential target of beneficial effect of 4-PBA.

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High hypoxic, glycolytic and acidosis metabolisms characterize cervical cancer tumors and have been described to be involved in chemoradioresistance mechanisms. Based on these observations, the present study assessed four selected novel biomarkers on the prognosis of locally advanced cervical carcinoma. A total of 66 patients with stage IIB/IIIB cervical cancer were retrospectively included. The protein expression levels of glucose transporter 1 (GLUT1), carbonic anhydrase 9 (CAIX) and hexokinase 1 (HKII) were investigated by immunohistochemistry on tumor biopsies, hemoglobin was measured and the disease outcome was monitored. A total of 53 patients (80.3%) presented a complete response. For these patients, the protein expression levels of GLUT1, CAIX and HKII were overexpressed. A significant difference was observed (P=0.0127) for hemoglobin levels (≤11 g/dl) in responsive compared with non-responsive patients. The expression of GLUT1 is associated with a lower rate of both overall and disease-free survival, with a trend of decreased risk of 1.1x and 1.5x, respectively. Co-expression of GLUT1 and HKII is associated with a decreased trend risk of 1.6x for overall survival. Patients with hemoglobin levels ≤11 g/dl had a 4.3-fold risk (P=0.02) in decreasing both to the rate of overall and disease-free survival. The presence of anemic hypoxia (hemoglobin ≤11 g/dl) and the expression of GLUT1 and/or HKII influence treatment response and are associated with a lower overall and disease-free survival. The present results demonstrated that these biomarkers may be used as predictive markers and suggested that these metabolic pathways can be used as potential novel therapeutic targets.