To see the other types of publications on this topic, follow the link: Glycolysis. Protein kinases Phosphorylation Metabolism.
Journal articles on the topic 'Glycolysis. Protein kinases Phosphorylation Metabolism'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Glycolysis. Protein kinases Phosphorylation Metabolism.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Horlock, Anthony D., Thomas J. R. Ormsby, Martin J. D. Clift, José E. P. Santos, John J. Bromfield, and I. Martin Sheldon. "Manipulating bovine granulosa cell energy metabolism limits inflammation." Reproduction 161, no. 5 (May 2021): 499–512. http://dx.doi.org/10.1530/rep-20-0554.
Full textAbstract:
Bovine granulosa cells are often exposed to energy stress, due to the energy demands of lactation, and exposed to lipopolysaccharide from postpartum bacterial infections. Granulosa cells mount innate immune responses to lipopolysaccharide, including the phosphorylation of mitogen-activated protein kinases and production of pro-inflammatory interleukins. Cellular energy depends on glycolysis, and energy stress activates intracellular AMPK (AMP-activated protein kinase), which in turn inhibits mTOR (mechanistic target of rapamycin). Here, we tested the hypothesis that manipulating glycolysis, AMPK or mTOR to mimic energy stress in bovine granulosa cells limits the inflammatory responses to lipopolysaccharide. We inhibited glycolysis, activated AMPK or inhibited mTOR in granulosa cells isolated from 4–8mm and from > 8.5 mm diameter ovarian follicles, and then challenged the cells with lipopolysaccharide and measured the production of interleukins IL-1α, IL-1β, and IL-8. We found that inhibiting glycolysis with 2-deoxy-d-glucose reduced lipopolysaccharide-stimulated IL-1α > 80%, IL-1β > 90%, and IL-8 > 65% in granulosa cells from 4–8 mm and from > 8.5 mm diameter ovarian follicles. Activating AMPK with AICAR also reduced lipopolysaccharide-stimulated IL-1α > 60%, IL-1β > 75%, and IL-8 > 20%, and shortened the duration of lipopolysaccharide-stimulated phosphorylation of the mitogen-activated protein kinase ERK1/2 and JNK. However, only the mTOR inhibitor Torin 1, and not rapamycin, reduced lipopolysaccharide-stimulated IL-1α and IL-1β. In conclusion, manipulating granulosa cell energy metabolism with a glycolysis inhibitor, an AMPK activator, or an mTOR inhibitor, limited inflammatory responses to lipopolysaccharide. Our findings imply that energy stress compromises ovarian follicle immune defences.
2
Chou, Po-Chien, Swati Rajput, Xiaoyun Zhao, Chadni Patel, Danielle Albaciete, Won Jun Oh, Heineken Queen Daguplo, et al. "mTORC2 Is Involved in the Induction of RSK Phosphorylation by Serum or Nutrient Starvation." Cells 9, no. 7 (June 27, 2020): 1567. http://dx.doi.org/10.3390/cells9071567.
Full textAbstract:
Cells adjust to nutrient fluctuations to restore metabolic homeostasis. The mechanistic target of rapamycin (mTOR) complex 2 responds to nutrient levels and growth signals to phosphorylate protein kinases belonging to the AGC (Protein Kinases A,G,C) family such as Akt and PKC. Phosphorylation of these AGC kinases at their conserved hydrophobic motif (HM) site by mTORC2 enhances their activation and mediates the functions of mTORC2 in cell growth and metabolism. Another AGC kinase family member that is known to undergo increased phosphorylation at the homologous HM site (Ser380) is the p90 ribosomal S6 kinase (RSK). Phosphorylation at Ser380 is facilitated by the activation of the mitogen-activated protein kinase/extracellular signal regulated kinase (MAPK/ERK) in response to growth factor stimulation. Here, we demonstrate that optimal phosphorylation of RSK at this site requires an intact mTORC2. We also found that RSK is robustly phosphorylated at Ser380 upon nutrient withdrawal or inhibition of glycolysis, conditions that increase mTORC2 activation. However, pharmacological inhibition of mTOR did not abolish RSK phosphorylation at Ser380, indicating that mTOR catalytic activity is not required for this phosphorylation. Since RSK and SIN1β colocalize at the membrane during serum restimulation and acute glutamine withdrawal, mTORC2 could act as a scaffold to enhance RSK HM site phosphorylation. Among the known RSK substrates, the CCTβ subunit of the chaperonin containing TCP-1 (CCT) complex had defective phosphorylation in the absence of mTORC2. Our findings indicate that the mTORC2-mediated phosphorylation of the RSK HM site could confer RSK substrate specificity and reveal that RSK responds to nutrient fluctuations.
3
Jaswal, Jagdip S., Manoj Gandhi, Barry A. Finegan, Jason R. B. Dyck, and Alexander S. Clanachan. "Effects of adenosine on myocardial glucose and palmitate metabolism after transient ischemia: role of 5′-AMP-activated protein kinase." American Journal of Physiology-Heart and Circulatory Physiology 291, no. 4 (October 2006): H1883—H1892. http://dx.doi.org/10.1152/ajpheart.01147.2005.
Full textAbstract:
Loss of cardioprotection by adenosine in hearts stressed by transient ischemia may be due to its effects on glucose metabolism. In the absence of transient ischemia, adenosine inhibits glycolysis, whereas it accelerates glycolysis after transient ischemia. Inasmuch as 5′-AMP-activated protein kinase (AMPK) is implicated as a regulator of glucose and fatty acid utilization, this study determined whether a differential alteration of AMPK activity contributes to acceleration of glycolysis by adenosine in hearts stressed by transient ischemia. Studies were performed in working rat hearts perfused aerobically under normal conditions or after transient ischemia (two 10-min periods of ischemia followed by 5 min of reperfusion). LV work was not affected by adenosine. AMPK phosphorylation was not affected by transient ischemia; however, phosphorylation and activity were increased nine- and threefold, respectively, by adenosine in stressed hearts. Phosphorylation of acetyl-CoA carboxylase and rates of palmitate oxidation were unaltered. Glycolysis and calculated proton production were increased 1.8- and 1.7-fold, respectively, in hearts with elevated AMPK activity. Elevated AMPK activity was associated with inhibition of glycogen synthesis and unchanged rates of glucose uptake and glycogenolysis. Phentolamine, an α-adrenoceptor antagonist, which prevents adenosine-induced activation of glycolysis in stressed hearts, prevented AMPK phosphorylation. These data demonstrate that adenosine-induced activation of AMPK after transient ischemia is not sufficient to alter palmitate oxidation or glucose uptake. Rather, activation of AMPK alters partitioning of glucose away from glycogen synthesis; the increase in glycolysis may in part contribute to loss of adenosine-induced cardioprotection in hearts subjected to transient ischemia.
4
Che, Pulin, Lei Yu, Gregory K. Friedman, Meimei Wang, Xiaoxue Ke, Huafeng Wang, Wenbin Zhang, Burt Nabors, Qiang Ding, and Xiaosi Han. "Integrin αvβ3 Engagement Regulates Glucose Metabolism and Migration through Focal Adhesion Kinase (FAK) and Protein Arginine Methyltransferase 5 (PRMT5) in Glioblastoma Cells." Cancers 13, no. 5 (March 5, 2021): 1111. http://dx.doi.org/10.3390/cancers13051111.
Full textAbstract:
Metabolic reprogramming promotes glioblastoma cell migration and invasion. Integrin αvβ3 is one of the major integrin family members in glioblastoma multiforme cell surface mediating interactions with extracellular matrix proteins that are important for glioblastoma progression. The role of αvβ3 integrin in regulating metabolic reprogramming and its mechanism of action have not been determined in glioblastoma cells. Integrin αvβ3 engagement with osteopontin promotes glucose uptake and aerobic glycolysis, while inhibiting mitochondrial oxidative phosphorylation. Blocking or downregulation of integrin αvβ3 inhibits glucose uptake and aerobic glycolysis and promotes mitochondrial oxidative phosphorylation, resulting in decreased migration and growth in glioblastoma cells. Pharmacological inhibition of focal adhesion kinase (FAK) or downregulation of protein arginine methyltransferase 5 (PRMT5) blocks metabolic shift toward glycolysis and inhibits glioblastoma cell migration and invasion. These results support that integrin αvβ3 and osteopontin engagement plays an important role in promoting the metabolic shift toward glycolysis and inhibiting mitochondria oxidative phosphorylation in glioblastoma cells. The metabolic shift in cell energy metabolism is coupled to changes in migration, invasion, and growth, which are mediated by downstream FAK and PRMT5 in glioblastoma cells.
5
Miwa, Hiroshi, Kazuto Suganuma, Masato Shikami, Norikazu Imai, Mayuko Sakai, Akihito Hiramatsu, Hidesuke Yamamoto, et al. "Energy Metabolism of Leukemia Cells: Glycolysis Vs Oxidative Phosphorylation." Blood 112, no. 11 (November 16, 2008): 2935. http://dx.doi.org/10.1182/blood.v112.11.2935.2935.
Full textAbstract:
Abstract Cancer cells are more dependent on glycolysis than oxidative phosphorylation in the mitochondria for generation of ATP as energy source. By using 2-deoxy-D-glucose (2-DG: glycolysis inhibitor) and oligomycin (inhibitor of oxidative phosphorylation), we examined the energy metabolism of various leukemia cell lines. The growth of the cell lines was measured by MTS assay, which detects viable cells in proliferation. 2-DG suppressed the growth of all leukemia cell lines examined in dose-dependent manners. The IC50 of each cell line was as follows: Kasumi-1 0.5±0.1mM, KG-1a 1.8±0.6mM, HL-60 3.3±0.1mM, NB4 3.8±0.4mM, and THP-1 23.1±3.8mM. The concentration of lactic acid (the final product of glycolytic pathway) in the culture supernatant was greatly reduced by the treatment with 0.2mM 2-DG for 24 hours in Kasumi-1 (54.5% of the control), compared with THP-1 (92.2%). It is suggested that the growth of Kasumi-1 was strongly suppressed by 2-DG through inhibition of glycolysis, which is supposed to be a main metabolic pathway in this cell line. On the other hand, treatment with oligomycin (1μg/ml) for 48 hours potently suppressed the growth of THP-1 (44.7%), then Kasumi-1 (72.1%). The growth of NB4, KG-1a and HL-60 was minimally suppressed (more than 90%) by oligomycin. Cell cycle was analyzed after 24 hours treatment with 2-DG or oligomycin. Sub-G1 fraction (apoptosis) was greatly increased by 2-DG (5mM) in Kasumi-1 (56.5%) and NB4 (30.6%), compared with THP-1 (7.6%). The apoptosis inducing effect was confirmed by annexinV staining. Oligomycin treatment (1μg/ml) increased apoptosis (subG1) in THP-1 (35.8%), then Kasumi-1 (16.6%) and NB4 (12.2%). Oligomycin treatment also increased G1 population (G1 arrest) in THP-1 (35.9% to 69.4%). AMP-activated protein kinase (AMPK) is activated by an elevated AMP/ATP ratio, which means the energy-deprived status of the cell. Western blot analysis using phospho-AMPK α (Thr172) antibody revealed that treatment with 2-DG or oligomycin induced prompt (30 min) phosphorylation of AMPK in leukemia cell lines. The extent of AMPK phosphorylation was almost proportional to the suppression of the growth. Collectively, it is suggested that leukemia cells are dependent almost exclusively on either glycolysis or oxidative phosphorylation in the mitochondria for energy production. Then, inhibition of glycolysis by 2-DG or oxidative phosphorylation by oligomycin results in growth suppression by inducing apoptosis and/or cell cycle arrest through activation of AMPK. Our data clarified the characteristics of the energy metabolism of each leukemia cell, and showed the key to produce novel therapeutic approach targeting metabolic pathway.
6
He, Nanhai, Weiwei Fan, Brian Henriquez, Ruth T. Yu, Annette R. Atkins, Christopher Liddle, Ye Zheng, Michael Downes, and Ronald M. Evans. "Metabolic control of regulatory T cell (Treg) survival and function by Lkb1." Proceedings of the National Academy of Sciences 114, no. 47 (November 6, 2017): 12542–47. http://dx.doi.org/10.1073/pnas.1715363114.
Full textAbstract:
The metabolic programs of functionally distinct T cell subsets are tailored to their immunologic activities. While quiescent T cells use oxidative phosphorylation (OXPHOS) for energy production, and effector T cells (Teffs) rely on glycolysis for proliferation, the distinct metabolic features of regulatory T cells (Tregs) are less well established. Here we show that the metabolic sensor LKB1 is critical to maintain cellular metabolism and energy homeostasis in Tregs. Treg-specific deletion of Lkb1 in mice causes loss of Treg number and function, leading to a fatal, early-onset autoimmune disorder. Tregs lacking Lkb1 have defective mitochondria, compromised OXPHOS, depleted cellular ATP, and altered cellular metabolism pathways that compromise their survival and function. Furthermore, we demonstrate that the function of LKB1 in Tregs is largely independent of the AMP-activated protein kinase, but is mediated by the MAP/microtubule affinity-regulating kinases and salt-inducible kinases. Our results define a metabolic checkpoint in Tregs that couples metabolic regulation to immune homeostasis and tolerance.
7
Rodríguez-Enríquez, Sara, Álvaro Marín-Hernández, Juan Carlos Gallardo-Pérez, Silvia Cecilia Pacheco-Velázquez, Javier Alejandro Belmont-Díaz, Diana Xochiquetzal Robledo-Cadena, Jorge Luis Vargas-Navarro, Norma Angélica Corona de la Peña, Emma Saavedra, and Rafael Moreno-Sánchez. "Transcriptional Regulation of Energy Metabolism in Cancer Cells." Cells 8, no. 10 (October 9, 2019): 1225. http://dx.doi.org/10.3390/cells8101225.
Full textAbstract:
Cancer development, growth, and metastasis are highly regulated by several transcription regulators (TRs), namely transcription factors, oncogenes, tumor-suppressor genes, and protein kinases. Although TR roles in these events have been well characterized, their functions in regulating other important cancer cell processes, such as metabolism, have not been systematically examined. In this review, we describe, analyze, and strive to reconstruct the regulatory networks of several TRs acting in the energy metabolism pathways, glycolysis (and its main branching reactions), and oxidative phosphorylation of nonmetastatic and metastatic cancer cells. Moreover, we propose which possible gene targets might allow these TRs to facilitate the modulation of each energy metabolism pathway, depending on the tumor microenvironment.
8
Ding, Hao, Lei Jiang, Jing Xu, Feng Bai, Yang Zhou, Qi Yuan, Jing Luo, Ke Zen, and Junwei Yang. "Inhibiting aerobic glycolysis suppresses renal interstitial fibroblast activation and renal fibrosis." American Journal of Physiology-Renal Physiology 313, no. 3 (September 1, 2017): F561—F575. http://dx.doi.org/10.1152/ajprenal.00036.2017.
Full textAbstract:
Chronic kidney diseases generally lead to renal fibrosis. Despite great progress having been made in identifying molecular mediators of fibrosis, the mechanism that governs renal fibrosis remains unclear, and so far no effective therapeutic antifibrosis strategy is available. Here we demonstrated that a switch of metabolism from oxidative phosphorylation to aerobic glycolysis (Warburg effect) in renal fibroblasts was the primary feature of fibroblast activation during renal fibrosis and that suppressing renal fibroblast aerobic glycolysis could significantly reduce renal fibrosis. Both gene and protein assay showed that the expression of glycolysis enzymes was upregulated in mouse kidneys with unilateral ureter obstruction (UUO) surgery or in transforming growth factor-β1 (TGF-β1)-treated renal interstitial fibroblasts. Aerobic glycolysis flux, indicated by glucose uptake and lactate production, was increased in mouse kidney with UUO nephropathy or TGF-β1-treated renal interstitial fibroblasts and positively correlated with fibrosis process. In line with this, we found that increasing aerobic glycolysis can remarkably induce myofibroblast activation while aerobic glycolysis inhibitors shikonin and 2-deoxyglucose attenuate UUO-induced mouse renal fibrosis and TGF-β1-stimulated myofibroblast activation. Furthermore, mechanistic study indicated that shikonin inhibits renal aerobic glycolysis via reducing phosphorylation of pyruvate kinase type M2, a rate-limiting glycolytic enzyme associated with cell reliance on aerobic glycolysis. In conclusion, our findings demonstrate the critical role of aerobic glycolysis in renal fibrosis and support treatment with aerobic glycolysis inhibitors as a potential antifibrotic strategy.
9
Kuranaga, Yuki, Nobuhiko Sugito, Haruka Shinohara, Takuya Tsujino, Kohei Taniguchi, Kazumasa Komura, Yuko Ito, Tomoyoshi Soga, and Yukihiro Akao. "SRSF3, a Splicer of the PKM Gene, Regulates Cell Growth and Maintenance of Cancer-Specific Energy Metabolism in Colon Cancer Cells." International Journal of Molecular Sciences 19, no. 10 (October 2, 2018): 3012. http://dx.doi.org/10.3390/ijms19103012.
Full textAbstract:
Serine and arginine rich splicing factor 3 (SRSF3), an SR-rich family protein, has an oncogenic function in various kinds of cancer. However, the detailed mechanism of the function had not been previously clarified. Here, we showed that the SRSF3 splicer regulated the expression profile of the pyruvate kinase, which is one of the rate-limiting enzymes in glycolysis. Most cancer cells express pyruvate kinase muscle 2 (PKM2) dominantly to maintain a glycolysis-dominant energy metabolism. Overexpression of SRSF3, as well as that of another splicer, polypyrimidine tract binding protein 1 (PTBP1) and heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1), in clinical cancer samples supported the notion that these proteins decreased the Pyruvate kinase muscle 1 (PKM1)/PKM2 ratio, which positively contributed to a glycolysis-dominant metabolism. The silencing of SRSF3 in human colon cancer cells induced a marked growth inhibition in both in vitro and in vivo experiments and caused an increase in the PKM1/PKM2 ratio, thus resulting in a metabolic shift from glycolysis to oxidative phosphorylation. At the same time, the silenced cells were induced to undergo autophagy. SRSF3 contributed to PKM mRNA splicing by co-operating with PTBP1 and hnRNPA1, which was validated by the results of RNP immunoprecipitation (RIP) and immunoprecipitation (IP) experiments. These findings altogether indicated that SRSF3 as a PKM splicer played a positive role in cancer-specific energy metabolism.
10
Murugina, Nina E., Anna S. Budikhina, Yulia A. Dagil, Polina V. Maximchik, Lyudmila S. Balyasova, Vladimir V. Murugin, Mikhail V. Melnikov, et al. "Glycolytic reprogramming of macrophages activated by NOD1 and TLR4 agonists: No association with proinflammatory cytokine production in normoxia." Journal of Biological Chemistry 295, no. 10 (January 31, 2020): 3099–114. http://dx.doi.org/10.1074/jbc.ra119.010589.
Full textAbstract:
Upon activation with pathogen-associated molecular patterns, metabolism of macrophages and dendritic cells is shifted from oxidative phosphorylation to aerobic glycolysis, which is considered important for proinflammatory cytokine production. Fragments of bacterial peptidoglycan (muramyl peptides) activate innate immune cells through nucleotide-binding oligomerization domain (NOD) 1 and/or NOD2 receptors. Here, we show that NOD1 and NOD2 agonists induce early glycolytic reprogramming of human monocyte-derived macrophages (MDM), which is similar to that induced by the Toll-like receptor 4 (TLR4) agonist lipopolysaccharide. This glycolytic reprogramming depends on Akt kinases, independent of mTOR complex 1 and is efficiently inhibited by 2-deoxy-d-glucose (2-DG) or by glucose starvation. 2-DG inhibits proinflammatory cytokine production by MDM and monocyte-derived dendritic cells activated by NOD1 or TLR4 agonists, except for tumor necrosis factor production by MDM, which is inhibited initially, but augmented 4 h after addition of agonists and later. However, 2-DG exerts these effects by inducing unfolded protein response rather than by inhibiting glycolysis. By contrast, glucose starvation does not cause unfolded protein response and, in normoxic conditions, only marginally affects proinflammatory cytokine production triggered through NOD1 or TLR4. In hypoxia mimicked by treating MDM with oligomycin (a mitochondrial ATP synthase inhibitor), both 2-DG and glucose starvation strongly suppress tumor necrosis factor and interleukin-6 production and compromise cell viability. In summary, the requirement of glycolytic reprogramming for proinflammatory cytokine production in normoxia is not obvious, and effects of 2-DG on cytokine responses should be interpreted cautiously. In hypoxia, however, glycolysis becomes critical for cytokine production and cell survival.
11
Wang, Xueting, Shouxiang Sun, Xiaojuan Cao, and Jian Gao. "Quantitative Phosphoproteomic Analysis Reveals the Regulatory Networks of Elovl6 on Lipid and Glucose Metabolism in Zebrafish." International Journal of Molecular Sciences 21, no. 8 (April 19, 2020): 2860. http://dx.doi.org/10.3390/ijms21082860.
Full textAbstract:
Elongation of very long-chain fatty acids protein 6 (Elovl6) has been reported to be associated with clinical treatments of a variety of metabolic diseases. However, there is no systematic and comprehensive study to reveal the regulatory role of Elovl6 in mRNA, protein and phosphorylation levels. We established the first knock-out (KO), elovl6−/−, in zebrafish. Compared with wild type (WT) zebrafish, KO presented significant higher whole-body lipid content and lower content of fasting blood glucose. We utilized RNA-Seq, tandem mass tag (TMT) labeling-based quantitative technology and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to perform the transcriptomic, proteomic and phosphoproteomic analyses of livers from WT and elovl6−/− zebrafish. There were 734 differentially expressed genes (DEG) and 559 differentially expressed proteins (DEP) between elovl6−/− and WT zebrafish, identified out of quantifiable 47251 transcripts and 5525 proteins. Meanwhile, 680 differentially expressed phosphoproteins (DEPP) with 1054 sites were found out of quantifiable 1230 proteins with 3604 sites. Gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) analysis of the transcriptomic and proteomic data further suggested that the abnormal lipid metabolism and glucose metabolism in KO were mainly related to fatty acid degradation and biosynthesis, glycolysis/gluconeogenesis and PPAR signaling pathway. Based on phosphoproteomic analyses, some kinases critical for lipid metabolism and glucose metabolism, including ribosomal protein S6 kinase (Rps6kb), mitogen-activated protein kinase14 (Mapk14) and V-akt murine thymoma viral oncogene homolog 2-like (Akt2l), were identified. These results allowed us to catch on the regulatory networks of elovl6 on lipid and glucose metabolism in zebrafish. To our knowledge, this is the first multi-omic study of zebrafish lacking elovl6, which provides strong datasets to better understand many lipid/glucose metabolic risks posed to human health.
12
Aleshin, Vasily A., Artem V. Artiukhov, Thilo Kaehne, Anastasia V. Graf, and Victoria I. Bunik. "Daytime Dependence of the Activity of the Rat Brain Pyruvate Dehydrogenase Corresponds to the Mitochondrial Sirtuin 3 Level and Acetylation of Brain Proteins, All Regulated by Thiamine Administration Decreasing Phosphorylation of PDHA Ser293." International Journal of Molecular Sciences 22, no. 15 (July 27, 2021): 8006. http://dx.doi.org/10.3390/ijms22158006.
Full textAbstract:
Coupling glycolysis and mitochondrial tricarboxylic acid cycle, pyruvate dehydrogenase (PDH) complex (PDHC) is highly responsive to cellular demands through multiple mechanisms, including PDH phosphorylation. PDHC also produces acetyl-CoA for protein acetylation involved in circadian regulation of metabolism. Thiamine (vitamin B1) diphosphate (ThDP) is known to activate PDH as both coenzyme and inhibitor of the PDH inactivating kinases. Molecular mechanisms integrating the function of thiamine-dependent PDHC into general redox metabolism, underlie physiological fitness of a cell or an organism. Here, we characterize the daytime- and thiamine-dependent changes in the rat brain PDHC function, expression and phosphorylation, assessing their impact on protein acetylation and metabolic regulation. Morning administration of thiamine significantly downregulates both the PDH phosphorylation at Ser293 and SIRT3 protein level, the effects not observed upon the evening administration. This action of thiamine nullifies the daytime-dependent changes in the brain PDHC activity and mitochondrial acetylation, inducing diurnal difference in the cytosolic acetylation and acetylation of total brain proteins. Screening the daytime dependence of central metabolic enzymes and proteins of thiol/disulfide metabolism reveals that thiamine also cancels daily changes in the malate dehydrogenase activity, opposite to those of the PDHC activity. Correlation analysis indicates that thiamine abrogates the strong positive correlation between the total acetylation of the brain proteins and PDHC function. Simultaneously, thiamine heightens interplay between the expression of PDHC components and total acetylation or SIRT2 protein level. These thiamine effects on the brain acetylation system change metabolic impact of acetylation. The changes are exemplified by the thiamine enhancement of the SIRT2 correlations with metabolic enzymes and proteins of thiol-disulfide metabolism. Thus, we show the daytime- and thiamine-dependent changes in the function and phosphorylation of brain PDHC, contributing to regulation of the brain acetylation system and redox metabolism. The daytime-dependent action of thiamine on PDHC and SIRT3 may be of therapeutic significance in correcting perturbed diurnal regulation.
13
Jaswal, Jagdip S., Manoj Gandhi, Barry A. Finegan, Jason R. B. Dyck, and Alexander S. Clanachan. "p38 mitogen-activated protein kinase mediates adenosine-induced alterations in myocardial glucose utilization via 5′-AMP-activated protein kinase." American Journal of Physiology-Heart and Circulatory Physiology 292, no. 4 (April 2007): H1978—H1985. http://dx.doi.org/10.1152/ajpheart.01121.2006.
Full textAbstract:
Adenosine-induced acceleration of glycolysis in hearts stressed by transient ischemia is accompanied by suppression of glycogen synthesis and by increases in activity of adenosine 5′-monophosphate-activated protein kinase (AMPK). Because p38 mitogen-activated protein kinase (MAPK) may regulate glucose metabolism and may be activated downstream of AMPK, this study determined the effects of the p38 MAPK inhibitors SB202190 and SB203580 on adenosine-induced alterations in glucose utilization and AMPK activity. Studies were performed in working rat hearts perfused aerobically following stressing by transient ischemia (2 × 10-min ischemia followed by 5-min reperfusion). Phosphorylation of AMPK and p38 MAPK each were increased fourfold by adenosine, and these effects were inhibited by either SB202190 or SB203580. Neither of these inhibitors directly affected AMPK activity. Attenuation of the adenosine-induced increase in AMPK and p38 MAPK phosphorylation by SB202190 and SB203580 occurred independently of any change in tissue ATP-to-AMP ratio and did not alter glucose uptake, but it was accompanied by an increase in glycogen synthesis and glycogen content and by inhibition of glycolysis and proton production. There was a significant inverse correlation between the rate of glycogen synthesis and AMPK activity and between AMPK activity and glycogen content. These data demonstrate that AMPK is likely downstream of p38 MAPK in mediating the effects of adenosine on glucose utilization in hearts stressed by transient ischemia. The ability of p38 MAPK inhibitors to relieve the inhibition of glycogen synthesis and to inhibit glycolysis and proton production suggests that these agents may restore adenosine-induced cardioprotection in stressed hearts.
14
Tabbi-Anneni, Imene, Jonathan Buchanan, Robert C. Cooksey, and E. Dale Abel. "Captopril Normalizes Insulin Signaling and Insulin-Regulated Substrate Metabolism in Obese (ob/ob) Mouse Hearts." Endocrinology 149, no. 8 (May 1, 2008): 4043–50. http://dx.doi.org/10.1210/en.2007-1646.
Full textAbstract:
The goal of this study was to determine whether inhibiting the renin-angiotensin system would restore insulin signaling and normalize substrate use in hearts from obese ob/ob mice. Mice were treated for 4 wk with Captopril (4 mg/kg·d). Circulating levels of free fatty acids, triglycerides, and insulin were measured and glucose tolerance tests performed. Rates of palmitate oxidation and glycolysis, oxygen consumption, and cardiac power were determined in isolated working hearts in the presence and absence of insulin, along with levels of phosphorylation of Akt and AMP-activated protein kinase (AMPK). Captopril treatment did not correct the hyperinsulinemia or impaired glucose tolerance in ob/ob mice. Rates of fatty acid oxidation were increased and glycolysis decreased in ob/ob hearts, and insulin did not modulate substrate use in hearts of ob/ob mice and did not increase Akt phosphorylation. Captopril restored the ability of insulin to regulate fatty acid oxidation and glycolysis in hearts of ob/ob mice, possibly by increasing Akt phosphorylation. Moreover, AMPK phosphorylation, which was increased in hearts of ob/ob mice, was normalized by Captopril treatment, suggesting that in addition to restoring insulin sensitivity, Captopril treatment improved myocardial energetics. Thus, angiotensin-converting enzyme inhibitors restore the responsiveness of ob/ob mouse hearts to insulin and normalizes AMPK activity independently of effects on systemic metabolic homeostasis.
15
Austin, James A., Rosalind E. Jenkins, Gemma M. Austin, Mark A. Glenn, Karen Dunn, Laura Scott, Claire M. Lucas, and Richard E. Clark. "Cancerous inhibitor of protein phosphatase 2A (CIP2A) modifies energy metabolism via 5′ AMP-activated protein kinase signalling in malignant cells." Biochemical Journal 476, no. 15 (August 15, 2019): 2255–69. http://dx.doi.org/10.1042/bcj20190121.
Full textAbstract:
Abstract Cancerous inhibitor of protein phosphatase 2A (CIP2A) is an adverse biomarker across many malignancies. Using K562 cells engineered to have high or low CIP2A expression, we show that high CIP2A levels significantly bias cellular energy production towards oxidative phosphorylation (OXPHOS) rather than glycolysis. Mass spectrometric analysis of CIP2A interactors and isobaric tagging for relative and absolute protein quantitation (ITRAQ) experiments identified many associated proteins, several of which co-vary with CIP2A level. Many of these CIP2A associating and co-varying proteins are involved in energy metabolism including OXPHOS, or in 5′ AMP-activated protein kinase (AMPK) signalling, and manipulating AMPK activity mimics the effects of low/high CIP2A on OXPHOS. These effects are dependent on the availability of nutrients, driven by metabolic changes caused by CIP2A. CIP2A level did not affect starvation-induced AMPK phosphorylation of Unc-51 autophagy activating kinase 1 (ULK-1) at Ser555, but autophagy activity correlated with an increase in AMPK activity, to suggest that some AMPK processes are uncoupled by CIP2A, likely via its inhibition of protein phosphatase 2A (PP2A). The data demonstrate that AMPK mediates this novel CIP2A effect on energy generation in malignant cells.
16
Ruzzolini, Jessica, Silvia Peppicelli, Francesca Bianchini, Elena Andreucci, Silvia Urciuoli, Annalisa Romani, Katia Tortora, Giovanna Caderni, Chiara Nediani, and Lido Calorini. "Cancer Glycolytic Dependence as a New Target of Olive Leaf Extract." Cancers 12, no. 2 (January 29, 2020): 317. http://dx.doi.org/10.3390/cancers12020317.
Full textAbstract:
Oleuropein (Ole), the main bioactive phenolic component of Olea europaea L. has recently attracted the scientific attention for its several beneficial properties, including its anticancer effects. This study is intended to investigate whether an olive leaf extract enriched in Ole (OLEO) may counteract the aerobic glycolysis exploited by tumor cells. We found that OLEO decreased melanoma cell proliferation and motility. OLEO was also able to reduce the rate of glycolysis of human melanoma cells without affecting oxidative phosphorylation. This reduction was associated with a significant decrease of glucose transporter-1, protein kinase isoform M2 and monocarboxylate transporter-4 expression, possible drivers of such glycolysis inhibition. Extending the study to other tumor histotypes, we observed that the metabolic effects of OLEO are not confined to melanoma, but also confirmed in colon carcinoma, breast cancer and chronic myeloid leukemia. In conclusion, OLEO represents a natural product effective in reducing the glycolytic metabolism of different tumor types, revealing an extended metabolic inhibitory activity that may be well suited in a complementary anti-cancer therapy.
17
Soltys, Carrie-Lynn M., Lori Buchholz, Manoj Gandhi, Alexander S. Clanachan, Kenneth Walsh, and Jason R. B. Dyck. "Phosphorylation of cardiac protein kinase B is regulated by palmitate." American Journal of Physiology-Heart and Circulatory Physiology 283, no. 3 (September 1, 2002): H1056—H1064. http://dx.doi.org/10.1152/ajpheart.00275.2002.
Full textAbstract:
In this study isolated perfused working rat hearts were used to investigate the role of palmitate-regulated protein kinase B (PKB) phosphorylation on glucose metabolism. Rat hearts were perfused aerobically in working mode with 11 mM glucose and either 100 μU/ml insulin or 100 μU/ml insulin and 1.2 mM palmitate. PKB activity and phosphorylation state were reduced in the presence of 1.2 mM palmitate, which correlates with a decrease in glycolysis (47%), glucose oxidation (84%), and glucose uptake (43%). In contrast to skeletal muscle, neither p38 nor ERK underwent changes in their phosphorylation states in response to insulin or insulin and palmitate. Moreover, pharmacological restoration of glucose oxidation rates in hearts perfused with 1.2 mM palmitate demonstrated no increase in PKB phosphorylation state. In cultured mouse cardiac muscle HL-1 cells, insulin markedly increased PKB phosphorylation, which was blunted by pre- and cotreatment with 1.2 mM palmitate. However, neither palmitate nor C2-ceramide treatment of insulin-stimulated cells was able to accelerate PKB dephosphorylation beyond that observed following the removal of insulin alone. Taken together, these experiments show the control of PKB phosphorylation by palmitate is independent of ceramide and suggest that this signaling event may be an important regulator of myocardial glucose uptake and oxidation.
18
Dawson, Neal J., Ryan A. V. Bell, and Kenneth B. Storey. "Purification and Properties of White Muscle Lactate Dehydrogenase from the Anoxia-Tolerant Turtle, the Red-Eared Slider, Trachemys scripta elegans." Enzyme Research 2013 (February 21, 2013): 1–8. http://dx.doi.org/10.1155/2013/784973.
Full textAbstract:
Lactate dehydrogenase (LDH; E.C. 1.1.1.27) is a crucial enzyme involved in energy metabolism in muscle, facilitating the production of ATP via glycolysis during oxygen deprivation by recycling NAD+. The present study investigated purified LDH from the muscle of 20 h anoxic and normoxic T. s. elegans, and LDH from anoxic muscle showed a significantly lower (47%) Km for L-lactate and a higher Vmax value than the normoxic form. Several lines of evidence indicated that LDH was converted to a low phosphate form under anoxia: (a) stimulation of endogenously present protein phosphatases decreased the Km of L-lactate of control LDH to anoxic levels, whereas (b) stimulation of kinases increased the Km of L-lactate of anoxic LDH to normoxic levels, and (c) dot blot analysis shows significantly less serine (78%) and threonine (58%) phosphorylation in anoxic muscle LDH as compared to normoxic LDH. The physiological consequence of anoxia-induced LDH dephosphorylation appears to be an increase in LDH activity to promote the reduction of pyruvate in muscle tissue, converting the glycolytic end product to lactate to maintain a prolonged glycolytic flux under energy-stressed anoxic conditions.
19
Moldogazieva, Nurbubu T., Innokenty M. Mokhosoev, and Alexander A. Terentiev. "Metabolic Heterogeneity of Cancer Cells: An Interplay between HIF-1, GLUTs, and AMPK." Cancers 12, no. 4 (April 2, 2020): 862. http://dx.doi.org/10.3390/cancers12040862.
Full textAbstract:
It has been long recognized that cancer cells reprogram their metabolism under hypoxia conditions due to a shift from oxidative phosphorylation (OXPHOS) to glycolysis in order to meet elevated requirements in energy and nutrients for proliferation, migration, and survival. However, data accumulated over recent years has increasingly provided evidence that cancer cells can revert from glycolysis to OXPHOS and maintain both reprogrammed and oxidative metabolism, even in the same tumor. This phenomenon, denoted as cancer cell metabolic plasticity or hybrid metabolism, depends on a tumor micro-environment that is highly heterogeneous and influenced by an intensity of vasculature and blood flow, oxygen concentration, and nutrient and energy supply, and requires regulatory interplay between multiple oncogenes, transcription factors, growth factors, and reactive oxygen species (ROS), among others. Hypoxia-inducible factor-1 (HIF-1) and AMP-activated protein kinase (AMPK) represent key modulators of a switch between reprogrammed and oxidative metabolism. The present review focuses on cross-talks between HIF-1, glucose transporters (GLUTs), and AMPK with other regulatory proteins including oncogenes such as c-Myc, p53, and KRAS; growth factor-initiated protein kinase B (PKB)/Akt, phosphatidyl-3-kinase (PI3K), and mTOR signaling pathways; and tumor suppressors such as liver kinase B1 (LKB1) and TSC1 in controlling cancer cell metabolism. The multiple switches between metabolic pathways can underlie chemo-resistance to conventional anti-cancer therapy and should be taken into account in choosing molecular targets to discover novel anti-cancer drugs.
20
Kuhla, Björn, Dirk Albrecht, Siegfried Kuhla, and Cornelia C. Metges. "Proteome analysis of fatty liver in feed-deprived dairy cows reveals interaction of fuel sensing, calcium, fatty acid, and glycogen metabolism." Physiological Genomics 37, no. 2 (April 2009): 88–98. http://dx.doi.org/10.1152/physiolgenomics.90381.2008.
Full textAbstract:
The liver of dairy cows is involved in signaling the current hepatic metabolic state to the brain via metabolites and nerval afferents to control and adjust feed intake. Feed deprivation may result in mobilization of body reserves favoring hepatic steatosis. While the overall metabolic changes are well characterized, specific regulatory mechanisms are not readily understood. To identify molecular events associated with metabolic adaptation and the control of energy homeostasis, liver specimens from six ad libitum-fed and six feed-deprived cows were analyzed for selected metabolites, for the activation of AMP kinase, and for regulatory/regulated proteins using two-dimensional gel electrophoresis and MALDI-TOF-MS. Feed deprivation increased total liver fat and the calcium content, as well as augmented AMPK phosphorylation, while it decreased the contents of protein, glucose, glycogen, and cholesterol when expressed as a percentage of dry matter. Among 34 differentially expressed proteins identified, we found downregulation of proteins associated with fatty acid oxidation, glycolysis, electron transfer, protein degradation, and antigen processing, as well as cytoskeletal rearrangement. Proteins upregulated after feed deprivation included enzymes of the urea cycle, fatty acid or cholesterol transport proteins, an inhibitor of glycolysis, and previously unknown changes in calcium signaling network. Direct correlation was found between expression of glycolytic enzymes and glucose/glycogen content, whereas inverse correlation exists between expression of β-oxidative enzymes and total liver fat content. In conclusion, the regulatory response of identified proteins may help to explain development and consequences of hepatic lipidosis but also offers novel candidates potentially involved in signaling for maintaining energy homeostasis.
21
Nam, KeeSoo, Sunhwa Oh, and Incheol Shin. "Ablation of CD44 induces glycolysis-to-oxidative phosphorylation transition via modulation of the c-Src–Akt–LKB1–AMPKα pathway." Biochemical Journal 473, no. 19 (September 27, 2016): 3013–30. http://dx.doi.org/10.1042/bcj20160613.
Full textAbstract:
Cluster of differentiation 44 (CD44) is a transmembrane glycoprotein that has been identified as a cancer stem cell marker in various cancer cells. Although many studies have focused on CD44 as a cancer stem cell marker, its effect on cancer cell metabolism remains unclear. To investigate the role of CD44 on cancer cell metabolism, we established CD44 knock-down cells via retroviral delivery of shRNA against CD44 in human breast cancer cells. Silencing of CD44 decreased the glycolytic phenotype of cancer cells, affecting glucose uptake, ATP production, and lactate production. We also found that ablation of the CD44-induced lactate dehydrogenase (LDH) isoenzyme results in a shift to LDH1 due to LDHA down-regulation and LDHB up-regulation, implying the importance of LDH isoenzyme modulation on cancer metabolism. The expression of glycolysis-related proteins including hypoxia inducible factor-1α (HIF-1α) and LDHA was decreased by CD44 silencing. These effects were due to the up-regulation of liver kinase B1 (LKB1)/AMP-activated protein kinase (AMPK)α activity by reduction in c-Src and Akt activity in CD44 knock-down cells. Finally, induction of LKB1/AMPKα activity blocked the expression of HIF-1α and its target gene, LDHA. Inversely, LDHB expression was repressed by HIF-1α. Collectively, these results indicate that the CD44 silencing-induced metabolic shift is mediated by the regulation of c-Src/Akt/LKB1/AMPKα/HIF-1α signaling in human breast cancer cells.
22
Anestis, Andreas, Antigone Lazou, Hans O. Pörtner, and Basile Michaelidis. "Behavioral, metabolic, and molecular stress responses of marine bivalve Mytilus galloprovincialis during long-term acclimation at increasing ambient temperature." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 293, no. 2 (August 2007): R911—R921. http://dx.doi.org/10.1152/ajpregu.00124.2007.
Full textAbstract:
The present study aimed to determine the thermal response of the Mediterranean mussel Mytilus galloprovincialis by integrating information from various levels of biological organization including behavior, metabolic adjustments, heat shock protein expression, and protein kinase activity. Behavioral responses were determined by examining the effect of warming on valve closure and opening. Metabolic impacts were assessed by examining the activity of the key glycolytic enzyme pyruvate kinase (PK). Molecular responses were addressed through the expression of Hsp70 and Hsp90 and the phosphorylation of stress-activated protein kinases, p38 mitogen-activated protein kinase (p38 MAPK) and cJun-N-terminal kinases (JNKs). Mussels increased the duration of valve closure by about sixfold when acclimated to 24°C rather than to 17°C. As indicated by the activity of PK, such behavior caused metabolic depression and probably a shift from aerobic to anaerobic metabolism. Acclimation to temperatures higher than 24°C caused an increase in mortality and induced the expression of Hsp72. Increased phosphorylation of p38 MAPK and JNKs indicated activation of MAPK signaling cascades. The potential involvement of MAPKs in the induction of Hsp genes in the tissues of M. galloprovincialis is discussed. In conclusion, it seems that M. galloprovincialis lives close to its acclimation limits and incipient lethal temperature and that a small degree of warming will elicit stress responses at whole organism and molecular levels.
23
Novellasdemunt, Laura, Laurent Bultot, Anna Manzano, Francesc Ventura, Jose Luis Rosa, Didier Vertommen, Mark H. Rider, Àurea Navarro-Sabate, and Ramon Bartrons. "PFKFB3 activation in cancer cells by the p38/MK2 pathway in response to stress stimuli." Biochemical Journal 452, no. 3 (May 31, 2013): 531–43. http://dx.doi.org/10.1042/bj20121886.
Full textAbstract:
PFK-2/FBPase-2 (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase) catalyses the synthesis and degradation of Fru-2,6-P2 (fructose 2,6-bisphosphate), a key modulator of glycolysis and gluconeogenesis. The PFKFB3 gene is involved in cell proliferation owing to its role in carbohydrate metabolism. In the present study we analysed the mechanism of regulation of PFKFB3 as an immediate early gene controlled by stress stimuli that activates the p38/MK2 [MAPK (mitogen-activated protein kinase)-activated protein kinase 2] pathway. We report that exposure of HeLa and T98G cells to different stress stimuli (NaCl, H2O2, UV radiation and anisomycin) leads to a rapid increase (15–30 min) in PFKFB3 mRNA levels. The use of specific inhibitors in combination with MK2-deficient cells implicate control by the protein kinase MK2. Transient transfection of HeLa cells with deleted gene promoter constructs allowed us to identify an SRE (serum-response element) to which SRF (serum-response factor) binds and thus transactivates PFKFB3 gene transcription. Direct binding of phospho-SRF to the SRE sequence (−918 nt) was confirmed by ChIP (chromatin immunoprecipiation) assays. Moreover, PFKFB3 isoenzyme phosphorylation at Ser461 by MK2 increases PFK-2 activity. Taken together, the results of the present study suggest a multimodal mechanism of stress stimuli affecting PFKFB3 transcriptional regulation and kinase activation by protein phosphorylation, resulting in an increase in Fru-2,6-P2 concentration and stimulation of glycolysis in cancer cells.
24
Fan, Qiwen, Baisheng Long, Guokai Yan, Zhichang Wang, Min Shi, Xiaoyu Bao, Jun Hu, et al. "Dietary leucine supplementation alters energy metabolism and induces slow-to-fast transitions in longissimus dorsi muscle of weanling piglets." British Journal of Nutrition 117, no. 9 (May 14, 2017): 1222–34. http://dx.doi.org/10.1017/s0007114517001209.
Full textAbstract:
AbstractLeucine plays an important role in promoting muscle protein synthesis and muscle remodelling. However, what percentage of leucine is appropriate in creep feed and what proteome profile alterations are caused by dietary leucine in the skeletal muscle of piglets remain elusive. In this case, we applied isobaric tags for relative and absolute quantitation to analyse the proteome profile of the longissimus dorsi muscles of weanling piglets fed a normal leucine diet (NL; 1·66 % leucine) and a high-leucine diet (HL; 2·1 % leucine). We identified 157 differentially expressed proteins between these two groups. Bioinformatics analysis of these proteins exhibited the suppression of oxidative phosphorylation and fatty acid β-oxidation, as well as the activation of glycolysis, in the HL group. For further confirmation, we identified that SDHB, ATP5F1, ACADM and HADHB were significantly down-regulated (P<0·01, except ATP5F1, P<0·05), whereas the glycolytic enzyme pyruvate kinase was significantly up-regulated (P<0·05) in the HL group. We also show that enhanced muscle protein synthesis and the transition from slow-to-fast fibres are altered by leucine. Together, these results indicate that leucine may alter energy metabolism and promote slow-to-fast transitions in the skeletal muscle of weanling piglets.
25
Rathmell, Jeffrey C., Casey J. Fox, David R. Plas, Peter S. Hammerman, Ryan M. Cinalli, and Craig B. Thompson. "Akt-Directed Glucose Metabolism Can Prevent Bax Conformation Change and Promote Growth Factor-Independent Survival." Molecular and Cellular Biology 23, no. 20 (October 15, 2003): 7315–28. http://dx.doi.org/10.1128/mcb.23.20.7315-7328.2003.
Full textAbstract:
ABSTRACT The serine/threonine kinase Akt is a component of many receptor signal transduction pathways and can prevent cell death following growth factor withdrawal. Here, we show that Akt inhibition of cell death is not dependent on new protein translation. Instead, Akt inhibition of cell death requires glucose hydrolysis through glycolysis. Akt was found to regulate multiple steps in glycolysis via posttranscriptional mechanisms that included localization of the glucose transporter, Glut1, to the cell surface and maintenance of hexokinase function in the absence of extrinsic factors. To test the role of glucose uptake and phosphorylation in growth factor-independent survival, cells were transfected with Glut1 and hexokinase 1 (Glut1/HK1) cells. Glut1/HK1 cells accumulated Glut1 on the cell surface and had high glucose uptake capacity similar to that of cells with constitutively active Akt (mAkt). Unlike mAkt-expressing cells, however, they did not consume more glucose, did not maintain prolonged phosphofructokinase-1 protein levels and activity, and did not maintain pentose phosphate shuttle activity in the absence of growth factor. Nevertheless, expression of Glut1 and HK1 promoted increased cytosolic NADH and NADPH levels relative to those of the control cells upon growth factor withdrawal, prevented activation of Bax, and promoted growth factor-independent survival. These data indicate that Bax conformation is sensitive to glucose metabolism and that maintaining glucose uptake and phosphorylation can promote cell survival in the absence of growth factor. Furthermore, Akt required glucose and the ability to perform glycolysis to prevent Bax activation. The prevention of Bax activation by posttranscriptional regulation of glucose metabolism may, therefore, be a required aspect of the ability of Akt to maintain long-term cell survival in the absence of growth factors.
26
Salani, Barbara, Alberto Del Rio, Cecilia Marini, Gianmario Sambuceti, Renzo Cordera, and Davide Maggi. "Metformin, cancer and glucose metabolism." Endocrine-Related Cancer 21, no. 6 (October 1, 2014): R461—R471. http://dx.doi.org/10.1530/erc-14-0284.
Full textAbstract:
Metformin is the first-line treatment for type 2 diabetes. Results from several clinical studies have indicated that type 2 diabetic patients treated with metformin might have a lower cancer risk. One of the primary metabolic changes observed in malignant cell transformation is an increased catabolic glucose metabolism. In this context, once it has entered the cell through organic cation transporters, metformin decreases mitochondrial respiration chain activity and ATP production that, in turn, activates AMP-activated protein kinase, which regulates energy homeostasis. In addition, metformin reduces cellular energy availability and glucose entrapment by inhibiting hexokinase-II, which catalyses the glucose phosphorylation reaction. In this review, we discuss recent findings on molecular mechanisms that sustain the anticancer effect of metformin through regulation of glucose metabolism. In particular, we have focused on the emerging action of metformin on glycolysis in normal and cancer cells, with a drug discovery perspective.
27
Liu, Peng, Ruizhi Yao, Hongzhao Shi, Yang Liu, Shuai Lian, Yuying Yang, Huanmin Yang, and Shize Li. "Effects of Cold-inducible RNA-binding Protein (CIRP) on Liver Glycolysis during Acute Cold Exposure in C57BL/6 Mice." International Journal of Molecular Sciences 20, no. 6 (March 23, 2019): 1470. http://dx.doi.org/10.3390/ijms20061470.
Full textAbstract:
Cold-inducible RNA-binding protein (CIRP) is a stress-responsive protein involved in several signal transduction pathways required for cellular function, which are associated with apoptosis and proliferation. The present study aimed to investigate the possible effects of CIRP-mediated regulation of glucose metabolism in the liver following acute cold exposure. The livers and serum of male C57BL/6 mice were collected following cold exposure at 4 °C for 0 h, 2 h, 4 h, and 6 h. Glucose metabolic markers and the expression of glucose metabolic-related proteins were detected in the liver. Acute cold exposure was found to increase the consumption of glycogen in the liver. Fructose-1,6-diphosphate (FDP) and pyruvic acid (PA) were found to show a brief increase followed by a sharp decrease during cold exposure. Anti-apoptotic protein (Bcl-2) expression was upregulated. CIRP protein expression displayed a sequential increase with prolonged acute cold exposure time. Acute cold exposure also increased the level of protein kinase B (AKT) phosphorylation, and activated the AKT-signaling pathway. Taken together, these findings indicate that acute cold exposure increased the expression of CIRP protein, which regulates mouse hepatic glucose metabolism and maintains hepatocyte energy balance through the AKT signaling pathway, thereby slowing the liver cell apoptosis caused by cold exposure.
28
Martínez-Reyes, Inmaculada, María Sánchez-Aragó, and José M. Cuezva. "AMPK and GCN2–ATF4 signal the repression of mitochondria in colon cancer cells." Biochemical Journal 444, no. 2 (May 11, 2012): 249–59. http://dx.doi.org/10.1042/bj20111829.
Full textAbstract:
Reprogramming of energetic metabolism is a phenotypic trait of cancer in which mitochondrial dysfunction represents a key event in tumour progression. In the present study, we show that the acquisition of the tumour-promoting phenotype in colon cancer HCT116 cells treated with oligomycin to inhibit ATP synthase is exerted by repression of the synthesis of nuclear-encoded mitochondrial proteins in a process that is regulated at the level of translation. Remarkably, the synthesis of glycolytic proteins is not affected in this situation. Changes in translational control of mitochondrial proteins are signalled by the activation of AMPK (AMP-activated protein kinase) and the GCN2 (general control non-derepressible 2) kinase, leading also to the activation of autophagy. Changes in the bioenergetic function of mitochondria are mimicked by the activation of AMPK and the silencing of ATF4 (activating transcription factor 4). These findings emphasize the relevance of translational control for normal mitochondrial function and for the progression of cancer. Moreover, they demonstrate that glycolysis and oxidative phosphorylation are controlled at different levels of gene expression, offering the cell a mechanistic safeguard strategy for metabolic adaptation under stressful conditions.
29
Cheng, Hui, Fumiko Isoda, Denise D. Belsham, and Charles V. Mobbs. "Inhibition of Agouti-Related Peptide Expression by Glucose in a Clonal Hypothalamic Neuronal Cell Line Is Mediated by Glycolysis, Not Oxidative Phosphorylation." Endocrinology 149, no. 2 (November 1, 2007): 703–10. http://dx.doi.org/10.1210/en.2007-0772.
Full textAbstract:
The regulation of neuroendocrine electrical activity and gene expression by glucose is mediated through several distinct metabolic pathways. Many studies have implicated AMP and ATP as key metabolites mediating neuroendocrine responses to glucose, especially through their effects on AMP-activated protein kinase (AMPK), but other studies have suggested that glycolysis, and in particular the cytoplasmic conversion of nicotinamide adenine dinucleotide (NAD+) to reduced NAD (NADH), may play a more important role than oxidative phosphorylation for some effects of glucose. To address these molecular mechanisms further, we have examined the regulation of agouti-related peptide (AgRP) in a clonal hypothalamic cell line, N-38. AgRP expression was induced monotonically as glucose concentrations decreased from 10 to 0.5 mm glucose and with increasing concentrations of glycolytic inhibitors. However, neither pyruvate nor 3-β-hydroxybutyrate mimicked the effect of glucose to reduce AgRP mRNA, but on the contrary, produced the opposite effect of glucose and actually increased AgRP mRNA. Nevertheless, 3β-hydroxybutyrate mimicked the effect of glucose to increase ATP and to decrease AMPK phosphorylation. Similarly, inhibition of AMPK by RNA interference increased, and activation of AMPK decreased, AgRP mRNA. Additional studies demonstrated that neither the hexosamine nor the pentose/carbohydrate response element-binding protein pathways mediate the effects of glucose on AgRP expression. These studies do not support that either ATP or AMPK mediate effects of glucose on AgRP in this hypothalamic cell line but support a role for glycolysis and, in particular, NADH. These studies support that cytoplasmic or nuclear NADH, uniquely produced by glucose metabolism, mediates effects of glucose on AgRP expression.
30
Moonira, Tabassum, Shruti S. Chachra, Brian E. Ford, Silvia Marin, Ahmed Alshawi, Natasha S. Adam-Primus, Catherine Arden, et al. "Metformin lowers glucose 6-phosphate in hepatocytes by activation of glycolysis downstream of glucose phosphorylation." Journal of Biological Chemistry 295, no. 10 (January 23, 2020): 3330–46. http://dx.doi.org/10.1074/jbc.ra120.012533.
Full textAbstract:
The chronic effects of metformin on liver gluconeogenesis involve repression of the G6pc gene, which is regulated by the carbohydrate-response element–binding protein through raised cellular intermediates of glucose metabolism. In this study we determined the candidate mechanisms by which metformin lowers glucose 6-phosphate (G6P) in mouse and rat hepatocytes challenged with high glucose or gluconeogenic precursors. Cell metformin loads in the therapeutic range lowered cell G6P but not ATP and decreased G6pc mRNA at high glucose. The G6P lowering by metformin was mimicked by a complex 1 inhibitor (rotenone) and an uncoupler (dinitrophenol) and by overexpression of mGPDH, which lowers glycerol 3-phosphate and G6P and also mimics the G6pc repression by metformin. In contrast, direct allosteric activators of AMPK (A-769662, 991, and C-13) had opposite effects from metformin on glycolysis, gluconeogenesis, and cell G6P. The G6P lowering by metformin, which also occurs in hepatocytes from AMPK knockout mice, is best explained by allosteric regulation of phosphofructokinase-1 and/or fructose bisphosphatase-1, as supported by increased metabolism of [3-3H]glucose relative to [2-3H]glucose; by an increase in the lactate m2/m1 isotopolog ratio from [1,2-13C2]glucose; by lowering of glycerol 3-phosphate an allosteric inhibitor of phosphofructokinase-1; and by marked G6P elevation by selective inhibition of phosphofructokinase-1; but not by a more reduced cytoplasmic NADH/NAD redox state. We conclude that therapeutically relevant doses of metformin lower G6P in hepatocytes challenged with high glucose by stimulation of glycolysis by an AMP-activated protein kinase–independent mechanism through changes in allosteric effectors of phosphofructokinase-1 and fructose bisphosphatase-1, including AMP, Pi, and glycerol 3-phosphate.
31
Jaswal, Jagdip S., Manoj Gandhi, Barry A. Finegan, Jason R. B. Dyck, and Alexander S. Clanachan. "Inhibition of p38 MAPK and AMPK restores adenosine-induced cardioprotection in hearts stressed by antecedent ischemia by altering glucose utilization." American Journal of Physiology-Heart and Circulatory Physiology 293, no. 2 (August 2007): H1107—H1114. http://dx.doi.org/10.1152/ajpheart.00455.2007.
Full textAbstract:
p38 mitogen-activated protein kinase (MAPK) and 5′-AMP-activated protein kinase (AMPK) are activated by metabolic stresses and are implicated in the regulation of glucose utilization and ischemia-reperfusion (IR) injury. This study tested the hypothesis that inhibition of p38 MAPK restores the cardioprotective effects of adenosine in stressed hearts by preventing activation of AMPK and the uncoupling of glycolysis from glucose oxidation. Working rat hearts were perfused with Krebs solution (1.2 mM palmitate, 11 mM [3H/14C]glucose, and 100 mU/l insulin). Hearts were stressed by transient antecedent IR (2 × 10 min I/5 min R) before severe IR (30 min I/30 min R). Hearts were treated with vehicle, p38 MAPK inhibitor (SB-202190, 10 μM), adenosine (500 μM), or their combination before severe IR. After severe IR, the phosphorylation (arbitrary density units) of p38 MAPK and AMPK, rates of glucose metabolism (μmol·g dry wt−1·min−1), and recovery of left ventricular (LV) work (Joules) were similar in vehicle-, SB-202190- and adenosine-treated hearts. Treatment with SB-202190 + adenosine versus adenosine alone decreased p38 MAPK (0.03 ± 0.01, n = 3 vs. 0.48 ± 0.10, n = 3, P < 0.05) and AMPK (0.00 ± 0.00, n = 3 vs. 0.26 ± 0.08, n = 3 P < 0.05) phosphorylation. This was accompanied by attenuated rates of glycolysis (1.51 ± 0.40, n = 7 vs. 3.95 ± 0.65, n = 7, P < 0.05) and H+ production (2.12 ± 0.76, n = 7 vs. 6.96 ± 1.48, n = 7, P < 0.05), and increased glycogen synthesis (1.91 ± 0.25, n = 6 vs. 0.27 ± 0.28, n = 6, P < 0.05) and improved recovery of LV work (0.81 ± 0.08, n = 7 vs. 0.30 ± 0.15, n = 8, P < 0.05). These data indicate that inhibition of p38 MAPK abolishes subsequent phosphorylation of AMPK and improves the coupling of glucose metabolism, thereby restoring adenosine-induced cardioprotection.
32
Gibadulinova, Adriana, Petra Bullova, Hynek Strnad, Kamil Pohlodek, Dana Jurkovicova, Martina Takacova, Silvia Pastorekova, and Eliska Svastova. "CAIX-Mediated Control of LIN28/let-7 Axis Contributes to Metabolic Adaptation of Breast Cancer Cells to Hypoxia." International Journal of Molecular Sciences 21, no. 12 (June 16, 2020): 4299. http://dx.doi.org/10.3390/ijms21124299.
Full textAbstract:
Solid tumors, including breast cancer, are characterized by the hypoxic microenvironment, extracellular acidosis, and chemoresistance. Hypoxia marker, carbonic anhydrase IX (CAIX), is a pH regulator providing a selective survival advantage to cancer cells through intracellular neutralization while facilitating tumor invasion by extracellular acidification. The expression of CAIX in breast cancer patients is associated with poor prognosis and metastases. Importantly, CAIX-positive hypoxic tumor regions are enriched in cancer stem cells (CSCs). Here we investigated the biological effects of CA9-silencing in breast cancer cell lines. We found that CAIX-downregulation in hypoxia led to increased levels of let-7 (lethal-7) family members. Simultaneously with the increase of let-7 miRNAs in CAIX-suppressed cells, LIN28 protein levels decreased, along with downstream metabolic pathways: pyruvate dehydrogenase kinase 1 (PDK1) and phosphorylation of its substrate, pyruvate dehydrogenase (PDH) at Ser-232, causing attenuation of glycolysis. In addition to perturbed glycolysis, CAIX-knockouts, in correlation with decreased LIN28 (as CSC reprogramming factor), also exhibit reduction of the further CSC-associated markers NANOG (Homeobox protein NANOG) and ALDH1 (Aldehyde dehydrogenase isoform 1). Oppositely, overexpression of CAIX leads to the enhancement of LIN28, ALDH1, and NANOG. In conclusion, CAIX-driven regulation of the LIN28/let-7 axis augments glycolytic metabolism and enhances stem cell markers expression during CAIX-mediated adaptation to hypoxia and acidosis in carcinogenesis.
33
Oikawa, Hirotaka, Shouhei Miyazaki, Rina Kurata, Mutsumi Hattori, Noriko Hayashi, Nami Kawaguchi, Tetsuya Hirata, Taro Ueda, and Takahiko Fujikawa. "Eucommia Leaf Extract Induces BDNF Production in Rat Hypothalamus and Enhances Lipid Metabolism and Aerobic Glycolysis in Rat Liver." Current Molecular Pharmacology 14, no. 2 (December 31, 2020): 234–44. http://dx.doi.org/10.2174/1874467213666200505094631.
Full textAbstract:
Background: Mutations in the brain-derived neurotrophic factor (BDNF) gene and its receptor, tyrosine receptor kinase B (TrkB), have been reported to cause severe obesity in rodents. Our previous study demonstrated that the oral administration of 5% Eucommia leaf extract (ELE) or ELE aroma treatment (ELE aroma) produced anti-obesity effects. Objective: In this study, we investigated the effects of ELE on glycolysis and lipid metabolism in male Sprague–Dawley rats, as well as the effects of ELE on BDNF in rat hypothalamus. Methods and Results: A significant reduction and a reduction tendency in the respiratory quotient were observed in association with 5% ELE and ELE aroma treatment, respectively. Furthermore, RT-qPCR results showed significant increases in Cpt2, Acad, Complex II, and Complex V mRNA levels in the liver with both treatments. In addition, in rat hypothalamus, significant elevations in BDNF, Akt, PLCγ proteins and CREB phosphorylation were observed in the 5% ELE group and the ELE aroma group. Furthermore, Ras protein was significantly increased in the ELE aroma group. On the other hand, significant dephosphorylation of ERK1/2 was observed by the western blotting in the 5% ELE group and the ELE aroma group. Conclusion: These findings suggest that the ELE treatment enhances the lipid metabolism and increases the aerobic glycolytic pathway, while ELE-induced BDNF may affect such energy regulation. Therefore, ELE has the possibility to control metabolic syndrome.
34
Tan, Kah Ni, Vicky M. Avery, and Catalina Carrasco-Pozo. "Metabolic Roles of Androgen Receptor and Tip60 in Androgen-Dependent Prostate Cancer." International Journal of Molecular Sciences 21, no. 18 (September 10, 2020): 6622. http://dx.doi.org/10.3390/ijms21186622.
Full textAbstract:
Androgen receptor (AR)-mediated signaling is essential for the growth and differentiation of the normal prostate and is the primary target for androgen deprivation therapy in prostate cancer. Tat interactive protein 60 kDa (Tip60) is a histone acetyltransferase that is critical for AR activation. It is well known that cancer cells rewire their metabolic pathways in order to sustain aberrant proliferation. Growing evidence demonstrates that the AR and Tip60 modulate key metabolic processes to promote the survival of prostate cancer cells, in addition to their classical roles. AR activation enhances glucose metabolism, including glycolysis, tricarboxylic acid cycle and oxidative phosphorylation, as well as lipid metabolism in prostate cancer. The AR also interacts with other metabolic regulators, including calcium/calmodulin-dependent kinase kinase 2 and mammalian target of rapamycin. Several studies have revealed the roles of Tip60 in determining cell fate indirectly by modulating metabolic regulators, such as c-Myc, hypoxia inducible factor 1α (HIF-1α) and p53 in various cancer types. Furthermore, Tip60 has been shown to regulate the activity of key enzymes in gluconeogenesis and glycolysis directly through acetylation. Overall, both the AR and Tip60 are master metabolic regulators that mediate cellular energy metabolism in prostate cancer, providing a framework for the development of novel therapeutic targets in androgen-dependent prostate cancer.
35
Novellasdemunt, Laura, Mercè Obach, Lluís Millán-Ariño, Anna Manzano, Francesc Ventura, Jose Luis Rosa, Albert Jordan, Àurea Navarro-Sabate, and Ramon Bartrons. "Progestins activate 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) in breast cancer cells." Biochemical Journal 442, no. 2 (February 13, 2012): 345–56. http://dx.doi.org/10.1042/bj20111418.
Full textAbstract:
PFKFB (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase) catalyses the synthesis and degradation of Fru-2,6-P2 (fructose-2,6-bisphosphate), a key modulator of glycolysis and gluconeogenesis. The PFKFB3 gene is extensively involved in cell proliferation owing to its key role in carbohydrate metabolism. In the present study we analyse its mechanism of regulation by progestins in breast cancer cells. We report that exposure of T47D cells to synthetic progestins (ORG2058 or norgestrel) leads to a rapid increase in Fru-2,6-P2 concentration. Our Western blot results are compatible with a short-term activation due to PFKFB3 isoenzyme phosphorylation and a long-term sustained action due to increased PFKFB3 protein levels. Transient transfection of T47D cells with deleted gene promoter constructs allowed us to identify a PRE (progesterone-response element) to which PR (progesterone receptor) binds and thus transactivates PFKFB3 gene transcription. PR expression in the PR-negative cell line MDA-MB-231 induces endogenous PFKFB3 expression in response to norgestrel. Direct binding of PR to the PRE box (−3490 nt) was confirmed by ChIP (chromatin immunoprecipiation) experiments. A dual mechanism affecting PFKFB3 protein and gene regulation operates in order to assure glycolysis in breast cancer cells. An immediate early response through the ERK (extracellular-signal-regulated kinase)/RSK (ribosomal S6 kinase) pathway leading to phosphorylation of PFKFB3 on Ser461 is followed by activation of mRNA transcription via cis-acting sequences on the PFKFB3 promoter.
36
Yao, Ruizhi, Yuying Yang, Shuai Lian, Hongzhao Shi, Peng Liu, Yang Liu, Huanmin Yang, and Shize Li. "Effects of Acute Cold Stress on Liver O-GlcNAcylation and Glycometabolism in Mice." International Journal of Molecular Sciences 19, no. 9 (September 18, 2018): 2815. http://dx.doi.org/10.3390/ijms19092815.
Full textAbstract:
Protein O-linked β-N-acetylglucosamine glycosylation (O-GlcNAcylation) regulates many biological processes. Studies have shown that O-GlcNAc modification levels can increase during acute stress and suggested that this may contribute to the survival of the cell. This study investigated the possible effects of O-GlcNAcylation that regulate glucose metabolism, apoptosis, and autophagy in the liver after acute cold stress. Male C57BL/6 mice were exposed to cold conditions (4 °C) for 0, 2, 4, and 6 h, then their livers were extracted and the expression of proteins involved in glucose metabolism, apoptosis, and autophagy was determined. It was found that acute cold stress increased global O-GlcNAcylation and protein kinase B (AKT) phosphorylation levels. This was accompanied by significantly increased activation levels of the glucose metabolism regulators 160 kDa AKT substrate (AS160), 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 2 (PFKFB2), and glycogen synthase kinase-3β (GSK3β). The levels of glycolytic intermediates, fructose-1,6-diphosphate (FDP) and pyruvic acid (PA), were found to show a brief increase followed by a sharp decrease. Additionally, adenosine triphosphate (ATP), as the main cellular energy source, had a sharp increase. Furthermore, the B-cell lymphoma 2(Bcl-2)/Bcl-2-associated X (Bax) ratio was found to increase, whereas cysteine-aspartic acid protease 3 (caspase-3) and light chain 3-II (LC3-II) levels were reduced after acute cold stress. Therefore, acute cold stress was found to increase O-GlcNAc modification levels, which may have resulted in the decrease of the essential processes of apoptosis and autophagy, promoting cell survival, while altering glycose transport, glycogen synthesis, and glycolysis in the liver.
37
Mao, Huimin, Andi Yang, Yunhe Zhao, Lang Lei, and Houxuan Li. "Succinate Supplement Elicited “Pseudohypoxia” Condition to Promote Proliferation, Migration, and Osteogenesis of Periodontal Ligament Cells." Stem Cells International 2020 (March 10, 2020): 1–14. http://dx.doi.org/10.1155/2020/2016809.
Full textAbstract:
Most mesenchymal stem cells reside in a niche of low oxygen tension. Iron-chelating agents such as CoCl2 and deferoxamine have been utilized to mimic hypoxia and promote cell growth. The purpose of the present study was to explore whether a supplement of succinate, a natural metabolite of the tricarboxylic acid (TCA) cycle, can mimic hypoxia condition to promote human periodontal ligament cells (hPDLCs). Culturing hPDLCs in hypoxia condition promoted cell proliferation, migration, and osteogenic differentiation; moreover, hypoxia shifted cell metabolism from oxidative phosphorylation to glycolysis with accumulation of succinate in the cytosol and its release into culture supernatants. The succinate supplement enhanced hPDLC proliferation, migration, and osteogenesis with decreased succinate dehydrogenase (SDH) expression and activity, as well as increased hexokinase 2 (HK2) and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3), suggesting metabolic reprogramming from oxidative phosphorylation to glycolysis in a normal oxygen condition. The succinate supplement in cell cultures promoted intracellular succinate accumulation while stabilizing hypoxia inducible factor-1α (HIF-1α), leading to a state of pseudohypoxia. Moreover, we demonstrate that hypoxia-induced proliferation was G-protein-coupled receptor 91- (GPR91-) dependent, while exogenous succinate-elicited proliferation involved the GPR91-dependent and GPR91-independent pathway. In conclusion, the succinate supplement altered cell metabolism in hPDLCs, induced a pseudohypoxia condition, and enhanced proliferation, migration, and osteogenesis of mesenchymal stem cells in vitro.
38
Folmes, Karalyn D., Lee A. Witters, Michael F. Allard, Martin E. Young, and Jason R. B. Dyck. "The AMPK γ1 R70Q mutant regulates multiple metabolic and growth pathways in neonatal cardiac myocytes." American Journal of Physiology-Heart and Circulatory Physiology 293, no. 6 (December 2007): H3456—H3464. http://dx.doi.org/10.1152/ajpheart.00936.2007.
Full textAbstract:
Although mutations in the γ-subunit of AMP-activated protein kinase (AMPK) can result in excessive glycogen accumulation and cardiac hypertrophy, the mechanisms by which this occurs have not been well defined. Because >65% of cardiac AMPK activity is associated with the γ1-subunit of AMPK, we investigated the effects of expression of an AMPK-activating γ1-subunit mutant (γ1 R70Q) on regulatory pathways controlling glycogen accumulation and cardiac hypertrophy in neonatal rat cardiac myocytes. Whereas expression of γ1 R70Q displayed the expected increase in palmitate oxidation rates, rates of glycolysis were significantly depressed. In addition, glycogen synthase activity was increased in cardiac myocytes expressing γ1 R70Q, due to both increased expression and decreased phosphorylation of glycogen synthase. The inhibition of glycolysis and increased glycogen synthase activity were correlated with elevated glycogen levels in γ1 R70Q-expressing myocytes. In association with the reduced phosphorylation of glycogen synthase, glycogen synthase kinase (GSK)-3β protein and mRNA levels were profoundly decreased in the γ1 R70Q-expressing myocytes. Consistent with GSK-3β negatively regulating hypertrophy via inhibition of nuclear factor of activated T cells (NFAT), the dramatic downregulation of GSK-3β was associated with increased nuclear activity of NFAT. Together, these data provide important new information about the mechanisms by which a mutation in the γ-subunit of AMPK causes altered AMPK signaling and identify multiple pathways involved in regulating both cardiac myocyte metabolism and growth that may contribute to the development of the γ mutant-associated cardiomyopathy.
39
Du, Jinwei, Qiang Li, Fangqiang Tang, Michelle Puchowitz, Hasashi Fujioka, Sally Dunwoodie, David Danielpour, and Yu-Chung Yang. "Cited2 Is Required For The Maintenance Of Glycolytic Metabolism In Adult Hematopoietic Stem Cells." Blood 122, no. 21 (November 15, 2013): 794. http://dx.doi.org/10.1182/blood.v122.21.794.794.
Full textAbstract:
Abstract Adult hematopoietic stem cells (HSCs) primarily reside in the hypoxic bone marrow microenvironment, and preferentially utilize anaerobic glycolysis to obtain energy. Cited2 is a cytokine-inducible gene, which plays various roles during mouse development. Our previous studies showed that deletion of Cited2 in adult mouse results in loss of HSC quiescence, increased apoptosis, and impaired HSC reconstitution capacity (Blood 2012, 119:2789-2798). In this study, we conditionally deleted Cited2 in Cited2fl/fl;Mx1-Cre mice and investigated the role of Cited2 in the metabolic regulation of HSCs. First, we examined mitochondrial alterations in Cited2 knockout (KO) long-term (LT-) and short-term (ST-) HSCs defined as “Flt3-CD34- LSK” and “Flt3-CD34+ LSK”, respectively. Staining with MitoTracker Green revealed that deletion of Cited2 resulted in a significant increase in mitochondrial mass in both LT- and ST-HSCs but not in the whole bone marrow cells. To explore the morphological changes of mitochondria in Cited2 KO HSCs, we sorted Flt3-LSK cells (containing LT- and ST- HSCs) and performed electron microscopy ultrastructural analysis. The mitochondria in wild type (WT) HSCs were mostly small, round or oval, and dark (Figure 1). However, Cited2 KO HSCs displayed markedly elongated and brighter mitochondria, similar to those observed in aged WT HSCs (20–24 months old mice) by others. The frequency of Cited2 KO LT-HSCs with high mitochondrial membrane potential was significantly increased (8.5% in WT versus 15.1% in KO). Furthermore, the reactive oxygen species (ROS) levels in Cited2 KO HSCs were significantly higher than those in WT controls. To further understand the metabolic changes in Cited2 KO HSCs, we measured glucose uptake using fluorescent indicator 2-NBDG. Glucose uptake was unchanged in the Cited2 KO LT- and ST- HSCs. Also, intracellular ATP content was maintained at the normal levels in Cited2 KO LT-HSCs, although slightly increased in ST-HSCs compared with WT controls. To assess the utilization of glycolysis in Cited2 KO HSCs, glycolytic flux was determined by glucose-derived 13C-lactate production using Gas Chromatography–Mass Spectrometry (GC-MS). We found that the rate of 13C-lactate production was significantly lower in both LT- and ST-HSCs lacking Cited2 than in WT controls. To further confirm this finding, we treated HSCs with antimycin A (AMA), a specific inhibitor of mitochondrial electron transport chain. We found that Cited2 KO HSCs displayed increased NADH after AMA treatment, compared with the WT control, indicating that mitochondrial respiration was increased in KO HSCs and produced more NADH. At the molecular level, deletion of Cited2 significantly reduced the expression of metabolism related genes in HSCs, such as lactate dehydrogenase (LDH) B and LDHD, pyruvate dehydrogenase kinase (Pdk) 2 and Pdk4, PYGL (phosphorylase, glycogen, liver), and GPX1 (glutathione peroxidase 1). Notably, Pdk2 and Pdk4 were recently shown to be critical controllers of glycolysis and checkpoint for cell cycle in HSCs. Consistent with reduced expression of Pdk, the phosphorylation of PDH-E1α was significantly decreased in Cited2 KO HSCs. Akt, mTOR, and FoxOs are known regulators of mitochondrial functions in HSCs. We found that Akt-mTOR signaling activity was increased in Cited2 KO HSCs, as indicated by increased phosphorylation of Akt and S6 ribosomal protein. However, in vitro treatment of LT-HSCs with mTORC1 inhibitor rapamycin did not resume decreased expression of LDHB, LDHD, Pdk2, and Pdk4, suggesting that elevated mTORC1 activity may not be the major contributor to the downregulation of glycolysis related genes. Meanwhile, we also found that in Cited2 KO LT-HSCs, phosphorylation of FoxO1 and FoxO3 was increased, both of which are known regulators of Pdk4 expression. Interestingly, in vitro treatment of LT-HSCs with PI3/Akt inhibitor LY294002, partially rescued the expression of Pdk4. Together, these findings suggest that the downregulation of Pdk4 in Cited2 KO HSCs is likely mediated by the inactivation of FoxOs caused by the elevated Akt activity. In summary, these results show that loss of Cited2 attenuates HSCs' glycolytic metabolism while simultaneously enhancing their overall mitochondrial oxidative phosphorylation, thus suggesting a critical role of Cited2 in the maintenance of adult HSC glycolytic metabolism likely through regulating LDH, Pdk, and Akt activity. Disclosures: No relevant conflicts of interest to declare.
40
Mascaraque, Marta, Pablo Delgado-Wicke, Cristina Nuevo-Tapioles, Tamara Gracia-Cazaña, Edgar Abarca-Lachen, Salvador González, José M. Cuezva, Yolanda Gilaberte, and Ángeles Juarranz. "Metformin as an Adjuvant to Photodynamic Therapy in Resistant Basal Cell Carcinoma Cells." Cancers 12, no. 3 (March 13, 2020): 668. http://dx.doi.org/10.3390/cancers12030668.
Full textAbstract:
Photodynamic Therapy (PDT) with methyl-aminolevulinate (MAL-PDT) is being used for the treatment of Basal Cell Carcinoma (BCC), although resistant cells may appear. Normal differentiated cells depend primarily on mitochondrial oxidative phosphorylation (OXPHOS) to generate energy, but cancer cells switch this metabolism to aerobic glycolysis (Warburg effect), influencing the response to therapies. We have analyzed the expression of metabolic markers (β-F1-ATPase/GAPDH (glyceraldehyde-3-phosphate dehydrogenase) ratio, pyruvate kinase M2 (PKM2), oxygen consume ratio, and lactate extracellular production) in the resistance to PDT of mouse BCC cell lines (named ASZ and CSZ, heterozygous for ptch1). We have also evaluated the ability of metformin (Metf), an antidiabetic type II compound that acts through inhibition of the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway to sensitize resistant cells to PDT. The results obtained indicated that resistant cells showed an aerobic glycolysis metabolism. The treatment with Metf induced arrest in the G0/G1 phase and a reduction in the lactate extracellular production in all cell lines. The addition of Metf to MAL-PDT improved the cytotoxic effect on parental and resistant cells, which was not dependent on the PS protoporphyrin IX (PpIX) production. After Metf + MAL-PDT treatment, activation of pAMPK was detected, suppressing the mTOR pathway in most of the cells. Enhanced PDT-response with Metf was also observed in ASZ tumors. In conclusion, Metf increased the response to MAL-PDT in murine BCC cells resistant to PDT with aerobic glycolysis.
41
Kim, Kyeongmin, Sungmin Lee, Hyunkoo Kang, Eunguk Shin, Hae Yu Kim, HyeSook Youn, and BuHyun Youn. "Dual Specificity Kinase DYRK3 Promotes Aggressiveness of Glioblastoma by Altering Mitochondrial Morphology and Function." International Journal of Molecular Sciences 22, no. 6 (March 15, 2021): 2982. http://dx.doi.org/10.3390/ijms22062982.
Full textAbstract:
Glioblastoma multiforme (GBM) is a malignant primary brain tumor with poor patient prognosis. Although the standard treatment of GBM is surgery followed by chemotherapy and radiotherapy, often a small portion of surviving tumor cells acquire therapeutic resistance and become more aggressive. Recently, altered kinase expression and activity have been shown to determine metabolic flux in tumor cells and metabolic reprogramming has emerged as a tumor progression regulatory mechanism. Here we investigated novel kinase-mediated metabolic alterations that lead to acquired GBM radioresistance and malignancy. We utilized transcriptomic analyses within a radioresistant GBM orthotopic xenograft mouse model that overexpresses the dual specificity tyrosine-phosphorylation-regulated kinase 3 (DYRK3). We find that within GBM cells, radiation exposure induces DYRK3 expression and DYRK3 regulates mammalian target of rapamycin complex 1 (mTORC1) activity through phosphorylation of proline-rich AKT1 substrate 1 (PRAS40). We also find that DYRK3 knockdown inhibits dynamin-related protein 1 (DRP1)-mediated mitochondrial fission, leading to increased oxidative phosphorylation (OXPHOS) and reduced glycolysis. Importantly, enforced DYRK3 downregulation following irradiation significantly impaired GBM cell migration and invasion. Collectively, we suggest DYRK3 suppression may be a novel strategy for preventing GBM malignancy through regulating mitochondrial metabolism.
42
Daniela, Ventro, Adam T. Utley, and Kelvin P. Lee. "CD28 Activation Induces Metabolic Adaptation in Multiple Myeloma Cells." Blood 124, no. 21 (December 6, 2014): 4708. http://dx.doi.org/10.1182/blood.v124.21.4708.4708.
Full textAbstract:
Abstract Alterations in cancer cell metabolism is a century old concept recently recognized as one of the hallmarks of cancer. Cancer cells, including multiple myeloma (MM), largely shift how they utilize the glucose they consume to glycolysis from that of oxidative phosphorylation (OXPHOS). This phenomenon supports the cancer cell’s large anabolic demands for continuous growth and proliferation and is reinforced by key signaling pathways. However, as a cancer of the previously non-dividing plasma cell, these metabolic adaptations are only beginning to be documented in MM. CD28 is classically known as the T-cell co-stimulatory receptor, but is also expressed on normal plasma cells and their malignant counterparts. Previous data suggests that CD28 is required for MM cell survival, protective during stress induced conditions, and correlates with poor prognosis in the clinic. Furthermore, studies using the anti-CD28 activating monoclonal antibody (mAb) have identified phosphatidyl-inositol 3-kinase (PI3K)/Akt activation to be a key driver of its pro-survival function. Akt is also an important integrator of cellular metabolism and cell growth and proliferation signaling pathways. Therefore, its CD28 mediated activation may uncover the mechanism by which MM cells are able to metabolically sustain stress induced conditions and thrive thereafter. Herein, we show that when CD28 is activated by anti-CD28 mAb (10µg/ml) under stressful conditions (media serum reduction), Akt (T308) phosphorylation increases, resulting in an increase of total protein and cell surface expression of the glucose transporter, GLUT1. To assess if cells take in more glucose in the presence of anti-CD28 mAb they were cultured in glucose free media and glucose was then added back at concentrations of 0.5, 1 and 5mM with or without activating anti-CD28 mAb. Significant increases in glucose uptake were seen in the 5mM anti-CD28 mAb treatment group when compared to the untreated control, correlating positively with the increase in GLUT1 protein expression. To evaluate whether or not CD28 activation induces a preferential for glycolytic breakdown of glucose, the same treatment conditions were repeated and lactate production/oxygen consumption, as a measure of glycolysis and OXPHOS respectively, were measured in a fluorometric kinetic assay. Lactate production significantly increased in MM cells treated with anti-CD28 mAb compared to untreated controls, confirming its role in enhancing glycolysis for cell growth and survival. This data is further supported by increased cell death observed in murine MM cells treated with the glycolysis inhibitor, 2-Deoxyglucose (2-DG). Interestingly, the level of oxygen consumption was comparable in all groups suggesting not only minimal effect in response to CD28 activation, but also relatively unimpaired OXPHOS in MM cells. Furthermore, analysis of mitochondrial biogenesis using the mitotracker green stain and production of reactive oxygen species by 2’,7’-difchlorofluorescin diacetate (DCFDA) oxidation in murine MM cells also revealed both processes to be intact and increased in the presence of CD28 activation. Taken together, these results suggest that CD28 signaling plays a strategic role in shifting the metabolic axis to that of increased glucose uptake and consumption via glycolysis through phosphorylation of PI3K/Akt and upregulation of GLUT1 expression. Pharmacological inhibition of CD28 is therefore an attractive avenue for therapeutic intervention in MM and we have previously shown that interfering with CD28 and its interacting ligands, CD80/CD86, using the CTLA4-Ig fusion protein, is effective in this regard. Disclosures No relevant conflicts of interest to declare.
43
Zeng, Ni, Yuetao Zhou, Shaqiu Zhang, Yogesh Singh, Bing Shi, Madhuri S. Salker, and Florian Lang. "1α,25(OH) 2D3 Sensitive Cytosolic pH Regulation and Glycolytic Flux in Human Endometrial Ishikawa Cells." Cellular Physiology and Biochemistry 41, no. 2 (2017): 678–88. http://dx.doi.org/10.1159/000458427.
Full textAbstract:
Background/Aims: Tumor cell proliferation is modified by 1,25-Dihydroxy-Vitamin D3 (1,25(OH)2D3), a steroid hormone predominantly known for its role in calcium and phosphorus metabolism. Key properties of tumor cells include enhanced glycolytic flux with excessive consumption of glucose and formation of lactate. As glycolysis is highly sensitive to cytosolic pH, maintenance of glycolysis requires export of H+ ions and lactate, which is in part accomplished by Na+/H+ exchangers, such as NHE1 and monocarboxylate transporters, such as MCT4. An effect of 1,25(OH)2D3 on those transport processes has, however, never been reported. As cytosolic pH impacts on apoptosis, the study further explored the effect of 1,25(OH)2D3 on apoptosis and on the apoptosis regulating kinase AKT, transcription factor Forkhead box O-3 (FOXO3A) and B-cell lymphoma protein BCL-2. Methods: In human endometrial adenocarcinoma (Ishikawa) cells, cytosolic pH (pHi) was determined utilizing (2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein [BCECF] fluorescence, Na+/H+ exchanger activity from Na+ dependent realkalinization after an ammonium pulse, NHE1 and MCT4 transcript levels using qRT-PCR, NHE1, MCT4, total & phospho AKT, total & phospho-FOXO3A and BCL-2 protein abundance by Western blotting, lactate concentration in the supernatant utilizing a colorimetric enzyme assay and cell death quantification using CytoTox 96®, Annexin V and Propidium Iodide staining. Results: A 24 hours treatment with 1,25(OH)2D3 (100 nM) significantly increased cytosolic pH (pHi), significantly decreased Na+/H+ exchanger activity, NHE1 and MCT4 transcript levels as well as protein abundance and significantly increased lactate concentration in the supernatant. Treatment of Ishikawa cells with 1,25(OH)2D3 (100 nM) further triggered apoptosis, an effect paralleled by decreased phosphorylation of AKT and FOXO3A as well as decreased abundance of BCL-2. Conclusions: In Ishikawa cells 1,25(OH)2D3 is a powerful stimulator of glycolysis, an effect presumably due to cytosolic alkalinization. Despite stimulation of glycolysis, 1,25(OH)2D3 stimulates slightly but significantly suicidal cell death, an effect presumably in part due to decreased activation of AKT with decreased inhibition of pro-apoptotic transcription factor FOXO3A and downregulation of the anti-apoptotic protein BCL-2.
44
Costa Leite, Tiago, Daniel Da Silva, Raquel Guimarães Coelho, Patricia Zancan, and Mauro Sola-Penna. "Lactate favours the dissociation of skeletal muscle 6-phosphofructo-1-kinase tetramers down-regulating the enzyme and muscle glycolysis." Biochemical Journal 408, no. 1 (October 29, 2007): 123–30. http://dx.doi.org/10.1042/bj20070687.
Full textAbstract:
For a long period lactate was considered as a dead-end product of glycolysis in many cells and its accumulation correlated with acidosis and cellular and tissue damage. At present, the role of lactate in several physiological processes has been investigated based on its properties as an energy source, a signalling molecule and as essential for tissue repair. It is noteworthy that lactate accumulation alters glycolytic flux independently from medium acidification, thereby this compound can regulate glucose metabolism within cells. PFK (6-phosphofructo-1-kinase) is the key regulatory glycolytic enzyme which is regulated by diverse molecules and signals. PFK activity is directly correlated with cellular glucose consumption. The present study shows the property of lactate to down-regulate PFK activity in a specific manner which is not dependent on acidification of the medium. Lactate reduces the affinity of the enzyme for its substrates, ATP and fructose 6-phosphate, as well as reducing the affinity for ATP at its allosteric inhibitory site at the enzyme. Moreover, we demonstrated that lactate inhibits PFK favouring the dissociation of enzyme active tetramers into less active dimers. This effect can be prevented by tetramer-stabilizing conditions such as the presence of fructose 2,6-bisphosphate, the binding of PFK to f-actin and phosphorylation of the enzyme by protein kinase A. In conclusion, our results support evidence that lactate regulates the glycolytic flux through modulating PFK due to its effects on the enzyme quaternary structure.
45
Tan, Hayden Weng Siong, Arthur Yi Loong Sim, Su Ling Huang, Ying Leng, and Yun Chau Long. "HC toxin (a HDAC inhibitor) enhances IRS1–Akt signalling and metabolism in mouse myotubes." Journal of Molecular Endocrinology 55, no. 3 (September 15, 2015): 197–207. http://dx.doi.org/10.1530/jme-15-0140.
Full textAbstract:
Exercise enhances numerous signalling pathways and activates substrate metabolism in skeletal muscle. Small molecule compounds that activate these cellular responses have been shown to recapitulate the metabolic benefits of exercise. In this study, a histone deacetylase (HDAC) inhibitor, HC toxin, was investigated as a small molecule compound that activates exercise-induced adaptations. In C2C12 myotubes, HC toxin treatment activated two exercise-stimulated pathways: AMP-activated protein kinase (AMPK) and Akt pathways. HC toxin increased the protein content and phosphorylation of insulin receptor substrate 1 as well as the activation of downstream Akt signalling. The effects of HC toxin on IRS1–Akt signalling were PI3K-dependent as wortmannin abolishes its effects on IRS1 protein accumulation and Akt phosphorylation. HC toxin-induced Akt activation was sufficient to enhance downstream mTOR complex 1 (mTORC1) signalling including p70S6K and S6, which were consistently abolished by PI3K inhibition. Insulin-stimulated glucose uptake, glycolysis, mitochondrial respiration and fatty acid oxidation were also enhanced in HC toxin-treated myotubes. When myotubes were challenged with serum starvation for the induction of atrophy, HC toxin treatment prevented the induction of genes that are involved in autophagy and proteasomal proteolysis. Conversely, IRS1–Akt signalling was not induced by HC toxin in several hepatoma cell lines, providing evidence for a favourable safety profile of this small molecule. These data highlight the potential of HDAC inhibitors as a novel class of small molecules for the induction of exercise-like signalling pathways and metabolism.
46
Ruberto, Anthony A., Samantha M. Logan, and Kenneth B. Storey. "Temperature and serine phosphorylation regulate glycerol-3-phosphate dehydrogenase in skeletal muscle of hibernating Richardson’s ground squirrels." Biochemistry and Cell Biology 97, no. 2 (April 2019): 148–57. http://dx.doi.org/10.1139/bcb-2018-0198.
Full textAbstract:
Glycerol-3-phosphate dehydrogenase (G3PDH) bridges carbohydrate and lipid metabolism by interconverting glycerol-3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP). This reversible reaction converts G3P derived from triglyceride hydrolysis to DHAP that can then enter glycolysis or gluconeogenesis and, in the reverse reaction, makes G3P for use in triglyceride biosynthesis. Small hibernating mammals rely almost exclusively on triglyceride reserves as their fuel for energy production during torpor and the recovery of glycerol after lipolysis is an important source of carbohydrate over the nonfeeding winter months. G3PDH (∼37 kDa) was purified from skeletal muscle of euthermic and hibernating Richardson’s ground squirrels (Urocitellus richardsonii) using three column chromatography steps. Analysis of enzyme kinetic properties revealed that G3PDH from hibernator muscle had higher affinities for G3P and NAD at low (5 °C) assay temperature compared with high (21 or 37 °C) and a greater stability in the presence of denaturing agents (urea, guanidine hydrochloride) or high temperature (50 °C). Immunoblotting showed that hibernator muscle G3PDH had a higher phosphoserine content than the enzyme from euthermic controls and incubation studies showed that enzyme affinity for G3P changed significantly by stimulating endogenous protein kinases or phosphatases. Overall, this study suggests that the properties of ground squirrel muscle G3PDH are modulated by temperature and post-translational phosphorylation to alter enzyme function under euthermic versus hibernating states.
47
Sobiepanek, Anna, Alessio Paone, Francesca Cutruzzolà, and Tomasz Kobiela. "Biophysical characterization of melanoma cell phenotype markers during metastatic progression." European Biophysics Journal 50, no. 3-4 (March 17, 2021): 523–42. http://dx.doi.org/10.1007/s00249-021-01514-8.
Full textAbstract:
AbstractMelanoma is the most fatal form of skin cancer, with increasing prevalence worldwide. The most common melanoma genetic driver is mutation of the proto-oncogene serine/threonine kinase BRAF; thus, the inhibition of its MAP kinase pathway by specific inhibitors is a commonly applied therapy. However, many patients are resistant, or develop resistance to this type of monotherapy, and therefore combined therapies which target other signaling pathways through various molecular mechanisms are required. A possible strategy may involve targeting cellular energy metabolism, which has been recognized as crucial for cancer development and progression and which connects through glycolysis to cell surface glycan biosynthetic pathways. Protein glycosylation is a hallmark of more than 50% of the human proteome and it has been recognized that altered glycosylation occurs during the metastatic progression of melanoma cells which, in turn facilitates their migration. This review provides a description of recent advances in the search for factors able to remodel cell metabolism between glycolysis and oxidative phosphorylation, and of changes in specific markers and in the biophysical properties of cells during melanoma development from a nevus to metastasis. This development is accompanied by changes in the expression of surface glycans, with corresponding changes in ligand-receptor affinity, giving rise to structural features and viscoelastic parameters particularly well suited to study by label-free biophysical methods.
48
Liu, Zhenqi, Yangsong Wu, Edward W. Nicklas, Linda A. Jahn, Wendie J. Price, and Eugene J. Barrett. "Unlike insulin, amino acids stimulate p70S6Kbut not GSK-3 or glycogen synthase in human skeletal muscle." American Journal of Physiology-Endocrinology and Metabolism 286, no. 4 (April 2004): E523—E528. http://dx.doi.org/10.1152/ajpendo.00146.2003.
Full textAbstract:
Insulin stimulates muscle glucose disposal via both glycolysis and glycogen synthesis. Insulin activates glycogen synthase (GS) in skeletal muscle by phosphorylating PKB (or Akt), which in turn phosphorylates and inactivates glycogen synthase kinase 3 (GSK-3), with subsequent activation of GS. A rapamycin-sensitive pathway, most likely acting via ribosomal 70-kDa protein S6 kinase (p70S6K), has also been implicated in the regulation of GSK-3 and GS by insulin. Amino acids potently stimulate p70S6K, and recent studies on cultured muscle cells suggest that amino acids also inactivate GSK-3 and/or activate GS via activating p70S6K. To assess the physiological relevance of these findings to normal human physiology, we compared the effects of amino acids and insulin on whole body glucose disposal, p70S6K, and GSK-3 phosphorylation, and on the activity of GS in vivo in skeletal muscle of 24 healthy human volunteers. After an overnight fast, subjects received intravenously either a mixed amino acid solution (1.26 μmol·kg-1·min-1× 6 h, n = 9), a physiological dose of insulin (1 mU·kg-1·min-1euglycemic hyperinsulinemic clamp × 2 h, n = 6), or a pharmacological dose of insulin (20 mU·kg-1·min-1euglycemic hyperinsulinemic clamp × 2 h, n = 9). Whole body glucose disposal rates were assessed by calculating the steady-state glucose infusion rates, and vastus lateralis muscle was biopsied before and at the end of the infusion. Both amino acid infusion and physiological hyperinsulinemia enhanced p70S6Kphosphorylation without affecting GSK-3 phosphorylation, but only physiological hyperinsulinemia also increased whole body glucose disposal and GS activity. In contrast, a pharmacological dose of insulin significantly increased whole body glucose disposal, p70S6K, GSK-3 phosphorylation, and GS activity. We conclude that amino acids at physiological concentrations mediate p70S6Kbut, unlike insulin, do not regulate GSK-3 and GS phosphorylation/activity in human skeletal muscle.
49
Sturgill, Eric M., and Monica L. Guzman. "Cytokine Induced Nuclear Localization Of Pyruvate Kinase M2 In Acute Myeloid Leukemia." Blood 122, no. 21 (November 15, 2013): 5406. http://dx.doi.org/10.1182/blood.v122.21.5406.5406.
Full textAbstract:
Abstract A common characteristic among nearly all cancers, including leukemia, is the cell’s metabolic proclivity for glycolysis over the more energy efficient process of oxidative phosphorylation (OXPHOS) in the presence of oxygen. This altered state of aerobic glycolysis was observed in tumor cells by Otto Warburg over fifty years ago (Warburg, 1956) and continues to be intensely investigated in hopes of ultimately exploiting this “Warburg effect” in the treatment of cancer (Vander Heiden et al. 2009). Recent studies have revealed that the M2 isoform of the enzyme pyruvate kinase (PKM2) plays a critical role in the maintenance of aerobic glycolysis in tumor cells and is important for their growth and development (Christofk et al. 2008). Pyruvate kinase produces pyruvate and one molecule of adenosine 5’-triphosphate (ATP) in the rate-limiting step of glycolysis. Pyruvate kinase coded for by PKM has two splice isoforms, the constitutively active PKM1 that exists only as a tetramer and PKM2 that can shift between a more active tetramer and less active dimers or monomers. The dynamic enzymatic activity of PKM2 is key to its preferential expression in tumor cells. By utilizing the less active form of PKM2, tumor cells can limit the levels of pyruvate available for OXPHOS and instead shunt glycolytic carbons towards anabolic processes. However, recent studies have revealed novel activities of PKM2 outside the realm of energy metabolism that also contribute to tumor formation, maintenance, and growth. The less active PKM2 dimer, whose structure is favored upon phosphorylation at Tyr105 (Hitosugi et al. 2009), can also translocate to the nucleus and act as a transcription factor for cell cycle associated genes like MYC and CCND1 upon stimulation with epidermal growth factor in certain cancer cell lines (Gao et al. 2012). Acute myeloid leukemia (AML) is a malignancy of hematopoietic progenitor cells characterized by the extraordinarily rapid growth of abnormal myeloid cells, making the proliferative influences of PKM2 an intriguing target for therapy. We have found that PKM2 is abundantly expressed in AML cell lines and primary AML patient samples and that low basal levels of PKM2 can be detected in their nuclei. Interestingly, stimulation with various cytokines such as IL-6 or GM-CSF can induce the nuclear translocation of PKM2 and association with histone H3 in these cells and concomitant treatment with PKM2 activating compounds that have been shown to promote its tetrameric structure and suppress tumor growth (Anastasiou et al. 2012) can inhibit this effect. These data show that the role of PKM2 in regulating transcription in addition to its metabolic activity may be important for the proliferation and maintenance of hematopoietic malignancies. Using fluorescence-activated cell sorting to isolate specific sub-populations of primary AML patient cells and elucidating PKM2’s interaction with protein kinases involved in known signaling pathways like JAK/STAT, ERK1/2, and FLT3, we show that the proliferative influences of PKM2 function and activity differ between AML cell phenotypes. For example, cells from AML patient samples sorted based on high or low levels of reactive oxygen species (ROS) differ in relative phosphorylation of PKM2 at Tyr105. These data, along with reports that the PKM2 dimer specifically plays a role in tumor cell antioxidant response (Anastasiou, et al. 2011) suggests that PKM2 may contribute to the maintenance of phenotypically ROS-low leukemia stem cells that are thought to contribute to patient relapse after achieving remission (Hope et al. 2004). Our data suggests that the broad cellular functions of PKM2 employed by AML cells and its direct influence on tumor growth and survival make it a promising potential target for therapy. Disclosures: No relevant conflicts of interest to declare.
50
Ma, Jianyu, Caifang Ren, Hua Yang, Jie Zhao, Feng Wang, and Yongjie Wan. "The Expression Pattern of p32 in Sheep Muscle and Its Role in Differentiation, Cell Proliferation, and Apoptosis of Myoblasts." International Journal of Molecular Sciences 20, no. 20 (October 18, 2019): 5161. http://dx.doi.org/10.3390/ijms20205161.
Full textAbstract:
The complement 1q binding protein C (C1QBP), also known as p32, is highly expressed in rapidly growing tissues and plays a crucial role in cell proliferation and apoptosis. However, there are no data interpreting its mechanisms in muscle development. To investigate the role of p32 in sheep muscle development, an 856 bp cDNA fragment of p32 containing an 837 bp coding sequence that encodes 278 amino acids was analyzed. We then revealed that the expression of p32 in the longissimus and quadricep muscles of fetal sheep was more significantly up-regulated than expression at other developmental stages. Furthermore, we found that the expression of p32 was increased during myoblasts differentiation in vitro. Additionally, the knockdown of p32 in sheep myoblasts effectively inhibited myoblast differentiation, proliferation, and promoted cell apoptosis in vitro. The interference of p32 also changed the energy metabolism from Oxidative Phosphorylation (OXPHOS) to glycolysis and activated AMP-activated protein kinase (AMPK) phosphorylation in sheep myoblasts in vitro. Taken together, our data suggest that p32 plays a vital role in the development of sheep muscle and provides a potential direction for future research on muscle development and some muscle diseases.