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Murali VS, Rajendran D, Isogai T, DeBerardinis RJ, Danuser G. RhoA activation promotes glucose uptake to elevate proliferation in MAPK inhibitor resistant melanoma cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.09.574940. [PMID: 38260449 PMCID: PMC10802590 DOI: 10.1101/2024.01.09.574940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Cutaneous melanomas harboring a B-RafV600E mutation are treated with immune check point inhibitors or kinase inhibitor combination therapies relying on MAPK inhibitors (MAPKi) Dabrafenib and Trametinib (Curti and Faries, 2021). However, cells become resistant to treatments over the timespan of a few months. Resistance to MAPKi has been associated with adoption of an aggressive amoeboid phenotype characterized by elevated RhoA signaling, enhanced contractility and thick cortical filamentous actin (F-actin) structures (Kim et al., 2016; Misek et al., 2020). Targeting active RhoA through Rho-kinase (ROCK) inhibitors, either alone or in combination with immunotherapies, reverts MAPKi-resistance (Misek et al., 2020; Orgaz et al., 2020). Yet, the mechanisms for this behavior remain largely unknown. Given our recent findings of cytoskeleton's role in cancer cell proliferation (Mohan et al., 2019), survival (Weems et al., 2023), and metabolism (Park et al., 2020), we explored possibilities by which RhoA-driven changes in cytoskeleton structure may confer resistance. We confirmed elevated activation of RhoA in a panel of MAPKi-resistant melanoma cell lines, leading to a marked increase in the presence of contractile F-actin bundles. Moreover, these cells had increased glucose uptake and glycolysis, a phenotype disrupted by pharmacological perturbation of ROCK. However, glycolysis was unaffected by disruption of F-actin bundles, indicating that glycolytic stimulation in MAPKi-resistant melanoma is independent of F-actin organization. Instead, our findings highlight a mechanism in which elevated RhoA signaling activates ROCK, leading to the activation of insulin receptor substrate 1 (IRS1) and P85 of the PI3K pathway, which promotes cell surface expression of GLUT1 and elevated glucose uptake. Application of ROCK inhibitor GSK269962A results in reduced glucose uptake and glycolysis, thus impeding cell proliferation. Our study adds a mechanism to the proposed use of ROCK inhibitors for long-term treatments on MAPKi-resistant melanomas.
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Affiliation(s)
- Vasanth Siruvallur Murali
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
- Cecil H. and Ida Green Center for Systems Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Divya Rajendran
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
- Cecil H. and Ida Green Center for Systems Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Tadamoto Isogai
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
- Cecil H. and Ida Green Center for Systems Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Ralph J. DeBerardinis
- Children’s Research Institute and Department of Pediatrics, UT Southwestern Medical Center, Dallas, TX, USA
- Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, TX, USA
- Eugene McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, TX, USA
| | - Gaudenz Danuser
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
- Cecil H. and Ida Green Center for Systems Biology, UT Southwestern Medical Center, Dallas, TX, USA
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Campos M, Albrecht LV. Hitting the Sweet Spot: How Glucose Metabolism Is Orchestrated in Space and Time by Phosphofructokinase-1. Cancers (Basel) 2023; 16:16. [PMID: 38201444 PMCID: PMC10778546 DOI: 10.3390/cancers16010016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/12/2023] [Accepted: 12/15/2023] [Indexed: 01/12/2024] Open
Abstract
Glycolysis is the central metabolic pathway across all kingdoms of life. Intensive research efforts have been devoted to understanding the tightly orchestrated processes of converting glucose into energy in health and disease. Our review highlights the advances in knowledge of how metabolic and gene networks are integrated through the precise spatiotemporal compartmentalization of rate-limiting enzymes. We provide an overview of technically innovative approaches that have been applied to study phosphofructokinase-1 (PFK1), which represents the fate-determining step of oxidative glucose metabolism. Specifically, we discuss fast-acting chemical biology and optogenetic tools that have delineated new links between metabolite fluxes and transcriptional reprogramming, which operate together to enact tissue-specific processes. Finally, we discuss how recent paradigm-shifting insights into the fundamental basis of glycolytic regulatory control have shed light on the mechanisms of tumorigenesis and could provide insight into new therapeutic vulnerabilities in cancer.
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Affiliation(s)
- Melissa Campos
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, CA 92697, USA;
| | - Lauren V. Albrecht
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, CA 92697, USA;
- Department of Pharmaceutical Sciences, School of Pharmacy & Pharmaceutical Sciences, University of California, Irvine, CA 92697, USA
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Actin dynamics in protein homeostasis. Biosci Rep 2022; 42:231720. [PMID: 36043949 PMCID: PMC9469105 DOI: 10.1042/bsr20210848] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/22/2022] [Accepted: 08/31/2022] [Indexed: 11/17/2022] Open
Abstract
Cell homeostasis is maintained in all organisms by the constant adjustment of cell constituents and organisation to account for environmental context. Fine-tuning of the optimal balance of proteins for the conditions, or protein homeostasis, is critical to maintaining cell homeostasis. Actin, a major constituent of the cytoskeleton, forms many different structures which are acutely sensitive to the cell environment. Furthermore, actin structures interact with and are critically important for the function and regulation of multiple factors involved with mRNA and protein production and degradation, and protein regulation. Altogether, actin is a key, if often overlooked, regulator of protein homeostasis across eukaryotes. In this review, we highlight these roles and how they are altered following cell stress, from mRNA transcription to protein degradation.
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DeWane G, Salvi AM, DeMali KA. Fueling the cytoskeleton - links between cell metabolism and actin remodeling. J Cell Sci 2021; 134:jcs248385. [PMID: 33558441 PMCID: PMC7888749 DOI: 10.1242/jcs.248385] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Attention has long focused on the actin cytoskeleton as a unit capable of organizing into ensembles that control cell shape, polarity, migration and the establishment of intercellular contacts that support tissue architecture. However, these investigations do not consider observations made over 40 years ago that the actin cytoskeleton directly binds metabolic enzymes, or emerging evidence suggesting that the rearrangement and assembly of the actin cytoskeleton is a major energetic drain. This Review examines recent studies probing how cells adjust their metabolism to provide the energy necessary for cytoskeletal remodeling that occurs during cell migration, epithelial to mesenchymal transitions, and the cellular response to external forces. These studies have revealed that mechanotransduction, cell migration, and epithelial to mesenchymal transitions are accompanied by alterations in glycolysis and oxidative phosphorylation. These metabolic changes provide energy to support the actin cytoskeletal rearrangements necessary to allow cells to assemble the branched actin networks required for cell movement and epithelial to mesenchymal transitions and the large actin bundles necessary for cells to withstand forces. In this Review, we discuss the emerging evidence suggesting that the regulation of these events is highly complex with metabolism affecting the actin cytoskeleton and vice versa.
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Affiliation(s)
- Gillian DeWane
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA 52246, USA
| | - Alicia M Salvi
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA 52246, USA
| | - Kris A DeMali
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA 52246, USA
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Li Y, Yu C, Li J, Zhang L, Gao F, Zhou G. Effects of dietary energy sources on early postmortem muscle metabolism of finishing pigs. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2017; 30:1764-1772. [PMID: 28728385 PMCID: PMC5666181 DOI: 10.5713/ajas.17.0090] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 04/26/2017] [Accepted: 05/22/2017] [Indexed: 11/27/2022]
Abstract
OBJECTIVE This study investigated the effects of different dietary energy sources on early postmortem muscle metabolism of finishing pigs. METHODS Seventy-two barrow (Duroc×Landrace×Yorkshire, DLY) pigs (65.0±2.0 kg) were allotted to three iso-energetic and iso-nitrogenous diets: A (44.1% starch, 5.9% crude fat, and 12.6% neutral detergent fibre [NDF]), B (37.6% starch, 9.5% crude fat, and 15.4% NDF) or C (30.9% starch, 14.3% crude fat, and 17.8% NDF). After the duration of 28-day feeding experiment, 24 pigs (eight per treatment) were slaughtered and the M. longissimus lumborum (LL) samples at 45 min postmortem were collected. RESULTS Compared with diet A, diet C resulted in greater adenosine triphosphate and decreased phosphocreatine (PCr) concentrations, greater activity of creatine kinase and reduced percentage bound activities of hexokinase (HK), and pyruvate kinase (PK) in LL muscles (p<0.05). Moreover, diet C decreased the phosphor-AKT level and increased the hydroxy-hypoxia-inducible factor-1α (HIF-1α) level, as well as decreased the bound protein expressions of HK II, PKM2, and lactate dehydrogenase A (p<0.05). CONCLUSION Diet C with the lowest level of starch and the highest levels of fat and NDF could enhance the PCr utilization and attenuate glycolysis early postmortem in LL muscle of finishing pigs.
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Affiliation(s)
- Yanjiao Li
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, China
- College of Animal Science and Technology, Jiangxi Province Key Laboratory of Animal Nutrition, Jiangxi Agricultural University, Nanchang 330045, China
| | - Changning Yu
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, China
| | - Jiaolong Li
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, China
| | - Lin Zhang
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, China
| | - Feng Gao
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, China
| | - Guanghong Zhou
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, China
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Li YJ, Gao T, Li JL, Zhang L, Gao F, Zhou GH. Effects of dietary starch types on early postmortem muscle energy metabolism in finishing pigs. Meat Sci 2017; 133:204-209. [PMID: 28734229 DOI: 10.1016/j.meatsci.2017.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 06/21/2017] [Accepted: 07/10/2017] [Indexed: 01/10/2023]
Abstract
This study aimed to investigate the effects of different dietary starch types on early postmortem muscle energy metabolism in finishing pigs. Ninety barrows (68.0±2.0kg) were randomly allotted to three experimental diets with five replicates of six pigs, containing pure waxy maize starch (WMS), nonwaxy maize starch (NMS), and pea starch (PS) (amylose/amylopectin were 0.07, 0.19 and 0.28 respectively). Compared with the WMS diet, pigs fed the PS diet exhibited greater creatine kinase activity, higher adenosine triphosphate and adenosine diphosphate contents, lower phosphocreatine (PCr), adenosine monophosphate and glycogen contents, and lower glycolytic potential (P<0.05). Moreover, the PS diet led to reduced percentage of bound hexokinase activity, decreased level of phosphorylated AKT (P<0.05) and increased level of hypoxia-inducible factor-1α (P<0.05). In conclusion, diet with high amylose content might promote PCr degradation and inhibit the rate of glycolysis, followed by attenuation of early postmortem glycolysis in finishing pigs.
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Affiliation(s)
- Y J Li
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, No. 1 Weigang, Xuanwu District, Nanjing 210095, PR China; College of Animal Science and Technology, Jiangxi Province Key Laboratory of Animal Nutrition, Jiangxi Agricultural University, No.1101 Zhimin Road, Economic and Technological Development District, Nanchang 330045, PR China
| | - T Gao
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, No. 1 Weigang, Xuanwu District, Nanjing 210095, PR China
| | - J L Li
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, No. 1 Weigang, Xuanwu District, Nanjing 210095, PR China
| | - L Zhang
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, No. 1 Weigang, Xuanwu District, Nanjing 210095, PR China
| | - F Gao
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, No. 1 Weigang, Xuanwu District, Nanjing 210095, PR China.
| | - G H Zhou
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, No. 1 Weigang, Xuanwu District, Nanjing 210095, PR China
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Al Hasawi N, Alkandari MF, Luqmani YA. Phosphofructokinase: a mediator of glycolytic flux in cancer progression. Crit Rev Oncol Hematol 2014; 92:312-21. [PMID: 24910089 DOI: 10.1016/j.critrevonc.2014.05.007] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 04/10/2014] [Accepted: 05/13/2014] [Indexed: 01/07/2023] Open
Abstract
In view of the current limitations of cancer chemotherapy, there has been resurgent interest in re-visiting glycolysis to determine whether tumors could be killed by energy deprivation rather than solely by strategies to inhibit proliferation. Cancer cells exhibit a uniquely high rate of glucose utilization, converting it into lactate whose export subsequently creates an acidic extracellular environment that is thought to promote invasion and metastasis, in preference to its complete oxidation even in the presence of adequate oxygen supply. Reductive analysis of each step of glycolysis shows that, of the three rate limiting enzymes of the pathway, isoforms of phosphofructokinase may afford the greatest opportunity as targets to deprive cancer cells from essential energy and substrates for macromolecular synthesis for proliferation while allowing normal cells to survive. Strategies discussed include restricting the substrate for this enzyme. While prospects for monotherapy with glycolytic inhibitors are poor, combination therapy may be productive.
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Affiliation(s)
- Nada Al Hasawi
- Faculty of Pharmacy, Kuwait University, PO Box 24923, Safat 13110, Kuwait.
| | - Mariam F Alkandari
- Faculty of Pharmacy, Kuwait University, PO Box 24923, Safat 13110, Kuwait.
| | - Yunus A Luqmani
- Faculty of Pharmacy, Kuwait University, PO Box 24923, Safat 13110, Kuwait.
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Yang H, Wu J, Guo R, Peng Y, Zheng W, Liu D, Song Z. Glycolysis in energy metabolism during seizures. Neural Regen Res 2014; 8:1316-26. [PMID: 25206426 PMCID: PMC4107649 DOI: 10.3969/j.issn.1673-5374.2013.14.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 03/27/2013] [Indexed: 01/23/2023] Open
Abstract
Studies have shown that glycolysis increases during seizures, and that the glycolytic metabolite lactic acid can be used as an energy source. However, how lactic acid provides energy for seizures and how it can participate in the termination of seizures remains unclear. We reviewed possible mechanisms of glycolysis involved in seizure onset. Results showed that lactic acid was involved in seizure onset and provided energy at early stages. As seizures progress, lactic acid reduces the pH of tissue and induces metabolic acidosis, which terminates the seizure. The specific mechanism of lactic acid-induced acidosis involves several aspects, which include lactic acid-induced inhibition of the glycolytic enzyme 6-diphosphate kinase-1, inhibition of the N-methyl-D-aspartate receptor, activation of the acid-sensitive 1A ion channel, strengthening of the receptive mechanism of the inhibitory neurotransmitter γ-minobutyric acid, and changes in the intra- and extracellular environment.
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Affiliation(s)
- Heng Yang
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Jiongxing Wu
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Ren Guo
- Department of Pharmacy, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Yufen Peng
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Wen Zheng
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Ding Liu
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Zhi Song
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
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Coelho WS, Sola-Penna M. Serotonin regulates 6-phosphofructo-1-kinase activity in a PLC-PKC-CaMK II- and Janus kinase-dependent signaling pathway. Mol Cell Biochem 2012; 372:211-20. [PMID: 23010892 DOI: 10.1007/s11010-012-1462-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 09/14/2012] [Indexed: 01/08/2023]
Abstract
Serotonin (5-HT) is a hormone that has been implicated in the regulation of many physiological and pathological events. One of the most intriguing properties of this hormone is its ability to up-regulate mitosis. Moreover, 5-HT stimulates glucose uptake and up-regulates PFK activity through the 5-HT(2A) receptor, resulting in the phosphorylation of a tyrosine residue of PFK and the intracellular redistribution of PFK within skeletal muscle. The present study investigated some of the signaling intermediates involved in the effects of 5-HT on 6-phosphofructo-1-kinase (PFK) regulation from skeletal muscle using kinetic assessments, immunoprecipitation, and western blotting assays. Our results demonstrate that 5-HT stimulates PFK from skeletal muscle via phospholipase C (PLC). The activation of PLC in skeletal muscle leads to the recruitment of protein kinase C (PKC) and calmodulin and the stimulation of calmodulin kinase II, which associates with PFK upon 5-HT action. Alternatively, 5-HT loses its ability to up-regulate PFK activity when Janus kinase is inhibited, suggesting that 5-HT is able to control glycolytic flux in the skeletal muscle of mice by recruiting different pathways and controlling PFK activity.
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Affiliation(s)
- Wagner Santos Coelho
- Laboratório de Enzimologia e Controle do Metabolismo (LabECoM), Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, RJ 21941-590, Brazil
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Da Silva D, Ausina P, Alencar EM, Coelho WS, Zancan P, Sola-Penna M. Metformin reverses hexokinase and phosphofructokinase downregulation and intracellular distribution in the heart of diabetic mice. IUBMB Life 2012; 64:766-74. [DOI: 10.1002/iub.1063] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 05/25/2012] [Indexed: 01/19/2023]
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Coelho WS, Da Silva D, Marinho-Carvalho MM, Sola-Penna M. Serotonin modulates hepatic 6-phosphofructo-1-kinase in an insulin synergistic manner. Int J Biochem Cell Biol 2012; 44:150-7. [DOI: 10.1016/j.biocel.2011.10.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 09/24/2011] [Accepted: 10/14/2011] [Indexed: 01/20/2023]
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12
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Coelho RG, Calaça IDC, Celestrini DDM, Correia AH, Costa MASM, Sola-Penna M. Clotrimazole disrupts glycolysis in human breast cancer without affecting non-tumoral tissues. Mol Genet Metab 2011; 103:394-8. [PMID: 21531601 DOI: 10.1016/j.ymgme.2011.04.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 04/11/2011] [Accepted: 04/11/2011] [Indexed: 12/26/2022]
Abstract
Human breast cancer tissues, as well as normal tissues from the same patients, were treated with clotrimazole (CTZ) and have their capacities for glucose consumption and lactate production evaluated. This treatment strongly decreased the lactate production rate by tumor tissues (85% inhibition) without affecting the other measurements made, i.e. lactate production by control tissues or glucose consumption by both, control and tumor tissues. This result directly correlates with the inhibition promoted by CTZ on the activity of the major regulatory glycolytic enzyme 6-phosphofructo-1-kinase (PFK) that was observed in tumor tissues (84% inhibition) but not in control tissues. Fractionation of the tissues revealed that this inhibition does not occur in the soluble fraction of the enzyme, but is exclusive of a particulate fraction. It has been previously shown that the particulate fraction of PFK activity in tumors is associated to actin filaments (f-actin). Thus, we investigated whether CTZ would affect the association between PFK and f-actin and we found that the drug directly induces the dissociation of the two proteins in the same extent that it inhibits lactate production, total PFK activity and the particulate PFK activity. We concluded that CTZ disrupts glycolysis on human breast tumor tissues, inhibiting PFK activity by dissociating the enzyme from f-actin.
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Affiliation(s)
- Raquel Guimarães Coelho
- Laboratório de Enzomologia e Controle do Metabolismo, Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil
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13
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Sola-Penna M, Da Silva D, Coelho WS, Marinho-Carvalho MM, Zancan P. Regulation of mammalian muscle type 6-phosphofructo-1-kinase and its implication for the control of the metabolism. IUBMB Life 2011; 62:791-6. [PMID: 21117169 DOI: 10.1002/iub.393] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Phosphofructokinase (PFK) is a major regulatory glycolytic enzyme and is considered to be the pacemaker of glycolysis. This enzyme presents a puzzling regulatory mechanism that is modulated by a large variety of metabolites, drugs, and intracellular proteins. To date, the mammalian enzyme structure has not yet been resolved. However, it is known that PFK undergoes an intricate oligomerization process, shifting among monomers, dimers, tetramers, and more complex oligomeric structures. The equilibrium between PFK dimers and tetramers is directly correlated with the enzyme regulation, because the dimer exhibits very low catalytic activity, whereas the tetramer is fully active. Several PFK ligands modulate the enzyme, favoring the formation of its dimers or tetramers. The present review integrates recent findings regarding the regulatory aspects of muscle type PFK and discusses their relation to the control of metabolism.
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Affiliation(s)
- Mauro Sola-Penna
- Laboratorio de Enzimologia e Controle do Metabolismo (LabECoM) and Laboratório de Oncobiologia Molecular (LabOMol), Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
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14
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Grechi J, Marinho-Carvalho M, Zancan P, Cinelli LP, Gomes AMO, Rodrigues ML, Nimrichter L, Sola-Penna M. Glucuronoxylomannan from Cryptococcus neoformans down-regulates the enzyme 6-phosphofructo-1-kinase of macrophages. J Biol Chem 2011; 286:14820-9. [PMID: 21388964 DOI: 10.1074/jbc.m110.177030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The encapsulated yeast Cryptococcus neoformans is the causative agent of cryptococosis, an opportunistic life-threatening infection. C. neoformans is coated by a polysaccharide capsule mainly composed of glucuronoxylomannan (GXM). GXM is considered a key virulence factor of this pathogen. The present work aimed at evaluating the effects of GXM on the key glycolytic enzyme, 6-phosphofructo-1-kinase (PFK). GXM inhibited PFK activity in cultured murine macrophages in both dose- and time-dependent manners, which occurred in parallel to cell viability decrease. The polysaccharide also inhibited purified PFK, promoting a decrease on the enzyme affinity for its substrates. In macrophages GXM and PFK partially co-localized, suggesting that internalized polysaccharide directly may interact with this enzyme. The mechanism of PFK inhibition involved dissociation of tetramers into weakly active dimers, as revealed by fluorescence spectroscopy. Allosteric modulators of the enzyme able to stabilize its tetrameric conformation attenuated the inhibition promoted by GXM. Altogether, our results suggest that the mechanism of GXM-induced cell death involves the inhibition of the glycolytic flux.
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Affiliation(s)
- Juliana Grechi
- Laboratório de Enzimologia e Controle do Metabolismo, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-590, Brazil
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Banaszak K, Mechin I, Obmolova G, Oldham M, Chang SH, Ruiz T, Radermacher M, Kopperschläger G, Rypniewski W. The crystal structures of eukaryotic phosphofructokinases from baker's yeast and rabbit skeletal muscle. J Mol Biol 2011; 407:284-97. [PMID: 21241708 DOI: 10.1016/j.jmb.2011.01.019] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 01/07/2011] [Accepted: 01/09/2011] [Indexed: 11/17/2022]
Abstract
Phosphofructokinase 1 (PFK) is a multisubunit allosteric enzyme that catalyzes the principal regulatory step in glycolysis-the phosphorylation of fructose 6-phosphate to fructose 1,6-bisphosphate by ATP. The activity of eukaryotic PFK is modulated by a number of effectors in response to the cell's needs for energy and building blocks for biosynthesis. The crystal structures of eukaryotic PFKs-from Saccharomyces cerevisiae and rabbit skeletal muscle-demonstrate how successive gene duplications and fusion are reflected in the protein structure and how they allowed the evolution of new functionalities. The basic framework inherited from prokaryotes is conserved, and additional levels of structural and functional complexity have evolved around it. Analysis of protein-ligand complexes has shown how PFK is activated by fructose 2,6-bisphosphate (a powerful PFK effector found only in eukaryotes) and reveals a novel nucleotide binding site. Crystallographic results have been used as the basis for structure-based effector design.
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Affiliation(s)
- Katarzyna Banaszak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
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16
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Real-Hohn A, Zancan P, Da Silva D, Martins ER, Salgado LT, Mermelstein CS, Gomes AM, Sola-Penna M. Filamentous actin and its associated binding proteins are the stimulatory site for 6-phosphofructo-1-kinase association within the membrane of human erythrocytes. Biochimie 2010; 92:538-44. [DOI: 10.1016/j.biochi.2010.01.023] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Accepted: 01/29/2010] [Indexed: 01/16/2023]
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17
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Silva DD, Zancan P, Coelho WS, Gomez LS, Sola-Penna M. Metformin reverses hexokinase and 6-phosphofructo-1-kinase inhibition in skeletal muscle, liver and adipose tissues from streptozotocin-induced diabetic mouse. Arch Biochem Biophys 2010; 496:53-60. [DOI: 10.1016/j.abb.2010.01.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 01/22/2010] [Accepted: 01/25/2010] [Indexed: 12/25/2022]
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18
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Acetylsalicylic acid and salicylic acid decrease tumor cell viability and glucose metabolism modulating 6-phosphofructo-1-kinase structure and activity. Biochem Pharmacol 2009; 77:46-53. [DOI: 10.1016/j.bcp.2008.09.020] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Revised: 09/14/2008] [Accepted: 09/15/2008] [Indexed: 11/23/2022]
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19
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Coelho WS, Costa KC, Sola-Penna M. Serotonin stimulates mouse skeletal muscle 6-phosphofructo-1-kinase through tyrosine-phosphorylation of the enzyme altering its intracellular localization. Mol Genet Metab 2007; 92:364-70. [PMID: 17720578 DOI: 10.1016/j.ymgme.2007.07.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Accepted: 07/11/2007] [Indexed: 11/24/2022]
Abstract
Serotonin (5-HT) is a hormone implicated in the regulation of many physiological and pathological events. One of its most intriguing properties is the ability to up-regulate mitosis. Moreover, it has been shown that 5-HT stimulate glucose uptake on skeletal muscle, suggesting that 5-HT may regulate glucose metabolism of peripheric tissues. Here we demonstrate that 5-HT stimulates skeletal muscle 6-phosphofructo-1-kinase (PFK) activity in a dose-response manner, through 5-HT(2A) receptor subtype. Maximal activation of the enzyme (2.5-fold compared to control) is achieved in the presence of 25pM 5-HT, increasing both PFK maximal velocity and affinity for the substrate fructose-6-phosphate. These effects occur due to tyrosine phosphorylation of the enzyme that is 2-fold enhanced upon 5-HT stimulation of skeletal muscles preparation. Once 5-HT-induced tyrosine phosphorylation of PFK is prevented by genistein, a tyrosine kinase inhibitor, the hormone stimulatory effect on PFK is abrogated. Wortmannin, a phosphatidylinositol-3-kinase (PI3K) inhibitor, does not interfere on 5-HT-induced stimulation of PFK, supporting that the observed effects are independent on insulin signaling pathway. Furthermore, 5-HT promotes the association of PFK to the muscle f-actin, suggesting that the hormone alters PFK intracellular distribution, favoring its association to the cytoskeleton. Altogether, our results support evidences that 5-HT augments skeletal muscle glucose consumption through stimulation of glycolysis key regulatory enzyme, PFK, throughout tyrosine phosphorylation and intracellular redistribution of the enzyme.
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Affiliation(s)
- Wagner Santos Coelho
- Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, RJ 21941-590, Brazil
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Costa Leite T, Da Silva D, Guimarães Coelho R, Zancan P, Sola-Penna M. Lactate favours the dissociation of skeletal muscle 6-phosphofructo-1-kinase tetramers down-regulating the enzyme and muscle glycolysis. Biochem J 2007; 408:123-30. [PMID: 17666012 PMCID: PMC2049071 DOI: 10.1042/bj20070687] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
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.
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Affiliation(s)
- Tiago Costa Leite
- *Laboratório de Enzimologia e Controle do Metabolismo (LabECoM), Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil 21941-590
- †Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil 21941-590
| | - Daniel Da Silva
- *Laboratório de Enzimologia e Controle do Metabolismo (LabECoM), Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil 21941-590
| | - Raquel Guimarães Coelho
- †Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil 21941-590
| | - Patricia Zancan
- *Laboratório de Enzimologia e Controle do Metabolismo (LabECoM), Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil 21941-590
| | - Mauro Sola-Penna
- *Laboratório de Enzimologia e Controle do Metabolismo (LabECoM), Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil 21941-590
- To whom correspondence should be addressed (email )
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Zancan P, Rosas AO, Marcondes MC, Marinho-Carvalho MM, Sola-Penna M. Clotrimazole inhibits and modulates heterologous association of the key glycolytic enzyme 6-phosphofructo-1-kinase. Biochem Pharmacol 2007; 73:1520-7. [PMID: 17291460 DOI: 10.1016/j.bcp.2007.01.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Revised: 01/09/2007] [Accepted: 01/10/2007] [Indexed: 11/30/2022]
Abstract
Clotrimazole is an antifungal azole derivative recently recognized as a calmodulin antagonist with promising anticancer effects. This property has been correlated with the ability of the drug to decrease the viability of tumor cells by inhibiting their glycolytic flux and consequently decreasing the intracellular concentration of ATP. The effects of clotrimazole on cell glycolysis and ATP production are considered to be due to the detachment of the glycolytic enzymes from the cytoskeleton. Here, we show that clotrimazole directly inhibits the key glycolytic enzyme 6-phosphofructo-1-kinase (PFK). This property is independent of the anti-calmodulin activity of the drug, since it is not mimicked by the classical calmodulin antagonist compound 48/80. However, the clotrimazole-inhibited enzyme can be activated by calmodulin, even though calmodulin has no effect on PFK activity in the absence of the drug. Clotrimazole alone induces the dimerization of PFK reducing the population of tetramers, which is not observed when calmodulin is also present. Since PFK dimers are less active than PFK tetramers, this can explain the inhibitory effect of clotrimazole on the enzyme. Additionally, clotrimazole positively modulates the association of PFK with erythrocyte membranes. Altogether, our data support a hitherto unrecognized action of clotrimazole as a negative modulator of glycolytic flux through direct inhibition of the key enzyme PFK.
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Affiliation(s)
- Patricia Zancan
- Laboratório de Enzimologia e Controle do Metabolismo, Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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22
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Marinho-Carvalho MM, Zancan P, Sola-Penna M. Modulation of 6-phosphofructo-1-kinase oligomeric equilibrium by calmodulin: formation of active dimers. Mol Genet Metab 2006; 87:253-61. [PMID: 16377227 DOI: 10.1016/j.ymgme.2005.11.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Revised: 11/04/2005] [Accepted: 11/08/2005] [Indexed: 01/04/2023]
Abstract
Muscle 6-phospho-1-kinase (PFK) is the key regulatory enzyme of the glycolytic pathway and is a calmodulin-binding protein binding two calmodulin molecules per PFK protomer. This enzyme is characterized by a complex regulation that involves its allosteric behavior modulated by several ligands, which modulate the equilibrium between the active tetramers and the inactive dimers of the enzyme. Calmodulin is described to induce the dimerization of PFK, so inhibiting its catalytic activity. Here, we show that binding of calmodulin specifically to its higher-affinity site of PFK induce its dimerization without compromising enzyme catalytic activity forming a hitherto not described active dimmer of PFK. It is also shown that the dimerization is a Ca2+ -dependent event that responds to physiological intracellular Ca2+ concentrations and decrease the interaction of the enzyme to membrane site, which stimulate its catalytic activity. We propose that the effects of calmodulin on PFK reported here are of great physiological significance due to the response to physiological concentrations of Ca2+ and due to be in accordance to the known effects of calmodulin on cell ATP production. We also propose that calmodulin might affect the interaction of PFK to other cellular components as the cytoskeleton.
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Affiliation(s)
- Monica M Marinho-Carvalho
- Laboratório de Enzimologia e Controle do Metabolismo (LabECoM), Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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23
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Zancan P, Sola-Penna M. Calcium influx: a possible role for insulin modulation of intracellular distribution and activity of 6-phosphofructo-1-kinase in human erythrocytes. Mol Genet Metab 2005; 86:392-400. [PMID: 16122962 DOI: 10.1016/j.ymgme.2005.07.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2005] [Revised: 07/12/2005] [Accepted: 07/12/2005] [Indexed: 11/22/2022]
Abstract
Human erythrocyte cells contain specific, active insulin receptor. However, the physiological relevance of this receptor is unclear. Here we show that Ca2+ influx is 4-fold higher in erythrocytes upon insulin stimulation. These effects are dose-dependent and are diminished by insulin concentrations of 150 nM and higher. The insulin-stimulated Ca2+ influx depends on a tyrosine-kinase activity and involves the verapamil-dependent Ca2+ channels. Elevated intracellular Ca2+, in association with the Ca2+-binding protein, calmodulin, stimulates erythrocytes 6-phosphofructo-1-kinase activity. This activation involves the detachment of the enzyme from erythrocyte membranes, which has been described as an important mechanism of glycolysis regulation on these cells. Altogether, these results support evidence that insulin may increases glucose consumption in human erythrocytes, through a mechanism involving Ca2+ influx, calmodulin and the detachment of 6-phosphofructo-1-kinase from the erythrocyte membrane.
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Affiliation(s)
- Patricia Zancan
- Laboratório de Enzimologia e Controle do Metabolismo (LabECoM), Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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24
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Zancan P, Sola-Penna M. Regulation of human erythrocyte metabolism by insulin: cellular distribution of 6-phosphofructo-1-kinase and its implication for red blood cell function. Mol Genet Metab 2005; 86:401-11. [PMID: 16102994 DOI: 10.1016/j.ymgme.2005.06.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Revised: 06/17/2005] [Accepted: 06/21/2005] [Indexed: 11/17/2022]
Abstract
Human erythrocytes are highly specialized cells whose function is oxygen transport. These cells' sole metabolic source of energy is the fermentation of glucose via glycolysis. They contain an active insulin receptor and respond to insulin by increasing phosphorylation of tyrosine residues in several proteins. However, no metabolic effects have yet been associated with activation of this receptor in human erythrocytes. Here, we show that insulin increases the rate of glycolysis in human erythrocytes. Lactate production increased 56 and 173% in the presence of 10 and 100 nM insulin, respectively. A higher insulin concentration (1000 nM) partially reversed the stimulation of glycolysis. These effects occur through activation of the key glycolytic enzyme 6-phosphofructo-1-kinase, which exhibits the same pattern of modulation by insulin as seen for glycolytic flux. This modulation also occurs physiologically since ex vivo experiments revealed 50% stimulation of 6-phosphofructo-1-kinase (PFK) activity following a high carbohydrate meal. Insulin increases phosphorylation of PFK and redistributes the enzyme in red blood cells, causing it to detach from the erythrocyte membrane: upon insulin stimulation, the amount of enzyme associated with the plasma decreases by 86%. Detachment is a common mechanism of enzyme activation. As a consequence, insulin prevents up to 68% of red cells hemolysis. These results show that insulin regulates erythrocyte glycolysis and viability and suggest that this regulation is associated to other erythrocyte functions such as oxygen transport. Finally, we suggest that this regulatory mechanism might be compromised in patients with diabetes mellitus.
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Affiliation(s)
- Patricia Zancan
- Laboratório de Enzimologia e Controle do Metabolismo (LabECoM), Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, RJ 21941-590, Brazil
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25
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Meira DD, Marinho-Carvalho MM, Teixeira CA, Veiga VF, Da Poian AT, Holandino C, de Freitas MS, Sola-Penna M. Clotrimazole decreases human breast cancer cells viability through alterations in cytoskeleton-associated glycolytic enzymes. Mol Genet Metab 2005; 84:354-62. [PMID: 15781197 DOI: 10.1016/j.ymgme.2004.11.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2004] [Revised: 11/22/2004] [Accepted: 11/22/2004] [Indexed: 10/25/2022]
Abstract
Cancer cells are characterized by a high rate of glycolysis, which is their primary energy source. Glycolysis is known to be controlled by allosteric regulators, as well as by reversible binding of glycolytic enzymes to cytoskeleton. Clotrimazole is an anti-fungal azole derivative recently recognized as a calmodulin antagonist with promising anti-cancer effect. Here, we show that clotrimazole induced morphological and functional alterations on human breast cancer derived cell line, MCF-7. The drug decreased cell viability in a dose- and time-dependent manner, exhibiting an IC50 of 88.6+/-5.3 microM and a t0.5 of 89.7+/-7.2 min, with 50 microM clotrimazole. Morphological changes were evident as observed by scanning electron microscopy, which revealed the completely loss of protrusion responsible for cell adhesion after a 180 min of treatment with 50 microM clotrimazole. Giemsa stained cells observed by optical microscopy show morphological alterations and a marked nuclear condensation. These changes occurred in parallel to the detachment of the glycolytic enzymes, 6-phosphofructo-1-kinase and aldolase, from cytoskeleton. After a 45 min treatment with 50 microM clotrimazole, the remaining activities in a cytoskeleton enriched fraction was 16.4+/-3.6% and 41.0+/-15.6% of control for 6-phosphofructo-1-kinase and aldolase, respectively. Immunocytochemistry experiments revealed a decrease in the co-localization of 6-phosphofructo-1-kinase and F-actin after clotrimazole treatment, suggesting the site of detachment of the enzymes. Altogether, our results support evidence for apoptotic events that might be started by clotrimazole involving inhibition of glycolytic flux in MCF-7 cells and makes this drug a promising agent in the fight against human breast cancer.
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Affiliation(s)
- Débora Dummer Meira
- Laboratório de Enzimologia e Controle do Metabolismo (LabECoM), Dept. Fármacos, Fac. Farmácia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
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