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Klepinina L, Klepinin A, Truu L, Chekulayev V, Vija H, Kuus K, Teino I, Pook M, Maimets T, Kaambre T. Colon cancer cell differentiation by sodium butyrate modulates metabolic plasticity of Caco-2 cells via alteration of phosphotransfer network. PLoS One 2021; 16:e0245348. [PMID: 33471801 PMCID: PMC7817017 DOI: 10.1371/journal.pone.0245348] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 12/28/2020] [Indexed: 12/12/2022] Open
Abstract
The ability of butyrate to promote differentiation of cancer cells has important implication for colorectal cancer (CRC) prevention and therapy. In this study, we examined the effect of sodium butyrate (NaBT) on the energy metabolism of colon adenocarcinoma Caco-2 cells coupled with their differentiation. NaBT increased the activity of alkaline phosphatase indicating differentiation of Caco-2 cells. Changes in the expression of pluripotency-associated markers OCT4, NANOG and SOX2 were characterized during the induced differentiation at mRNA level along with the measures that allowed distinguishing the expression of different transcript variants. The functional activity of mitochondria was studied by high-resolution respirometry. Glycolytic pathway and phosphotransfer network were analyzed using enzymatical assays. The treatment of Caco-2 cells with NaBT increased production of ATP by oxidative phosphorylation, enhanced mitochondrial spare respiratory capacity and caused rearrangement of the cellular phosphotransfer networks. The flexibility of phosphotransfer networks depended on the availability of glutamine, but not glucose in the cell growth medium. These changes were accompanied by suppressed cell proliferation and altered gene expression of the main pluripotency-associated transcription factors. This study supports the view that modulating cell metabolism through NaBT can be an effective strategy for treating CRC. Our data indicate a close relationship between the phosphotransfer performance and metabolic plasticity of CRC, which is associated with the cell differentiation state.
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Affiliation(s)
- Ljudmila Klepinina
- Laboratory of Chemical Biology, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
- * E-mail:
| | - Aleksandr Klepinin
- Laboratory of Chemical Biology, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Laura Truu
- Laboratory of Chemical Biology, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Vladimir Chekulayev
- Laboratory of Chemical Biology, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Heiki Vija
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Kaisa Kuus
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Indrek Teino
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Martin Pook
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Toivo Maimets
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Tuuli Kaambre
- Laboratory of Chemical Biology, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
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Feng WW, Wilkins O, Bang S, Ung M, Li J, An J, Del Genio C, Canfield K, DiRenzo J, Wells W, Gaur A, Robey RB, Guo JY, Powles RL, Sotiriou C, Pusztai L, Febbraio M, Cheng C, Kinlaw WB, Kurokawa M. CD36-Mediated Metabolic Rewiring of Breast Cancer Cells Promotes Resistance to HER2-Targeted Therapies. Cell Rep 2020; 29:3405-3420.e5. [PMID: 31825825 PMCID: PMC6938262 DOI: 10.1016/j.celrep.2019.11.008] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 08/22/2019] [Accepted: 11/04/2019] [Indexed: 11/18/2022] Open
Abstract
Although it is established that fatty acid (FA) synthesis supports anabolic growth in cancer, the role of exogenous FA uptake remains elusive. Here we show that, during acquisition of resistance to HER2 inhibition, metabolic rewiring of breast cancer cells favors reliance on exogenous FA uptake over de novo FA synthesis. Through cDNA microarray analysis, we identify the FA transporter CD36 as a critical gene upregulated in cells with acquired resistance to the HER2 inhibitor lapatinib. Accordingly, resistant cells exhibit increased exogenous FA uptake and metabolic plasticity. Genetic or pharmacological inhibition of CD36 suppresses the growth of lapatinib-resistant but not lapatinib-sensitive cells in vitro and in vivo. Deletion of Cd36 in mammary tissues of MMTV-neu mice significantly attenuates tumorigenesis. In breast cancer patients, CD36 expression increases following anti-HER2 therapy, which correlates with a poor prognosis. Our results define CD36-mediated metabolic rewiring as an essential survival mechanism in HER2-positive breast cancer.
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Affiliation(s)
- William W Feng
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA; Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Owen Wilkins
- Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Scott Bang
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Matthew Ung
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Jiaqi Li
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Jennifer An
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA
| | - Carmen Del Genio
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA
| | - Kaleigh Canfield
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - James DiRenzo
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Wendy Wells
- Department of Pathology, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA; Norris Cotton Cancer Center, Lebanon, NH 03756, USA
| | - Arti Gaur
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA
| | - R Brooks Robey
- Department of Medicine, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA; Department of Medical Education, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA; White River Junction Veterans Affairs Medical Center, White River Junction, VT 05009, USA
| | | | - Ryan L Powles
- Breast Medical Oncology, Yale Cancer Center, Yale School of Medicine, New Haven, CT 05620, USA
| | - Christos Sotiriou
- Breast Cancer Translational Research Laboratory J.-C. Heuson, Institut Jules Bordet, Université Libre de Bruxelles, Brussels, Belgium
| | - Lajos Pusztai
- Breast Medical Oncology, Yale Cancer Center, Yale School of Medicine, New Haven, CT 05620, USA
| | - Maria Febbraio
- Department of Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Chao Cheng
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA; Department of Biomedical Data Science, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA; Norris Cotton Cancer Center, Lebanon, NH 03756, USA; Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - William B Kinlaw
- Department of Medicine, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA; Norris Cotton Cancer Center, Lebanon, NH 03756, USA
| | - Manabu Kurokawa
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA; Department of Biological Sciences, Kent State University, Kent, OH 44242, USA.
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Tepp K, Puurand M, Timohhina N, Adamson J, Klepinin A, Truu L, Shevchuk I, Chekulayev V, Kaambre T. Changes in the mitochondrial function and in the efficiency of energy transfer pathways during cardiomyocyte aging. Mol Cell Biochem 2017; 432:141-158. [PMID: 28293876 DOI: 10.1007/s11010-017-3005-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/04/2017] [Indexed: 12/11/2022]
Abstract
The role of mitochondria in alterations that take place in the muscle cell during healthy aging is a matter of debate during recent years. Most of the studies in bioenergetics have a focus on the model of isolated mitochondria, while changes in the crosstalk between working myofibrils and mitochondria in senescent cardiomyocytes have been less studied. The aim of our research was to investigate the modifications in the highly regulated ATP production and energy transfer systems in heart cells in old rat cardiomyocytes. The results of our work demonstrated alterations in the diffusion restrictions of energy metabolites, manifested by changes in the apparent Michaelis-Menten constant of mitochondria to exogenous ADP. The creatine kinase (CK) phosphotransfer pathway efficiency declines significantly in senescence. The ability of creatine to stimulate OXPHOS as well as to increase the affinity of mitochondria for ADP is falling and the most critical decline is already in the 1-year group (middle-age model in rats). Also, a moderate decrease in the adenylate kinase phosphotransfer system was detected. The importance of glycolysis increases in senescence, while the hexokinase activity does not change during healthy aging. The main result of our study is that the decline in the heart muscle performance is not caused by the changes in the respiratory chain complexes activity but mainly by the decrease in the energy transfer efficiency, especially by the CK pathway.
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Affiliation(s)
- Kersti Tepp
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia.
| | - Marju Puurand
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Natalja Timohhina
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Jasper Adamson
- Laboratory of Chemical Physics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Aleksandr Klepinin
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Laura Truu
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Igor Shevchuk
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Vladimir Chekulayev
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Tuuli Kaambre
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia.,School of Natural Sciences and Health, Tallinn University, Tallinn, Estonia
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Chekulayev V, Mado K, Shevchuk I, Koit A, Kaldma A, Klepinin A, Timohhina N, Tepp K, Kandashvili M, Ounpuu L, Heck K, Truu L, Planken A, Valvere V, Kaambre T. Metabolic remodeling in human colorectal cancer and surrounding tissues: alterations in regulation of mitochondrial respiration and metabolic fluxes. Biochem Biophys Rep 2015; 4:111-125. [PMID: 29124194 PMCID: PMC5668899 DOI: 10.1016/j.bbrep.2015.08.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 07/02/2015] [Accepted: 08/26/2015] [Indexed: 12/21/2022] Open
Abstract
The aim of the work was to evaluate whether or not there is glycolytic reprogramming in the neighboring cells of colorectal cancer (CRC). Using postoperative material we have compared the functional capacity of oxidative phosphorylation (OXPHOS) in CRC cells, their glycolytic activity and their inclination to aerobic glycolysis, with those of the surrounding and healthy colon tissue cells. Experiments showed that human CRC cannot be considered a hypoxic tumor, since the malignancy itself and cells surrounding it exhibited even higher rates of OXPHOS than healthy large intestine. The absence of acute hypoxia in colorectal carcinomas was also confirmed by their practically equal glucose-phosphorylating capacity as compared with surrounding non-tumorous tissue and by upregulation of VEGF family and their ligands. Studies indicated that human CRC cells in vivo exert a strong distant effect on the energy metabolism of neighboring cells, so that they acquire the bioenergetic parameters specific to the tumor itself. The growth of colorectal carcinomas was associated with potent downregulation of the creatine kinase system. As compared with healthy colon tissue, the tumor surrounding cells display upregulation of OXPHOS and have high values of basal and ADP activated respiration rates. Strong differences between the normal and CRC cells in the affinity of their mitochondria for ADP were revealed; the corresponding Km values were measured as 93.6±7.7 µM for CRC cells and 84.9±9.9 µM for nearby tissue; both these apparent Km (ADP) values were considerably (by almost 3 times) lower in comparison with healthy colon tissue cells (256±34 µM). Human colorectal cancer is not a pure hypoxic tumor of the Warburg phenotype. The total hexokinase activity of CRC cells is close to that in nearby tissues. In the tumor there is overexpression of VEGFs (A, B, and C) and their receptors. CRC has higher rates of OXPHOS as compared with healthy tissue cells. Tumor-surrounding cells cannot fuel via a lactate shunt the growth of CRC cells.
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Key Words
- AK, adenylate kinase
- ANT, adenine nucleotide translocator
- AP5A, diadenosine pentaphosphate
- ATP-synthasome
- BB-CK, – brain type creatine kinase
- BSA, bovine serum albumin
- CAT, carboxyatractyloside
- CIMP, CpG island methylator phenotype
- CK, creatine kinase
- COX, cytochrome c oxidase
- CRC, colorectal cancer
- ETC, electron transport chain
- Energy metabolism
- FDG, 18-fluorodeoxyglucose
- Glycolysis
- HK, hexokinase
- Human colorectal cancer
- Km, Michaelis–Menten constant
- MI, Mitochondrial Interactosome
- MOM, mitochondrial outer membrane
- Mitochondria
- OXPHOS
- OXPHOS, oxidative phosphorylation
- PCr, phosphocreatine
- PEP, phosphoenolpyruvate
- PET, positron emission tomography
- PYK, pyruvate kinase
- Respiration
- TMPD, N,N,N′,N′-tetramethyl-p-phenylenediamine
- V0, basal respiration level
- VDAC, voltage dependent anion channel
- VEGF, vascular endothelial growth factor
- Vm, maximal respiration rate
- qPCR, real-time quantitative PCR
- uMtCK, ubiquitous mitochondrial creatine kinase
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Affiliation(s)
- Vladimir Chekulayev
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Kati Mado
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Igor Shevchuk
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Andre Koit
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Andrus Kaldma
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Aleksandr Klepinin
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Natalja Timohhina
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Kersti Tepp
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | | | - Lyudmila Ounpuu
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | | | - Laura Truu
- Tallinn University of Technology, Tallinn, Estonia
| | - Anu Planken
- Competence Centre for Cancer Research, Tallinn, Estonia
| | | | - Tuuli Kaambre
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia.,Tallinn University, Tallinn, Estonia
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Targeting prostate cancer cell metabolism: impact of hexokinase and CPT-1 enzymes. Tumour Biol 2014; 36:2893-905. [PMID: 25501281 DOI: 10.1007/s13277-014-2919-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 11/28/2014] [Indexed: 10/24/2022] Open
Abstract
Glycolysis has been shown to be required for the cell growth and proliferation in several cancer cells. However, prostate cancer cells were accused of using more fatty acid than glucose to meet their bioenergetic demands. The present study was designed to evaluate the involvement of hexokinase and CPT-1 in the cell growth and proliferation of human prostate cancer cell lines, PC3, and LNCaP-FGC-10. Hexokinase and CPT-1 activities were examined in the presence of different concentrations of their inhibitors, lonidamine and etomoxir, to find the concentration of maximum inhibition ([I max]). To assess cell viability and proliferation, dimethylthiazol (MTT) assay was carried out using [I max] for 24, 48, and 72 h on PC3 and LNCaP cells. Apoptosis was determined using annexin-V, caspase-3 activity assay, Hoechst 33258 staining, and evaluation of mitochondrial membrane potential (MMP). Moreover, ATP levels were measured following lonidamine and etomoxir exposure. In addition, to define the impact of exogenous fatty acid on the cell growth and proliferation, CPT-1 activity was evaluated in the presence of palmitate (50 μM). Hexokinase and CPT-1 activities were significantly inhibited by lonidamine [600 μM] and etomoxir [100 μM] in both cell lines. Treatment of the cells with lonidamine [600 μM] resulted in a significant ATP reduction, cell viability and apoptosis, caspase-3 activity elevation, MMP reduction, and appearance of apoptosis-related morphological changes in the cells. In contrast, etomoxir [100 μM] just decreased ATP levels in both cell lines without significant cell death and apoptosis. Compared with glucose (2 g/L), palmitate intensified CPT-1 activity in both cell lines, especially in LNCaP cells. In addition, activity of CPT-1 was higher in LNCaP than PC3 cells. Our results suggest that prostate cancer cells may metabolize glucose as a source of bioenergetic pathways. ATP could also be produced by long-chain fatty acid oxidation. In addition, these data might suggest that LNCaP is more compatible with palmitate.
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Kaldma A, Klepinin A, Chekulayev V, Mado K, Shevchuk I, Timohhina N, Tepp K, Kandashvili M, Varikmaa M, Koit A, Planken M, Heck K, Truu L, Planken A, Valvere V, Rebane E, Kaambre T. An in situ study of bioenergetic properties of human colorectal cancer: the regulation of mitochondrial respiration and distribution of flux control among the components of ATP synthasome. Int J Biochem Cell Biol 2014; 55:171-86. [PMID: 25218857 DOI: 10.1016/j.biocel.2014.09.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 08/12/2014] [Accepted: 09/02/2014] [Indexed: 11/25/2022]
Abstract
The aim of this study is to characterize the function of mitochondria and main energy fluxes in human colorectal cancer (HCC) cells. We have performed quantitative analysis of cellular respiration in post-operative tissue samples collected from 42 cancer patients. Permeabilized tumor tissue in combination with high resolution respirometry was used. Our results indicate that HCC is not a pure glycolytic tumor and the oxidative phosphorylation (OXPHOS) system may be the main provider of ATP in these tumor cells. The apparent Michaelis-Menten constant (Km) for ADP and maximal respiratory rate (Vm) values were calculated for the characterization of the affinity of mitochondria for exogenous ADP: normal colon tissue displayed low affinity (Km = 260 ± 55 μM) whereas the affinity of tumor mitochondria was significantly higher (Km = 126 ± 17 μM). But concurrently the Vm value of the tumor samples was 60-80% higher than that in control tissue. The reason for this change is related to the increased number of mitochondria. Our data suggest that in both HCC and normal intestinal cells tubulin β-II isoform probably does not play a role in the regulation of permeability of the MOM for adenine nucleotides. The mitochondrial creatine kinase energy transfer system is not functional in HCC and our experiments showed that adenylate kinase reactions could play an important role in the maintenance of energy homeostasis in colorectal carcinomas instead of creatine kinase. Immunofluorescent studies showed that hexokinase 2 (HK-2) was associated with mitochondria in HCC cells, but during carcinogenesis the total activity of HK did not change. Furthermore, only minor alterations in the expression of HK-1 and HK-2 isoforms have been observed. Metabolic Control analysis showed that the distribution of the control over electron transport chain and ATP synthasome complexes seemed to be similar in both tumor and control tissues. High flux control coefficients point to the possibility that the mitochondrial respiratory chain is reorganized in some way or assembled into large supercomplexes in both tissues.
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Affiliation(s)
- Andrus Kaldma
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Aleksandr Klepinin
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Vladimir Chekulayev
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Kati Mado
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Igor Shevchuk
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Natalja Timohhina
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Kersti Tepp
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | | | - Minna Varikmaa
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Andre Koit
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | | | | | - Laura Truu
- Tallinn University of Technology, Tallinn, Estonia
| | - Anu Planken
- Cancer Research Competence Center, Tallinn, Estonia
| | | | - Egle Rebane
- Cancer Research Competence Center, Tallinn, Estonia
| | - Tuuli Kaambre
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia; Tallinn University, Tallinn, Estonia.
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Tribbles 3 regulates the fibrosis cytokine TGF- β 1 through ERK1/2-MAPK signaling pathway in diabetic nephropathy. J Immunol Res 2014; 2014:240396. [PMID: 25133193 PMCID: PMC4124808 DOI: 10.1155/2014/240396] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 05/21/2014] [Accepted: 06/03/2014] [Indexed: 01/14/2023] Open
Abstract
To reveal the expression and possible role of tribbles homolog 3 (TRB3) in the incidence of type 2 diabetic nephropathy, we used immunohistochemistry, real-time quantitative PCR, western blot analysis, and enzyme-linked immunosorbent assay (ELISA) to study the expression of TRB3, extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase (ERK1/2 MAPK), transforming growth factor β1 (TGF-β1), and collagen type IV in kidneys of db/db diabetic mice and in murine renal mesangial cells stimulated with high glucose. The expression of TRB3, TGF-β1, and collagen type IV was increased in kidneys of db/db diabetic mice. TGF-β1 and collagen type IV regulated by high glucose through ERK1/2 MAPK were downregulated by silencing TRB3 in renal mesangial cells. TRB3 may be involved in diabetic nephropathy by regulating the fibrosis cytokine TGF-β1 and collagen type IV through the ERK1/2 MAPK signaling pathway.
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Kaambre T, Chekulayev V, Shevchuk I, Karu-Varikmaa M, Timohhina N, Tepp K, Bogovskaja J, Kütner R, Valvere V, Saks V. Metabolic control analysis of cellular respiration in situ in intraoperational samples of human breast cancer. J Bioenerg Biomembr 2012; 44:539-58. [PMID: 22836527 DOI: 10.1007/s10863-012-9457-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 06/21/2012] [Indexed: 12/19/2022]
Abstract
The aim of this study was to analyze quantitatively cellular respiration in intraoperational tissue samples taken from human breast cancer (BC) patients. We used oxygraphy and the permeabilized cell techniques in combination with Metabolic Control Analysis (MCA) to measure a corresponding flux control coefficient (FCC). The activity of all components of ATP synthasome, and respiratory chain complexes was found to be significantly increased in human BC cells in situ as compared to the adjacent control tissue. FCC(s) were determined upon direct activation of respiration with exogenously-added ADP and by titrating the complexes with their specific inhibitors to stepwise decrease their activity. MCA showed very high sensitivity of all complexes and carriers studied in human BC cells to inhibition as compared to mitochondria in normal oxidative tissues. The sum of FCC(s) for all ATP synthasome and respiratory chain components was found to be around 4, and the value exceeded significantly that for normal tissue (close to 1). In BC cells, the key sites of the regulation of respiration are Complex IV (FCC = 0.74), ATP synthase (FCC = 0.61), and phosphate carrier (FCC = 0.60); these FCC(s) exceed considerably (~10-fold) those for normal oxidative tissues. In human BC cells, the outer mitochondrial membrane is characterized by an increased permeability towards adenine nucleotides, the mean value of the apparent K(m) for ADP being equal to 114.8 ± 13.6 μM. Our data support the two-compartment hypothesis of tumor metabolism, the high sum of FCC(s) showing structural and functional organization of mitochondrial respiratory chain and ATP synthasome as supercomplexes in human BC.
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Affiliation(s)
- Tuuli Kaambre
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Estonia.
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Wei LH, Su H, Hildebrandt IJ, Phelps ME, Czernin J, Weber WA. Changes in tumor metabolism as readout for Mammalian target of rapamycin kinase inhibition by rapamycin in glioblastoma. Clin Cancer Res 2008; 14:3416-26. [PMID: 18519772 DOI: 10.1158/1078-0432.ccr-07-1824] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Inhibition of the protein kinase mammalian target of rapamycin (mTOR) is being evaluated for treatment of a variety of malignancies. However, the effects of mTOR inhibitors are cytostatic and standard size criteria do not reliably identify responding tumors. The aim of this study was to evaluate whether response to mTOR inhibition could be assessed by positron emission tomography (PET) imaging of tumor metabolism. EXPERIMENT DESIGN Glucose, thymidine, and amino acid utilization of human glioma cell lines with varying degrees of sensitivity to mTOR inhibition were assessed by measuring in vitro uptake of [18F]fluorodeoxyglucose ([18F]FDG), [18F]fluorothymidine ([18F]FLT), and [3H]l-tyrosine before and after treatment with the mTOR inhibitor rapamycin. The tumor metabolic activity in vivo was monitored by small-animal PET of tumor-bearing mice. The mechanisms underlying changes in metabolic activity were analyzed by measuring expression and functional activity of enzymes and transporters involved in the uptake of the studied imaging probes. RESULTS In sensitive cell lines, rapamycin decreased [18F]FDG and [18F]FLT uptake by up to 65% within 24 hours after the start of therapy. This was associated with inhibition of hexokinase and thymidine kinase 1. In contrast, [3H]l-tyrosine uptake was unaffected by rapamycin. The effects of rapamycin on glucose and thymidine metabolism could be imaged noninvasively by PET. In sensitive tumors, [18F]FDG and [18F]FLT uptake decreased within 48 hours by 56 +/- 6% and 52 +/- 8%, respectively, whereas there was no change in rapamycin-resistant tumors. CONCLUSIONS These encouraging preclinical data warrant clinical trials evaluating [18F]FDG and [18F]FLT-PET for monitoring treatment with mTOR inhibitors in patients.
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Affiliation(s)
- Liu Hua Wei
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA
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Wang Z, Gardiner NJ, Fernyhough P. Blockade of hexokinase activity and binding to mitochondria inhibits neurite outgrowth in cultured adult rat sensory neurons. Neurosci Lett 2008; 434:6-11. [PMID: 18308470 DOI: 10.1016/j.neulet.2008.01.057] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 12/19/2007] [Accepted: 01/10/2008] [Indexed: 01/03/2023]
Abstract
Hexokinase is known as the first enzyme and rate-limiting step in glycolysis. The role of hexokinase activity and localization in regulating the rate of axonal regeneration was studied in cultured adult sensory neurons of dorsal root ganglia (DRG). Immunofluorescent staining of DRG demonstrated that small-medium neurons and satellite cells exhibited high levels of expression of hexokinase I. Large neurons had negative staining for hexokinase I. Intracellular localization and biochemical studies in cultured adult rat sensory neurons revealed that hexokinase I was almost exclusively found in the mitochondrial compartment. The hypothesis that neurotrophic factor dependent activation of Akt would regulate hexokinase association with the mitochondria was tested and quantitative Western blotting showed no effect of blockade of the phosphoinositide 3-kinase (PI 3-kinase)/Akt pathway using the inhibitor LY294002, indicating this interaction of hexokinase with mitochondria was not neurotrophic factor or Akt-dependent. Finally, pharmacological blockade of hexokinase activity and inhibition of localization to the mitochondrial compartment with hexokinase II VDAC binding domain (Hxk2VBD) peptide caused a significant inhibition of neurotrophic factor-directed axon outgrowth. The results support a key role for hexokinase activity and/or localization to the mitochondria in the regulation of neurite outgrowth in cultured adult sensory neurons.
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Affiliation(s)
- Zuocheng Wang
- Division of Neurodegenerative Disorders, St Boniface Research Centre, Winnipeg, Manitoba, Canada
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11
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Gardiner NJ, Wang Z, Luke C, Gott A, Price SA, Fernyhough P. Expression of hexokinase isoforms in the dorsal root ganglion of the adult rat and effect of experimental diabetes. Brain Res 2007; 1175:143-54. [PMID: 17803972 DOI: 10.1016/j.brainres.2007.08.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Revised: 07/31/2007] [Accepted: 08/02/2007] [Indexed: 11/21/2022]
Abstract
The effect of streptozotocin (STZ)-induced diabetes on expression and activity of hexokinase, the first enzyme and rate-limiting step in glycolysis, was studied in sensory neurons of lumbar dorsal root ganglia (DRG). The DRG and sciatic nerve of adult rats expressed the hexokinase I isoform only. Immunofluorescent staining of lumbar DRG demonstrated that small-medium neurons and satellite cells exhibited high levels of expression of hexokinase I. Large, mainly proprioceptive neurons, had very low or negative staining for hexokinase I. Intracellular localization and biochemical studies on intact DRG from adult rats and cultured adult rat sensory neurons revealed that hexokinase I was almost exclusively found in the mitochondrial compartment. Duration of STZ-diabetes of 6 or 12 weeks diminished hexokinase activity by 28% and 30%, respectively, in lumbar DRG compared with age matched controls (P<0.05). Quantitative Western blotting showed no effect of diabetes on hexokinase I protein expression in homogenates or mitochondrial preparations from DRG. Immunofluorescent staining for hexokinase I showed no diabetes-dependent change in small-medium neuron expression in DRG, however, large neurons became positive for hexokinase I (P<0.05). Such complex effects of diabetes on hexokinase I expression in the DRG may be due to glucose-driven up-regulation of expression or the result of impaired axonal transport and perikaryal accumulation in the large neuron sub-population. Because hexokinase is the rate-limiting enzyme of glycolysis these results imply that metabolic flux through the glycolytic pathway is reduced in diabetes. This finding, therefore, questions the role of high glucose-induced metabolic flux as a key driving force in reactive oxygen species generation by mitochondria.
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Affiliation(s)
- Natalie J Gardiner
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, UK
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12
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Pysher MD, Sollome JJ, Regan S, Cardinal TR, Hoying JB, Brooks HL, Vaillancourt RR. Increased hexokinase II expression in the renal glomerulus of mice in response to arsenic. Toxicol Appl Pharmacol 2007; 224:39-48. [PMID: 17643460 PMCID: PMC2042004 DOI: 10.1016/j.taap.2007.06.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Revised: 06/12/2007] [Accepted: 06/19/2007] [Indexed: 12/13/2022]
Abstract
Epidemiological studies link arsenic exposure to increased risks of cancers of the skin, kidney, lung, bladder and liver. Additionally, a variety of non-cancerous conditions such as diabetes mellitus, hypertension, and cardiovascular disease have been associated with chronic ingestion of low levels of arsenic. However, the biological and molecular mechanisms by which arsenic exerts its effects remain elusive. Here we report increased renal hexokinase II (HKII) expression in response to arsenic exposure both in vivo and in vitro. In our model, HKII was up-regulated in the renal glomeruli of mice exposed to low levels of arsenic (10 ppb or 50 ppb) via their drinking water for up to 21 days. Additionally, a similar effect was observed in cultured renal mesangial cells exposed to arsenic. This correlation between our in vivo and in vitro data provides further evidence for a direct link between altered renal HKII expression and arsenic exposure. Thus, our data suggest that alterations in renal HKII expression may be involved in arsenic-induced pathological conditions involving the kidney. More importantly, these results were obtained using environmentally relevant arsenic concentrations.
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Affiliation(s)
- Michele D Pysher
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, 1703 E. Mabel Street, Tucson, AZ 85721, USA
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13
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Rivera I, Zhang S, Fuller BS, Edwards B, Seki T, Wang MH, Marrero MB, Inscho EW. P2 receptor regulation of [Ca2+]i in cultured mouse mesangial cells. Am J Physiol Renal Physiol 2007; 292:F1380-9. [PMID: 17213463 DOI: 10.1152/ajprenal.00349.2006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Experiments were performed to establish the pharmacological profile of purinoceptors and to identify the signal transduction pathways responsible for increases in intracellular calcium concentration ([Ca(2+)](i)) for cultured mouse mesangial cells. Mouse mesangial cells were loaded with fura 2 and examined using fluorescent spectrophotometry. Basal [Ca(2+)](i) averaged 102 +/- 2 nM (n = 346). One hundred micromolar concentrations of ATP, ADP, 2',3'-(benzoyl-4-benzoyl)-ATP (BzATP), ATP-gamma-S, and UTP in normal Ca(2+) medium evoked peak increases in [Ca(2+)](i) of 866 +/- 111, 236 +/- 18, 316 +/- 26, 427 +/- 37, and 808 +/- 73 nM, respectively. UDP or 2-methylthio-ATP (2MeSATP) failed to elicit significant increases in [Ca(2+)](i), whereas identical concentrations of adenosine, AMP, and alpha,beta-methylene ATP (alpha,beta-MeATP) had no detectable effect on [Ca(2+)](i). Removal of Ca(2+) from the extracellular medium had no significant effect on the peak increase in [Ca(2+)](i) induced by ATP, ADP, BzATP, ATP-gamma-S, or UTP compared with normal Ca(2+); however, Ca(2+)-free conditions did accelerate the rate of decline in [Ca(2+)](i) in cells treated with ATP and UTP. [Ca(2+)](i) was unaffected by membrane depolarization with 143 mM KCl. Western blot analysis for P2 receptors revealed expression of P2X(2), P2X(4), P2X(7), P2Y(2), and P2Y(4) receptors. No evidence of P2X(1) and P2X(3) receptor expression was detected, whereas RT-PCR analysis reveals mRNA expression for P2X(1), P2X(2), P2X(3), P2X(4), P2X(7), P2Y(2), and P2Y(4) receptors. These data indicate that receptor-specific P2 receptor activation increases [Ca(2+)](i) by stimulating calcium influx from the extracellular medium and through mobilization of Ca(2+) from intracellular stores in cultured mouse mesangial cells.
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Affiliation(s)
- Ian Rivera
- Department of Physiology, Medical College of Georgia, Augusta, Georgia 30912-3000, USA
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Su H, Bodenstein C, Dumont RA, Seimbille Y, Dubinett S, Phelps ME, Herschman H, Czernin J, Weber W. Monitoring tumor glucose utilization by positron emission tomography for the prediction of treatment response to epidermal growth factor receptor kinase inhibitors. Clin Cancer Res 2006; 12:5659-67. [PMID: 17020967 DOI: 10.1158/1078-0432.ccr-06-0368] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE The mechanisms underlying the sensitivity of non-small cell lung cancer to epidermal growth factor receptor (EGFR) kinase inhibitors are complex, and there are no established markers to accurately predict treatment outcome in individual patients. EXPERIMENTAL DESIGN We investigated whether tumors responding to EGFR inhibitors can be identified by measuring treatment-induced changes in glucose utilization by positron emission tomography with the glucose analogue fluorodeoxyglucose (FDG-PET). We studied a panel of cell lines with a spectrum of sensitivity to EGFR kinase inhibitors. After incubation with the EGFR kinase inhibitor gefitinib for various time points, FDG uptake, glucose transport rates, and hexokinase activity were determined. FDG uptake in vivo was assessed by microPET imaging of tumor xenografts in mice. RESULTS In gefitinib-sensitive cell lines, there was a dramatic decrease in FDG uptake as early as 2 hours after treatment. Immunoblots showed the translocation of glucose transporters (GLUT3) from the plasma membrane to the cytosol; glucose transport rates were reduced 2.6-fold at this time. There was also a modest reduction of hexokinase activity. These metabolic alterations preceded changes in cell cycle distribution, thymidine uptake, and apoptosis. MicroPET studies showed an up to 55% decrease of tumor FDG uptake in sensitive xenografts within 48 hours. In contrast, gefitinib-resistant cells exhibited no measurable changes in FDG uptake, either in cell culture or in vivo. CONCLUSION Glucose metabolic activity closely reflects response to gefitinib therapy. FDG-PET may be a valuable clinical predictor, early in the course of treatment, for therapeutic responses to EGFR kinase inhibitors.
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Affiliation(s)
- Helen Su
- Department of Molecular Medicine and Pharmacology, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California at Los Angeles, 650 Charles Young Drive, Los Angeles, CA 90095, USA
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Huang TJ, Verkhratsky A, Fernyhough P. Insulin enhances mitochondrial inner membrane potential and increases ATP levels through phosphoinositide 3-kinase in adult sensory neurons. Mol Cell Neurosci 2005; 28:42-54. [PMID: 15607940 DOI: 10.1016/j.mcn.2004.08.009] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2004] [Revised: 07/08/2004] [Accepted: 08/18/2004] [Indexed: 11/21/2022] Open
Abstract
We tested the hypothesis that neurotrophic factors control neuronal metabolism by directly regulating mitochondrial function in the absence of effects on survival. Real-time whole cell fluorescence video microscopy was utilized to analyze mitochondrial inner membrane potential (Delta Psi(m)), which drives ATP synthesis, in cultured adult sensory neurons. These adult neurons do not require neurotrophic factors for survival. Insulin and other neurotrophic factors increased Delta Psi(m) 2-fold compared with control over a 6- to 24-h period (P < 0.05). Insulin modulated Delta Psi(m) by activation of the phosphoinositide 3-kinase (PI 3-K) pathway. Insulin also induced rapid and long-term (30 h) PI 3-K-dependent phosphorylation of Akt and cAMP response element binding protein (CREB). Additionally, insulin elevated the redox state of the mitochondrial NAD(P)H pool, increased hexokinase activity (first committed step of glycolysis), and raised ATP levels. This study demonstrates that insulin utilizes the PI 3-K/Akt pathway to augment ATP synthesis that we propose contributes to the energy requirement for neurotrophic factor-driven axon regeneration.
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Affiliation(s)
- Tze-Jen Huang
- School of Biological Sciences, University of Manchester, Manchester M13 9PT, UK
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Taneja N, Coy PE, Lee I, Bryson JM, Robey RB. Proinflammatory interleukin-1 cytokines increase mesangial cell hexokinase activity and hexokinase II isoform abundance. Am J Physiol Cell Physiol 2004; 287:C548-57. [PMID: 15070811 DOI: 10.1152/ajpcell.00126.2003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mesangial cell hexokinase (HK) activity is increased by a diverse array of factors that share both an association with pathological conditions and a common requirement for classic MAPK pathway activation. To better understand the relationship between glucose (Glc) metabolism and injury and to indirectly test the hypothesis that these changes constitute a general adaptive response to insult, we have sought to identify and characterize injury-associated factors that couple to mesangial cell HK regulation. Proinflammatory interleukin-1 (IL-1) cytokines activate the MAPK pathway and have known salutary effects in this cell type. We therefore examined their ability to influence mesangial cell HK activity, Glc utilization, MAPK pathway activation, and individual HK isoform abundance. IL-1β increased HK activity in both a time- and concentration-dependent manner: activity increased maximally by ∼50% between 12 and 24 h with an apparent EC50of 3 pM. IL-1α mimicked, but did not augment, the effects of IL-1β. Specific IL-1 receptor antagonism and selective MAPK/ERK kinase or upstream Ras inhibition prevented these increases, whereas PKC inhibition did not. Changes in HK activity were associated with both increased Glc metabolism and selective increases in HKII isoform abundance. We conclude that IL-1 cytokines can regulate cellular Glc phosphorylating capacity via an IL-1 receptor-, Ras-, and classic MAPK pathway-mediated increase in HKII abundance. These findings suggest a novel, previously undescribed mechanism whereby metabolism may be coupled to inflammation and injury.
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Affiliation(s)
- Navin Taneja
- Dept. of Medicine, Section of Nephrology, University of Illinois at Chicago College of Medicine, 820 South Wood Street, Rm. 418W CSN (M/C 793), Chicago, IL 60612-7315, USA
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17
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Henningsen C, Zahner G, Thaiss F. High glucose induces type 1 hexokinase gene expression in isolated glomeruli of diabetic rats and in mesangial cells. NEPHRON. PHYSIOLOGY 2003; 93:p67-75. [PMID: 12660493 DOI: 10.1159/000069555] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2002] [Accepted: 11/20/2002] [Indexed: 11/19/2022]
Abstract
BACKGROUND Diabetic nephropathy, which is characterized by renal hypertrophy and accumulation of extracellular matrix, is one of the leading causes for end-stage renal disease. Pathophysiological changes, which finally lead to the development of diabetic nephropathy, act through an increase in the intracellular NADH/NAD ratio and the activation of the polyol and protein kinase C pathways. The first rate-limiting enzymes in intracellular glucose metabolism are the hexokinases, which catalyze the phosphorylation of glucose. Therefore, in order to examine a possible link between increased glucose metabolism and the development of diabetic nephropathy mRNA and protein expression as well as enzyme activity of type 1 hexokinase were examined in kidneys of control and diabetic rats and in mesangial cells. METHODS Diabetes in rats was induced by intravenous injection of streptozotocin and animals were treated or not treated with insulin. RNA or protein was extracted from isolated glomeruli at different time intervals. In addition, glomerular mesangial cells were incubated in high glucose medium and hexokinase expression determined along with enzyme activity. RESULTS The experiments demonstrate a significant increase in gene and protein expression of type 1 hexokinase in glomeruli of diabetic rats throughout a three week observation period. Insulin therapy reduced glomerular type 1 hexokinase mRNA expression. Gene expression and hexokinase enzyme activity were also increased in mesangial cells grown in high glucose medium. CONCLUSION The present experiments demonstrate that the expression of type 1 hexokinase is increased in isolated glomeruli of diabetic animals and is regulated by high ambient glucose concentrations. These results add further evidence to the fact that the kidney is one of the tissues most sensitive to high glucose levels in diabetes.
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Affiliation(s)
- C Henningsen
- Department of Internal Medicine, Division of Nephrology and Osteology, University Hospital, Hamburg, Germany
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18
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Coy PE, Taneja N, Lee I, Hecquet C, Bryson JM, Robey RB. LPA is a novel lipid regulator of mesangial cell hexokinase activity and HKII isoform expression. Am J Physiol Renal Physiol 2002; 283:F271-9. [PMID: 12110510 DOI: 10.1152/ajprenal.00093.2001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The prototypical extracellular phospholipid mediator, lysophosphatidic acid (LPA), exhibits growth factor-like properties and represents an important survival factor in serum. This potent mesangial cell mitogen is increased in conditions associated with glomerular injury. It is also a known activator of the classic mitogen-activated protein kinase (MAPK) pathway, which plays an important role in the regulation of mesangial cell hexokinase (HK) activity. To better understand the mechanisms coupling metabolism to injury, we examined the ability of LPA to regulate HK activity and expression in cultured murine mesangial cells. LPA increased total HK activity in a concentration- and time-dependent manner, with maximal increases of >50% observed within 12 h of exposure to LPA concentrations > or =25 microM (apparent ED(50) 2 microM). These effects were associated with increased extracellular signal-regulated kinase (ERK) activity and were prevented by the pharmacological inhibition of either MAPK/ERK kinase or protein kinase C (PKC). Increased HK activity was also associated with increased glucose (Glc) utilization and lactate accumulation, as well as selectively increased HKII isoform abundance. The ability of exogenous LPA to increase HK activity was both Ca2+ independent and pertussis toxin insensitive and was mimicked by LPA-generating phospholipase A2. We conclude that LPA constitutes a novel lipid regulator of mesangial cell HK activity and Glc metabolism. This regulation requires sequential activation of both Ca2+-independent PKC and the classic MAPK pathway and culminates in increased HKII abundance. These previously unrecognized metabolic consequences of LPA stimulation have both physiological and pathophysiological implications. They also suggest a novel mechanism whereby metabolism may be coupled to cellular injury via extracellular lipid mediators.
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Affiliation(s)
- Platina E Coy
- Section of Nephrology, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois 60612-7315, USA
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19
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Robey RB, Ma J, Santos AVP, Noboa OA, Coy PE, Bryson JM. Regulation of mesangial cell hexokinase activity and expression by heparin-binding epidermal growth factor-like growth factor: epidermal growth factors and phorbol esters increase glucose metabolism via a common mechanism involving classic mitogen-activated protein kinase pathway activation and induction of hexokinase II expression. J Biol Chem 2002; 277:14370-8. [PMID: 11782486 DOI: 10.1074/jbc.m111722200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Heparin-binding epidermal growth factor -like growth factor (HB-EGF) expression and hexokinase (HK) activity are increased in various pathologic renal conditions. Although the mitogenic properties of HB-EGF have been well characterized, its effects on glucose (Glc) metabolism have not. We therefore examined the possibility that HB-EGF might regulate HK activity and expression in glomerular mesangial cells, which constitute the principal renal cell type affected by a variety of pathologic conditions. Protein kinase C (PKC)-dependent classic mitogen-activated protein kinase (MAPK) pathway activation has been associated with increased HK activity in this cell type, so we also examined dependence upon these signaling intermediates. HB-EGF (> or =10 nm) increased total HK activity over 50% within 12-24 h, an effect mimicked by other EGF receptor agonists, but not by IGF-1 or elevated Glc. EGF receptor and classic MAPK pathway antagonists prevented this increase, as did general inhibitors of gene transcription and protein synthesis. Both HB-EGF and phorbol esters activated the classic MAPK pathway, albeit via PKC-independent and PKC-dependent mechanisms, respectively. Both stimuli were associated with increased HK activity, selectively increased HKII isoform expression, and increased Glc metabolism via both the glycolytic-tricarboxylic acid cycle route and the pentose phosphate pathway. HB-EGF thus constitutes a novel regulator of mesangial cell HK activity and Glc metabolism. HKII is the principal regulated isoform in these cells, as it is in insulin-sensitive peripheral tissues, such as muscle. However, the uniform requirement for classic MAPK pathway activation distinguishes HKII regulation in mesangial cells from that observed in muscle. These findings suggest a novel mechanism whereby growth factors may couple metabolism to glomerular injury.
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Affiliation(s)
- R Brooks Robey
- Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois 60612, USA.
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20
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Bryson JM, Coy PE, Gottlob K, Hay N, Robey RB. Increased hexokinase activity, of either ectopic or endogenous origin, protects renal epithelial cells against acute oxidant-induced cell death. J Biol Chem 2002; 277:11392-400. [PMID: 11751868 DOI: 10.1074/jbc.m110927200] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glucose (Glc) metabolism protects cells against oxidant injury. By virtue of their central position in both Glc uptake and utilization, hexokinases (HKs) are ideally suited to contribute to these effects. Compatible with this hypothesis, endogenous HK activity correlates inversely with injury susceptibility in individual renal cell types. We recently reported that ectopic HK expression mimics the anti-apoptotic effects of growth factors in cultured fibroblasts, but anti-apoptotic roles for HKs have not been examined in other cell types or in a cellular injury model. We therefore evaluated HK overexpression for the ability to mitigate acute oxidant-induced cell death in an established epithelial cell culture injury model. In parallel, we examined salutary heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) treatment for the ability to 1) increase endogenous HK activity and 2) mimic the protective effects of ectopic HK expression. Both HK overexpression and HB-EGF increased Glc-phosphorylating capacity and metabolism, and these changes were associated with markedly reduced susceptibility to acute oxidant-induced apoptosis. The uniform Glc dependence of these effects suggests an important adaptive role for Glc metabolism, and for HK activity in particular, in the promotion of epithelial cell survival. These findings also support the contention that HKs contribute to the protective effects of growth factors.
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Affiliation(s)
- Jane M Bryson
- Department of Medicine, College of Medicine, University of Illinois, Chicago 60612, USA
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21
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Gottlob K, Majewski N, Kennedy S, Kandel E, Robey RB, Hay N. Inhibition of early apoptotic events by Akt/PKB is dependent on the first committed step of glycolysis and mitochondrial hexokinase. Genes Dev 2001; 15:1406-18. [PMID: 11390360 PMCID: PMC312709 DOI: 10.1101/gad.889901] [Citation(s) in RCA: 707] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The serine/threonine kinase Akt/PKB is a major downstream effector of growth factor-mediated cell survival. Activated Akt, like Bcl-2 and Bcl-xL, prevents closure of a PT pore component, the voltage-dependent anion channel (VDAC); intracellular acidification; mitochondrial hyperpolarization; and the decline in oxidative phosphorylation that precedes cytochrome c release. However, unlike Bcl-2 and Bcl-xL, the ability of activated Akt to preserve mitochondrial integrity, and thereby inhibit apoptosis, requires glucose availability and is coupled to its metabolism. Hexokinases are known to bind to VDAC and directly couple intramitochondrial ATP synthesis to glucose metabolism. We provide evidence that such coupling serves as a downstream effector function for Akt. First, Akt increases mitochondria-associated hexokinase activity. Second, the antiapoptotic activity of Akt requires only the first committed step of glucose metabolism catalyzed by hexokinase. Finally, ectopic hexokinase expression mimics the ability of Akt to inhibit cytochrome c release and apoptosis. We therefore propose that Akt increases coupling of glucose metabolism to oxidative phosphorylation and regulates PT pore opening via the promotion of hexokinase-VDAC interaction at the outer mitochondrial membrane.
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Affiliation(s)
- K Gottlob
- Department of Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607, USA
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22
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Stenberg LM, Nilsson E, Ljungberg O, Stenflo J, Brown MA. Synthesis of gamma-carboxylated polypeptides by alpha-cells of the pancreatic islets. Biochem Biophys Res Commun 2001; 283:454-9. [PMID: 11327723 DOI: 10.1006/bbrc.2001.4808] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
gamma-Carboxylated proteins were detected in normal human pancreas by immunohistochemistry with a monoclonal antibody (M3B) specific for gamma-carboxyglutamyl residues. Staining appeared to be localized to the glucagon-secreting alpha-cells in the islets of Langerhans. Consistent with this, sections from a glucagonoma were stained much more intensely with the M3B antibody than those from an insulinoma. A murine alpha-cell line (alphaTC1 Clone 9) was cultured and gamma-carboxylated polypeptides, identified immunologically as prothrombin, protein S and (tentatively) Gas6, were isolated from the intracellular compartment by chromatography on an M3B-coupled resin. As in liver, prothrombin is synthesized by alpha-cells as a gamma-carboxylated zymogen that can be cleaved by ecarin to form an active serine protease that is inhibited by hirudin. The pancreas thus appears to be a novel site of synthesis for certain vitamin K-dependent proteins.
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Affiliation(s)
- L M Stenberg
- Department of Clinical Chemistry, Department of Pathology, Lund University, University Hospital, Malmö, Sweden
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23
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Robey RB, Ruiz OS, Baniqued J, Mahmud D, Espiritu DJ, Bernardo AA, Arruda JA. SFKs, Ras, and the classic MAPK pathway couple muscarinic receptor activation to increased Na-HCO(3) cotransport activity in renal epithelial cells. Am J Physiol Renal Physiol 2001; 280:F844-50. [PMID: 11292627 DOI: 10.1152/ajprenal.2001.280.5.f844] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cholinergic agents are known to affect the epithelial transport of H2O and electrolytes in the kidney. In proximal tubule cells, cholinergic agonists increase basolateral Na-HCO(3) cotransport activity via M(1) muscarinic receptor activation. The signaling intermediates that couple these G protein-coupled receptors to cotransporter activation, however, are not well defined. We therefore sought to identify distal effectors of muscarinic receptor activation that contribute to increased NBC activity in cultured proximal tubule cells. As demonstrated previously for acute CO2-regulated cotransport activity, we found that inhibitors of Src family kinases (SFKs) or the classic mitogen-activated protein kinase (MAPK) pathway prevented the stimulation of NBC activity by carbachol. The ability of carbachol to activate Src, as well as the proximal (Raf) and distal [extracellular signal-regulated kinases 1 and 2 (ERK1/2)] elements of the classic MAPK module, was compatible with these findings. Cholinergic stimulation of ERK1/2 activity was also completely prevented by overexpression of a dominant negative mutant of Ras (N17-Ras). Taken together, these findings suggest a requirement for the sequential activation of SFKs, Ras, and the classic MAPK pathway [Raf-->MAPK/ERK kinase (MEK)-->ERK]. These findings provide important insights into the molecular mechanisms underlying cholinergic regulation of NBC activity in renal epithelial cells. They also suggest a specific mechanism whereby cholinergic stimulation of the kidney can contribute to pH homeostasis.
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Affiliation(s)
- R B Robey
- Section of Nephrology, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, IL 60612, USA
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24
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Stenberg LM, Brown MA, Nilsson E, Ljungberg O, Stenflo J. A functional prothrombin gene product is synthesized by human kidney cells. Biochem Biophys Res Commun 2001; 280:1036-41. [PMID: 11162631 DOI: 10.1006/bbrc.2000.4145] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
gamma-carboxylated polypeptides were detected in the human kidney by immunohistochemistry with a monoclonal antibody (M3B) specific for gamma-carboxyglutamyl residues. An approximately 70-kDa gamma-carboxylated protein, subsequently identified as prothrombin, was isolated from the intracellular compartment of cultured human embryonic kidney (HEK293) cells by immunoaffinity chromatography on M3B-coupled resin. Immunohistochemical analyses demonstrated that prothrombin and another vitamin K-dependent protein, the growth arrest-specific protein 6, were detectable in human kidney. As in the liver, the kidney synthesizes prothrombin as a zymogen that can be cleaved by ecarin to an amidolytically active serine protease that is inhibited by hirudin. This demonstrates for the first time the de novo synthesis of a full-length, gamma-carboxylated, and functional prothrombin gene product by human kidney cells.
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Affiliation(s)
- L M Stenberg
- Department of Clinical Chemistry, Lund University, Malmö, S-205 02, Sweden
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