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Khalil AA, Jameson MJ. Sodium Orthovanadate Inhibits Proliferation and Triggers Apoptosis in Oral Squamous Cell Carcinoma in vitro. BIOCHEMISTRY (MOSCOW) 2017; 82:149-155. [PMID: 28320298 DOI: 10.1134/s0006297917020067] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Sodium orthovanadate (SOV) is a general inhibitor of tyrosine phosphatases, a large family of enzymes that catalyze the removal of phosphate groups from tyrosine residues. SOV is commonly used in the laboratory to preserve the protein tyrosyl phosphorylation state of proteins under study. It has shown promising antineoplastic activity in some human cancer cell lines; this effect has not been fully investigated in head and neck squamous cell carcinoma. In this study, the effect of SOV on cell growth, proliferation, viability, and apoptosis was assessed in Cal27 cells, an oral squamous cell carcinoma (OSCC) cell line. SOV exhibited dose-dependent inhibition of cell growth and decrease in cell viability and colony formation. The IC50 values for treatment lasting 72 h and 7 days were 25 and 10 µM, respectively. The cytotoxic effect of the drug was associated with poly(ADP-ribose)polymerase cleavage detected by immunoblot. Flow cytometry of Cal27 cells stained with annexin V-FITC and propidium iodide showed a dose-dependent increase in apoptosis that reached approximately 40% at 25 µM SOV. These findings demonstrate that SOV has in vitro antiproliferative and proapoptotic effect on OSCC cells.
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Affiliation(s)
- A A Khalil
- University of Virginia Health System, Division of Head and Neck Oncologic and Microvascular Surgery, Department of Otolaryngology, Head and Neck Surgery, Virginia, USA.
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2
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McGuire VA, Ruiz-Zorrilla Diez T, Emmerich CH, Strickson S, Ritorto MS, Sutavani RV, Weiβ A, Houslay KF, Knebel A, Meakin PJ, Phair IR, Ashford MLJ, Trost M, Arthur JSC. Dimethyl fumarate blocks pro-inflammatory cytokine production via inhibition of TLR induced M1 and K63 ubiquitin chain formation. Sci Rep 2016; 6:31159. [PMID: 27498693 PMCID: PMC4976367 DOI: 10.1038/srep31159] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 07/15/2016] [Indexed: 12/24/2022] Open
Abstract
Dimethyl fumarate (DMF) possesses anti-inflammatory properties and is approved for the treatment of psoriasis and multiple sclerosis. While clinically effective, its molecular target has remained elusive - although it is known to activate anti-oxidant pathways. We find that DMF inhibits pro-inflammatory cytokine production in response to TLR agonists independently of the Nrf2-Keap1 anti-oxidant pathway. Instead we show that DMF can inhibit the E2 conjugating enzymes involved in K63 and M1 polyubiquitin chain formation both in vitro and in cells. The formation of K63 and M1 chains is required to link TLR activation to downstream signaling, and consistent with the block in K63 and/or M1 chain formation, DMF inhibits NFκB and ERK1/2 activation, resulting in a loss of pro-inflammatory cytokine production. Together these results reveal a new molecular target for DMF and show that a clinically approved drug inhibits M1 and K63 chain formation in TLR induced signaling complexes. Selective targeting of E2s may therefore be a viable strategy for autoimmunity.
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Affiliation(s)
- Victoria A McGuire
- Division of Cell Signaling and Immunology, School of Life Sciences, Wellcome Trust Building, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - Tamara Ruiz-Zorrilla Diez
- Division of Cell Signaling and Immunology, School of Life Sciences, Wellcome Trust Building, University of Dundee, Dow St, Dundee, DD1 5EH, UK.,Department of Chemistry and Biochemistry, Faculty of Pharmacy, CEU San Pablo University, Urbanización Montepríncipe, 28668 Madrid, Spain
| | - Christoph H Emmerich
- MRC Protein Phosphorylation and ubiquitylation Unit, School of Life Sciences, Sir James Black Centre, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - Sam Strickson
- MRC Protein Phosphorylation and ubiquitylation Unit, School of Life Sciences, Sir James Black Centre, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - Maria Stella Ritorto
- MRC Protein Phosphorylation and ubiquitylation Unit, School of Life Sciences, Sir James Black Centre, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - Ruhcha V Sutavani
- Division of Cell Signaling and Immunology, School of Life Sciences, Wellcome Trust Building, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - Anne Weiβ
- Division of Cell Signaling and Immunology, School of Life Sciences, Wellcome Trust Building, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - Kirsty F Houslay
- Division of Cell Signaling and Immunology, School of Life Sciences, Wellcome Trust Building, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - Axel Knebel
- MRC Protein Phosphorylation and ubiquitylation Unit, School of Life Sciences, Sir James Black Centre, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - Paul J Meakin
- Cardiovascular and Diabetes Medicine, Medical Research Institute, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, DD1 9SY, UK
| | - Iain R Phair
- Division of Cell Signaling and Immunology, School of Life Sciences, Wellcome Trust Building, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - Michael L J Ashford
- Cardiovascular and Diabetes Medicine, Medical Research Institute, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, DD1 9SY, UK
| | - Matthias Trost
- MRC Protein Phosphorylation and ubiquitylation Unit, School of Life Sciences, Sir James Black Centre, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - J Simon C Arthur
- Division of Cell Signaling and Immunology, School of Life Sciences, Wellcome Trust Building, University of Dundee, Dow St, Dundee, DD1 5EH, UK
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3
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Sasaki MS, Tachibana A, Takeda S. Cancer risk at low doses of ionizing radiation: artificial neural networks inference from atomic bomb survivors. JOURNAL OF RADIATION RESEARCH 2014; 55:391-406. [PMID: 24366315 PMCID: PMC4014156 DOI: 10.1093/jrr/rrt133] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Revised: 10/20/2013] [Accepted: 10/22/2013] [Indexed: 06/03/2023]
Abstract
Cancer risk at low doses of ionizing radiation remains poorly defined because of ambiguity in the quantitative link to doses below 0.2 Sv in atomic bomb survivors in Hiroshima and Nagasaki arising from limitations in the statistical power and information available on overall radiation dose. To deal with these difficulties, a novel nonparametric statistics based on the 'integrate-and-fire' algorithm of artificial neural networks was developed and tested in cancer databases established by the Radiation Effects Research Foundation. The analysis revealed unique features at low doses that could not be accounted for by nominal exposure dose, including (i) the presence of a threshold that varied with organ, gender and age at exposure, and (ii) a small but significant bumping increase in cancer risk at low doses in Nagasaki that probably reflects internal exposure to (239)Pu. The threshold was distinct from the canonical definition of zero effect in that it was manifested as negative excess relative risk, or suppression of background cancer rates. Such a unique tissue response at low doses of radiation exposure has been implicated in the context of the molecular basis of radiation-environment interplay in favor of recently emerging experimental evidence on DNA double-strand break repair pathway choice and its epigenetic memory by histone marking.
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Affiliation(s)
- Masao S. Sasaki
- Kyoto University, 17-12 Shironosato, Nagaokakyo-shi, Kyoto 617-0835, Japan
| | - Akira Tachibana
- Department of Biology, Faculty of Science, Ibaraki University, Bunkyo 2-1-1, Mito, Ibaraki 310-8512, Japan
| | - Shunichi Takeda
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-konoecho, Sakyo-ku, Kyoto 606-8501, Japan
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Jayakumar C, Mohamed R, Ranganathan PV, Ramesh G. Intracellular kinases mediate increased translation and secretion of netrin-1 from renal tubular epithelial cells. PLoS One 2011; 6:e26776. [PMID: 22046354 PMCID: PMC3202578 DOI: 10.1371/journal.pone.0026776] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 10/03/2011] [Indexed: 01/12/2023] Open
Abstract
Background Netrin-1 is a laminin-related secreted protein, is highly induced after tissue injury, and may serve as a marker of injury. However, the regulation of netrin-1 production is not unknown. Current study was carried out in mouse and mouse kidney cell line (TKPTS) to determine the signaling pathways that regulate netrin-1 production in response to injury. Methods and Principal Findings Ischemia reperfusion injury of the kidney was induced in mice by clamping renal pedicle for 30 minutes. Cellular stress was induced in mouse proximal tubular epithelial cell line by treating with pervanadate, cisplatin, lipopolysaccharide, glucose or hypoxia followed by reoxygenation. Netrin-1 expression was quantified by real time RT-PCR and protein production was quantified using an ELISA kit. Cellular stress induced a large increase in netrin-1 production without increase in transcription of netrin-1 gene. Mitogen activated protein kinase, ERK mediates the drug induced netrin-1 mRNA translation increase without altering mRNA stability. Conclusion Our results suggest that netrin-1 expression is suppressed at the translational level and MAPK activation leads to rapid translation of netrin-1 mRNA in the kidney tubular epithelial cells.
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Affiliation(s)
- Calpurnia Jayakumar
- Vascular Biology Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Riyaz Mohamed
- Vascular Biology Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | | | - Ganesan Ramesh
- Vascular Biology Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
- * E-mail:
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Zhang Z, Humphreys BD, Bonventre JV. Shedding of the urinary biomarker kidney injury molecule-1 (KIM-1) is regulated by MAP kinases and juxtamembrane region. J Am Soc Nephrol 2008; 18:2704-14. [PMID: 17898236 DOI: 10.1681/asn.2007030325] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Kidney injury molecule-1 (KIM-1) is markedly upregulated in renal proximal tubule cells by stimuli that promote dedifferentiation, including ischemic or toxic injury, as well as in cases of tubulointerstitial disease, polycystic kidney disease, and renal cell carcinoma. Structurally, KIM-1 possesses a single transmembrane domain and undergoes membrane-proximal cleavage, which leads to the release of soluble KIM-1 ectodomain into the urine. Urinary KIM-1 ectodomain is a promising sensitive and specific biomarker for acute kidney injury in humans, and therefore it is important to determine what regulates KIM-1 shedding. We found that constitutive cleavage of KIM-1 is mediated by ERK activation, and that cleavage is accelerated by p38 MAP kinase activation. After cleavage, a 14-kD membrane-bound fragment of KIM-1, which contains two highly conserved tyrosine residues, was tyrosine-phosphorylated. Mutagenesis studies demonstrated that the juxtamembrane secondary structure, not the primary amino acid sequence, was critical to the cleavage of KIM-1.
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Affiliation(s)
- Zhiwei Zhang
- Renal Division, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, and Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology, Boston, Massachusetts, USA
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6
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Blanchette J, Pouliot P, Olivier M. Role of protein tyrosine phosphatases in the regulation of interferon-γ-induced macrophage nitric oxide generation: implication of ERK pathway and AP-1 activation. J Leukoc Biol 2006; 81:835-44. [PMID: 17170076 DOI: 10.1189/jlb.0505252] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
NO is a potent molecule involved in the cytotoxic events mediated by macrophages (MØ) against microorganisms. We reported previously that inhibition of MØ protein tyrosine phosphatases (PTPs) mediates a protective effect against Leishmania infection, which was NO-dependent. Herein, we show that the PTP inhibitors of the peroxovanadium (pV) class, bpV(phen) and bpV(pic), can similarly increase murine MØ IFN-gamma-induced NO generation. Using various second messenger (JAK2, MEK, Erk1/Erk2, and p38) antagonists, we found that the Erk1/Erk2 pathway was the principal pathway submitted to regulation by PTPs in the context of IFN-gamma-driven MØ activation and increase in NO production. We observed that bpV(phen) increases inducible NO synthase (iNOS) expression, resulting in enhanced NO production, whereas the bpV(pic) increase of NO production does not seem to result from a modulation of iNOS expression. Transcription factors STAT-1alpha and NF-kappaB, recognized for their importance in NO generation, were not affected by the pV treatment. However, AP-1 was strongly activated by bpV(phen) but not by bpV(pic). Collectively, our results suggest that increased IFN-gamma-induced NO production, observed after bpV(phen) treatment, involves the activation of the transcription factor AP-1 by Erk1/Erk2- and stress-activated protein kinase/JNK-dependent transduction mechanisms.
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Affiliation(s)
- Julie Blanchette
- Centre de Recherche en Infectiologie and Département de Biologie Médicale, Centre Hospitalier Universitaire de Québec, Pavillon CHUL, Université Laval, Ste-Foy, Québec, Canada
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7
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Rumora L, Hadzija M, Maysinger D, Zanić-Grubisić T. Positive regulation of ERK activation and MKP-1 expression by peroxovanadium complex bpV (phen). Cell Biol Toxicol 2005; 20:293-301. [PMID: 15685932 DOI: 10.1007/s10565-004-5104-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Lower micromolar concentrations of peroxovanadium compound potassium bisperoxo(1,10-phenanthroline)oxovanadate (V) [bpV (phen)] stimulate RINm5F cell metabolic activity. 1 and 3 micromol/L bpV (phen) induces strong and sustained activation of extracellular signal-regulated kinase (ERK). However, it seems that bpV (phen) does not effect c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) phosphorylation. In addition, bpV (phen) induces mitogen-activated protein kinase phosphatase-1 (MKP-1) expression. We found that ERK activation could be completely abolished if RINm5F cells were incubated with both bpV (phen) and PD 98059, a specific inhibitor of upstream ERK kinase MEK1. On the other hand, this combined treatment up-regulated activation of stress kinases, JNK and p38 MAPK, significantly suppressed MKP-1 expression and induced cell death. Thus, our results suggest that the mechanism underlying bpV (phen) survival-enhancing effect could be associated with induced ERK activation and MKP-1 expression.
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Affiliation(s)
- L Rumora
- Department of Medical Biochemistry and Hematology, Faculty of Pharmacy and Biochemistry, Zagreb, Croatia.
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Borbiev T, Birukova A, Liu F, Nurmukhambetova S, Gerthoffer WT, Garcia JGN, Verin AD. p38 MAP kinase-dependent regulation of endothelial cell permeability. Am J Physiol Lung Cell Mol Physiol 2004; 287:L911-8. [PMID: 15475493 DOI: 10.1152/ajplung.00372.2003] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We have previously shown that thrombin induces endothelial cell barrier dysfunction via cytoskeleton activation and contraction and have determined the important role of endothelial cell myosin light chain kinase (MLCK) in this process. In the present study we explored p38 MAP kinase as a potentially important enzyme in thrombin-mediated endothelial cell contractile response and permeability. Thrombin induces significant p38 MAP kinase activation in a time-dependent manner with maximal effect at 30 min, which correlates with increased phosphorylation of actin- and myosin-binding protein, caldesmon. Both SB-203580 and dominant negative p38 adenoviral vector significantly attenuated thrombin-induced declines in transendothelial electrical resistance. Consistent with these data SB-203580 decreased actin stress fiber formation produced by thrombin in endothelium. In addition, dominant negative p38 had no effect on thrombin-induced myosin light chain diphosphorylation. Thrombin-induced total and site-specific caldesmon phosphorylation (Ser789) as well as dissociation of caldesmon-myosin complex were attenuated by SB-203580 pretreatment. These results suggest the involvement of p38 MAP kinase activities and caldesmon phosphorylation in the MLCK-independent regulation of thrombin-induced endothelial cell permeability.
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Affiliation(s)
- Talaibek Borbiev
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21224, USA
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9
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Rumora L, Barisić K, Maysinger D, Zanić Grubisić T. BpV (phen) induces apoptosis of RINm5F cells by modulation of MAPKs and MKP-1. Biochem Biophys Res Commun 2003; 300:877-83. [PMID: 12559954 DOI: 10.1016/s0006-291x(02)02952-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We investigated the mechanism of toxicity of peroxovanadium complex bpV (phen) in RINm5F cells. Treatment with bpV (phen) provoked cell death, predominantly by apoptosis. This compound induced strong and sustained JNK and p38 MAPK activation. However, ERK phosphorylation was not affected. The level of expression of MAPK phosphatase MKP-1 was suppressed after bpV (phen) treatment. In addition, this compound did not stimulate proteolytic processing of procaspase-3, suggesting that caspase-3 is not activated during the course of bpV (phen)-induced apoptosis. A correlative inhibition of JNK activation by immunosuppressive drug FK 506 induced ERK activation and MKP-1 expression, and suppressed RINm5F cell death. A specific p38 inhibitor SB 203580 also stimulated ERK activation and cell survival. Furthermore, simultaneous pretreatment with both FK 506 and SB 203580 almost completely abolished cell death. Thus, our results suggest that stress kinases and MKP-1 have a role in bpV (phen)-induced apoptosis of RINm5F cells.
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Affiliation(s)
- Lada Rumora
- Department of Medical Biochemistry and Haematology, Faculty of Pharmacy and Biochemistry, Domagojeva 2, 10 000 Zagreb, Croatia.
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10
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Garcia JGN, Wang P, Schaphorst KL, Becker PM, Borbiev T, Liu F, Birukova A, Jacobs K, Bogatcheva N, Verin AD. Critical involvement of p38 MAP kinase in pertussis toxin-induced cytoskeletal reorganization and lung permeability. FASEB J 2002; 16:1064-76. [PMID: 12087068 DOI: 10.1096/fj.01-0895com] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Bordetella pertussis is an important cause of infection in humans worldwide, with full expression of the syndrome associated with characteristic increases in lung permeability and airway edema. The exact cellular mechanisms by which pertussis toxin (PTX) exerts pulmonary toxicity remain unknown, but may involve its ability to ADP-ribosylate-specific G-proteins. We determined that PTX directly and reproducibly reduced lung endothelial and epithelial cell barrier function in vitro and in vivo assessed by decreases in transmonolayer electrical resistance (TER) and isolated perfused lung preparations. Alterations in lung permeability began approximately 30 min after PTX and were dependent on intrinsic ADP-ribosyltransferase activity, as neither the cell binding beta-oligomer subunit or a genetically engineered PTX mutant (devoid of ADP-ribosyltransferase activity) altered TER. PTX-induced barrier dysfunction was associated with mild increases in F-actin stress fiber formation and causally linked to p38 MAP kinase activities. PTX-mediated p38 MAP kinase activation did not involve either p42/p44 ERK, p60src, Rho family of GTPases, or phosphatidylinositol-3' kinase pathways. PTX-mediated decreases in TER were temporally linked to phosphorylation of the actin binding proteins Hsp27 and caldesmon, known substrates for the Ser/Thr kinase MAPKAP2, whose activity is regulated by p38 MAP kinase. In addition to defining novel signaling pathways involved in PTX-induced respiratory pathophysiology, these data suggest that the direct cell-activating effects of PTX be carefully considered as a potential limitation to its use as a tool in signal transduction analysis.
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Affiliation(s)
- Joe G N Garcia
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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11
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Goswami M, Uzgare AR, Sater AK. Regulation of MAP kinase by the BMP-4/TAK1 pathway in Xenopus ectoderm. Dev Biol 2001; 236:259-70. [PMID: 11476570 DOI: 10.1006/dbio.2001.0338] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Bone morphogenetic protein-4 (BMP-4) induces epidermis and represses neural fate in Xenopus ectoderm. Our previous findings implicate p42 Erk MAP kinase (MAPK) in the response to neural induction. We have examined the effects of BMP-4 on MAPK activity in gastrula ectoderm. Expression of a dominant negative BMP-4 receptor resulted in a 4.5-fold elevation in MAPK activity in midgastrula ectoderm. MAPK activity was reduced in ectoderm expressing a constitutively active BMP-4 receptor, or ectoderm treated with BMP-4 protein in the presence or absence of cycloheximide. Overexpression of TAK1 led to a reduction in MAPK activity in early gastrula ectoderm. The inhibitory effects of TAK1 could be reversed by 1 microM SB 203580, a p38 inhibitor. Treatment of isolated ectoderm with SB 203580 led to expression of otx2, NCAM, and noggin. Western blot analyses indicated that the BMP-4 pathway does not activate JNKs in ectoderm. Our findings indicate that BMP-4 inhibits ectodermal MAPK activity through a TAK1/p38-type pathway. MAPK has been shown to inactivate Smad1. Thus, our results suggest that BMP-4 and MAPK pathways are mutually antagonistic in Xenopus ectoderm, and that interactions between these pathways may govern the choice between epidermal and neural fate.
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Affiliation(s)
- M Goswami
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204-5513, USA
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Yan S, Wenner CE. Modulation of cyclin D1 and its signaling components by the phorbol ester TPA and the tyrosine phosphatase inhibitor vanadate. J Cell Physiol 2001; 186:338-49. [PMID: 11169972 DOI: 10.1002/1097-4652(2000)9999:9999<000::aid-jcp1032>3.0.co;2-b] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The mechanism by which 12-O-tetradecanoylphorbol-13-acetate (TPA) triggers cell-cycle progression at G1 phase in mouse embryonic fibroblast C3H 10T1/2 cells was examined. TPA treatment resulted in a temporary induction of cyclin D1 peaking at 9 h post stimulation. PD98059 (10 microM), the specific inhibitor of MAPK kinase, completely blocked TPA-stimulated cyclin D1 induction and DNA synthesis, confirming that MAPK activation plays an essential role in TPA-stimulated cell-cycle progression. Although both PKCalpha and PKCepsilon are expressed in C3H 10T1/2 cells, inhibitor studies suggest that PKCepsilon activation is required for the activation of MEK/MAPK signal transduction cascade. p70s6K, an important kinase involved in the regulation of protein synthesis and cell-cycle progression, has been reported to be activated through a PKC-dependent pathway (TPA-activatable) in addition to a PI3K-dependent pathway. Here, we demonstrate for the first time that TPA-stimulated MAPK activation is essential for the phosphorylation of several key residues involved in the activation of p70s6K, namely, thr389, thr421, and ser424. Vanadate, the tyrosine phosphatase inhibitor, triggered a sustained elevation of the level of active MAPK. However, corresponding to a rapid loss of cyclin D1 protein, vanadate treatment resulted in a significant shut out of 3H-thymidine incorporation into DNA regardless of TPA cotreatment. Vanadate treatment also led to the increase of active MEK, increased phosphorylation of p70s6K at thr389, thr421, and ser424 yet without activation of PKB. These data suggest that vanadate can selectively perturb the activation of signaling components which raises the interesting issue as to how vanadate downregulates the cyclin D1 level.
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Affiliation(s)
- S Yan
- Department of Biochemistry, Roswell Park Cancer Institute, Buffalo, New York 14260, USA
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Daum G, Pham J, Deou J. Arsenite inhibits Ras-dependent activation of ERK but activates ERK in the presence of oncogenic Ras in baboon vascular smooth muscle cells. Mol Cell Biochem 2001; 217:131-6. [PMID: 11269657 DOI: 10.1023/a:1007276812824] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Exposure to arsenical compounds enhances the risk of atherosclerosis. The reason is unknown but it might be because an effect of arsenite (As3+) on plaque smooth muscle cells (SMCs) activation of extracellular signal-regulated kinase (ERK), a crucial mediator of SMC function. We found that arsenite inhibits the activation of ERK by platelet-derived growth factor-BB (PDGF-BB). This inhibitory effect depends on the time of arsenite exposure, is reversible, and is attenuated by preincubation of SMCs with the antioxidant N-acetyl-cysteine. These observations are consistent with the assumption that oxidative stress is involved. The blockade of ERK by arsenite may be mediated by an inhibition of Ras as arsenite prevents GTP-loading of Ras in response to PDGF-BB. Moreover, the Ras blockade by arsenite is not specific for PDGF-BB because it was also observed following stimulation of SMCs with EGF. To address the role of Ras, we expressed constitutively active, GTP-bound Ha-Ras (V12Ras). Unexpectedly, in V12Ras expressing-SMCs, arsenite stimulates ERK, but still decreases ERK activity in the presence of PDGF-BB. Our data suggest that arsenite inhibits the Ras/ERK pathway in SMCs, and that arsenite may activate ERK in Ras-transformed cells by mechanisms different from those employed by growth factors.
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Affiliation(s)
- G Daum
- Department of Surgery, University of Washington, Seattle 98195-6410, USA
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14
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Kim SO, Xu Y, Katz S, Pelech S. Cyclic GMP-dependent and -independent regulation of MAP kinases by sodium nitroprusside in isolated cardiomyocytes. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1496:277-84. [PMID: 10771096 DOI: 10.1016/s0167-4889(00)00026-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sodium nitroprusside (SNP) elicits various physiological effects, in part through generation of the membrane permeable mediator nitric oxide (NO). In the heart, besides its role in regulating contractility, NO is involved in both protection from and induction of cellular damage. The present study investigated the role of SNP in the regulation of the mitogen-activated protein kinases (MAPKs) in isolated adult rat cardiomyocytes. SNP maximally activated Erk1, Erk2, p38 MAPK and MAPKAPK2 in 5-10 min. The activation of MAPKAPK2 by SNP was blocked by the soluble guanylyl cyclase inhibitor, 1H-[1, 2,4]oxadiazolol[4,3-a]quinoxalin-1-one (ODQ) and the p38 MAPK inhibitor, SB203580. The activation of Erk1 was insensitive to ODQ but completely blocked by the Mek1 inhibitor PD98059. The membrane-permeable homologue of cGMP, 8-Br-cGMP, also activated p38 MAPK (A(0.5) approximately 50 microM) but not Erk1 and Erk2. These results indicate that p38 MAPK and MAPKAPK2 are activated by SNP in cGMP-dependent pathways, while the Erk1 activation by SNP is independent of cGMP levels.
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Affiliation(s)
- S O Kim
- Department of Medicine, University of British Columbia, Rm S125, 2nd Floor, Koerner Pavilion, 2211 Wesbrook Mall, Vancouver, B.C., Canada
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15
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Mehta KD, Miller L. Inhibition of stress-activated p38 mitogen-activated protein kinase induces low-density lipoprotein receptor expression. Trends Cardiovasc Med 1999; 9:201-5. [PMID: 10881752 DOI: 10.1016/s1050-1738(00)00021-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We have recently shown that different signal transduction pathways initiated by a variety of agents converge on growth-responsive p42/44MAPK signaling cascade to induce low-density lipoprotein (LDL) receptor expression. Our recent demonstration that stress-activated p38MAPK negatively regulates LDL receptor expression in an isoform-specific manner via modulation of p42/44MAPK cascade represents a new dimension of complexity in the molecular communication that governs LDL receptor expression. The suggested one-way communication between p38MAPK and p42/44MAPK provides a potential mechanism for fine-tuning cellular levels of cholesterol in response to a diverse set of environmental cues, including stress. Cross talk between MAPKs opens new avenues toward understanding a variety of pathogenic processes; this makes them tempting targets for therapeutic interventions in cardiovascular diseases.
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Affiliation(s)
- K D Mehta
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock 72205, USA
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16
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Feng L, Zhou X, Liao J, Omary MB. Pervanadate-mediated tyrosine phosphorylation of keratins 8 and 19 via a p38 mitogen-activated protein kinase-dependent pathway. J Cell Sci 1999; 112 ( Pt 13):2081-90. [PMID: 10362538 DOI: 10.1242/jcs.112.13.2081] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glandular epithelia express the keratin intermediate filament (IF) polypeptides 8, 18 and 19 (K8/18/19). These proteins undergo significant serine phosphorylation upon stimulation with growth factors and during mitosis, with subsequent modulation of their organization and interaction with associated proteins. Here we demonstrate reversible and dynamic tyrosine phosphorylation of K8 and K19, but not K18, upon exposure of intact mouse colon or cultured human cells to pervanadate. K8/19 tyrosine phosphorylation was confirmed by metabolic 32PO4-labeling followed by phosphoamino acid analysis, and by immunoblotting with anti-phosphotyrosine antibodies. Pervanadate treatment increases keratin solubility and also indirectly increases K8/18 serine phosphorylation at several known sites, some of which were previously shown to be associated with EGF stimulation, extracellular signal-regulated kinase (ERK), or p38 kinase activation. However, K8/19 tyrosine phosphorylation is independent of EGF signaling or ERK activation while inhibition of p38 kinase activity blocks pervanadate-induced K8/19 tyrosine phosphorylation. Our results demonstrate tyrosine phosphatase inhibitor-mediated in vivo tyrosine phosphorylation of K8/19, but not K18, and suggest that tyrosine phosphorylation may be a general modification of other IF proteins. K8/19 tyrosine phosphorylation involves a pathway that utilizes the p38 mitogen-activated protein kinase, but appears independent of EGF signaling or ERK kinase activation.
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Affiliation(s)
- L Feng
- Dept of Medicine, VA Palo Alto Health Care System, Mail code 154J, Palo Alto, CA 94304, USA
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17
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Bornfeldt KE, Krebs EG. Crosstalk between protein kinase A and growth factor receptor signaling pathways in arterial smooth muscle. Cell Signal 1999; 11:465-77. [PMID: 10405757 DOI: 10.1016/s0898-6568(99)00020-0] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Crosstalk between the cyclic AMP-dependent protein kinase (PKA) and growth factor receptor signaling is one of many emerging concepts of crosstalk in signal transduction. Understanding of PKA crosstalk may have important implications for studies of crosstalk between other, less well known, signaling pathways. This review focuses on PKA crosstalk in arterial smooth muscle. Proliferation and migration of arterial smooth muscle cells (SMCs) contribute to the thickening of the blood vessel wall that occurs in many types of cardiovascular disease. PKA potently inhibits SMC proliferation by antagonizing the major mitogenic signaling pathways induced by growth factors in SMCs. PKA also inhibits growth factor-induced SMC migration. An intricate crosstalk between PKA and the mitogen-activated protein kinase (MAPK/ERK) pathway, the p70 S6 kinase pathway and cyclin-dependent kinases has been described. Further, PKA regulates expression of growth regulatory molecules. The result of PKA activation in SMCs is the potent inhibition of cell cycle traverse and SMC migration. In this review, we discuss recent advances in our understanding of the crosstalk between PKA and signaling pathways induced by growth factor receptors in SMCs, and where relevant, in other cell types in which interesting examples of PKA crosstalk have been described.
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Affiliation(s)
- K E Bornfeldt
- Department of Pathology, University of Washington, Seattle 98195-7470, USA.
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18
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Rosenberger SF, Gupta A, Bowden GT. Inhibition of p38 MAP kinase increases okadaic acid mediated AP-1 expression and DNA binding but has no effect on TRE dependent transcription. Oncogene 1999; 18:3626-32. [PMID: 10380884 DOI: 10.1038/sj.onc.1202695] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
By performing in vitro kinase assays we found in papilloma producing 308 mouse keratinocytes that okadaic acid elevated activities of extracellular signal-regulated kinase (ERK) 1/2, c-Jun N-terminal kinases (JNKs) and p38 mitogen-activated protein kinases (MAPKs). This okadaic acid mediated activation of MAP kinases correlated with increased AP-1 binding to a consensus TPA responsive element (TRE) and elevated TRE dependent transcription. To determine the role of p38 MAP kinases in these processes we employed the specific p38 MAP kinase inhibitor SB 203580. Using orthophosphate labeling we showed a decrease in phosphorylation of MAPK activated protein kinase-2 (MAPKAP-K2) indicating reduced activity of p38 MAPKs utilizing this kinase as substrate. In contrast, we found that SB 203580 raised activities of ERK-1/2 and JNKs. Electrophoretic mobility shift assays revealed an increase in TRE binding activity in response to SB 203580 most likely resulting from increased expression of the major TRE binding components JunD and FosB as indicated by Western blot analyses. Increased TRE DNA binding failed to lead to increased transactivation correlating with the inability of SB 203580 to increase phosphorylation of these AP-1 proteins. These data indicate that SB 203580 sensitive p38 MAP kinases are not involved in okadaic acid mediated increases in TRE DNA binding and transactivation.
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Affiliation(s)
- S F Rosenberger
- Department of Radiation Oncology, The University of Arizona Health Sciences Center, Tucson 85724, USA
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Kalmes A, Deou J, Clowes AW, Daum G. Raf-1 is activated by the p38 mitogen-activated protein kinase inhibitor, SB203580. FEBS Lett 1999; 444:71-4. [PMID: 10037150 DOI: 10.1016/s0014-5793(99)00034-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
SB203580 (4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imi dazole) is widely used as a specific inhibitor of p38 mitogen-activated protein kinase (MAPK). Here, we report that SB203580 activates the serine/threonine kinase Raf-1 in quiescent smooth muscle cells in a dose-dependent fashion. The concentrations of SB203580 required lie above those necessary to inhibit p38 MAPK and we were unable to detect basal levels of active p38 MAPK. SB203580 does not directly activate Raf-1 in vitro, and fails to activate Ras, MEK, and ERK in intact cells. In vitro, however, SB203580-stimulated Raf-1 activates MEK1 in a coupled assay. We conclude that activation of Raf-1 by SB203580 is not mediated by an inhibition of p38 MAPK, is Ras-independent, and is uncoupled from MEK/ERK signaling.
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Affiliation(s)
- A Kalmes
- Department of Surgery, University of Washington, Seattle 98195-6410, USA.
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Miller SC, Furniss MJ. Bruton's tyrosine kinase activity and inositol 1,4,5-trisphosphate production are not altered in DT40 lymphoma B cells exposed to power line frequency magnetic fields. J Biol Chem 1998; 273:32618-26. [PMID: 9830001 DOI: 10.1074/jbc.273.49.32618] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Exposure of wild-type DT40 lymphoma B cells or Bruton's tyrosine kinase (BTK)-deficient DT40 cells reconstituted with the human btk gene to a 1-gauss 60-Hz electromagnetic field (EMF) has been reported to rapidly increase inositol 1,4,5-trisphosphate (Ins 1,4, 5-P3) production (1,2). Here we have used BTK-deficient DT40 B cells reconstituted with the human btk gene to evaluate the reproducibility of these findings. An experimental design with blinded exposures and anti-IgM treatment to induce Ins 1,4,5-P3 production as a positive control, showed no significant effect of a 1-gauss 60-Hz EMF on Ins 1,4,5-P3 production. Because recent work has shown that the activation of BTK was required for EMF-responsiveness (2), we also evaluated the reproducibility of this finding in wild-type DT40 cells. BTK was activated in a dose- and time-dependent manner by treatment with the tyrosine phosphatase inhibitor pervanadate. However, the ability to detect BTK activation, as measured by increased autophosphorylation by immune complex kinase assay, was dependent on the kinase buffer. Using cells from the original investigators, no evidence was obtained to support the hypothesis that exposure to a 1-gauss 60-Hz EMF had a causal effect on protein-tyrosine kinase activities affecting Ins 1,4,5-P3 production.
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Affiliation(s)
- S C Miller
- Signal Transduction Laboratory, Pharmaceutical Discovery Division, SRI International, Menlo Park, California 94025, USA.
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Alexandrov A, Keffel S, Goepel M, Michel MC. Stimulation of alpha1A-adrenoceptors in Rat-1 cells inhibits extracellular signal-regulated kinase by activating p38 mitogen-activated protein kinase. Mol Pharmacol 1998; 54:755-60. [PMID: 9804610 DOI: 10.1124/mol.54.5.755] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In Rat-1 fibroblasts, endothelin-1 and a protein kinase C-stimulating phorbol ester stimulated extracellular signal-regulated kinase (ERK), whereas phenylephrine, acting at stably transfected human alpha1A-adrenoceptors, inhibited basal and endothelin-1- and phorbol ester-stimulated ERK. On the other hand, phenylephrine stimulated p38 mitogen-activated protein kinase (MAPK). Anisomycin caused p38 activation and ERK inhibition quantitatively similar to those produced by phenylephrine. SB 203,580, an inhibitor of p38, significantly attenuated phenylephrine- and anisomycin-induced ERK inhibition. The ERK inhibition by phenylephrine was not affected by the cytosolic phospholipase A2 inhibitor arachidonyltrifluoromethyl ketone or the cyclooxygenase inhibitor indomethacin but was significantly attenuated by a combination of the phosphatase inhibitors Na3VO4 and okadaic acid. Neither SB 203,580 nor the phosphatase inhibitors significantly affected ERK inhibition by the adenylyl cyclase activator forskolin. We conclude that there is a previously unrecognized interaction between ERK and p38 MAPK, in which activation of p38 causes inhibition of ERK; this may at least partly involve MAPK phosphatases that inactivate ERK.
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Affiliation(s)
- A Alexandrov
- Department of Medicine, University of Essen, 45122 Essen, Germany
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