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Li CH, Wang RM, Zhang QG, Zhang GY. Activated mitogen-activated protein kinase kinase 7 redistributes to the cytosol and binds to Jun N-terminal kinase-interacting protein 1 involving oxidative stress during early reperfusion in rat hippocampal CA1 region. J Neurochem 2005; 93:290-8. [PMID: 15816852 DOI: 10.1111/j.1471-4159.2005.03086.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mitogen-activated protein kinase kinase (MKK) 7, a specific upstream activator of Jun N-terminal kinases (JNKs) in the stress-activated protein kinase (SAPK)/JNK signaling pathway, plays an important role in response to global cerebral ischemia. We investigated the subcellular localization of activated (phosphorylated) MKK (p-MKK) 7 using western blotting, immunoprecipitation and immunohistochemistry analysis in rat hippocampus. Transient forebrain ischemia was induced by the four-vessel occlusion method on Sprague-Dawley rats. Our results showed that both protein expression and activation of MKK7 were increased rapidly with peaks at 10 min of reperfusion in the nucleus of the hippocampal CA1 region. Simultaneously, in the cytosol activated MKK7 enhanced gradually and peaked at 30 min of reperfusion. In addition, we also detected JNK-interacting protein (JIP) 1, which accumulated in the perinuclear region of neurons at 30 min of reperfusion. Interestingly, at the same time-point the binding of JIP-1 to p-MKK7 reached a maximum. Consequently, we concluded that MKK7 was rapidly activated and then translocated from the nucleus to the cytosol depending on its activation in the hippocampal CA1 region. To further elucidate the possible mechanism of MKK7 activation and translocation, the antioxidant N-acetylcysteine was injected into the rats 20 min before ischemia. The result showed that the levels of MKK7 activation, translocation and binding of p-MKK7 to JIP-1 were obviously limited by N-acetylcysteine in the cytosol at 30 min after reperfusion. The findings suggested that MKK7 activation, translocation and binding to JIP-1 were closely associated with reactive oxygen species and might play a pivotal role in the activation of the JNK signaling pathway in brain ischemic injury.
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Affiliation(s)
- Chun-Hong Li
- Research Center for Biochemistry and Molecular Biology, Xuzhou Medical College, Xuzhou, Jiangsu, China
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52
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Howe CJ, LaHair MM, Robinson PJ, Rodriguez-Mora O, McCubrey JA, Franklin RA. Models of anergy in the human Jurkat T cell line. Assay Drug Dev Technol 2004; 1:537-44. [PMID: 15090250 DOI: 10.1089/154065803322302790] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We investigated two model systems to study anergy in a human T cell line. OKT3 or calcium ionophore stimulation of Jurkat cells, in the absence of costimulation, resulted in a steep reduction in the transcription and secretion of IL-2 in response to subsequent stimulation via CD3 and CD28. Treatment of anergic Jurkat cells with the combination of the phorbol ester, PMA, and ionomycin restored IL-2 production in cells rendered anergic by both mechanisms. However, hydrogen peroxide, which also stimulates kinases downstream of the proposed block that occurs in anergic murine cells, did not reverse the anergic state of these cells induced by either stimulus. The cause of unresponsiveness in these two models was found to differ. OKT3-induced anergy resulted in a substantial down-regulation of the CD3 on these cells. In contrast, anergy induced by treatment with a calcium ionophore did not result in CD3 down-regulation. These data indicate that the Jurkat cell line may serve as a suitable model for studying anergy in human T cells; however, the mechanism by which anergy is induced may vary dramatically in response to these two commonly used anergy-inducing strategies. Understanding the similarities and differences between these two models of anergy may lead to a better overall understanding of the anergic state of the T cell.
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Affiliation(s)
- Christopher J Howe
- Department of Microbiology and Immunology, Brody School of Medicine at East Carolina University, Greenville, NC 27858, USA
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53
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Jang BC, Lim KJ, Paik JH, Cho JW, Baek WK, Suh MH, Park JB, Kwon TK, Park JW, Kim SP, Shin DH, Song DK, Bae JH, Mun KC, Suh SI. Tetrandrine-induced apoptosis is mediated by activation of caspases and PKC-δ in U937 cells. Biochem Pharmacol 2004; 67:1819-29. [PMID: 15130759 DOI: 10.1016/j.bcp.2004.01.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2003] [Accepted: 01/14/2004] [Indexed: 10/26/2022]
Abstract
Tetrandrine, which is isolated from Chinese herb Stephania tetrandrae, possesses anti-inflammatory, immunosuppressive, and cytoprotective properties. Though it was previously shown that tetrandrine causes a G1 blockade and apoptosis in various cell types, however, the mechanism by which tetrandrine initiates apoptosis remains poorly understood. In present study, we investigated the mechanisms of apoptosis induced by tetrandrine in U937 leukemia cells. Tetrandrine inhibited U937 cell growth by inducing apoptosis. After treatment of U937 cells with tetrandrine (10microM) for 24h, alteration of cell morphology, chromatin fragmentation, cytochrome c release, and caspase activation were observed. Tetrandrine also induced early oxidative stress, which resulted in activation of JNK, but not ERK and p38 MAPK. A broad-spectrum caspase inhibitor and antioxidants significantly blocked tetrandrine-induced caspase-3 activation. However, inhibition of the JNK activity with SP600125 did not block tetrandrine-induced apoptosis. Tetrandrine-induced apoptosis of U937 cells also required activity of PKC-delta, because pretreatment with a specific PKC-delta inhibitor greatly blocked tetrandrine-induced caspase-3 activation. In addition, the apoptotic response to tetrandrine was significantly attenuated in dominant-negative PKC-delta transfected MCF-7 cells, suggesting that PKC-delta plays an important role in tetrandrine-induced apoptosis and can induce caspase activation. These results suggest that tetrandrine induces oxidative stress, JNK activation, and caspase activation. However, JNK activation by ROS is not involved in the tetrandrine-induced apoptosis. In addition, tetrandrine induces caspase-dependent generation of a catalytically active fragment of PKC-delta, and this fragment also appears to play a role in the activation of caspases.
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Affiliation(s)
- Byeong-Churl Jang
- Chronic Disease Research Center, Institute for Medical Science, School of Medicine, Keimyung University, Daegu 700-712, South Korea
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54
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Chen F. Reactive Oxygen Species in the Activation and Regulation of Intracellular Signaling Events. OXYGEN/NITROGEN RADICALS 2004. [DOI: 10.1201/b14147-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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55
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Zhang Y, Chen F. Reactive oxygen species (ROS), troublemakers between nuclear factor-kappaB (NF-kappaB) and c-Jun NH(2)-terminal kinase (JNK). Cancer Res 2004; 64:1902-5. [PMID: 15026320 DOI: 10.1158/0008-5472.can-03-3361] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Nuclear factor-kappaB (NF-kappaB) and c-Jun NH(2)-terminal kinase (JNK) are activated simultaneously under a variety of stress conditions. They also share several common signaling pathways for their activation in response to cytokines or growth factors. Recent studies, however, demonstrated a new form of interplay between these two allies. Inhibition of NF-kappaB by ikkbeta or rela gene deficiency sensitizes stress responses through enhanced or prolonged activation of JNK. Conversely, sustained activation of NF-kappaB inhibits cytokine-induced JNK activation. The mechanisms of how NF-kappaB and JNK become rivals for each other are under extensive debate.
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Affiliation(s)
- Yadong Zhang
- Institute for Nutritional Sciences, Chinese Academy of Sciences, Shanghai, P. R. China
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56
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Ma C, Lin H, Leonard SS, Shi X, Ye J, Luo J. Overexpression of ErbB2 enhances ethanol-stimulated intracellular signaling and invasion of human mammary epithelial and breast cancer cells in vitro. Oncogene 2003; 22:5281-90. [PMID: 12917629 DOI: 10.1038/sj.onc.1206675] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Both epidemiological and experimental studies indicate that ethanol is a tumor promoter and may promote metastasis of breast cancer. However, the molecular mechanisms underlying ethanol-mediated tumor promotion remain unknown. Overexpression of ErbB proteins in breast cancer patients is generally associated with poor prognosis. The ErbB proteins are a family of receptor kinases that include four closely related members: epidermal growth factor receptor (EGFR/ErbB1), ErbB2/neu, ErbB3, and ErbB4. Particularly, ErbB2 plays a pivotal role in ErbB-mediated activities. Here we demonstrated that amplification of ErbB2 expression sensitized a specific cellular response to ethanol. Human breast cancer cells or mammary epithelial cells with a high expression of ErbB2 exhibited an enhanced response to ethanol-stimulated cell invasion in vitro. Ethanol also stimulated cell proliferation; however, this stimulation was independent of ErbB2 levels. Ethanol triggered divergent intracellular signaling among cells expressing different ErbB2 levels. In the cells overexpressing ErbB2, ethanol was more effective in the activation of c-Jun NH2 terminal protein kinases (JNKs) and p38 mitogen-activated protein kinase (p38 MAPK) as well as the induction of reactive oxygen species (ROS) than the cells with normal ErbB2 expression. Blockage of either JNKs or p38 MAPK activation eliminated ethanol-mediated cell invasion. In contrast, the reduction of hydrogen peroxide concentration by catalase exposure had little effect on ethanol-induced cell invasion. These results indicated that ethanol-induced cell invasion was primarily mediated by JNKs and p38 MAPK, whereas the involvement of ROS formation might be minimal. Our study suggests that overexpression of ErbB2 may augment ethanol-elicited signaling and promote ethanol-stimulated tumor metastasis.
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Affiliation(s)
- Cuiling Ma
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, WV 26506, USA
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57
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MacKenzie CJ, Paul A, Wilson S, de Martin R, Baker AH, Plevin R. Enhancement of lipopolysaccharide-stimulated JNK activity in rat aortic smooth muscle cells by pharmacological and adenovirus-mediated inhibition of inhibitory kappa B kinase signalling. Br J Pharmacol 2003; 139:1041-9. [PMID: 12839879 PMCID: PMC1573924 DOI: 10.1038/sj.bjp.0705330] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2003] [Accepted: 04/06/2003] [Indexed: 12/13/2022] Open
Abstract
1. In rat aortic smooth muscle cells (RASMCs), the putative nuclear factor kappa B (NFkappaB) inhibitor Pyrrolidine dithiocarbamate (PDTC) was found to inhibit lipopolysaccharide (LPS)-stimulated NFkappaB DNA-binding. However, further investigation identified the site of inhibition as being at, or upstream of, the inhibitory kappa B kinases (IKKs) as their kinase activity was substantially reduced. 2. In addition, PDTC potentiated LPS-stimulated c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAP kinase) and MAP kinase-activated protein kinase-2 activity (the downstream target of p38 MAP kinase). 3. Another inhibitor of NFkappaB signalling, the serine protease inhibitor Nalphap-tosyl-L-lysine chloro-methylketone (TLCK), also inhibited LPS-stimulated IKK activity and potentiated JNK activity in response to LPS, suggesting that cross-talk may occur between the NFkappaB and stress-activated protein kinase pathways at the level of IKK or at a common point upstream. 4. Infection of RASMCs with an adenovirus encoding either inhibitory kappa Balpha or a dominant-negative IKKbeta potentiated LPS-stimulated JNK activity. 5. These studies therefore suggest that the loss of NFkappaB DNA-binding and resultant transcriptional activity, rather than the loss of IKK activity, is sufficient to cause an increase in JNK activity. This shows that either pharmacological or molecular inhibition of NFkappaB DNA-binding enhances JNK activation in vascular smooth muscle cells, an effect that may contribute to the pathophysiological effects of LPS.
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MESH Headings
- Adenoviridae/physiology
- Animals
- Aorta, Thoracic/cytology
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/enzymology
- Cells, Cultured
- Enzyme Activation/drug effects
- Enzyme Activation/physiology
- Enzyme Inhibitors/pharmacology
- JNK Mitogen-Activated Protein Kinases
- Lipopolysaccharides/pharmacology
- MAP Kinase Kinase 4
- MAP Kinase Signaling System/drug effects
- MAP Kinase Signaling System/physiology
- Male
- Mitogen-Activated Protein Kinase Kinases/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Protein Serine-Threonine Kinases/antagonists & inhibitors
- Protein Serine-Threonine Kinases/physiology
- Rats
- Rats, Sprague-Dawley
- NF-kappaB-Inducing Kinase
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Affiliation(s)
- Christopher J MacKenzie
- Department of Physiology and Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, 27 Taylor Street, Glasgow G4 0NR, Scotland.
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58
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Di Mari JF, Mifflin RC, Adegboyega PA, Saada JI, Powell DW. IL-1alpha-induced COX-2 expression in human intestinal myofibroblasts is dependent on a PKCzeta-ROS pathway. Gastroenterology 2003; 124:1855-65. [PMID: 12806619 DOI: 10.1016/s0016-5085(03)00399-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Intestinal myofibroblasts (IMFs) express cyclooxygenase 2 (COX-2) early on in polyp progression and respond to pro-inflammatory cytokines. Interleukin (IL)-1alpha induces COX-2 expression in IMF via mitogen-activated protein kinase (MAPK), protein kinase C (PKC), and nuclear factor kappa B (NF-kappaB)-dependent pathways. Because NF-kappaB activity can be mediated by PKC activation and reactive oxygen species (ROS) generation, we examined the relationship of these pathways to IL-1alpha-induced COX-2 expression. METHODS The effects of specific PKC inhibitors and antioxidants on PKC activation, ROS generation, and COX-2 expression were studied. RESULTS Immunoprecipitation/kinase (IPK) analysis showed that IL-1alpha increased PKC alpha, delta, and zeta activity 4.5-, 3.1-, and 2.6-fold, respectively, within 5 minutes. Single-cell fluorescence microscopy of 2',7'-dichlorofluorescin diacetate (DCF)-loaded cells showed that IL-1alpha increased ROS levels 2-fold within 15 minutes and this increase was inhibited by 10 micromol/L bisindolylymaleimide I (BIS), a pan-specific PKC inhibitor that also inhibits COX-2 expression. Chelerythrine chloride (CC) (0.5 micromol/L) inhibited classic and novel PKC activity, but not PKCzeta, and enhanced IL-1alpha-mediated ROS generation 4.0-fold and COX-2 expression 1.8-fold. The use of a PKCzeta pseudosubstrate prevented IL-1 from increasing ROS greater than control levels and abolished IL-1alpha-induced COX-2 expression. Small inhibitory RNA (siRNA) for PKCzeta confirmed its role in COX-2 expression. Antioxidants inhibited ROS generation and diminished IL-1alpha-induced COX-2 expression by 80%, without affecting PKC activation. Neither the PKC inhibitors nor the antioxidants prevented NF-kappaB-mediated transcription as determined by reporter gene analysis. CONCLUSIONS PKCzeta and threshold ROS generation are critical for IL-1alpha-induced COX-2 expression and act concomitantly with NF-kappaB translocation in IMF.
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Affiliation(s)
- John F Di Mari
- Department of Internal Medicine, 9.138 MRB, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1064, USA.
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59
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Preston TJ, Woodgett JR, Singh G. JNK1 activity lowers the cellular production of H2O2 and modulates the growth arrest response to scavenging of H2O2 by catalase. Exp Cell Res 2003; 285:146-58. [PMID: 12681294 DOI: 10.1016/s0014-4827(03)00015-6] [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: 01/01/2023]
Abstract
Hydrogen peroxide (H(2)O(2)) can interact with intracellular signaling pathways to regulate cell behavior. The c-Jun NH(2)-terminal kinase 1 (JNK1) signal, involved in diverse aspects of cellular functioning, is implicated as a cell sensor of redox stress. The growth-inhibitory effect of both high-level H(2)O(2) and H(2)O(2)-scavenging catalase treatments is accompanied by increased JNK1 activity. To investigate the role of this response in growth regulation, the JNK1 signal was increased by the introduction of ectopic HA-JNK1. HA-JNK1 expression correlated with increases in basal c-Jun phosphorylation in a dose-dependent manner. Transient expression of HA-JNK1 potentiated cell growth arrest by catalase; however, with stable expression a degree of resistance to this response was observed. Resistance was accompanied by a lowered endogenous production of H(2)O(2). Transient HA-JNK1 expression also reduced H(2)O(2) generation, and this effect was reversed by the JNK inhibitor SP600125. These results indicate that the JNK1 stress response contributes to growth inhibition by catalase treatment via inhibition of cellular H(2)O(2) production. Stable amplification of the JNK1 pathway leads to cellular adaptation to its signal, resulting in a diminished reliance upon H(2)O(2) for efficient growth.
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60
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Pluquet O, North S, Bhoumik A, Dimas K, Ronai Z, Hainaut P. The cytoprotective aminothiol WR1065 activates p53 through a non-genotoxic signaling pathway involving c-Jun N-terminal kinase. J Biol Chem 2003; 278:11879-87. [PMID: 12531896 DOI: 10.1074/jbc.m207396200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
WR1065 is an aminothiol with selective cytoprotective effects in normal cells compared with cancer cells. In a previous study (North, S., El-Ghissassi, F., Pluquet, O., Verhaegh, G., and Hainaut, P. (2000) Oncogene 19, 1206-1214), we have shown that WR1065 activates wild-type p53 in cultured cells. Here we show that WR1065 induces p53 to accumulate through escape from proteasome-dependent degradation. This accumulation is not prevented by inhibitors of phosphatidylinositol 3-kinases and is not accompanied by phosphorylation of Ser-15, -20, or -37, which are common targets of the kinases activated in response to DNA damage. Furthermore, WR1065 activates the JNK (c-Jun N-terminal kinase), decreases complex formation between p53 and inactive JNK, and phosphorylates p53 at Thr-81, a known site of phosphorylation by JNK. A dominant negative form of JNK (JNK-APF) reduces by 50% the activation of p53 by WR1065. Thus, WR1065 activates p53 through a JNK-dependent signaling pathway. This pathway may prove useful for pharmacological modulation of p53 activity through non-genotoxic mechanisms.
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Affiliation(s)
- Olivier Pluquet
- Unit of Molecular Carcinogenesis, International Agency for Research on Cancer, 69372 Lyon Cedex 08, France
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61
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Pluquet O, North S, Richard MJ, Hainaut P. Activation of p53 by the cytoprotective aminothiol WR1065: DNA-damage-independent pathway and redox-dependent modulation of p53 DNA-binding activity. Biochem Pharmacol 2003; 65:1129-37. [PMID: 12663048 DOI: 10.1016/s0006-2952(02)01655-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
WR1065 is an aminothiol with selective cytoprotective effects in normal compared to cancer cells, which is used to protect tissues against the damaging effect of radiation and chemotherapeutic drugs. WR1065 has been shown to induce wild-type p53 accumulation and activation in cultured cells, suggesting a role of p53 in cytoprotection. However, the molecular mechanisms by which WR1065 activates p53 remain unclear. Here, we demonstrated that p53 accumulation by WR1065 in MCF-7 cells did not result from the formation of DNA-damage as measured by DNA fragmentation and Comet assay, nor from oxidative stress as detected by measurement of glutathione levels, lipid peroxidation and reactive oxygen species production. p53 activation by WR1065 was not prevented by inhibition of PI-3 kinases, and was still detectable in MCF-7 cells stably transfected with the oncoprotein E6, which repressed p53 induction by DNA damage. These data provided evidence that WR1065 induces p53 by a pathway different than the one elicited by DNA-damage. Direct reduction by WR1065 of key cysteines in p53 may play an important role in this alternative pathway, as shown by the fact that WR1065 activated the redox-dependent, DNA-binding activity of p53 in vitro.
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Affiliation(s)
- Olivier Pluquet
- Unit of Molecular Carcinogenesis, International Agency for Research on Cancer, 69372 Lyon Cedex 08, France
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62
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Weizman N, Shiloh Y, Barzilai A. Contribution of the Atm protein to maintaining cellular homeostasis evidenced by continuous activation of the AP-1 pathway in Atm-deficient brains. J Biol Chem 2003; 278:6741-7. [PMID: 12496286 DOI: 10.1074/jbc.m211168200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Maintenance of genome stability is essential for keeping cellular homeostasis. The DNA damage response is a central component in maintaining genome integrity. Among of the most cytotoxic DNA lesions are double strand breaks (DSBs) caused by ionizing radiation or radiomimetic chemicals. ATM is missing or inactivated in patients with ataxia-telangiectasia. Ataxia-telangiectasia patients display a pleiotropic phenotype and suffer primarily from progressive ataxia caused by degeneration of cerebellar Purkinje and granule neurons. Additional features are immunodeficiency, genomic instability, radiation sensitivity, and cancer predisposition. Disruption of the mouse Atm locus creates a murine model of ataxia-telangiectasia that exhibits most of the clinical features of the human disease but very mild neuronal abnormality. The ATM protein is a multifunctional protein kinase, which serves as a master regulator of cellular responses to DSBs. There is growing evidence that ATM may be involved in addition to the DSB response in other processes that maintain processes in cellular homeostasis. For example, mounting evidence points to increased oxidative stress in the absence of ATM. Here we report that the AP-1 pathway is constantly active in the brains of Atm-deficient mice not treated with DNA damaging agents. A canonical activation (increased phosphorylation of mitogen-activated protein kinase kinase-4, c-Jun N-terminal kinase, and c-Jun) of the AP-1 pathway was found in Atm-deficient cerebra, whereas induction of the AP-1 pathway in Atm-deficient cerebella is likely to mediate elevated expression of c-Fos and c-Jun. Although Atm(+/+) mice are capable of responding to ionizing radiation by activating stress responses such as the AP-1 pathway, Atm-deficient mice display higher basal AP-1 activity but gradually lose their ability to activate AP-1 DNA-binding activity in response to ionizing radiation. Our results further demonstrate that inactivation of the ATM gene results in a state of constant stress.
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Affiliation(s)
- Nir Weizman
- Department of Neurobiochemistry, George S. Wise Faculty of Life Sciences, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 Israel
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63
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Chen YR, Han J, Kori R, Kong ANT, Tan TH. Phenylethyl isothiocyanate induces apoptotic signaling via suppressing phosphatase activity against c-Jun N-terminal kinase. J Biol Chem 2002; 277:39334-42. [PMID: 12171915 DOI: 10.1074/jbc.m202070200] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dietary isothiocyanates induce apoptosis in various cancer cell lines through a c-Jun N-terminal kinase (JNK)-dependent mechanism. We found that phenylethyl isothiocyanate (PEITC) was capable of inducing JNK activation and apoptosis in prostate cancer cell lines with distinct p53 statuses. PEITC induced JNK-mediated apoptotic signaling via a different pathway than that used by DNA-damaging agents, because genotoxicresistant LNCaP prostate cancer cells were equally sensitive to PEITC as parental LNCaP cells. PEITC did not induce significant MKK4 or MKK7 activation and did not activate JNK directly, suggesting that JNK and JNK upstream kinases are not primary targets of PEITC. The JNK dephosphorylation and inactivation rates were decreased in cells exposed to PEITC. Expression levels of M3/6, a JNK-specific phosphatase, were down-regulated by PEITC via a proteasome-dependent mechanism. Taken together, our data suggest that PEITC activates JNK through suppression of JNK dephosphorylation and that PEITC may be an alternative therapeutic agent for cancers that are resistant to genotoxic agents. This study also reveals that JNK phosphatases are potential targets for the development of novel cancer therapeutic agents.
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Affiliation(s)
- Yi-Rong Chen
- Department of Immunology, Baylor College of Medicine, Houston, Texas 77030, USA
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64
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Martindale JL, Holbrook NJ. Cellular response to oxidative stress: signaling for suicide and survival. J Cell Physiol 2002; 192:1-15. [PMID: 12115731 DOI: 10.1002/jcp.10119] [Citation(s) in RCA: 1672] [Impact Index Per Article: 76.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Reactive oxygen species (ROS), whether produced endogenously as a consequence of normal cell functions or derived from external sources, pose a constant threat to cells living in an aerobic environment as they can result in severe damage to DNA, protein, and lipids. The importance of oxidative damage to the pathogenesis of many diseases as well as to degenerative processes of aging has becoming increasingly apparent over the past few years. Cells contain a number of antioxidant defenses to minimize fluctuations in ROS, but ROS generation often exceeds the cell's antioxidant capacity, resulting in a condition termed oxidative stress. Host survival depends upon the ability of cells and tissues to adapt to or resist the stress, and repair or remove damaged molecules or cells. Numerous stress response mechanisms have evolved for these purposes, and they are rapidly activated in response to oxidative insults. Some of the pathways are preferentially linked to enhanced survival, while others are more frequently associated with cell death. Still others have been implicated in both extremes depending on the particular circumstances. In this review, we discuss the various signaling pathways known to be activated in response to oxidative stress in mammalian cells, the mechanisms leading to their activation, and their roles in influencing cell survival. These pathways constitute important avenues for therapeutic interventions aimed at limiting oxidative damage or attenuating its sequelae.
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Affiliation(s)
- Jennifer L Martindale
- Cell Stress and Aging Section, Laboratory of Cellular and Molecular Biology, National Institute on Aging, Baltimore, Maryland, USA
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65
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Abstract
Anticancer therapy is frequently efficient in early stages of the disease, whereas advanced tumors are usually resistant to the same treatments. The molecular basis for this change is not entirely understood. Many anticancer agents are DNA- or cytoskeleton-damaging drugs that show some specificity towards dividing cells. However, recent studies show that these agents also activate stress-signaling cascades that may play a role in eliciting the observed therapeutic effects. We discuss recent findings that suggest that induction of stress signaling in oncogenically transformed cells is integrated into apoptotic pathways. Reactive oxygen species (ROS) and stress-activated protein kinases (SAPKs), which are potentiated in recently transformed cells, emerge as key effectors of cell death. In advanced tumors, however, these agents are downregulated and, consequently, death signaling is suppressed. Such changes in ROS and SAPK activity levels during the course of tumor development may underlie the changes in responsiveness to anticancer therapy.
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Affiliation(s)
- Moran Benhar
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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Zhu JW, Yu BM, Ji YB, Zheng MH, Li DH. Upregulation of vascular endothelial growth factor by hydrogen peroxide in human colon cancer. World J Gastroenterol 2002; 8:153-7. [PMID: 11833093 PMCID: PMC4656609 DOI: 10.3748/wjg.v8.i1.153] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2001] [Revised: 09/11/2001] [Accepted: 09/27/2001] [Indexed: 02/06/2023] Open
Abstract
AIM To evaluate the effect of reactive oxygen species such as hydrogen peroxide on the progression of human colon cancer. METHODS Human colon carcinoma cell lines, LS174T and HCT8, were treated respectively with 10(-5), 10(-7) or 10(-9) mol x L(-1) hydrogen peroxide for 24h,and co-cultured with human endothelial cell line ECV-304. The migration of ECV-304 induced by cancer cells was calculated and the expression level of vascular endothelial growth factor in cancer cells was determined by RT-PCR analysis and ELISA. Dactinomycin of 1.5mg x L(-1) which could block transcription of cancer cells was applied to observing the effects of H(2)O(2) on transcriptional activity and the relative half-life of VEGF mRNA. Finally,to evaluate the effect of H2O2 on NF-kappaB activity in colon cancer cells, NF-kappaB in cytoplasm and nucleus of the cells were detected with FITC-tagged antibody and its presence in the nucleus(Fn) vs cytoplasm(Fc) was monitored by measuring the green fluorescence integrated over the nucleus by laser scanning cytometry(LSC). RESULTS Exogenouse hydrogen peroxide of low concentration increased the migration of endothelial cell induced by colon cancer cells. When cancer cells were treated with 10(-5) mol x L(-1) H2O2, the migration number of endothelial cells induced by LS174T cells was 203+/-70 and the number induced by HCT8 cells was 145+/-65. The two values were significantly higher than those treated with other concentrations of H2O2 (P<0.01). The expression of vascular endothelial growth factor in cancer cells, which could be blocked by dactinomycin, were increased to a certain degree, while the relative half-life of VEGF mRNA was not prolonged after treatment with hydrogen peroxide. The activity of NF-kappaB in colon cells rose after the cells were exposed to hydrogen peroxide for 24h. The Fn values in HCT8 cells were 91+/-13 (0 mol x L(-1) H2O2) and 149+/-40(10(-5) mol x L(-1) H2O2)(P<0.05), in LS174T cells were 127+/-35(0 mol x L(-1) H2O2) and 192+/-11(10(-5)mol x L(-1) H2O2) (P<0.05). It is similar to the case of VEGF expression in cancer cells. CONCLUSION Hydrogen peroxide increases vascular endothelial growth factor expression in colon cancer cells, and it is likely that reactive oxygen species such as hydrogen peroxide facilitates the development of colon cancer.
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Affiliation(s)
- Jian-Wei Zhu
- Shanghai Institute of Digestive Sugery,Ruijin Hospital,Shanghai Second Medical University,Shanghai 200025,China.
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