Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.11.10 (IKK)
4,900 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Overexpression of multidrug resistance genes and their encoded P-glycoproteins is a major mechanism for the development of multidrug resistance in cancer cells. The hepatocarcinogen 2-acetylaminofluorene (2-AAF) efficiently activates rat mdr1b expression. However, the underlying mechanisms are largely unknown. In this study, we demonstrated that a NF-kappa B site on the mdr1b promoter was required for this induction. Overexpression of antisense p65 and I kappa B alpha partially abolished the induction. We then delineated the pathway through which 2-AAF activates NF-kappa B. 2-AAF treatment led to the increase of intracellular reactive oxygen species (ROS) which causes activation of IKK kinases, degradation of I kappa B beta (but not I kappa B alpha), and increase in NF-kappa B DNA binding activity. Consistent with the idea that ROS may participate in mdr1b regulation, antioxidant N-acetylcysteine inhibited the induction of mdr1b by 2-AAF. Overproduction of a physiological antioxidant glutathione (GSH) blocked the activation of IKK kinase complex and NF-kappa B DNA binding. Based on these results, we conclude that 2-AAF up-regulates mdr1b through the generation of ROS, activation of IKK kinase, degradation of I kappa B beta, and subsequent activation of NF-kappa B. This is the first report that reveals the specific cis-elements and signaling pathway responsible for the induction of mdr1b by the chemical carcinogen 2-AAF.
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PMID:2-acetylaminofluorene up-regulates rat mdr1b expression through generating reactive oxygen species that activate NF-kappa B pathway. 1102 Mar 83

The role of p44/42 mitogen-activated protein kinase (MAPK), p38, and c-Jun NH(2)-terminal kinase (JNK) in tumor necrosis factor (TNF)-alpha-induced cyclooxygenase (COX)-2 expression was studied in NCI-H292 epithelial cells. TNF-alpha-mediated COX-2 expression and COX-2 promoter activity were inhibited by the MAPK kinase inhibitor PD98059 or the p38 inhibitor SB203580. Treatment of cells for 10 min with TNF-alpha resulted in activation of p44/42 MAPK, p38, and JNK. C2-ceramide (a cell-permeable ceramide analog), bacterial neutral sphingomyelinase (Smase; an enzyme that degrades sphingomyelin to ceramide), and N-oleoylethanolamine (a ceramidase inhibitor) all induced activation of MAPKs, COX-2 expression, nuclear factor (NF)-kappaB DNA-protein binding, and COX-2 promoter activity. The inactive analog, dihydro-C2-ceramide, had no effect. SMase- or C2-ceramide-induced COX-2 expression and COX-2 promoter activity were also inhibited by PD98059 or SB203580. Glutathione, a neutral SMase inhibitor, attenuated TNF-alpha- or SMase-induced activation of MAPKs, COX-2 expression, and COX-2 promoter activity. TNF-alpha- or C2-ceramide-induced COX-2 promoter activity was inhibited by the dominant negative mutant of extracellular signal-regulated kinase 2, p38, JNK, IkappaB kinase (IKK)1, or IKK2. IKK activity was stimulated by either TNF-alpha or C2-ceramide, and these effects were inhibited by PD98059 or SB203580. All these results suggest that, in NCI-H292 epithelial cells, activation of MAPKs by ceramide contributes to the TNF-alpha signaling that occurs downstream of neutral SMase activation and results in the stimulation of IKK1/2, and NF-kappaB in the COX-2 promoter, followed by initiation of COX-2 expression.
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PMID:Tumor necrosis factor-alpha-induced cyclooxygenase-2 expression via sequential activation of ceramide-dependent mitogen-activated protein kinases, and IkappaB kinase 1/2 in human alveolar epithelial cells. 1117 44

Curcumin (diferuloylmethane), an anti-inflammatory agent used in traditional medicine, has been shown to suppress cellular transformation, proliferation, invasion, angiogenesis, and metastasis through a mechanism not fully understood. Because several genes that mediate these processes are regulated by nuclear factor-kappaB (NF-kappaB), we have postulated that curcumin mediates its activity by modulating NF-kappaB activation. Indeed, our laboratory has shown previously that curcumin can suppress NF-kappaB activation induced by a variety of agents (J Biol Chem 270:24995-50000, 1995). In the present study, we investigated the mechanism by which curcumin manifests its effect on NF-kappaB and NF-kappaB-regulated gene expression. Screening of 20 different analogs of curcumin showed that curcumin was the most potent analog in suppressing the tumor necrosis factor (TNF)-induced NF-kappaB activation. Curcumin inhibited TNF-induced NF-kappaB-dependent reporter gene expression in a dose-dependent manner. Curcumin also suppressed NF-kappaB reporter activity induced by tumor necrosis factor receptor (TNFR)1, TNFR2, NF-kappaB-inducing kinase, IkappaB kinase complex (IKK), and the p65 subunit of NF-kappaB. Such TNF-induced NF-kappaB-regulated gene products involved in cellular proliferation [cyclooxygenase-2 (COX-2), cyclin D1, and c-myc], antiapoptosis [inhibitor of apoptosis protein (IAP)1, IAP2, X-chromosome-linked IAP, Bcl-2, Bcl-x(L), Bfl-1/A1, TNF receptor-associated factor 1, and cellular Fas-associated death domain protein-like interleukin-1beta-converting enzyme inhibitory protein-like inhibitory protein], and metastasis (vascular endothelial growth factor, matrix metalloproteinase-9, and intercellular adhesion molecule-1) were also down-regulated by curcumin. COX-2 promoter activity induced by TNF was abrogated by curcumin. We found that curcumin suppressed TNF-induced nuclear translocation of p65, which corresponded with the sequential suppression of IkappaBalpha kinase activity, IkappaBalpha phosphorylation, IkappaBalpha degradation, p65 phosphorylation, p65 nuclear translocation, and p65 acetylation. Curcumin also inhibited TNF-induced Akt activation and its association with IKK. Glutathione and dithiothreitol reversed the effect of curcumin on TNF-induced NF-kappaB activation. Overall, our results indicated that curcumin inhibits NF-kappaB activation and NF-kappaB-regulated gene expression through inhibition of IKK and Akt activation.
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PMID:Curcumin (diferuloylmethane) down-regulates expression of cell proliferation and antiapoptotic and metastatic gene products through suppression of IkappaBalpha kinase and Akt activation. 1621 5

Cigarette smoke-mediated oxidative stress induces an inflammatory response in the lungs by stimulating the release of proinflammatory cytokines. Chromatin remodeling due to histone acetylation and deacetylation is known to play an important role in transcriptional regulation of proinflammatory genes. The aim of this study was to investigate the molecular mechanism(s) of inflammatory responses caused by cigarette smoke extract (CSE) in the human macrophage-like cell line MonoMac6 and whether the treatment of these cells with the antioxidant glutathione (GSH) monoethyl ester, or modulation of the thioredoxin redox system, can attenuate cigarette smoke-mediated IL-8 release. Exposure of MonoMac6 cells to CSE (1% and 2.5%) increased IL-8 and TNF-alpha production vs. control at 24 h and was associated with significant depletion of GSH levels associated with increased reactive oxygen species release in addition to activation of NF-kappaB. Inhibition of IKK ablated the CSE-mediated IL-8 release, suggesting that this process is dependent on the NF-kappaB pathway. CSE also reduced histone deacetylase (HDAC) activity and HDAC1, HDAC2, and HDAC3 protein levels. This was associated with posttranslational modification of HDAC1, HDAC2, and HDAC3 protein by nitrotyrosine and aldehyde-adduct formation. Pretreatment of cells with GSH monoethyl ester, but not thioredoxin/thioredoxin reductase, reversed cigarette smoke-induced reduction in HDAC levels and significantly inhibited IL-8 release. Thus cigarette smoke-induced release of IL-8 is associated with activation of NF-kappaB via IKK and reduction in HDAC levels/activity in macrophages. Moreover, cigarette smoke-mediated proinflammatory events are regulated by the redox status of the cells.
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PMID:Cigarette smoke induces proinflammatory cytokine release by activation of NF-kappaB and posttranslational modifications of histone deacetylase in macrophages. 1647 65

The primary objective of this study was to evaluate the ability and mechanism of action of kaempferol, which is contained in extracts from Nelumbo nucifera, a well-known Oriental herb used in traditional medicine, with regard to the inhibition of iNOS and TNF-alpha expression in aged rat gingival tissues. We conducted an investigation into the age-related effects of kaempferol on reactive oxygen species (ROS) and GSH oxidative status in samples of aged gingival tissues. Western blotting was conducted in order to determine the expression of iNOS, TNF-alpha, p38 MAPK, NIK/IKK, p65 and IkappaBalpha in the sample tissues. Electrophoretic mobility shift assays (EMSA) were conducted in an effort to characterize the binding activities of NF-kappaB transcription factors in the aged rat gingival nuclear extracts. Our results indicate that kaempferol reduced ROS levels and augmented GSH levels in a dose-dependent manner in the aged gingival tissues. Kaempferol was shown to effect a significant reduction in iNOS and TNF-alpha protein levels, as compared to control gingival tissue samples. The results of Western blot analysis revealed that kaempferol treatment effected the reduction of iNOS and TNF-alpha expression, decreased nuclear p65 and increased cytosolic p65, down-regulation of Erk, p38, JNK and NIK/IKK expression. The EMSA results also indicated that kaempferol, when administered to the rat tissues, attenuated the NF-kappaB nuclear binding activity. Kaempferol may inhibit ROS generation via the inhibition of iNOS and TNF-alpha expression in aged gingival tissues, via the modulation of the NF-kappaB and mitogen-activated protein kinase (MAPK) pathways.
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PMID:Down-regulation of iNOS and TNF-alpha expression by kaempferol via NF-kappaB inactivation in aged rat gingival tissues. 1727 14

Reduced glutathione (GSH) plays a crucial role in hepatocyte function, and GSH depletion by diethyl maleate was shown previously to inhibit expression of NF-kappaB target genes induced by tumor necrosis factor alpha (TNFalpha) and sensitize primary cultured mouse hepatocytes to TNF-mediated apoptotic killing. Here we demonstrate in the same system that GSH depletion down-regulates TNF-induced NF-kappaB transactivation via two mechanisms, depending on the extent of the depletion. With moderate GSH depletion (approximately 50%), the down-regulation is IkappaB kinase (IKK)-independent and likely acts on NF-kappaB transcriptional activity because TNF-induced IKK activation, IkappaBalpha phosphorylation and degradation, NF-kappaB nuclear translocation, NF-kappaB DNA binding in vitro, and NF-kappaB subunit RelA(p65) recruitment to kappaB sites of target gene promoters all appear unaltered. On the other hand, with profound GSH depletion (approximately 80%), the down-regulation also is IKK-dependent, and a timeline is established linking the inhibition of polyubiquitination of receptor-interacting protein 1 in TNF receptor 1 complex to partial blockage of IKK activation, IkappaBalpha phosphorylation and degradation, and NF-kappaB nuclear translocation. Of note, pretreatment with antioxidant trolox protects against the inhibitory effect of profound GSH depletion on IKK activation and NF-kappaB nuclear translocation but fails to restore expression of NF-kappaB target genes, revealing both IKK-dependent and -independent inhibition. These findings provide new insights into the complex effects of oxidative stress and redox perturbations on the NF-kappaB pathway.
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PMID:Glutathione depletion down-regulates tumor necrosis factor alpha-induced NF-kappaB activity via IkappaB kinase-dependent and -independent mechanisms. 1769 92

S-adenosylmethionine (SAM), N-acetylcysteine (NAC) and quercetin exhibit a chemoprotective effect. Likely this effect is mediated by counteracting, oxidative stress and NF-kB activation. To test this hypothesis F344 rats were subjected to hepatocarcinogenesis with or without antioxidants. NAC decreased foci in number and area, SAM and quercetin decreased area. Lipid-peroxidation was decreased by antioxidants, but only SAM increased glutathione. SAM, in its regulation from IKK downwards, abolished the NF-kB activation. NAC decreased IKK and IkB-a phosphorylation, and Rel-A/p65 and NF-kB binding, though the last two were affected with less intensity compared to the NF-kB inhibitor. Quercetin decreased Rel-A/p65, without modifying upstream signalling. Although all antioxidants inhibited oxidative stress as shown by reduction of lipid peroxidation, not all exerted the same effect on NF-kB signalling pathway and only SAM increased GSH. The mechanisms exerted by SAM in the reduction of foci makes this compound a potential liver cancer therapeutic agent.
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PMID:The differential NF-kB modulation by S-adenosyl-L-methionine, N-acetylcysteine and quercetin on the promotion stage of chemical hepatocarcinogenesis. 1840 32

Although there has been considerable interest in the regulation of NFkappaB activation by glutathionylation, the possibility of IkappaB as a target for glutathionylation has not been investigated. We now report that Cys(189) of IkappaB alpha is a target for S-glutathionylation. This modification is reversed by thiols such as dithiothreitol and GSH. The glutathionylated IkappaB alpha appears to be significantly less susceptible than is native protein to phosphorylation by IkappaB kinase and casein kinase II, as well as to in vitro ubiquitination. This finding suggests that glutathionylation plays a regulatory role, presumably through structural alterations. HeLa cells treated with oxidant inducing GSH oxidation such as diamide showed the accumulation of glutathionylated IkappaB alpha. This mechanism suggests an alternative modification to the redox regulation of cysteine in IkappaB alpha and a possible mechanism in the regulation of NFkappaB activation.
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PMID:Glutathionylation regulates IkappaB. 1855 96

Nuclear factor-kappaB (NF-kappaB) is a pleiotropic transcription factor that generally enhances cellular resistance to apoptotic cell death. It has been shown to be constitutively active in some cancers and is being pursued as potential anticancer target. Sulfasalazine which is used clinically to treat Crohn's disease has emerged as a potential inhibitor of NF-kappaB and has shown promising results in two pre-clinical studies to target primary brain tumors, gliomas. Once digested, sulfasalazine is cleaved into sulfapyridine and 5-aminosalicylic acid (5-ASA; mesalamine) by colonic bacteria, and the latter, too, is reported to suppress NF-kappaB activity. We now show that glioma cells obtained from patient biopsies or glioma cell lines do not show significant constitutive NF-kappaB activation, unless exposed to inflammatory cytokines. This does not change when gliomas are implanted into the cerebrum of severe combined immun-deficient mice. Nevertheless, sulfasalazine but not its cleaved form 5-ASA caused a dose-dependent inhibition of glioma growth. This effect was entirely attributable to the inhibition of cystine uptake via the system x(c)(-) cystine-glutamate transporter. It could be mimicked by S-4-carboxy-phenylglycine (S-4-CPG) a more specific system x(c)(-) inhibitor, and lentiviral expression of a constitutively active form of IkappaB kinase b was unable to overcome the growth retarding effects of sulfasalazine or S-4-CPG. Both drugs inhibited cystine uptake causing a chronic depletion of intracellular GSH and consequently compromised cellular redox defense which stymied tumor growth. This data suggests that system x(c)(-) is a promising therapeutic target in gliomas and possibly other cancers and that it can be pharmacologically inhibited by Sulfasalazine, an FDA-approved drug.
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PMID:Sulfasalazine inhibits the growth of primary brain tumors independent of nuclear factor-kappaB. 1945 25

Parthenolide, a sesquiterpene lactone derived from the leaves of feverfew (Tanacetum parthenium), is considered a main bioactive component of this herb. Feverfew has been used orally or as an infusion for the treatment of migraine, arthritis, fever, and stomachache. Besides its anti-inflammatory and anti-migraine properties, parthenolide also shows anticancer activities in a variety of cell lines. It contains an alpha-methylene-gamma-lactone ring and an epoxide moiety which are able to interact with nucleophilic sites of biologically important molecules. Parthenolide modulates multiple targets, thereby contributing to its various in vitro and in vivo effects. Inhibition of NF-kappaB activity, constitutive in many types of cancers, via either interaction with IKK or more directly with the p65 subunit of NF-kappaB, is considered one of the main mechanisms of its action. In addition, inhibition of STAT and MAP kinase activities and the induction of sustained JNK activity as well as p53 activity via influencing MDM2 and HDAC1 levels lead to an increased susceptibility of cancer cells to chemo- and radiotherapy. At the epigenetic level, parthenolide reduces HDAC1 level and, by inhibiting DNMT2 activity, induces global hypomethylation of DNA, which can restore the expressions of some suppressor genes. Moreover, this compound reduces the cellular level of GSH in cancer cells, followed by ROS accumulation and apoptosis. A unique property of parthenolide is its ability to induce cell death mainly in cancer cells, while sparing healthy ones and it also protects normal cells from UVB and oxidative stress. More remarkably, it seems to have the potential to target some cancer stem cells. Its wide array of biological activity and low toxicity make parthenolide a very promising drug with multi-pharmacological potential, largely dependent on the cellular context.
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PMID:[Molecular mechanisms of parthenolide's action: Old drug with a new face]. 2035 59


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