Inhibition Of IkappaBalpha Phosphorylation Research Articles

Detecting modification of biomedical events using a deep parsing approach

BackgroundThis work describes a system for identifying event mentions in bio-molecular research abstracts that are either speculative (e.g. analysis of IkappaBalpha phosphorylation, where it is not specified whether phosphorylation did or did not occur) or negated (e.g. inhibition of IkappaBalpha phosphorylation, where phosphorylation did not occur). The data comes from a standard dataset created for the BioNLP 2009 Shared Task. The system uses a machine-learning approach, where the features used for classification are a combination of shallow features derived from the words of the sentences and more complex features based on the semantic outputs produced by a deep parser.MethodTo detect event modification, we use a Maximum Entropy learner with features extracted from the data relative to the trigger words of the events. The shallow features are bag-of-words features based on a small sliding context window of 3-4 tokens on either side of the trigger word. The deep parser features are derived from parses produced by the English Resource Grammar and the RASP parser. The outputs of these parsers are converted into the Minimal Recursion Semantics formalism, and from this, we extract features motivated by linguistics and the data itself. All of these features are combined to create training or test data for the machine learning algorithm.ResultsOver the test data, our methods produce approximately a 4% absolute increase in F-score for detection of event modification compared to a baseline based only on the shallow bag-of-words features.ConclusionsOur results indicate that grammar-based techniques can enhance the accuracy of methods for detecting event modification.

Enhanced anti-tumor effect of intra-peritoneal paclitaxel by nuclear factor-kappaB inhibition for peritoneal dissemination of gastric cancer in mice

INTRODUCTION: Intra-peritoneal administration (i.p.) of paclitaxel is a useful treatment for peritoneal dissemination of malignant tumors, but the therapeutic efficacy is limited. Chemoresistance due to paclitaxel-induced nuclear factor-kappaB (NF-kappaB) activation is an important cause of suboptimal therapeutic effect. We previously reported that nafamostat mesilate (FUT175), a synthetic serine protease inhibitor, inhibits NF-kappaB activation due to suppression of IkappaBalpha phosphorylation and promotes caspase-8-mediated apoptosis in pancreatic cancer. We hypothesized that addition of FUT175 to i.p. paclitaxel may enhance anti-tumor effect in peritoneal dissemination of gastric cancer.

Cyanidin-3-O-β-glucoside inhibits LPS-induced expression of inflammatory mediators through decreasing IκBα phosphorylation in THP-1 cells

As a common phytochemical, cyanidin 3-O-beta-glucoside (C3G) has a role in inhibiting inflammatory mediators; however, its mechanism of action remains unclear. The purpose of this study was to explore the effect of C3G on lipopolysaccharide (LPS)-stimulated TNFalpha and IL-6 expression in the human monocyte/macrophage cell line THP-1, and to explore the mechanisms involved. Differentiated THP-1 cells were treated with different concentrations of C3G (0.005, 0.05, 0.5,10 microM) in the absence or presence of 1 ng/mL LPS. mRNA expression levels were detected by real time PCR, and secretion of TNFalpha and IL-6, phosphorylated IkappaBalpha, and nuclear factor-kappa B (NF-kappaB) P65 were monitored by ELISA or Western blotting analysis. The role of an inhibitor of IkappaBalpha phosphorylation, BAY 11-7082, in C3G inhibition of LPS-induced cytokines expression was investigated. C3G (0.05-0.5 microM) treatment significantly inhibited LPS-stimulated TNFalpha and IL-6 mRNA expression and secretion of these proteins by THP-1 cells. Phosphorylation of IkappaBalpha and NF-kappaB nuclear translocation could be blocked by 0.5 microM C3G. BAY 11-7082 treatment abolished C3G-induced reduction of TNFalpha and IL-6. Our results suggest that C3G exerts its anti-inflammatory effect through inhibiting IkappaBalpha phosphorylation, thereby suppressing NF-kappaB activity in THP-1 cells.

Escin, a pentacyclic triterpene, chemosensitizes human tumor cells through inhibition of nuclear factor-kappaB signaling pathway.

Agents that can enhance tumor cell apoptosis and inhibit invasion have potential for the treatment of cancer. Here, we report the identification of escin, a pentacyclic triterpenoid from horse chestnut that exhibits antitumor potential against leukemia and multiple myeloma. Whether examined by esterase staining, phosphatidyl-serine staining, DNA breakage, or caspase-mediated poly(ADP-ribose) polymerase cleavage, escin potentiated tumor necrosis factor (TNF)-induced apoptosis but inhibited tumor cell invasion. This correlated with the down-regulation of bcl-2, cellular inhibitor of apoptosis protein-2, cyclin D1, cyclooxygenase-2, intercellular adhesion molecule-1, matrix metalloproteinase-9, and vascular endothelial growth factor, which are all regulated by the activation of the transcription factor NF-kappaB. When examined by electrophoretic mobility shift assay, the triterpenoid suppressed nuclear factor-kappaB (NF-kappaB) activation induced by TNF and other inflammatory agents, and this correlated with the inhibition of IkappaBalpha phosphorylation and degradation, inhibition of IkappaB kinase complex (IKK) activation, suppression of p65 phosphorylation and nuclear translocation, and abrogation of NF-kappaB-dependent reporter activity. Overall, our results demonstrate that escin inhibits activation of NF-kappaB through inhibition of IKK, leading to down-regulation of NF-kappaB-regulated cell survival and metastatic gene products and thus resulting in sensitization of cells to cytokines and chemotherapeutic agents.

Rg1 protects the MPP+-treated MES23.5 cells via attenuating DMT1 up-regulation and cellular iron uptake

Ginsenoside-Rg1 is one of the pharmacologically active component isolated from ginseng. Our previous study observed the protective effect of Rg1 on iron accumulation in the substantia nigra (SN) in 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine (MPTP)-treated Parkinson's disease (PD) mice. However, the mechanisms of this neuroprotective effect of Rg1 are unknown. In this study, we elucidated possible mechanisms for this effect using 1-methyl-4-phenylpyridinium (MPP(+))-treated MES23.5 cells. Previous study showed MPP+ treatment induced up-regulation of divalent metal transporter 1 without iron responsive element (DMT1-IRE) in MES23.5 cells. In the present study, we observed that pretreatment with Rg1 could inhibit MPP+-induced up-regulation of DMT1-IRE in MES23.5 cells. Up-regulation of DMT1-IRE by MPP+ treatment was associated with ROS production and translocation of nuclear factor-kappaB (NF-kappaB) to nuclei, both of which were significantly inhibited by Rg1 pretreatment. The role of ROS and NF-kappaB in the up-regulation of DMT1-IRE was supported by application of an antioxidant NAC and BAY 11-7082, an inhibitor of IkappaBalpha phosphorylation. Furthermore, we also showed Rg1 could decrease DMT1-mediated ferrous iron uptake and iron-induced cell damage by inhibiting the up-regulation of DMT1-IRE. These results indicate that Rg1 protected the MPP+-treated MES23.5 cells via attenuating DMT1-IRE up-regulation likely through inhibition of ROS-NF-kappaB pathway; Attenuation of DMT1-IRE expression decreased the iron influx and iron-induced oxidative stress.

Comprehensive evaluation of a novel nuclear factor‐κB inhibitor, quinoclamine, by transcriptomic analysis

The transcription factor nuclear factor-kappaB (NF-kappaB) has been linked to the cell growth, apoptosis and cell cycle progression. NF-kappaB blockade induces apoptosis of cancer cells. Therefore, NF-kappaB is suggested as a potential therapeutic target for cancer. Here, we have evaluated the anti-cancer potential of a novel NF-kappaB inhibitor, quinoclamine (2-amino-3-chloro-1,4-naphthoquinone). In a large-scale screening test, we found that quinoclamine was a novel NF-kappaB inhibitor. The global transcriptional profiling of quinoclamine in HepG2 cells was therefore analysed by transcriptomic tools in this study. Quinoclamine suppressed endogenous NF-kappaB activity in HepG2 cells through the inhibition of IkappaB-alpha phosphorylation and p65 translocation. Quinoclamine also inhibited induced NF-kappaB activities in lung and breast cancer cell lines. Quinoclamine-regulated genes interacted with NF-kappaB or its downstream genes by network analysis. Quinoclamine affected the expression levels of genes involved in cell cycle or apoptosis, suggesting that quinoclamine exhibited anti-cancer potential. Furthermore, quinoclamine down-regulated the expressions of UDP glucuronosyltransferase genes involved in phase II drug metabolism, suggesting that quinoclamine might interfere with drug metabolism by slowing down the excretion of drugs. This study provides a comprehensive evaluation of quinoclamine by transcriptomic analysis. Our findings suggest that quinoclamine is a novel NF-kappaB inhibitor with anti-cancer potential.

Allylmethylsulfide Down-Regulates X-Ray Irradiation-Induced Nuclear Factor-κB Signaling in C57/BL6 Mouse Kidney

Allylmethylsulfide (AMS), a volatile organosulfur derivative from garlic, has been shown to have radioprotective effects in radiation-challenged cell and animal models, but the mechanism of radioprotection is not well understood. To determine the mechanism of radioprotection in an in vivo model, we first verified the antioxidant capacity of AMS using 2,2'-azobis(2-amidinopropane) dihydrochloride-induced human embryonic kidney 293T cells by measuring reactive oxygen species generation, reduced glutathione, protein tyrosine kinase/protein tyrosine phosphatase balance, and nuclear factor-kappaB (NF-kappaB) protein levels. We then investigated the protective effects of AMS (55 and 275 micromol/kg, intraperitoneal treatment) on 15 Gy X-ray-irradiated mouse kidney. The results showed that AMS decreased the free radical-induced lipid peroxidation in mice exposed to X-rays. Moreover, the antioxidative AMS suppressed the activation of NF-kappaB and its dependent genes such as vascular cell adhesion molecule-1, inducible nitric oxide synthase, and cyclooxygenase-2 through inhibition of IkappaBalpha phosphorylation and activation of IkappaB kinase alpha/beta and mitogen-activated protein kinases (MAPKs). Based on these results, AMS may be a useful radioprotective agent by down-regulating the MAPKs and NF-kappaB signaling pathway that can be induced via X-ray irradiation.

Interleukin‐1β enhances nucleotide‐induced and α‐secretase‐dependent amyloid precursor protein processing in rat primary cortical neurons via up‐regulation of the P2Y2 receptor

The heterologous expression and activation of the human P2Y(2) nucleotide receptor (P2Y(2)R) in human 1321N1 astrocytoma cells stimulates alpha-secretase-dependent cleavage of the amyloid precursor protein (APP), causing extracellular release of the non-amyloidogenic protein secreted amyloid precursor protein (sAPPalpha). To determine whether a similar response occurs in a neuronal cell, we analyzed whether P2Y(2)R-mediated production of sAPPalpha occurs in rat primary cortical neurons (rPCNs). In rPCNs, P2Y(2)R mRNA and receptor activity were virtually absent in quiescent cells, whereas overnight treatment with the pro-inflammatory cytokine interleukin-1beta (IL-1beta) up-regulated both P2Y(2)R mRNA expression and receptor activity by four-fold. The up-regulation of the P2Y(2)R was abrogated by pre-incubation with Bay 11-7085, an IkappaB-alpha phosphorylation inhibitor, which suggests that P2Y(2)R mRNA transcript levels are regulated through nuclear factor-kappa-B (NFkappaB) signaling. Furthermore, the P2Y(2)R agonist Uridine-5'-triphosphate (UTP) enhanced the release of sAPPalpha in rPCNs treated with IL-1beta or transfected with P2Y(2)R cDNA. UTP-induced release of sAPPalpha from rPCNs was completely inhibited by pre-treatment of the cells with the metalloproteinase inhibitor TACE inhibitor (TAPI-2) or the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002, and was partially inhibited by the MAPK/extracellular signal-regulated kinase inhibitor U0126 and the protein kinase C inhibitor GF109203. These data suggest that P2Y(2)R-mediated release of sAPPalpha from cortical neurons is directly dependent on a disintegrin and metalloproteinase (ADAM) 10/17 and PI3K activity, whereas extracellular signal-regulated kinase 1/2 and PI3K activity may indirectly regulate APP processing. These results demonstrate that elevated levels of pro-inflammatory cytokines associated with neurodegenerative diseases, such as IL-1beta, can enhance non-amyloidogenic APP processing through up-regulation of the P2Y(2)R in neurons.

Hyperthermia induced NFκB mediated apoptosis in normal human monocytes

Conceptual approaches of heat-induced cytotoxic effects against tumor cells must address factors affecting therapeutic index, i.e., the relative toxicity for neoplastic versus normal tissues. Accordingly, we investigated the effect of hyperthermia treatment (HT) on the induction of DNA fragmentation, apoptosis, cell-cycle distribution, NFkappaB mRNA expression, DNA-binding activity, and phosphorylation of IkappaBalpha in the normal human Mono Mac 6 (MM6) cells. For HT, cells were exposed to 43 degrees C. FACS analysis showed a 48.5% increase in apoptosis, increased S-phase fraction, and reduced G2 phase fraction after 43 degrees C treatments. EMSA analysis showed a dose-dependent inhibition of NFkappaB DNA-binding activity after HT. This HT-mediated inhibition of NFkappaB was persistent even after 48 h. Immunoblotting analysis revealed dose-dependent inhibition of IkappaBalpha phosphorylation. Similarly, RPA analysis showed that HT persistently inhibits NFkappaB mRNA. These results demonstrate that apoptosis upon HT exposure of MM6 cells is regulated by IkappaBalpha phosphorylation mediated suppression of NFkappaB.

Synergistic chondroprotective effects of curcumin and resveratrol in human articular chondrocytes: inhibition of IL-1β-induced NF-κB-mediated inflammation and apoptosis

IntroductionCurrently available treatments for osteoarthritis (OA) are restricted to nonsteroidal anti-inflammatory drugs, which exhibit numerous side effects and are only temporarily effective. Thus novel, safe and more efficacious anti-inflammatory agents are needed for OA. Naturally occurring polyphenolic compounds, such as curcumin and resveratrol, are potent agents for modulating inflammation. Both compounds mediate their effects by targeting the NF-κB signalling pathway.MethodsWe have recently demonstrated that in chondrocytes resveratrol modulates the NF-κB pathway by inhibiting the proteasome, while curcumin modulates the activation of NF-κB by inhibiting upstream kinases (Akt). However, the combinational effects of these compounds in chondrocytes has not been studied and/or compared with their individual effects. The aim of this study was to investigate the potential synergistic effects of curcumin and resveratrol on IL-1β-stimulated human chondrocytes in vitro using immunoblotting and electron microscopy.ResultsTreatment with curcumin and resveratrol suppressed NF-κB-regulated gene products involved in inflammation (cyclooxygenase-2, matrix metalloproteinase (MMP)-3, MMP-9, vascular endothelial growth factor), inhibited apoptosis (Bcl-2, Bcl-xL, and TNF-α receptor-associated factor 1) and prevented activation of caspase-3. IL-1β-induced NF-κB activation was suppressed directly by cocktails of curcumin and resveratrol through inhibition of Iκκ and proteasome activation, inhibition of IκBα phosphorylation and degradation, and inhibition of nuclear translocation of NF-κB. The modulatory effects of curcumin and resveratrol on IL-1β-induced expression of cartilage specific matrix and proinflammatory enzymes were mediated in part by the cartilage-specific transcription factor Sox-9.ConclusionsWe propose that combining these natural compounds may be a useful strategy in OA therapy as compared with separate treatment with each individual compound.

Vanillin Inhibits Matrix Metalloproteinase-9 Expression through Down-Regulation of Nuclear Factor-κB Signaling Pathway in Human Hepatocellular Carcinoma Cells

Vanillin has been reported to exhibit anti-invasive and antimetastatic activities by suppressing the enzymatic activity of matrix metalloproteinase-9 (MMP-9). However, the underlying mechanism of anti-invasive activity remains unclear so far. Herein we demonstrate that vanillin reduced 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced MMP-9 gelatinolytic activity and suppressed cell invasion through the down-regulation of MMP-9 gene transcription in HepG2 cells. Vanillin significantly reduced the 6.6-fold invasive capacity of HepG2 cells in noncytotoxic concentrations, and this anti-invasive effect was concentration-dependent in the Matrigel invasion assay. Moreover, vanillin significantly suppressed the TPA-induced enzymatic activity of MMP-9 and decreased the induced mRNA level of MMP-9. Analysis of the transcriptional regulation indicated that vanillin suppressed MMP-9 transcription by inhibiting nuclear factor-kappaB (NF-kappaB) activity. Western blot further confirmed that vanillin inhibited NF-kappaB activity through the inhibition of IkappaB-alpha phosphorylation and degradation. In conclusion, vanillin might be a potent antiinvasive agent that suppresses the MMP-9 enzymatic activity via NF-kappaB signaling pathway.

Retracted: A modified version of galectin‐9 induces cell cycle arrest and apoptosis of Burkitt and Hodgkin lymphoma cells

The identification of galectin-9 as a ligand for T-cell immunoglobulin- and mucin-domain-containing molecule-3 (Tim-3), expressed on T-helper type-1 (Th1) cells, has established the Tim-3-galectin-9 pathway as a regulator of Th1 immunity. Whereas there is compelling evidence for the effects of galectin-9 on T-cell fate, limited information is available on the impact of galectin-9 on B lymphocytes. We found that protease-resistant galectin-9, hG9NC(null), but not galectin-1 or -8, prevented cell growth of malignant B cells, such as Burkitt lymphoma (BL) and Hodgkin lymphoma (HL). beta-galactoside binding was essential for galectin-9-induced cell growth suppression. hG9NC(null) induced cell cycle arrest by reducing the expression of cyclin D1, D2, B1, Cdk4, Cdc25C and c-Myc, and apoptosis by reducing the expression of XIAP, c-IAP2 and survivin. Most of the genes that encode these proteins are regulated by nuclear factor-kappaB (NF-kappaB), and constitutive activation of NF-kappaBeta is a common characteristic of both types of malignancies. hG9NC(null) inhibited IkappaBalpha phosphorylation, resulting in suppression of NF-kappaB. AP-1 has also been implicated in the control of cell survival. hG9NC(null) inhibited the expression of JunD, resulting in the suppression of AP-1. Our results suggest that hG9NC(null) is a potentially suitable agent for the management of BL and HL.

Tanshinone IIA from Salvia miltiorrhiza BUNGE inhibits human aortic smooth muscle cell migration and MMP‐9 activity through AKT signaling pathway

Smooth muscle cell (SMC) migration plays an important role in normal angiogenesis and is relevant to disease-related vascular remodeling in conditions such as brain arteriovenous malformations, pulmonary hypertension, arteriosclerosis, and restenosis after angioplasty. In this present study, we showed that tanshinone IIA, the major lipid-soluble pharmacological constituent of Salvia miltiorrhiza BUNGE, inhibits human aortic smooth muscle cell (HASMC) migration and MMP-9 activity. Tanshinone IIA significantly inhibited IkappaBalpha phosphorylation and p65 nuclear translocation through inhibition of AKT phosphorylation. Tanshinone IIA inhibited TNF-alpha-induced ERK and c-jun phosphorylation, but not other MAPKs such as JNK and p38. Tanshinone IIA also inhibited NF-kappaB and AP-1 DNA-binding. Moreover, tanshinone IIA inhibited the migration of TNF-alpha-induced HASMCs. Our results provide evidence that tanshinone IIA has multiple effects in the inhibition of HASMC migration and may offer a therapeutic approach to block HASMC migration.

Dexamethasone Inhibits Interleukin-1β-Induced Corneal Neovascularization: Role of Nuclear Factor-κB-Activated Stromal Cells in Inflammatory Angiogenesis

Dexamethasone, a synthetic corticosteroid, is widely used as a potent anti-inflammatory drug in various diseases including corneal angiogenesis. However, dexamethasone's impact on interleukin (IL)-1beta-dependent inflammatory angiogenesis is unknown. Here, we show that dexamethasone inhibits IL-1beta-induced neovascularization and the expression of the angiogenesis-related factors, vascular endothelial growth factor-A, KC, and prostaglandin E(2) in the mouse cornea 2 days after IL-1beta implantation. IL-1beta caused IkappaB-alpha phosphorylation in corneal stromal cells but not in infiltrated CD11b(+) cells 2 days after IL-1beta implantation. In contrast, both cell types were positive for phosphorylated IkappaB-alpha 4 days after IL-1beta implantation. Dexamethasone significantly inhibited IkappaB-alpha phosphorylation 2 and 4 days after IL-1beta implantation. Furthermore, dexamethasone inhibited IL-1beta-induced expression of vascular endothelial growth factor-A, KC, and prostaglandin E(2), and signaling of nuclear factor (NF)-kappaB in corneal fibroblasts in vitro. A selective NF-kappaB inhibitor attenuated IL-1beta-induced corneal angiogenesis. These findings suggest that NF-kappaB activation in the corneal stromal cells is an important early event during IL-1beta-induced corneal angiogenesis and that dexamethasone inhibits IL-1beta-induced angiogenesis partially via blocking NF-kappaB signaling.

Mechanisms of synthetic serine protease inhibitor (FUT‐175)‐mediated cell death

Constitutive activation of nuclear factor-kappaB (NF-kappaB) is a frequent molecular alteration in pancreatic cancer and a number of studies have suggested that constitutive NF-kappaB activity plays a key role in the aggressive behavior of this disease. In an attempt to identify an effective therapeutic agent for pancreatic cancer, the authors studied the role of FUT-175, a synthetic serine protease inhibitor, in the inhibition of NF-kappaB activation and the induction of apoptotic responses. To examine the effect of FUT-175 on the inhibition of NF-kappaB and the induction of apoptosis in pancreatic cancer cell lines, Western and Northern blot analyses, electromobility shift (EMSA), luciferase reporter gene, DNA fragmentation, immunoprecipitation, in vitro kinase, small interfering RNA (siRNA), and chromatin immunoprecipitation (ChIP) assays were performed. In a time-dependent and dose-dependent manner, FUT-175 inhibited IkappaBalpha phosphorylation and NF-kappaB activation, thereby inhibiting the antiapoptotic activity of NF-kappaB. Simultaneously, FUT-175 up-regulated the expression of tumor necrosis factor receptor-1 (TNFR1), which in turn activated the proapoptotic caspase-8 and Bid pathways and induced apoptosis in pancreatic cancer cells. FUT-175-induced activation of Fas-associated death domain (FADD) and caspase-8 was suppressed by RNA interference-mediated inhibition of TNFR1 expression. Furthermore, expression of the transcription factor PEA3 was up-regulated by FUT-175 and was involved in FUT-175-mediated TNFR1 expression. These results suggested a possible mechanism by which FUT-175 may disrupt interconnected signaling pathways by both suppressing the NF-kappaB antiapoptotic activity and inducing TNFR-mediated apoptosis. Supported by this unique function as a NF-kappaB inhibitor and apoptosis inducer, this well-established synthetic serine protease inhibitor with as-of-yet poorly understood mechanisms of actions appears to be a potentially therapeutic agent for pancreatic cancer.

Basic fibroblast growth factor stimulates fibronectin expression through phospholipase C γ, protein kinase C α, c‐Src, NF‐κB, and p300 pathway in osteoblasts

Fibronectin (Fn) is involved in early stages of bone formation and basic fibroblast growth factor (bFGF) is an important factor regulating osteogenesis. bFGF increased Fn expression, which was attenuated by phosphatidylinositol phospholipase inhibitor (U73122), protein kinase C inhibitor (GF109203X), Src inhibitor (PP2), NF-kappaB inhibitor (PDTC), IkappaBalpha phosphorylation inhibitor (Bay 117082), or IkappaB protease inhibitor (TPCK). bFGF-induced increase of Fn-luciferase activity was antagonized by cells transfected with Fn construct without NF-kappaB regulatory site. Stimulation of osteoblasts with bFGF activated IkappaB kinase alpha/beta (IKK alpha/beta) and increased IkappaBalpha phosphorylation, IkappaBalpha degradation, p65 and p50 translocation from the cytosol to the nucleus, the formation of an NF-kappaB-specific DNA-protein complex and kappaB-luciferase activity. bFGF-mediated an increase of IKKalpha/beta activity and DNA-binding activity was inhibited by U73122, GF109203X, or PP2. The binding of p65 to the NF-kappaB element, as well as the recruitment of p300 and the enhancement of p50 acetylation on the Fn promoter was enhanced by bFGF. Overexpression of constitutively active FGF receptor 2 (FGFR2) increased Fn-luciferase activity, which was inhibited by co-transfection with dominant negative (DN) mutants of PLCgamma2, PKCalpha, c-Src, IKKalpha, or IKKbeta. Our results suggest that bFGF increased Fn expression in rat osteoblasts via the FGFR2/PLCgamma2/PKCalpha/c-Src/NF-kappaB signaling pathway.

A Selective Small Molecule IκB Kinase β Inhibitor Blocks Nuclear Factor κB-Mediated Inflammatory Responses in Human Fibroblast-Like Synoviocytes, Chondrocytes, and Mast Cells

IkappaB kinase (IKK) beta is essential for inflammatory cytokine-induced activation of nuclear factor kappaB (NF-kappaB). NF-kappaB plays a pivotal role in the function of major cell types that contribute to the pathophysiological process of rheumatoid arthritis (RA). Here, we report the mechanism and the effect of the IKKbeta inhibitor N-(6-chloro-7-methoxy-9H-beta-carbolin-8-yl)-2-methylnicotinamide (ML120B), a beta-carboline derivative, on NF-kappaB signaling and gene activation in RA-relevant cell systems. ML120B is a potent, selective, reversible, and ATP-competitive inhibitor of IKKbeta with an IC50 of 60 nM when evaluated in an IkappaBalpha kinase complex assay. ML120B does not inhibit other IKK isoforms or a panel of other kinases. ML120B concentration-dependently inhibits tumor necrosis factor alpha (TNFalpha)-stimulated NF-kappaB signaling via inhibition of IkappaBalpha phosphorylation, degradation, and NF-kappaB translocation into the nucleus. For the first time, we have demonstrated that in human fibroblast-like synoviocytes, TNFalpha- or interleukin (IL)-1beta-induced monocyte chemoattractant protein-1 regulated on activation, normal T cell expressed and secreted and production is IKKbeta-dependent. In addition, for the first time, we have demonstrated that lipopolysaccharide- or peptidoglycan-induced cytokine production in human cord blood-derived mast cells is IKKbeta-dependent. In addition, in human chondrocytes, ML120B inhibited IL-1beta-induced matrix metalloproteinase production with an IC50 of approximately 1 microM. ML120B also blocked IL-1beta-induced prostaglandin E2 production. In summary, ML120B blocked numerous NF-kappaB-regulated cell responses that are involved in inflammation and destructive processes in the RA joint. Our findings support the evaluation of IKKbeta inhibitors as anti-inflammatory agents for the treatment of RA.

Induction of Interleukin-13 Receptor Expression Via Nuclear Factor-Kappab Activation in Human Tonsillar B Cells

RATIONALE: The ability of CD40 signaling to regulate B cell growth, survival, differentiation, and Ig class switching involves changes in gene expression. CD40 ligation activates the Rel/NF-κB transcription factors, which are major regulators of immune and inflammatory responses and potentially activates both type 1 (p105/p50) and type 2 (p100/p52) NF-κB activation pathways. Using primary B cells, we investigated the contribution of NFκb activation on CD40 mediated IL-13 receptor expression, using BAY11, an IkappaB-alpha phosphorylation inhibitor.

Curcumin Suppresses Interleukin 1β-Mediated Microsomal Prostaglandin E Synthase 1 by Altering Early Growth Response Gene 1 and Other Signaling Pathways

Curcumin (diferuloylmethane) is one of the phytophenolic compounds found in the turmeric plant with anti-inflammatory and anticarcinogenic activities. One possible mechanism for these activities is the inhibition of prostaglandin (PG) E(2) formation. In this study and other reports, curcumin suppresses interleukin-1beta-induced formation of prostaglandin E(2) in a concentration-dependent manner. Interleukin-1beta-induced microsomal prostaglandin E synthase 1 (mPGES-1) and cyclooxygenase-2 were attenuated by curcumin at the protein and mRNA levels, but a more dramatic inhibition of mPGES-1 expression was observed at lower concentrations of curcumin in A549 human lung epithelial cells. The inhibition of mPGES-1 expression by curcumin shifted the arachidonic acid profile from PGE(2) to PGF(2alpha) and 6-keto-PGF(1alpha) as major metabolites. The expression of early growth response gene 1 (EGR-1), a key transcription factor of cytokine-induced mPGES-1, was inhibited by curcumin. Incubation with siRNA for EGR-1 inhibited interleukin (IL)-1beta-induced mPGES-1, and the controlled expression of EGR-1 increased the mPGES-1 expression. Several proinflammatory signaling molecules, such as nuclear factor kappaB (NF-kappaB) and mitogen-activated protein kinases, are also known to affect curcumin-regulated gene expression. Curcumin inhibited IkappaBalpha phosphorylation and degradation and thus reduced the expression of mPGES-1. Curcumin suppressed cytokine-induced mPGES-1 by inhibiting phosphorylation of Jun N-terminal kinase (JNK)1/2. However, EGR-1 expression was suppressed by lower concentrations of curcumin, as compared with JNK1/2 and IkappaBalpha. These results indicate that curcumin inhibits IL-1beta-induced PGE(2) formation by inhibiting the expression of mPGES-1 that is mediated by suppression of EGR-1 expression as well as NF-kappaB and JNK1/2.

Activation of NF-κB by Extracellular Matrix Is Involved in Spreading and Glucose-stimulated Insulin Secretion of Pancreatic Beta Cells

Laminin-5-rich extracellular matrix derived from 804G cells (804G-ECM) engages beta1 integrins to induce spreading, improve glucose-stimulated insulin secretion (GSIS), and increase survival of pancreatic beta cells. The present study examines whether 804G-ECM activates the transcriptional activity of NF-kappaB and the involvement of NF-kappaB in those effects of 804G-ECM on pancreatic beta cells. 804G-ECM induces nuclear translocation and the DNA binding activity of the p65 subunit of NF-kappaB. 804G-ECM-induced nuclear translocation of NF-kappaB was weak as compared with that induced by interleukin-1beta. Transient 804G-ECM-induced DNA binding activity of NF-kappaB (peak at 2 h) and overexpression of NF-kappaB target genes IkappaB alpha and NF-kappaB1(p105) (peak at 4 h) were observed. When NF-kappaB was inhibited by an inhibitor of IkappaB alpha phosphorylation (Bay 11-7082) or by a recombinant adenovirus expressing the nonphosphorylatable form of IkappaB alpha, 804G-ECM-induced cell spreading and actin cytoskeleton organization were reduced. GSIS from cells on 804G-ECM was inhibited 5-fold, whereas cell survival was not affected. In summary, the results indicate that 804G-ECM induces a transient and moderate NF-kappaB activity. This study shows for the first time that ECM-induced NF-kappaB activity is necessary in maintaining GSIS, although it does not affect survival of pancreatic beta cells. The effects of ECM-induced NF-kappaB activity contrast with the deleterious effects of cytokine-induced NF-kappaB activity. It is proposed that transient and moderate NF-kappaB activity is essential for proper function of the pancreatic beta cell.