Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sulindac sulfone (exisulind), although a nonsteroidal anti-inflammatory drug derivative, induces apoptosis in tumor cells by a mechanism that does not involve cyclooxygenase inhibition. SW480 colon tumor cells contain guanosine 3',5'-monophosphate (cGMP) phosphodiesterase (PDE) isoforms of the PDE5 and PDE2 gene families that are inhibited by exisulind and new synthetic analogues. The analogues maintain rank order of potency for PDE inhibition, apoptosis induction, and growth inhibition. A novel mechanism for exisulind to induce apoptosis is studied involving sustained increases in cGMP levels and cGMP-dependent protein kinase (PKG) induction not found with selective PDE5 or most other PDE inhibitors. Accumulated beta-catenin, shown to be a substrate for PKG, is decreased by exisulind, suggesting a mechanism to explain apoptosis induction in neoplastic cells harboring adenomatous polyposis coli gene mutations.
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PMID:Exisulind induction of apoptosis involves guanosine 3',5'-cyclic monophosphate phosphodiesterase inhibition, protein kinase G activation, and attenuated beta-catenin. 1091 34

There is increasing evidence suggesting that chondrocyte death may contribute to the progression of osteoarthritis (OA). This study focused on the characterization of signaling cascade during NO-induced cell death in human OA chondrocytes. The NO generator, sodium nitroprusside (SNP), promoted chondrocyte death in association with DNA fragmentation, caspase-3 activation, and down-regulation of Bcl-2. Both caspase-3 inhibitor Z-Asp(OCH3)-Glu(OCH3)-Val-Asp(OCH3)-CH2F and caspase-9 inhibitor Z-Leu-Glu(OCH3)-His-Asp(OCH3)-CH2F prevented the chondrocyte death. Blocking the mitogen-activated protein kinase pathway by the mitogen-activated protein kinase kinase 1/2 inhibitor PD98059 or p38 kinase inhibitor SB202190 also inhibited the SNP-mediated cell death, suggesting possible requirements of both extracellular signal-related protein kinase 1/2 and p38 kinase for the NO-induced cell death. Furthermore, the selective inhibition of cyclooxygenase (COX)-2 by NS-398 or the inhibition of COX-1/COX-2 by indomethacin blocked the SNP-induced cell death. The chondrocyte death induced by SNP was associated with an overexpression of COX-2 protein (as determined by Western blotting) and an increase in PGE2 release. PD98059 and SB202190, but neither Z-DEVD FMK nor Z-LEHD FMK completely inhibited the SNP-mediated PGE2 production. Analysis of interactions between PGE2 and the cell death showed that PGE2 enhanced the SNP-mediated cell death, whereas PGE2 alone did not induce the chondrocyte death. These data indicate that NO-induced chondrocyte death signaling includes PGE2 production via COX-2 induction and suggest that both extracellular signal-related protein kinase 1/2 and p38 kinase pathways are upstream signaling of the PGE2 production. The results also demonstrate that exogenous PGE2 may sensitize human OA chondrocytes to the cell death induced by NO.
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PMID:The induction of cell death in human osteoarthritis chondrocytes by nitric oxide is related to the production of prostaglandin E2 via the induction of cyclooxygenase-2. 1097 59

Endothelins (ETs) are a family of 21-amino acid hypertensive peptides, which together with their receptors ETA and ETB are expressed in human adrenal cortex. Evidence has been provided that ETs exert a potent secretagogue effect on human adrenocortical cells, acting through both ETA and ETB receptors. Therefore, it seemed worthwhile to study the signaling cascades mediating the cortisol secretagogue effect of the two receptor subtypes. Normal adrenal glands were obtained from consenting patients undergoing unilateral nephrectomy with ipsilateral adrenalectomy for renal cancer. Dispersed zona fasciculata-reticularis (ZF/R) cells were obtained by collagenase digestion and mechanical disaggregation. The selective activation of ETA and ETB receptors was obtained by exposing dispersed cells to ET-1 plus the ETB receptor antagonist BQ-788 and to the selective ETB receptor agonist BQ-3020, respectively. ETA and ETB receptors about equally contributed to the cortisol response of dispersed ZF/R cells to ETs. The phospholipase (PL) C inhibitor U-73122 abolished ETA-mediated secretory response, but only partially prevented the ETB-mediated one. The phosphatidylinositol 3-kinase inhibitor wortmannin and the protein kinase (PK) C inhibitor calphostin-C significantly blunted the secretory responses ensuing from the activation of both receptor subtypes, while the Ca(2+)-channel blocker nifedipine was ineffective. The ETB receptor-, but not the ETA receptor-mediated cortisol response was partially reversed by the cyclooxygenase (COX) inhibitor indomethacin, which when added together with U-73122 abolished it. The inhibitors of adenylate cyclase, PKA, tyrosine kinase and lipoxygenase did not affect the secretory response to the activation of either receptor subtype. ETA-receptor activation raised inositol triphosphate (IP3) production from dispersed ZF/R cells, while ETB-receptor stimulation enhanced both IP3 and prostaglandin-E(2) production. Collectively, our findings indicate that ETs stimulate cortisol secretion from human ZF/R cells, acting through ETA receptors exclusively coupled with PLC/PKC-dependent pathway and ETB receptors coupled with both PLC/PKC- and COX-dependent cascades.
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PMID:Signaling pathways involved in the A and B receptor-mediated cortisol secretagogue effect of endothelins in the human adrenal cortex. 1117 11

Compelling evidence indicates that endothelins (ETs) stimulates aldosterone secretion from rat zona glomerulosa (ZG) cells, acting through the ETB receptor subtype. We have investigated the mechanisms transducing the aldosterone secretagogue signal elicited by the pure activation of ETB receptors. Aldosterone response of dispersed rat ZG cells to the selective ETB-receptor agonist BQ-3020 was not affected by inhibitors of adenylate cyclase/protein kinase (PK)A, tyrosine kinase-, mitogen-activated PK-, cyclooxygenase- and lipoxygenase-dependent pathways. In contrast, the inhibitor of phospholipase C (PLC) U-73122 abrogated, and the inhibitors of PKC, phosphatidylinositol trisphosphate (IP(3))-kinase and calmodulin (calphostin-C, wortmannin and W-7, respectively) partially prevented aldosterone response to BQ-3020. When added together, calphostin-C and wortmannin or W-7 abolished the secretagogue effect of BQ-3020. BQ-3020 elicited a marked increase in the intracellular Ca2+ concentration ([Ca2+]i) in dispersed rat ZG cells, and the effect was abolished by the Ca(2+)-release inhibitor dantrolene. The Ca2+ channel blocker nifedipine affected neither aldosterone nor Ca2+ response to BQ-3020. Collectively, our findings suggest that (1) ETs stimulate aldosterone secretion from rat ZG cells through the activation of PLC-coupled ETB receptors; (2) PLC stimulation leads to the activation of PKC and to the rise in [Ca2+]i with the ensuing activation of calmodulin; and (3) the increase in [Ca2+] is exclusively dependent on the stimulation of IP(3)-dependent Ca2+ release from intracellular stores.
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PMID:Endothelins stimulate aldosterone secretion from dispersed rat adrenal zona glomerulosa cells, acting through ETB receptors coupled with the phospholipase C-dependent signaling pathway. 1117 5

Pregnancy is established in ruminants through inhibitory actions of interferon (IFN)-tau on the release of prostaglandin F2alpha (PGF), which allows the corpus luteum to survive and continue to produce progesterone. Experiments were designed to 1) delineate the signal transduction pathway coordinating the synthesis of PGF, 2) determine how rapidly recombinant bovine (rb) IFN-tau attenuated phorbol ester (PDBu)-induced secretion of PGF, and 3) establish the site at which rbIFN-tau attenuates the secretion of PGF in cultured bovine endometrial (BEND) cells. BEND cells were untreated (control) or treated for 5, 10, 60, 180, or 300 min with PDBu (100 ng/ml), rbIFN-tau (50 or 500 ng/ml), PDBu + rbIFN-tau, or PDBu + PD98059 (MEK-1 inhibitor; 50 microM). Secretion of PGF was induced (P < 0.0001) by PDBu within 180 min, but induction was inhibited 74% by the addition of rbIFN-tau (P < 0.0001) and was ablated completely by PD98059. Parallel results were obtained for cyclooxygenase (COX)-2 protein expression. PDBu induced (P < 0.05) activation of the Raf-1/MEK-1/ERK-1/2 pathway, which was obligatory for the expression of COX-2 and secretion of PGF but was not altered by cotreatment with rbIFN-tau. PDBu induced (P < 0.05) transcription of c-jun and c-fos mRNAs within 30 min; induction was inhibited (P < 0.05) by cotreatment with PD98059 but not by cotreatment with rbIFN-tau. Treatment of BEND cells with rbIFN-tau also did not attenuate PDBu-induced degradation of IkappaBalpha, suggesting that the IkappaBalpha/NFkappaB pathway is not a site of IFN-tau inhibition of PGF. However, rbIFN-tau did block transcription of the COX-2 gene induced by PDBu within 30 min. In conclusion, COX-2 expression and PGF secretion induced by PDBu is mediated through the Raf-1/MEK-1/ERK-1/2 pathway, but this pathway is not disrupted by rbIFN-tau. Because rbIFN-tau inhibits COX-2 mRNA within 30 min, we hypothesized that transcription factors activated by rbIFN-tau rapidly and directly attenuate COX-2 gene expression, thereby suppressing secretion of PGF.
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PMID:Interferon-tau suppresses prostaglandin F2alpha secretion independently of the mitogen-activated protein kinase and nuclear factor kappa B pathways. 1120 14

The spinal cord is one of the sites where non-steroidal anti-inflammatory drugs (NSAIDs) act to produce analgesia and antinociception. Expression of cyclooxygenase(COX)-1 and COX-2 in the spinal cord and primary afferents suggests that NSAIDs act here by inhibiting the synthesis of prostaglandins (PGs). Basal release of PGD(2), PGE(2), PGF(2alpha) and PGI(2) occurs in the spinal cord and dorsal root ganglia. Prostaglandins then bind to G-protein-coupled receptors located in intrinsic spinal neurons (receptor types DP and EP2) and primary afferent neurons (EP1, EP3, EP4 and IP). Acute and chronic peripheral inflammation, interleukins and spinal cord injury increase the expression of COX-2 and release of PGE(2) and PGI(2). By activating the cAMP and protein kinase A pathway, PGs enhance tetrodotoxin-resistant sodium currents, inhibit voltage-dependent potassium currents and increase voltage-dependent calcium inflow in nociceptive afferents. This decreases firing threshold, increases firing rate and induces release of excitatory amino acids, substance P, calcitonin gene-related peptide (CGRP) and nitric oxide. Conversely, glutamate, substance P and CGRP increase PG release. Prostaglandins also facilitate membrane currents and release of substance P and CGRP induced by low pH, bradykinin and capsaicin. All this should enhance elicitation and synaptic transfer of pain signals in the spinal cord. Direct administration of PGs to the spinal cord causes hyperalgesia and allodynia, and some studies have shown an association between induction of COX-2, increased PG release and enhanced nociception. NSAIDs diminish both basal and enhanced PG release in the spinal cord. Correspondingly, spinal application of NSAIDs generally diminishes neuronal and behavioral responses to acute nociceptive stimulation, and always attenuates behavioral responses to persistent nociception. Spinal application of specific COX-2 inhibitors sometimes diminishes behavioral responses to persistent nociception.
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PMID:Prostaglandins and cyclooxygenases [correction of cycloxygenases] in the spinal cord. 1127 57

Fatty acids have been postulated to regulate uncoupling protein (UCP) gene expression in skeletal muscle in vivo. We have identified, at least in part, the mechanism by which polyunsaturated fatty acids increase UCP-2 expression in primary culture of human muscle cells. omega-6 fatty acids and arachidonic acid induced a 3-fold rise in UCP-2 mRNA levels possibly through transcriptional activation. This effect was prevented by indomethacin and mimicked by prostaglandin (PG) E(2) and carbaprostacyclin PGI(2), consistent with a cyclooxygenase-mediated process. Incubation of myotubes for 6 h with 100 micrometer arachidonic acid resulted in a 150-fold increase in PGE(2) and a 15-fold increase in PGI(2) in the culture medium. Consistent with a role of cAMP and protein kinase A, both prostaglandins induced a marked accumulation of cAMP in human myotubes, and forskolin reproduced the effect of arachidonic acid on UCP-2 mRNA expression. Inhibition of protein kinase A with H-89 suppressed the effect of PGE(2), whereas cPGI(2) and arachidonic acid were still able to increase ucp-2 gene expression, suggesting additional mechanisms. We found, however, that the MAP kinase pathway was not involved. Prostaglandins, particularly PGI(2), are potent activators of the peroxisome proliferator-activated receptors. A specific agonist of peroxisome proliferator-activated receptor (PPAR) beta (L165041) increased UCP-2 mRNA levels in myotubes, whereas activation of PPARalpha or PPARgamma was ineffective. These results suggest thus that ucp-2 gene expression is regulated by omega-6 fatty acids in human muscle cells through mechanisms involving at least protein kinase A and the nuclear receptor PPARbeta.
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PMID:The regulation of uncoupling protein-2 gene expression by omega-6 polyunsaturated fatty acids in human skeletal muscle cells involves multiple pathways, including the nuclear receptor peroxisome proliferator-activated receptor beta. 1127 77

Norepinephrine (NE) stimulates phospholipase D (PLD) through a Ras/MAPK pathway in rabbit vascular smooth muscle cells (VSMC). NE also activates calcium influx and calmodulin (CaM)-dependent protein kinase II-dependent cytosolic phospholipase A(2) (cPLA(2)). Arachidonic acid (AA) released by cPLA(2)-catalyzed phospholipid hydrolysis is then metabolized into hydroxyeicosatetraenoic acids (HETEs) through lipoxygenase and cytochrome P450 4A (CYP4A) pathways. HETEs, in turn, have been shown to stimulate Ras translocation and to increase MAPK activity in VSMC. This study was conducted to determine the contribution of cPLA(2)-derived AA and its metabolites (HETEs) to the activation of PLD. NE-induced PLD activation was reduced by two structurally distinct CaM antagonists, W-7 and calmidazolium, and by CaM-dependent protein kinase II inhibition. Blockade of cPLA(2) activity or protein depletion with selective cPLA(2) antisense oligonucleotides abolished NE-induced PLD activation. The increase in PLD activity elicited by NE was also blocked by inhibitors of lipoxygenases (baicalein) and CYP4A (17-octadecynoic acid), but not of cyclooxygenase (indomethacin). AA and its metabolites (12(S)-, 15(S)-, and 20-HETEs) increased PLD activity. PLD activation by AA and HETEs was reduced by inhibitors of Ras farnesyltransferase (farnesyl protein transferase III and BMS-191563) and MEK (U0126 and PD98059). These data suggest that HETEs are the mediators of cPLA(2)-dependent PLD activation by NE in VSMC. In addition to cPLA(2), PLD was also found to contribute to AA release for prostacyclin production via the phosphatidate phosphohydrolase/diacylglycerol lipase pathway. Finally, a catalytically inactive PLD(2) (but not PLD(1)) mutant inhibited NE-induced PLD activity, and PLD(2) was tyrosine-phosphorylated in response to NE by a MAPK-dependent pathway. We conclude that NE stimulates cPLA(2)-dependent PLD(2) through lipoxygenase- and CYP4A-derived HETEs via the Ras/ERK pathway by a mechanism involving tyrosine phosphorylation of PLD(2) in rabbit VSMC.
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PMID:Phospholipase D activation by norepinephrine is mediated by 12(s)-, 15(s)-, and 20-hydroxyeicosatetraenoic acids generated by stimulation of cytosolic phospholipase a2. tyrosine phosphorylation of phospholipase d2 in response to norepinephrine. 1127 12

Tumor necrosis factor (TNF)-alpha increases mitochondrial reactive oxygen species (ROS) production in tumor cells and hepatocytes. However, whether TNF-alpha stimulates mitochondrial ROS production in endothelial cells (EC) has not yet been reported. We studied the effect of TNF-alpha on mitochondrial ROS generation in EC and the signaling pathways involved. Cultured human umbilical vein EC (HUVEC) were studied by fluorescence microscopy, using dichlorodihydrofluorescein diacetate (DCFH-DA) as a marker of ROS production and propidium iodide uptake for cell viability. TNF-alpha increased DCFH oxidation in HUVEC dose-dependently. To determine the source of ROS, the mitochondrial respiratory chain inhibitors rotenone + thenoyltrifluoroacetone (TTFA), which inhibit electron entry to ubiquinone, and antimycin A (AA), a blocker of ubisemiquinone, were used. Rotenone and TTFA inhibited (n = 7, P < 0.05), whereas AA increased (118% in 3 min; n = 4, P < 0.01) ROS generation in HUVEC. In contrast, ROS production was not abolished by the nicotinamide adenine dinucleotide phosphate-dependent oxidase inhibitor diphenylene iodonium, by the xanthine oxidase inhibitor allopurinol, nor by the nitric oxide and cyclooxygenase pathway inhibitors N(omega)-nitro-L-arginine and mefenamic acid. In addition, TNF-alpha-induced ROS production was inhibited by the acidic sphingomyelinase inhibitor desipramine (5 microM; -80%, n = 4, P < 0.01) and totally blocked by the ceramide-activated protein kinase (CAPK) inhibitor dimethylaminopurine (1 mM; n = 6, P < 0.05). Thus, TNF-alpha induces mitochondrial ROS production in HUVEC that primarily occurs at the ubisemiquinone site and is mediated by ceramide-dependent signaling pathways involving CAPK.
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PMID:Rapid reactive oxygen species production by mitochondria in endothelial cells exposed to tumor necrosis factor-alpha is mediated by ceramide. 1141 43

Resveratrol is a naturally occurring polyphenol with cancer chemopreventive properties. The objective of the current study was to investigate the effect of resveratrol on the human colonic adenocarcinoma cell line Caco-2. The compound inhibited cell growth and proliferation of Caco-2 cells in a dose-dependent manner (12.5-200 micromol/L) as assessed by crystal violet assay, [(3)H]thymidine and [(14)C]leucine incorporation. Furthermore, apoptosis was determined by measuring caspase-3 activity, which increased significantly after 24 and 48 h of treatment with 200 micromol/L resveratrol. Perturbed cell cycle progression from the S to G2 phase was observed for concentrations up to 50 micromol/L, whereas higher concentrations led to reversal of the S phase arrest. These effects were specific for resveratrol; they were not observed after incubation with the stilbene analogs stilbenemethanol and rhapontin. Levels of cyclin D1 and cyclin-dependent kinase (cdk) 4 proteins were decreased, as revealed by immunoblotting. In addition, resveratrol enhanced the expression of cyclin E and cyclin A. The protein levels of cdk2, cdk6 and proliferating cell nuclear antigen were unaffected. Similar results were obtained for the colon carcinoma cell line HCT-116, indicating that cell cycle inhibition by resveratrol is independent of cyclooxygenase inhibition. The phosphorylation state of the retinoblastoma protein in Caco-2 cells was shifted from hyperphosphorylated to hypophosphorylated at 200 micromol/L, which may account for reversal of the S phase block at concentrations exceeding 50 micromol/L. These findings suggest that resveratrol exerts chemopreventive effects on colonic cancer cells by inhibition of the cell cycle.
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PMID:Downregulation of the cyclin D1/Cdk4 complex occurs during resveratrol-induced cell cycle arrest in colon cancer cell lines. 1148 17


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