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)

Nitric oxide (NO) is an important signaling molecule in the CNS, regulating neuronal survival, proliferation and differentiation. Here, we explored the mechanism by which NO, produced from the NO donor S-nitroso-acetyl-d-l-penicillamine (SNAP), exerts its neuroprotective effect in purified cultures of chick retinal neurons. Cultures prepared from 8-day-old chick embryo retinas and incubated for 24 h (1 day in culture, C1) were treated or not with SNAP, incubated for a further 72 h (up to 4 days in culture, C4), fixed, and the number of cells estimated, or processed for cell death estimation, by measuring the reduction of the metabolic dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Experimental cultures were run in parallel but were re-fed with fresh medium in the absence or presence of SNAP at culture day 3 (C3), incubated for a further 24 h up to C4, then fixed or processed for the MTT assay. Previous studies showed that the re-feeding procedure promotes extensive cell death. SNAP prevented this death in a concentration- and time-dependent manner through the activation of soluble guanylate cyclase; this protection was significantly reversed by the enzyme inhibitors 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ) or LY83583, and mimicked by 8-bromo cyclic guanosine 5'-phosphate (8Br-cGMP) (GMP) or 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1), guanylate cyclase activators. The effect was blocked by the NO scavenger 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO). The effect of NO was also suppressed by LY294002, Wortmannin, PD98059, KN93 or H89, indicating the involvement, respectively, of phosphatidylinositol-3 kinase, extracellular-regulated kinases, calmodulin-dependent kinases and protein kinase A signaling pathways. NO also induced a significant increase of neurite outgrowth, indicative of neuronal differentiation, and blocked cell death induced by hydrogen peroxide. Cyclosporin A, an inhibitor of the mitochondrial permeability transition pore considered an important mediator of apoptosis and necrosis, as well as boc-aspartyl (OMe) fluoromethylketone (BAF), a caspase inhibitor, also blocked cell death induced by re-feeding the cultures. These findings demonstrate that NO inhibits apoptosis of retinal neurons in a cGMP/protein kinase G (PKG)-dependent way, and strengthens the notion that NO plays an important role during CNS development.
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PMID:Nitric oxide regulates cell survival in purified cultures of avian retinal neurons: involvement of multiple transduction pathways. 1711 29

HIV-1 protease inhibitor (PI), nelfinavir (NFV) induced growth arrest and apoptosis of NCI-H460 and -H520, A549, EBC-1 and ABC-1 non-small-cell lung cancer (NSCLC) cells in association with upregulation of p21waf1, p27kip1 and p53, and downregulation of Bcl-2 and matrix metalloproteinase (MMP)-2 proteins. We found that NFV blocked Akt signalling in these cells as measured by Akt kinase assay with glycogen synthase kinase-3alpha/beta (GSK-3alpha/beta) as a substrate. To explore the role of Akt signalling in NFV-mediated growth inhibition of NSCLC cells, we blocked this signal pathway by transfection of Akt small interfering RNA (siRNA) in these cells; transient transfection of Akt siRNA in NCI-H460 cells decreased the level of Bcl-2 protein and slowed their proliferation compared to the nonspecific siRNA-transfected cells. Conversely, forced-expression of Akt partially reversed NFV-mediated growth inhibition of these cells, suggesting that Akt may be a molecular target of NFV in NSCLC cells. Also, we found that inhibition of Akt signalling by NFV enhanced the ability of docetaxel to inhibit the growth of NCI-H460 and -H520 cells, as measured by MTT assay. Importantly, NFV slowed the proliferation and induced apoptosis of NCI-H460 cells present as tumour xenografts in nude mice without adverse systemic effects. Taken together, this family of compounds might be useful for the treatment of individuals with NSCLC.
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PMID:NFV, an HIV-1 protease inhibitor, induces growth arrest, reduced Akt signalling, apoptosis and docetaxel sensitisation in NSCLC cell lines. 1713 72

Recently we demonstrated that IGF-1 expression is increased in the diabetic kidney and that it may involve in renal hypertrophy and extracellular matrix protein (ECM) accumulation in mesangial cells as seen in diabetic glomerulopathy. The present study investigates the molecular mechanism(s) of IGF-1 and Akt/glycogen synthase kinase-3beta (GSK-3beta) signaling pathway in the regulation of fibronectin and cyclin D1 expression and survival of renal mesangial cells. A proteomic approach is also employed to identify protein targets of IGF-1 signaling via GSK-3beta inhibition in mesangial cells. We show that IGF-1 (100 ng/ml) significantly increases the protein kinase Akt/PKB activity (1.5-2-fold, p<0.05) within 1-5 minutes, which is completely blocked by the presence of 100 nM Wortmannin (phosphatidyl-inositol 3-kinase inhibitor). Akt activation is coupled with Ser9 phosphorylation and inactivation of its down-stream target GSK-3beta. IGF-1 increases the cyclic AMP-responsive element (CRE) binding transcription factor CREB phosphorylation at Ser 133 and CRE-binding activity in mesangial cells, which parallels cyclin D1 and fibronectin expressions. Both proteins are known to have CRE-sequences in their promoter regions upstream of the transcription start site. Suppression of GSK-3beta by SB216763 (100 nM) increases CREB phosphorylation, cyclin D1 and fibronectin levels. Two dimensional gel electrophoresis followed by MALDI-TOF mass spectrometric analysis of mesangial proteins reveals that IGF-1 treatment or an inhibition of GSK-3beta increases the expression of the phosphorylated Ser/Thr binding signal adapter protein 14-3-3zeta. Immuno-precipitation of 14-3-3zeta followed by Western blotting validates the association of phosphorylated GSK-3beta with 14-3-3zeta in renal mesangial cells. Stable expression of a constitutively active GSK-3beta(Ser9Ala) induces cell death while overexpression of HA-tagged 14-3-3zeta increases cell viability as measured by MTT assays. These results indicate that the Akt/GSK-3beta pathway and the adapter protein 14-3-3zeta may play an important role in IGF-1 signaling and survival of mesangial cells in diabetic nephropathy.
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PMID:Proteomic identification of 14-3-3zeta as an adapter for IGF-1 and Akt/GSK-3beta signaling and survival of renal mesangial cells. 1720 Jun 89

Our previous studies have shown that Ginkgo biloba extract increased endothelial progenitor-cell (EPC) numbers and functional activity. However, the mechanisms remain to be determined. Recent studies have demonstrated that increased EPC numbers and activity were associated with the inhibition of EPC senescence, which involved activation of telomerase. Therefore, we investigated whether Ginkgo biloba extract inhibited the onset of EPC senescence through telomerase activation, leading to potentiation of cellular activity. After ex vivo cultivation, EPCs became senescent as determined by acidic ss-galactosidase staining. Ginkgo biloba extract dose-dependently prevented the onset of EPC senescence in culture. Moreover, Ginkgo biloba extract increased proliferation of EPCs as assessed by MTT assay and colony-forming capacity. To get further insights into the underlying mechanisms of these effects, we measured telomerase activity and determined the phosphorylation of Akt by Western blotting. Ginkgo biloba extract significantly increased telomerase activity and phosphorylation of the serine/threonine protein kinase Akt, a downstream effector of phosphoinositide 3-kinase (PI3K). Moreover, pretreatment with PI3K inhibitor, LY294002, significantly attenuated the Ginkgo biloba extract-induced telomerase activity. Taken together, the results indicated that Ginkgo biloba extract delayed the onset of EPC senescence, which may be related to activation of telomerase through the PI3k/Akt signaling pathway. The inhibition of EPC senescence by Ginkgo biloba extract in vitro may improve the functional activity of EPCs in a way that is important for potential cell therapy.
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PMID:Ginkgo biloba extract reduces endothelial progenitor-cell senescence through augmentation of telomerase activity. 1731 53

In the pig, conceptus-derived oestrogens (days 11 and 12 of pregnancy) seem to be a critical component of the signalling mechanism for maternal recognition of pregnancy. Embryonic oestrogens can mediate effects on endometrial function by interactions with epithelial and stromal oestrogen receptors (ER). Recent data demonstrate that cell membrane ER interacts with the phosphatidylinositol 3-kinase/Akt pathway in several types of cells. The protein kinase Akt is involved in the control of cell growth, survival and proliferation. One distinct function of the Akt signalling cascade is its ability to phosphorylate the eukaryotic initiation factor-4E (eIF-4E)-binding protein 1 (4E-BP1). This phosphorylation suppresses the inhibitory effect of 4E-BP1 on the translation initiation factor eIF4E and in such a way potentially stimulates gene expression at the level of translational initiation. The aim of the present study was to examine if embryonic oestradiol (E(2)) transmits its effect by such a mechanism. Endometrial cells of cyclic gilts (day 13 of the oestrous cycle, n = 4) were cultured and supplemented with vehicle (control), E(2) (50 and 100 pm/l) or with the selective ER modulator raloxifen (10 and 1000 nm/l), and incubated for 24 h. The cell viability was detected by MTT assay, the abundance and phosphorylation of Akt, 4E-BP1 and ERalpha was analysed by Western blotting. Incubation with E(2) or raloxifen did not alter endometrial cell viability. The phosphorylation of Akt at Ser(473) seems to be increased by E(2) (p < 0.05) and decreased by raloxifen (p > 0.05). Raloxifen (1000 nm/l) induced a band shift in 4E-BP1 to the highest electrophoretic mobility which reflects a decrease in phosphorylation (p < 0.05), whereas an influence of E(2) on 4E-BP1 phosphorylation could not be detected. The decrease (p < 0.05) of the abundance of the 80 kDa ERalpha form both by E(2) and raloxifen indicates that the E(2)-stimulated Akt phosphorylation and the inhibition of 4E-BP1 phosphorylation by raloxifen is an E(2) ER-transmitted process. Therefore, embryonic oestrogens can potentially transmit their effect by influencing signalling cascades which modulate gene expression at the level of translational initiation.
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PMID:The embryonic pregnancy signal oestradiol influences gene expression at the level of translational initiation in porcine endometrial cells. 1734 74

1. We have isolated a novel human erythrocyte-derived depressing factor (EDDF) that has a significant antihypertensive effect in various rat models of hypertension. The aim of the present study was to examine the mechanisms of action of EDDF on vascular function in two-kidney, one-clip (2K1C) renovascular hypertensive rats. 2. The EDDF was prepared from human erythrocytes. Experiments were performed in 18 male Wistar rats. The vascular ring perfusion assay and a two-photon laser scanning fluorescence microscope (TMP) were used to evaluate the vascular contractile response. The effects of EDDF on phenylephrine (PE)- and noradrenaline (NA)-induced vascular contraction were evaluated in 2K1C hypertensive rats. The proliferation and DNA synthesis in vascular smooth muscle cells (VSMC) were determined using the [3H]-TdR (thymidine) incorporation and 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays. Flow cytometry, reverse transcription-polymerase chain reaction and western blots were used to measure cell cycle and apoptotic profiles, platelet-derived growth factor (PDGF)-A expression and the activity of extracellular signal-regulated kinase (ERK)-1/2, as well as the expression of cyclin D1 and cyclin-dependent kinase (CDK) 4. 3. At 10(-5) g/mL, EDDF significantly decreased the PE- and NA-induced hypertensive vascular contraction. In addition, EDDF inhibited DNA synthesis in primary VSMC from 2K1C rats. The mRNA expression of PDGF-A in VSMC was twofold higher in 2K1C rats compared with control rats, whereas EDDF significantly inhibited the increment in PDGF-A mRNA expression. In addition, EDDF inhibited the phosphorylation of ERK1/2 and decreased the expression of cyclin D1 and CDK4; p21 (Cip1) levels were increased after treatment with EDDF. 4. In conclusion, EDDF inhibits VSMC proliferation in 2K1C rats through G0/G1 cell cycle arrest. The effects may be mediated, in part, by enhanced expression of p21 (Cip1) and the inhibition of ERK1/2 phosphorylation and the expression of cyclin D1/CDK4 and PDGF-A.
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PMID:Protective role of a novel erythrocyte-derived depressing factor on blood vessels of renovascular hypertensive rats. 1743 6

Alpha-synuclein is a presynaptic protein which is implicated in some neurodegenerative disorders including Parkinson's disease, dementia with Lewy bodies, multiple systems atrophy, and Hallervorden-Spatz disease, and its overexpression contributes to the loss of dopaminergic neurons. Although the role of alpha-synuclein in these paradigms has been widely documented, its exact function is still elusive. And the dysfunction of the transcription factor nuclear factor (NF-kappaB) also exists in many neurodegenerative diseases. In this reason the purpose of this study was to investigate the molecular mechanism of alpha-synuclein's toxicity and its association with NF-kappaB by MTT assay, Western blot method, and luciferase assay. Results showed that overexpressed alpha-synuclein and 1-methyl-4-phenylpyridinium (MPP(+)) suppressed the SH-SY5Y cell viability and attenuate NF-kappaB-mediated luciferase expression significantly. Moreover, the impairment function was enhanced with the increase of alpha-synuclein protein level. We also found that overexpressed alpha-synuclein localized both in the cytoplasms and nuclei, down-regulated the anti-apoptotic Bcl-2 expression and up-regulated the pro-apoptotic glycogen synthase kinase 3beta (GSK3beta) protein level. In conclusion, all these findings mentioned above suggested that alpha-synuclein shared some toxic functional homology with neurotoxin MPP(+), and the proapoptotic effects of alpha-synuclein might be mediated at least in part by the impairment of NF-kappaB signaling pathway which involves GSK3beta.
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PMID:Overexpressed alpha-synuclein regulated the nuclear factor-kappaB signal pathway. 1771 23

This study investigated the inhibitory effects of 2'-benzoyloxycinnamaldehyde (BCA) on cancer cells, including various drug-resistant cancer cell lines. To observe this activity, the anticancer drug-resistant cell lines were established by continuously exposing the parental cells to 5-fluorouracil (5-FU) and cyclophosphamide (CDDP), and examining the cells with the MTT assay and flow cytometric analysis. The BCA treatment produced similar growth inhibitory effects and apoptotic cell death on the drug-resistant cancer cells as their parental cells. The activation of the p38-mitogen activated protein kinase, an increased level of reactive oxygen species (ROS) generation and downregulation of Bcl-2 were observed in both the drug resistant and non-drug resistant cell lines. The GSH treatment effectively inhibited BCA-induced apoptosis by blocking ROS generation, suggesting that ROS is a major regulator in BCA-induced apoptotic cell death. These results suggest that BCA can be a useful drug candidate for treating drug-resistant cells.
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PMID:The activity of 2'-benzoyloxycinnamaldehyde against drug-resistant cancer cell lines. 1785 88

The neuropeptide PACAP (pituitary adenylate cyclase activating polypeptide) and its receptors are widely expressed in the nervous system and various other tissues. PACAP has well-known anti-apoptotic effects in neuronal cell lines. Recent data suggest that PACAP exerts anti-apoptotic effects also in non-neuronal cells. The peptide is present in the cardiovascular system, and has various distinct effects. The aim of the present study was to investigate whether PACAP is protective against in vitro ischemia/reperfusion-induced apoptosis in cardiomyocytes. Cultured cardiomyocytes were exposed to 60 min ischemia followed by 120 min reperfusion. The addition of PACAP1-38 significantly increased cell viability and decreased the ratio of apoptotic cells as measured by MTT test and flow cytometry. PACAP induced the phosphorylation of Akt and protein kinase A. In the present study we also examined the possible involvement of Akt- and protein kinase A-induced phosphorylation and thus inactivation of Bad, a pro-apoptotic member of the Bcl-2 family. It was found that ischemia significantly decreased the levels of phosphorylated Bad, which was counteracted by PACAP. Furthermore, PACAP increased the levels of Bcl-xL and 14-3-3 protein, both of which promote cell survival, and decreased the apoptosis executor caspase-3 cleavage. All effects of PACAP1-38 were inhibited by the PACAP antagonist PACAP6-38. In summary, our results show that PACAP has protective effects against ischemia/reperfusion-induced cardiomyocyte apoptosis and provides new insights into the signaling mechanisms involved in the PACAP-mediated anti-apoptotic effects.
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PMID:PKA-Bad-14-3-3 and Akt-Bad-14-3-3 signaling pathways are involved in the protective effects of PACAP against ischemia/reperfusion-induced cardiomyocyte apoptosis. 1798 49

Paullones constitute a class of potent cyclin-dependent kinase inhibitors. To overcome the insufficient solubility and bioavailability, which hamper their potential medical application, we aim at the development of metal-based derivatives. Two types of paullone ligands, L (1) - L (3) and L (4) , with different locations of metal-binding sites, were prepared. They were found to form organometallic complexes of the general formula [M (II)Cl(eta (6)- p-cymene)L]Cl ( 1- 4, L = L (1) - L (4) ; a, M = Ru; b, M = Os). The complexes were characterized by X-ray crystallography, one- and two-dimensional NMR spectroscopy and other physical methods. Complexes 1- 3, with a coordinated amidine unit, were found to undergo E/ Z isomerization in solution. The reaction was studied by NMR spectroscopy, and activation parameters Delta H (double dagger) and Delta S (double dagger) were determined. Antiproliferative activity in the low micromolar range was observed in vitro in three human cancer cell lines by means of MTT assays. (3)H-Thymidine incorporation assays revealed the compounds to lower the rate of DNA synthesis, and flow cytometric analyses showed cell cycle arrest mainly in G 0/ G 1 phase.
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PMID:Metal-based paullones as putative CDK inhibitors for antitumor chemotherapy. 1799 19


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