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:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Satratoxin G (SG) is a macrocyclic trichothecene mycotoxin produced by Stachybotrys chartarum, a mold suggested to play an etiologic role in damp building-related illnesses. Acute intranasal exposure of mice to SG specifically induces apoptosis in olfactory sensory neurons of the nose. The PC-12 rat pheochromocytoma cell model was used to elucidate potential mechanisms of SG-induced neuronal cell death. Agarose gel electrophoresis revealed that exposure to SG at 10 ng/ml or higher for 48-h induced DNA fragmentation characteristic of apoptosis in PC-12 cells. SG-induced apoptosis was confirmed by microscopic morphology, hypodiploid fluorescence and annexin V-fluorescein isothiocyanate (FITC) uptake. Messenger RNA expression of the proapoptotic genes p53, double-stranded RNA-activated protein kinase (PKR), BAX, and caspase-activated DNAse was significantly elevated from 6 to 48 h after SG treatment. SG also induced apoptosis and proapoptotic gene expression in neural growth factor-differentiated PC-12 cells. Although SG-induced caspase-3 activation, caspase inhibition did not impair apoptosis. Moreover, SG induced nuclear translocation of apoptosis-inducing factor (AIF), a known contributor to caspase-independent neuronal cell death. SG-induced apoptosis was not affected by inhibitors of oxidative stress or mitogen-activated protein kinases but was suppressed by the PKR inhibitor C16 and by PKR siRNA transfection. PKR inhibition also blocked SG-induced apoptotic gene expression and AIF translocation but not caspase-3 activation. Taken together, SG-induced apoptosis in PC-12 neuronal cells is mediated by PKR via a caspase-independent pathway possibly involving AIF translocation.
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PMID:Satratoxin G-induced apoptosis in PC-12 neuronal cells is mediated by PKR and caspase independent. 1853 2

The ethanol extract of Dunaliella salina (EDS) on proliferation and apoptosis in the A549 human lung cancer cell line and their associated protein expressions were investigated. After 24 and 48 h treatment, MTT assay showed that 25 microg/ml of EDS significantly reduced A549 cell proliferation by 25.2% (p<0.05) and 48.3% (p<0.01), respectively. To explore its molecular mechanisms in regulating cell proliferation, we first showed that EDS markedly reduced A549 proliferation via inhibition of BrdU incorporation at 25 microg/ml by 65.8% (p<0.001). By cytometric analysis, EDS was found to induce apoptosis and cell cycle arrest in the G0/G1 phase. In the DNA gel electrophoresis assay, EDS (25, 50 and 100 microg/ml) induced significant apoptosis at 48 h. Annexin V/Propodium iodide double staining demonstrated that administration of EDS (25 microg/ml) in 12, 24 and 48 h induces apoptosis of 27.7%, 30.7%, and 38.7%. Western blotting assay demonstrated that EDS significantly increased the expression of cyclin-dependent kinase (CDK) inhibitors p53 and p21 and death-receptor proteins Fas and FasL. Bax expression was also elevated by treatment with EDS. Our data suggested that EDS could influence the antiproliferative effects and induce cell cycle G0/G1 arrest and apoptosis of A549 lung cancer cells.
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PMID:Ethanol extract of Dunaliella salina induces cell cycle arrest and apoptosis in A549 human non-small cell lung cancer cells. 1861 Jul 50

Although there is strong evidence that ligand activation of peroxisome proliferator-activated receptor (PPAR)-beta/delta induces terminal differentiation and attenuates cell growth, some studies suggest that PPARbeta/delta actually enhances cell proliferation. For example, it was suggested recently that retinoic acid (RA) is a ligand for PPARbeta/delta and potentiates cell proliferation by activating PPARbeta/delta. The present study examined the effect of ligand activation of PPARbeta/delta on cell proliferation, cell cycle kinetics, and target gene expression in human HaCaT keratinocytes using two highly specific PPARbeta/delta ligands [4-[[[2-[3-fluoro-4-(trifluoromethyl)phenyl]-4-methyl-5-thiazolyl]methyl]thio]-2-methylphenoxy acetic acid (GW0742) and 2-methyl-4-((4-methyl-2-(4-trifluoromethylphenyl)-1,3-thiazol-5-yl)-methylsulfanyl)phenoxy-acetic acid (GW501516)] and RA. Both PPARbeta/delta ligands and RA inhibited cell proliferation of HaCaT keratinocytes. GW0742 and GW501516 increased expression of known PPARbeta/delta target genes, whereas RA did not; RA increased the expression of known retinoic acid receptor/retinoid X receptor target genes, whereas GW0742 did not affect these genes. GW0742, GW501516, and RA did not modulate the expression of 3-phosphoinositide-dependent protein kinase or alter protein kinase B phosphorylation. GW0742 and RA increased annexin V staining as quantitatively determined by flow cytometry. The effects of GW0742 and RA were also examined in wild-type and PPARbeta/delta-null primary mouse keratinocytes to determine the specific role of PPARbeta/delta in modulating cell growth. Although inhibition of keratinocyte proliferation by GW0742 was PPARbeta/delta-dependent, inhibition of cell proliferation by RA occurred in both genotypes. Results from these studies demonstrate that ligand activation of PPARbeta/delta inhibits keratinocyte proliferation through PPARbeta/delta-dependent mechanisms. In contrast, the observed inhibition of cell proliferation in mouse and human keratinocytes by RA is mediated by PPARbeta/delta-independent mechanisms and is inconsistent with the notion that RA potentiates cell proliferation by activating PPARbeta/delta.
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PMID:Ligand activation of peroxisome proliferator-activated receptor-beta/delta inhibits cell proliferation in human HaCaT keratinocytes. 1868 7

The herpes simplex virus type 1 (HSV-1) protein ICP27 has been implicated in a variety of functions important for viral replication including host shutoff, viral gene expression, activation of mitogen-activated protein kinases p38 and Jun N-terminal protein kinase (JNK), and apoptosis inhibition. In the present study we sought to examine the functions of ICP27 in the absence of viral infection by creating stable HeLa cell lines that inducibly express ICP27. Here, we characterize two such cell lines and show that ICP27 expression is associated with a cellular growth defect. The observed defect is caused at least in part by the induction of apoptosis as indicated by caspase-3 activation, annexin V staining, and characteristic changes in cellular morphology. In an effort to identify the function of ICP27 responsible for inducing apoptosis, we show that ICP27 expression is sufficient to activate p38 signaling to a level that is similar to that observed during wild-type HSV-1 infection. However, ICP27 expression alone is unable to lead to a strong activation of JNK signaling. Using chemical inhibitors, we show that the ICP27-mediated activation of p38 signaling is responsible for the observed induction of apoptosis in the induced cell lines. Our findings suggest that during viral infection, ICP27 activates p38 and JNK signaling pathways via two distinct mechanisms. ICP27 directly activates p38 signaling, leading to stimulation of the host cell apoptotic pathways. In contrast, robust activation of JNK signaling by ICP27 requires one or more delayed early or late viral gene products and may be associated with the inhibition of apoptosis.
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PMID:Herpes simplex virus type 1 ICP27 induces p38 mitogen-activated protein kinase signaling and apoptosis in HeLa cells. 1907 44

Signaling by the B cell antigen receptor (BCR) is essential for B lymphocyte homeostasis and immune function. In immature B cells, ligation of the BCR promotes growth arrest and apoptosis, and BCR-driven balancing between pro-apoptotic extracellular signal-regulated kinase 1 and 2 (ERK1/2) and anti-apoptotic phosphoinositide 3-kinase-dependent Akt seems to define the final cellular apoptotic response. Dysfunction of these late BCR signaling events can lead to the development of immunological diseases. Here we report on novel cyclic AMP-dependent mechanisms of BCR-induced growth arrest and apoptosis in the immature B lymphoma cell line WEHI-231. BCR signaling to ERK1/2 and Akt requires cyclic AMP-regulated Epac, the latter acting as a guanine nucleotide exchange factor for Rap1 and H-Ras independent of protein kinase A. Importantly, activation of endogenously expressed Epac by a specific cyclic AMP analog enhanced the induction of growth arrest (reduced DNA synthesis) and apoptosis (nuclear condensation, annexin V binding, caspase-3 cleavage and poly-ADP-ribose polymerase processing) by the BCR. Our data indicate that cyclic AMP-dependent Epac signals to ERK1/2 and Akt upon activation of Rap1 and H-Ras, and is involved in BCR-induced growth arrest and apoptosis in WEHI-231 cells.
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PMID:B cell receptor-induced growth arrest and apoptosis in WEHI-231 immature B lymphoma cells involve cyclic AMP and Epac proteins. 1916 86

Cdk5 is a small serine/threonine protein kinase which belongs to Cdk family. Unlike other Cdk members, so far Cdk5 is known to be irrelevant in cell cycle. Cdk5 kinase activity is regulated by binding with its activator, p35. Our previous results indicate that CdkS and p35 are involved in drugs-induced apoptosis of prostate cancer cells. Retinoic acid (RA) is one of the vitamin A-related compounds. Because of its potency on biological functions, it has been widely studied in its novel actions including the ability to inhibit cancer cell growth and to induce apoptosis. Here, we report that RA treatment decreased the growth of human cervical cancer cell line, HeLa, and Cdk5 contributed to this effect. The involvement of Cdk5 in RA-reduced cell survival was performed by treatments of Cdk5 inhibitor and siRNA. We further identified that RA-induced growth inhibition was partly correlated to Cdk5 activity-related apoptosis by detecting cell cycle distribution of sub G1 phase and the signals of Annexin V staining. In addition, our results also indicated that Cdk5 activity was involved in RA-induced HeLa apoptosis by detecting cleavages of caspase-3 and its substrate, PARP (poly (ADP-ribose) polymerases) Interestingly, the nuclear localizations of Cdk5 and p35 proteins were increased by RA treatment, which, again, suggests the involvement of Cdk5 and p35 in RA-induced apoptotic effects. In conclusion, we provide evidence to suggest that Cdk5 and p35 might play important roles in RA-induced HeLa apoptosis.
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PMID:The role of Cdk5 in retinoic acid-induced apoptosis of cervical cancer cell line. 1976 50

We had earlier demonstrated that chronic exposure (30 days) to micro-molar concentration (0.50 microM) of arsenic induced head kidney macrophage (HKM) death in Clarias batrachus. The purpose of the present study is to characterize the nature of HKM death induced by arsenic and elucidate the signal transduction pathways involved in the process. Arsenic-induced HKM death was apoptotic in nature as evident from DNA gel, Annexin V-propidium iodide, Hoechst 33342 staining and TdT-mediated dUTP nick end labeling (TUNEL) assays. Inhibitor studies and immunoblot analyses further demonstrated that arsenic-induced HKM apoptosis involved activation of caspase-3 and cleavage of poly(ADP-ribose) polymerase, a well-characterized caspase-3 substrate. Preincubation with antioxidants N-acetyl-cysteine or dimethyl sulfoxide significantly lowered reactive oxygen species (ROS) levels in arsenic-treated HKM and prevented caspase activation, malondialdehyde formation and HKM apoptosis. Arsenic induced membrane translocation of the NADPH oxidase subunit p47(phox). Preincubation with apocynin and diphenyleneiodonium chloride, both selective inhibitors of NADPH oxidases, prevented p47(phox) translocation, ROS production and HKM death. Exposure of HKM to arsenic induced the activation of mitogen-activated protein kinase family (MAPK) proteins including c-Jun NH(2)-terminal protein kinase (JNK) and p38 mitogen-activated protein kinase (p38). Preincubation of HKM with p38 inhibitor SB203580 and JNK inhibitor SP600125 protected the HKM against arsenic-induced apoptosis. We conclude that exposure to micro-molar concentration of arsenic induces ROS generation through the activation of NADPH oxidases, which in turn causes caspase-3 mediated HKM apoptosis. In addition, the study also indicates a role of p38-JNK pathway in arsenic-induced HKM apoptosis in C. batrachus.
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PMID:Low concentration of arsenic could induce caspase-3 mediated head kidney macrophage apoptosis with JNK-p38 activation in Clarias batrachus. 1978 97

Melanoma differentiation associated gene-7/interleukin 24 (mda-7/IL-24) is a unique interleukin (IL)-10 family cytokine displaying selective apoptosis-inducing activity in transformed cells without harming normal cells. The present studies focused on defining the mechanism(s) by which recombinant adenoviral delivery of MDA-7/IL-24 inhibits cell survival of human ovarian carcinoma cells. Expression of MDA-7/IL-24 induced phosphorylation of protein kinase R-like endoplasmic reticulum kinase (PERK) and eukaryotic initiation factor2alpha (eIF2alpha). In a PERK-dependent fashion, MDA-7/IL-24 reduced ERK1/2 and AKT phosphorylation and activated c-Jun NH(2)-terminal kinase (JNK) 1/2 and p38 mitogen-activated protein kinase (MAPK). MDA-7/IL-24 reduced MCL-1 and BCL-XL and increased BAX levels via PERK signaling; cell-killing was mediated via the intrinsic pathway, and cell killing was primarily necrotic as judged using Annexin V/propidium iodide staining. Inhibition of p38 MAPK and JNK1/2 abolished MDA-7/IL-24 toxicity and blocked BAX and BAK activation, whereas activation of mitogen-activated extracellular-regulated kinase (MEK) 1/2 or AKT suppressed enhanced killing and JNK1/2 activation. MEK1/2 signaling increased expression of the MDA-7/IL-24 and PERK chaperone BiP/78-kDa glucose regulated protein (GRP78), and overexpression of BiP/GRP78 suppressed MDA-7/IL-24 toxicity. MDA-7/IL-24-induced LC3-green fluorescent protein vesicularization and processing of LC3; and knockdown of ATG5 suppressed MDA-7/IL-24-mediated toxicity. MDA-7/IL-24 and cisplatin interacted in a greater than additive fashion to kill tumor cells that was dependent on a further elevation of JNK1/2 activity and recruitment of the extrinsic CD95 pathway. MDA-7/IL-24 toxicity was enhanced in a weak additive fashion by paclitaxel; paclitaxel enhanced MDA-7/IL-24 + cisplatin lethality in a greater than additive fashion via BAX. Collectively, our data demonstrate that MDA-7/IL-24 induces an endoplasmic reticulum stress response that activates multiple proapoptotic pathways, culminating in decreased ovarian tumor cell survival.
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PMID:Cisplatin enhances protein kinase R-like endoplasmic reticulum kinase- and CD95-dependent melanoma differentiation-associated gene-7/interleukin-24-induced killing in ovarian carcinoma cells. 1991 Apr 52

Death receptor-dependent apoptosis is an important mechanism of growth control. It has been demonstrated that Ras association domain family protein 1A (RASSF1A) is a tumor suppressor protein involved in death receptor-dependent apoptosis. However, it is unclear how RASSF1A-mediated cell death is initiated. We have now detailed 14-3-3 dependent regulation of RASSF1A-mediated cell death. We demonstrate that basal association of RASSF1A with 14-3-3 was lost following stimulation with tumor necrosis factor alpha (TNFalpha) or TNFalpha related apoptosis inducing ligand (TRAIL). Subsequent to the loss of 14-3-3 association, RASSF1A associated with modulator of apoptosis (MOAP-1) followed by death receptor association with either TNFalpha receptor 1 (TNF-R1) or TRAIL receptor 1 (TRAIL-R1). 14-3-3 association required basal phosphorylation by the serine/threonine kinase, glycogen synthase kinase 3beta (GSK-3beta), on serine 175, 178, and 179. Mutation of these critical serines resulted in the loss of 14-3-3 association and earlier recruitment of RASSF1A to MOAP-1, TNF-R1, and TRAIL-R1. Furthermore, stable cells containing a triple serine mutant of RASSF1A [serine (S) 175 to alanine (A) [S175A], S178A, and S179A] resulted in increased basal cell death, enhanced Annexin V staining and enhanced cleavage of poly (ADP-ribose) polymerase (PARP) following TNFalpha stimulation when compared to stable cells containing wild type RASSF1A. RASSF1A-mediated cell death is, therefore, tightly controlled by 14-3-3 association.
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PMID:14-3-3 mediated regulation of the tumor suppressor protein, RASSF1A. 2006 57

Previous reports suggested that bladder cancer patients who continue to smoke while receiving chemotherapy have poorer outcomes than their nonsmoking counterparts. Nicotine, the major addictive compound in cigarette smoke, is known to induce chemoresistance in some cancer cells. Chemoresistance has been linked to the activation of Stat3 (signal transducer and activator of transcription). The objective of this study was to identify the role of Stat3 in chemoresistance induced by nicotine in human bladder cancer cell line, T24 cells. Chemoresistant T24 cells were established by persistent nicotine treatment. Apoptosis and cell cycle parameters were analyzed by Annexin V staining, poly(ADP-ribose) polymerase degradation, caspase activity, and propidium iodide staining. Signal transduction mediating the chemoresistance was detected by Western blotting and small interfering RNA (siRNA) transfection. We provide evidence for the first time that nicotine strongly activated Stat3, leading to Cyclin D1 overexpression, cell cycle perturbations, and chemoresistance. Furthermore, nicotine mobilized Stat3 signaling, resulting in the loss of extracellular signal-regulated protein kinase 1/2 (ERK 1/2) activation and reduced chemosensitivity via nicotinic acetylcholine receptors and beta-adrenoceptors. Inhibition of Stat3 by siRNA or a specific inhibitor restored chemosensitivity in T24 cells. Stat3 could be the major target for increasing chemosensitivity in patients who develop chemoresistance during chemotherapy, and avoidance of cigarette smoking or nicotine-based treatments may increase the efficacy of chemotherapy.
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PMID:Long-term nicotine exposure-induced chemoresistance is mediated by activation of Stat3 and downregulation of ERK1/2 via nAChR and beta-adrenoceptors in human bladder cancer cells. 2010 47


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