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:3.4.22.56 (caspase-3)
35,750 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

p38 mitogen-activated protein kinase is activated and involved in cleavage of caspase-3 during apoptosis induced by a number of stimuli. However, the signaling events triggered by p38 that result in caspase-3 activation are still unknown. In human leukemia cells, two reactive oxygen species, singlet oxygen and hydrogen peroxide (H(2)O(2)), selectively stimulated the phosphorylation of p38. Preincubation of cells with SB203580, a specific inhibitor of p38, dose dependently inhibited DNA fragmentation induced by singlet oxygen but not by H(2)O(2). Protection from apoptosis by SB203580 correlated with inhibition of caspase-3, and several events that are associated with caspase-3 activation, including Bid cleavage, decrease in mitochondrial transmembrane potential and release of cytochrome c from mitochondria, whereas caspase-8 cleavage was not affected by this inhibitor. In contrast, blockade of caspase-8 with Ile-Glu-Thr-Asp-fluoromethyl ketone is sufficient to prevent formation of DNA fragments and to inhibit all the above signaling events, with exception of p38 phosphorylation, in both singlet oxygen- and H(2)O(2)-treated cells. These data suggest that caspase-3 activation is regulated through redundant signaling pathways that involve p38 and caspase-8 acting upstream of Bid during singlet oxygen-induced apoptosis, whereas the activation of caspase-3 by H(2)O(2) is only governed by a caspase-8-mediated apoptotic pathway.
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PMID:p38 mitogen-activated protein kinase mediates bid cleavage, mitochondrial dysfunction, and caspase-3 activation during apoptosis induced by singlet oxygen but not by hydrogen peroxide. 1083 70

Extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) are major signaling molecules activated in human neutrophils stimulated by cytokines. Both molecules were cleaved at the N-terminal portion in neutrophils undergoing apoptosis induced by in vitro culture alone or treatment with TNF and/or cycloheximide. The cleavage of both molecules was inhibited by G-CSF and benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, a caspase inhibitor, both of which can inhibit neutrophil apoptosis. In a cell-free system, ERK and p38 MAPK were not cleaved by recombinant caspase-3 or caspase-8 while gelsolin was cleaved by caspase-3 under the same condition. The cleavage of both molecules appears to be specific to mature neutrophils, since it was not detected in immature cells (HL-60 and Jurkat) undergoing apoptosis, indicating that proteases responsible for the cleavage of both molecules may develop during differentiation into mature neutrophils. Concomitant with the cleavage of ERK and p38 MAPK, GM-CSF- and TNF-induced superoxide release, adherence, and phosphorylation of ERK and p38 MAPK were decreased in neutrophils undergoing apoptosis. In addition, GM-CSF- and TNF-induced superoxide release and adherence were inhibited by PD98059 MAPK/ERK kinase inhibitor) as well as SB203580 (p38 MAPK inhibitor), suggesting possible involvement of ERK and p38 MAPK in superoxide release and adherence induced by these cytokines. These findings indicate that ERK and p38 MAPK are cleaved and degraded in neutrophils undergoing apoptosis in a caspase-dependent manner and the cleavage of both molecules may be partly responsible for decreased functional responsiveness to inflammatory cytokines.
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PMID:Cleavage of mitogen-activated protein kinases in human neutrophils undergoing apoptosis: role in decreased responsiveness to inflammatory cytokines. 1114

Apoptosis induction may be a mechanism mediating the anticancer activity of selenium. Our earlier work indicated that distinct cell death pathways are likely involved in apoptosis induced by the CH3SeH and the hydrogen selenide pools of selenium metabolites. To explore the role of caspases in cancer cell apoptosis induced by selenium, we examined the involvement of these molecules in the death of the DU-145 human prostate carcinoma cells induced by methylseleninic acid (MSeA), a novel penultimate precursor of the putative critical anticancer metabolite CH3SeH. Sodium selenite, a representative of the genotoxic selenium pool, was used as a reference for comparison. The results show that MSeA-induced apoptosis was accompanied by the activation of multiple caspases (caspase-3, -7, -8, and -9), mitochondrial release of cytochrome c (CC), poly(ADP-ribose) polymerase (PARP) cleavage, and DNA fragmentation. In contrast, selenite-induced apoptotic DNA fragmentation was observed in the absence of these changes, but was associated with the phosphorylation of c-Jun-NH2-terminal kinase 1/2 and p38 mitogen-activated protein kinase/stress-activated protein kinase 2. A general caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-(OMe) fluoromethyl ketone, blocked MSeA-induced cleavage of procaspases and PARP, CC release, and DNA nucleosomal fragmentation, but did not prevent cell detachment. Furthermore, PARP cleavage and caspase activation were confined exclusively to detached cells, indicating that MSeA induction of cell detachment was a prerequisite for caspase activation and apoptosis execution. This process therefore resembled "anoikis," a special mode of apoptosis induction in which adherent cells lose contact with the extracellular matrix. Additional experiments with irreversible caspase inhibitors show that MSeA-induced anoikis involved caspase-3- and -7-mediated PARP cleavage that was initiated by caspase-8 and probably amplified through CC-caspase-9 activation and a feedback activation loop from caspase-3. Taken together, the data support a methyl selenium-specific induction of DU-145 cell apoptosis that involves cell detachment as a prerequisite (anoikis) and is executed principally through caspase-8 activation and its cross-talk with multiple caspases.
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PMID:Caspases as key executors of methyl selenium-induced apoptosis (anoikis) of DU-145 prostate cancer cells. 1130 88

Because high D-glucose significantly stimulates endothelial cell death, we examined the molecular mechanisms of high D-glucose-induced endothelial apoptosis. Treatment of human aortic endothelial cells with high D-glucose (25 mmol/l), but not mannitol and L-glucose, resulted in a significant decrease in cell number and a significant increase in apoptotic cells as compared with a physiological concentration (5 mmol/l). Interestingly, high D-glucose treatment significantly increased bax protein, accompanied by translocation of bax protein from cytosol to mitochondria-enriched heavy membrane fraction. In contrast, the expression and distribution of bcl-2 protein were not altered by high D-glucose. In addition, the activity of caspase-3 proteases was increased after exposure to high glucose, whereas caspase inhibitors prevented endothelial cell death induced by high D-glucose. On the other hand, p38 mitogen-activated protein kinase (MAPK) was markedly phosphorylated and showed sustained phosphorylation after stimulation. A specific inhibitor of p38 MAPK, SB 203580, and the overexpression of kinase-inactive p38 MAPK significantly attenuated cell death induced by high D-glucose in human aortic endothelial cells, whereas at 6 h after high D-glucose treatment, SB 203580 and overexpression of kinase-inactive p38 MAPK did not attenuate caspase-3 activation induced by high D-glucose. Importantly, caspase inhibitors significantly attenuated the sustained phosphorylation of p38 MAPK induced by high D-glucose. Thus, we finally focused the MAPK kinase (MEK) kinase 1 (MEKK1) to further examine the cross-talk between p38 MAPK and the bax-caspase proteases pathway. High D-glucose treatment induced MEKK1 cleavage, whereas caspase inhibitors significantly attenuated the cleavage. Importantly, kinase-inactive MEKK1 also blocked the phosphorylation of p38 MAPK induced by high D-glucose. Here, we demonstrated that high D-glucose induced apoptosis in human endothelial cells through activation of the bax-caspase proteases pathway and through phosphorylation of p38 MAPK mediated by MEKK1. Phosphorylation of p38 MAPK downstream of the bax-caspase pathway may play a pivotal role in endothelial apoptosis mediated by high D-glucose.
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PMID:Phosphorylation of p38 mitogen-activated protein kinase downstream of bax-caspase-3 pathway leads to cell death induced by high D-glucose in human endothelial cells. 1137 50

Oxidative stress generated by dopamine (DA) oxidation could be one of the factors underlying the selective vulnerability of nigral dopaminergic neurons in Parkinson's diseases. Here we show that DA induces apoptosis in SH-SY5Y neuroblastoma cells demonstrated by activation of caspase-9 and caspase-3, cleavage of poly(ADP-ribose) polymerase as well as nuclear condensation. We also show that p38 mitogen-activated protein kinase is activated within 10 min of DA treatment, which precedes the onset of apoptosis because the potent p38 kinase inhibitor SB203580 protects against DA-induced cell death as well as against caspase-9 and caspase-3 activation. In addition, the antioxidant N-acetyl-L-cysteine (NAC) effectively blocks DA-induced p38 kinase activation, caspase-9 and caspase-3 cleavage and subsequent apoptosis, indicating that DA triggers apoptosis via a signaling pathway that is initiated by the generation of reactive oxygen species (ROS). Dopamine exerts its toxicity principally intracellularly as the DA uptake inhibitor, nomifensine significantly reduces DA-induced cell death as well as activation of p38 kinase and caspase-3. Furthermore, DA induces mitochondrial cytochrome c release, which is dependent on p38 kinase activation and precedes the cleavage of caspases. These observations indicate that DA induces apoptosis primarily by generating ROS, p38 kinase activation, cytochrome c release followed by caspase-9 and caspase-3 activation.
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PMID:Apoptotic signaling in dopamine-induced cell death: the role of oxidative stress, p38 mitogen-activated protein kinase, cytochrome c and caspases. 1146 73

During trophoblast invasion, luminal and glandular endometrial epithelial cells (EEC) have been found to undergo apoptosis through undetermined mechanisms. We postulate that nitric oxide (NO) and progesterone may mediate apoptosis in EEC because they are produced by trophoblasts at concentrations that can cause apoptosis in non-uterine cells. Using a cultured EEC line, RL95-2, we found that sodium nitroprusside (SNP) or S-nitroso-N-acetylpenicillamine (SNAP), two commonly used NO-releasing agents, caused the death of EEC in a dose-dependent manner and progesterone markedly enhanced NO-induced cytotoxicity. Cells treated with NO/progesterone showed a significant increase in the percentage of condensed nuclei, as detected by DAPI staining, and in caspase-3 activity, indicating that these cells underwent apoptosis. Immunoblot analysis revealed that SNP/NO could activate extracellular signal-regulated kinase (ERK) and, to a lesser extent, p38 mitogen-activated protein kinase (MAPK). While pretreatment with PD98059 (an ERK inhibitor) did not prevent cell death, the addition of SB203580 (a p38 MAPK inhibitor) effectively rescued the cells from NO/progesterone treatment. Moreover, SNP/NO-induced p38 MAPK activation was significantly up-regulated by progesterone. Our results demonstrate that NO and progesterone may synergistically activate p38 MAPK to induce apoptosis in EEC, a process that may facilitate implantation.
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PMID:Nitric oxide induces extensive apoptosis in endometrial epithelial cells in the presence of progesterone: involvement of mitogen-activated protein kinase pathways. 1147 Aug 63

Rho family GTPases are critical molecular switches that regulate the actin cytoskeleton and cell function. In the current study, we investigated the involvement of Rho GTPases in regulating neuronal survival using primary cerebellar granule neurons. Clostridium difficile toxin B, a specific inhibitor of Rho, Rac, and Cdc42, induced apoptosis of granule neurons characterized by c-Jun phosphorylation, caspase-3 activation, and nuclear condensation. Serum and depolarization-dependent survival signals could not compensate for the loss of GTPase function. Unlike trophic factor withdrawal, toxin B did not affect the antiapoptotic kinase Akt or its target glycogen synthase kinase-3beta. The proapoptotic effects of toxin B were mimicked by Clostridium sordellii lethal toxin, a selective inhibitor of Rac/Cdc42. Although Rac/Cdc42 GTPase inhibition led to F-actin disruption, direct cytoskeletal disassembly with Clostridium botulinum C2 toxin was insufficient to induce c-Jun phosphorylation or apoptosis. Granule neurons expressed high basal JNK and low p38 mitogen-activated protein kinase activities that were unaffected by toxin B. However, pyridyl imidazole inhibitors of JNK/p38 attenuated c-Jun phosphorylation. Moreover, both pyridyl imidazoles and adenoviral dominant-negative c-Jun attenuated apoptosis, suggesting that JNK/c-Jun signaling was required for cell death. The results indicate that Rac/Cdc42 GTPases, in addition to trophic factors, are critical for survival of cerebellar granule neurons.
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PMID:An essential role for Rac/Cdc42 GTPases in cerebellar granule neuron survival. 1150 62

Caspase-11 plays a crucial role in both inflammation and apoptosis. Caspase-11 not only activates caspase-1, that is required for the maturation of proinflammatory cytokines such as interleukin (IL)-1 and IL-18, but also activates caspase-3, leading to cellular apoptosis under pathological conditions. Here, we cloned the rat homolog of caspase-11, and investigated its inducibility by inflammatory stimuli and signal transduction pathways involved. Deduced amino acid sequence of rat caspase-11 showed 88.7% similarity to mouse caspase-11, and in vitro translation of rat caspase-11 cDNA yielded approximately a 43 kDa polypeptide, which was in agreement with predicted protein size generated from full-length rat caspase-11 cDNA. The expression of caspase-11 was strongly induced at both mRNA and protein levels by inflammatory stimuli such as lipopolysaccharide (LPS), interferon-gamma, and tumor necrosis factor-alpha in C6 rat glial cells as well as primary astrocytes. LPS induced activation of both p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) in C6 cells. However, SB203580 (specific inhibitor of p38 kinase), but not PD98059 (specific inhibitor of ERK kinase), inhibited LPS induction of caspase-11, indicating that induction of caspase-11 by LPS in astrocytes was mediated through the p38 MAPK pathway. Inflammatory induction of caspase-11 in astrocytes may play an important role in both inflammatory responses involving these cells and auto-regulatory apoptosis of activated astrocytes in inflammatory sites.
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PMID:Induction of caspase-11 by inflammatory stimuli in rat astrocytes: lipopolysaccharide induction through p38 mitogen-activated protein kinase pathway. 1168 90

Neutrophil apoptosis is essential for resolution of inflammatory reactions. Here, we studied the role of two apoptosis/survival-associated protein kinases in this process. We discovered a previously undetected early and transient inhibition of the activity of p38 mitogen-activated protein kinase (p38 MAPK) during both spontaneous and Fas-induced apoptosis. Pharmacological inhibition of this enzyme augmented the activation of caspases and the apoptotic response, which suggests that the p38 MAPK signals survival in neutrophils. Our finding that caspase-3 activity was initiated during the transient inhibition of p38 MAPK suggests that apoptosis is initiated during this inhibition. Furthermore, such transient inhibition was counteracted by granulocyte-macrophage colony-stimulating factor, which elicits survival. We also found that neither this inhibition of p38 MAPK nor the spontaneous apoptotic response depended on Fas. Instead, the early inhibition of p38 MAPK concurred with a Fas-induced activation of phosphatidylinositol 3-kinase, inhibition of which reduced apoptosis. Thus, the Fas-induced augmentation of spontaneous apoptosis can be explained by its activation of phosphatidylinositol 3-kinase. We conclude that p38 MAPK activity represents a survival signal that is inactivated transiently during both spontaneous and Fas-induced apoptosis, whereas Fas-induced phosphatidylinositol 3-kinase activity is a proapoptotic signal in isolated human neutrophils.
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PMID:p38 Mitogen-activated protein kinase and phosphatidylinositol 3-kinase activities have opposite effects on human neutrophil apoptosis. 1172 3

CpG DNA has been recognized as a powerful stimulant of dendritic cells (DCs). In this study, we demonstrate that CpG DNA inhibits spontaneous apoptosis of DCs. CpG DNA up-regulated cellular inhibitor of apoptosis proteins (cIAPs) as well as Bcl-2 and Bcl-x(L), but down-regulated active caspase-3. Although CpG DNA activated p38 mitogen-activated protein kinase, extracellular signal-related kinase, and phosphatidylinositide-3'-OH kinase (PI3K), only the blocking of PI3K inhibited the CpG DNA-induced DC survival. Moreover, while the expression of Bcl-2 and Bcl-x(L) depends on both PI3K and p38 mitogen-activated protein kinase, the up-regulation of cIAPs and the down-regulation of active caspase-3 by CpG DNA require PI3K activation, suggesting PI3K-dependent up-regulation of cIAPs in the antiapoptotic activity of CpG DNA in DCs. This study indicates that CpG DNA provides a survival signal to DCs, which might be one of mechanisms by which bacterial DNA stimulates and maintains the innate immune responses.
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PMID:Cutting Edge: CpG DNA inhibits dendritic cell apoptosis by up-regulating cellular inhibitor of apoptosis proteins through the phosphatidylinositide-3'-OH kinase pathway. 1175 39


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