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)

The effect of 3-nitrosobenzamide (NOBA) on the etoposide, staurosporine and dexamethason induced rapid (4-6 hr), caspase-dependent apoptosis was investigated in thymocytes and lymphoma cells by flow cytometric assay of DNA fragmentation. When NOBA (ED(50) = 4 microM) was added to these cell systems, the rapid onset of apoptosis was prevented. Such apparent protection by NOBA was related to the inactivation of caspase-3, by s-nitrosylation of 1.3 mol -SH per enzyme molecule out of 7 -SH groups. Since NOBA by itself induces DNA fragmentation within 18 hr in lymphoma cells, our results indicate that at least two active cell death pathways exist with apparent dissimilar kinetics and molecular mechanisms.
Int J Cancer 1999 Sep 09
PMID:Interaction of cytocidal drugs and the inhibition of caspase-3 by 3-nitrosobenzamide. 1044 56

Follicular dendritic cells (FDCs) select B cells during germinal center (GC) reactions. The B cells that are able to bind to the FDCs receive a signal that leads to the termination of endonuclease activity in the nuclei of those B cells. This signal must be in addition to the signals transferred through the cross-linkage of the B cell receptors and signals resulting from the interactions of the adhesion molecules lymphocyte function-associated Ag-1 and very late Ag-4 with ICAM-1 and VCAM-1, respectively. In this report, we present evidence that the FDCs silence all apoptotic processes in GC B lymphocytes and additionally switch off pre-present endonuclease activity. We also show that GC B cell apoptosis requires cathepsin activity downstream of caspase-3. This cathepsin activity is directly connected to endonuclease activity and therefore may be an interesting target for the antiapoptotic factors produced by FDCs.
J Immunol 1999 Sep 01
PMID:Germinal center B cell apoptosis requires both caspase and cathepsin activity. 1045 83

Mitochondria are sites of cellular energy production but may also influence life and death decisions by initiating or inhibiting cell death. Mitochondrial depolarization and the subsequent release of pro-apoptotic factors have been suggested to be required for the activation of a cell death program in some forms of neuronal apoptosis. We induced apoptosis in cultured rat hippocampal neurons by exposure to the protein kinase inhibitor staurosporine (STS) (300 nM). The time course of mitochondrial membrane potential (DeltaPsi(m)) during apoptosis was examined using the probe tetramethylrhodamine ethyl ester (TMRE). Cells exhibited no decrease in TMRE fluorescence, indicative of mitochondrial depolarization, up to 8 hr after STS exposure. Rather, baseline TMRE fluorescence remained unchanged up to 2 hr and thereafter actually increased significantly. Throughout this time period, the mitochondria could also be depolarized with the protonophore carbonyl cyanide p-trifluoromethoxy-phenylhydrazone (FCCP, 0.1 microM), exhibiting the same relative magnitude of fluorescence release (unquenching) as controls. Even after 16 hr of staurosporine treatment, neurons that showed signs of nuclear apoptosis maintained DeltaPsi(m) and could be depolarized with FCCP. In contrast, caspase-3-like activity had increased roughly sevenfold by 2 hr and >20-fold by 8 hr. Double-labeling of hippocampal neurons with the potential-sensitive probe Mitotracker Red Chloromethyl X-Rosamine and an antibody to cytochrome c demonstrated at the subcellular level that mitochondrial cytochrome c release also occurred in the absence of mitochondrial depolarization. These data suggest that mitochondrial depolarization is not a decisive event in neuronal apoptosis.
J Neurosci 1999 Sep 01
PMID:Mitochondrial depolarization is not required for neuronal apoptosis. 1046 Feb 46

We studied the novel hypothesis that an up-modulation of channels for outward delayed rectifier K+ current (I(K)) plays a key role in ceramide-induced neuronal apoptosis. Exposure for 6-10 h to the membrane-permeable C2-ceramide (25 microM) or to sphingomyelinase (0.2 unit/ml), but not to the inactive ceramide analogue C2-dihydroceramide (25 microM), enhanced the whole-cell I(K) current without affecting the transient A-type K+ current and increased caspase activity, followed by neuronal apoptosis 24 h after exposure onset. Tetraethylammonium (TEA) or 4-chloro-N,N-diethyl-N-heptylbenzenebutanaminium tosylate (clofilium), at concentrations inhibiting I(K), attenuated the C2-ceramide-induced caspase-3-like activation as well as neuronal apoptosis. Raising extracellular K+ to 25 mM similarly blocked the C2-ceramide-induced cell death; the neuroprotection by 25 mM K+ or TEA was not eliminated by blocking voltage-gated Ca2+ channels. An inhibitor of tyrosine kinases, herbimycin A (10 nM) or lavendustin A (0.1-1 microM), suppressed I(K) enhancement and/or apoptosis induced by C2-ceramide. It is suggested that ceramide-induced I(K) current enhancement is mediated by tyrosine phosphorylation and plays a critical role in neuronal apoptosis.
J Neurochem 1999 Sep
PMID:Role of the outward delayed rectifier K+ current in ceramide-induced caspase activation and apoptosis in cultured cortical neurons. 1046 82

Mitochondria have recently been shown to serve a central role in programmed cell death. In addition, reactive oxygen species (ROS) have been implicated in cell death pathways upon treatment with a variety of agents; however, the specific cellular source of the ROS generation is unknown. We hypothesize that mitochondria-derived free radicals play a critical role in apoptotic cell death. To directly test this hypothesis, we treated murine fibrosarcoma cell lines, which expressed a range of mitochondrial manganese superoxide dismutase (MnSOD) activities, with respiratory chain inhibitors. Apoptosis was confirmed by DNA fragmentation analysis and electron microscopy. MnSOD overexpression specifically protected against cell death upon treatment with rotenone or antimycin. We examined bcl-x(L), p53 and poly(ADP-ribose) polymerase (PARP) to identify specific cellular pathways that might contribute to the mitochondrial-initiated ROS-mediated cell death. Cells overexpressing MnSOD contained less bcl-x(L) within the mitochondria compared to control (NEO) cells, therefore excluding the role of bcl-x(L). p53 was undetectable by Western analysis and examination of the proapoptotic protein bax, a p53 target gene, did not increase with treatment. Activation of caspase-3 (CPP-32) occurred in the NEO cells independent of cytochrome c release from the mitochondria. PARP, a target protein of CPP-32 activity, was cleaved to a 64 kDa fragment in the NEO cells prior to generation of nucleosomal fragments. Taken together, these findings suggest that mitochondrial-mediated ROS generation is a key event by which inhibition of respiration causes cell death, and identifies CPP-32 and the PARP-linked pathway as targets of mitochondrial-derived ROS-induced cell death.
FASEB J 1999 Sep
PMID:Overexpression of manganese superoxide dismutase protects against mitochondrial-initiated poly(ADP-ribose) polymerase-mediated cell death. 1046 52

An immortalized dorsal root ganglion cell line F-11 exhibits many properties of spinal cord neurons and undergoes apoptosis in response to growth factor withdrawal and the exogenous addition of inhibitors of phosphatidylinositol-3-kinase (PI3K). To elucidate the mechanism of apoptosis we generated F-11 clones which overexpressed either the p110 subunit of PI3K, a constitutively active form of protein kinase B/Akt (Myristoylated Akt), or a dominant-negative form (c-Akt). The first two constructs were protective against apoptosis induced by PI3K inhibitors such as wortmannin and LY294002. Caspase-3 (CPP32) levels peaked at 4 hr to 6 hr in response to pro-apoptotic drugs, and this increase was attenuated by 50% in F-11 with constitutively active Akt. The Akt protection was confirmed by DNA fragmentation studies. Both neo-transfected and the c-Akt dominant-negative transfected F-11 cells showed increased ceramide formation (twofold) in response to staurosporine, wortmannin, or LY294002; whereas cells with a constitutively active Akt (Myr-Akt) showed no increase in ceramide when treated with staurosporine, wortmannin, or LY294002. Ceramide was a more potent activator of CPP32 and an inducer of apoptosis when added as the native form (hydroxy- or nonhydroxy-), rather than the more water-soluble C(2)-ceramide. Overexpression of PI3K (p110) and Akt protected cells against ceramide-induced apoptosis, suggesting that Ceramide action is upstream of Akt in these cells and suggesting that Akt might be a target for inhibition by ceramide. Both staurosporine and C(2)-ceramide activated the Jun kinase (JNK) cascade and C(2)-ceramide increased caspase-3 (CPP32) activity in cells expressing wild-type c-Jun, but not dominant-negative (TAM-67) c-Jun. We suggest that this pathway is also involved in apoptosis, consistent with the idea that ceramide has multiple kinase and kinase-modulating targets in the apoptotic pathway of neurons. J. Neurosci. Sci. 57:884-893, 1999.
J Neurosci Res 1999 Sep 15
PMID:Overexpression of Akt (protein kinase B) confers protection against apoptosis and prevents formation of ceramide in response to pro-apoptotic stimuli. 1046 60

Endothelial cells (EC) are subject to oxidative-induced cell death. Activation of poly(ADP-ribose) polymerase (PARP) occurs early in oxidant-induced EC injury and putatively mediates cell death by depleting its substrate, NAD(+). In this study, the role of PARP in H(2)O(2)-induced EC death was investigated. EC were exposed to oxidant stress and viability continuously monitored using fluorescent dye exclusion. Inhibition of PARP with 1, 5-dihydroxyisoquinoline (DIQ) delayed the time course of oxidant-induced EC death. Concurrent addition of the protein synthesis inhibitor, cycloheximide, or the endonuclease inhibitor, aurintricarboxylic acid, to PARP-inhibited cells further delayed the onset and attenuated the extent of H(2)O(2)-induced cell lysis, consistent with an active mode of cell death. Caspase-3-like activity, a hallmark of apoptosis, was negligible in oxidant-treated EC alone, however, inhibition of PARP by 3-aminobenzamide or DIQ dramatically increased caspase-3-like activity. Morphological assessment confirmed that the primary mode of death in oxidant-stressed EC was oncosis. However, following PARP inhibition, the cells switched to apoptosis. Since inflammation is associated with oncosis and not apoptosis, the results presented here could explain the beneficial effects seen with PARP inhibition in various in vivo models of oxidant injury and provide a mechanism to manipulate this injury into a state of cell death that could ultimately be controlled.
Exp Cell Res 1999 Sep 15
PMID:Poly(ADP-ribose) polymerase inhibition in oxidant-stressed endothelial cells prevents oncosis and permits caspase activation and apoptosis. 1047 25

Many cell types undergo apoptosis under conditions of ischemia. Little is known, however, about the molecular pathways that mediate this response. A cellular and biochemical approach to elucidate such signaling pathways was undertaken in primary cultures of cardiac myocytes, a cell type that is especially sensitive to ischemia-induced apoptosis. Deprivation of serum and glucose, components of ischemia in vivo, resulted in myocyte apoptosis, as determined by nuclear fragmentation, internucleosomal cleavage of DNA, and processing of caspase substrates. These manifestations of apoptosis were blocked by zVAD-fmk, a peptide caspase inhibitor, indicating that caspase activity is necessary for the progression of apoptosis in this model. In contrast to control cells, apoptotic myocytes exhibited cytoplasmic accumulation of cytochrome c, indicating release from the mitochondria. Furthermore, both caspase-9 and caspase-3 were processed to their active forms in serum-/glucose-deprived myocytes. Caspase processing, but not cytochrome c release, was inhibited by zVAD-fmk, placing the latter event upstream of caspase activation. This evidence demonstrates that components of ischemia activate the mitochondrial death pathway in cardiac myocytes.
Circ Res 1999 Sep 03
PMID:The mitochondrial apoptotic pathway is activated by serum and glucose deprivation in cardiac myocytes. 1047 70

The regulation of caspases, cysteine proteinases that cleave their substrates after aspartic residues, is poorly understood, even though they are involved in tightly regulated cellular processes. The recently discovered serpin analogue proteinase inhibitor 9 (PI9) is unique among human serpin analogues in that it has an acidic residue in the putative specificity-determining position of the reactive-site loop. We measured the ability of PI9 to inhibit the amidolytic activity of several caspases. The hydrolysis of peptide substrates by caspase-1 (interleukin-1beta-converting enzyme), caspase-4 and caspase-8 is inhibited by PI9 in a time-dependent manner. The rate of reaction of caspase-1 with PI9, as well as the rate of substrate hydrolysis of the initial caspase-PI9 complex, shows a hyperbolic dependence on the concentration of PI9, indicative of a two-step kinetic mechanism for inhibition with an apparent second-order rate constant of 7x10(2) M(-1).s(-1). The hydrolysis of a tetrapeptide substrate by caspase-3 is not inhibited by PI9. The complexes of caspase-1 and caspase-4 with PI9 can be immunoprecipitated but no complex with caspase-3 can be detected. No complex can be immunoprecipitated if the active site of the caspase is blocked with a covalent inhibitor. These results show that PI9 is an inhibitor of caspase-1 and to a smaller extent caspase-4 and caspase-8, but not of the more distantly related caspase-3. PI9 is the first example of a human serpin analogue that inhibits members of this class of cysteine proteinases.
Biochem J 1999 Sep 15
PMID:Caspase-1 (interleukin-1beta-converting enzyme) is inhibited by the human serpin analogue proteinase inhibitor 9. 1047 77

Glucocorticoids (GC) are potent anti-inflammatory and immunosuppressive agents that act on a variety of immune cells, including monocytes and macrophages. However, the exact cellular mechanisms underlying this anti-inflammatory capacity are still unknown. In our study, we determined the induction of apoptosis by GC in human monocytes. Peripheral blood monocytes were isolated by density centrifugation methods with a purity of >90% and were cultured in RPMI 1640 medium. Monocyte apoptosis was determined by four independent methods, including annexin-V staining, TUNEL, DNA-laddering, and typical morphology by means of transmission electron microscopy. TNF-alpha and IL-1beta were measured by ELISA. GC receptor was blocked with mifepristone. Caspase 3 was inhibited with caspase-3 inhibitor (DEVD-CHO). Stimulation with different GC at therapeutic concentrations resulted in monocyte apoptosis in a time- and dose-dependent manner. Necrosis was excluded by propidium iodide staining. Proinflammatory cytokines such as IL-1beta and TNF-alpha were down-regulated by GC treatment. Continuous treatment of monocytes with IL-1beta, but not with TNF-alpha, could almost completely prevent GC-induced cell death. The addition of mifepristone or caspase-3 inhibitor could partially abrogate GC-induced apoptosis as well as GC-induced inhibition of IL-1beta. This is the first study to demonstrate induction of apoptosis by GC in human monocytes. GC-induced monocyte apoptosis may be partially mediated through effects on IL-1beta production. It is conceivable that GC exert their anti-inflammatory capacity in various diseases, at least in part, by the induction of apoptosis in monocytes.
J Immunol 1999 Sep 15
PMID:Glucocorticoids induce apoptosis in human monocytes: potential role of IL-1 beta. 1047 21


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