Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P42574 (caspase-3)
 45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We found that treatment of U937 cells with ZnCl(2) resulted in marked inhibition of ricin-induced DNA fragmentation and nuclear morphological change. Zn(2+) also completely inhibited the activation of caspase-3-, caspase-6-, and caspase-9-like proteases in ricin-treated cells, while no significant effect of Zn(2+) on these protease activities was observed when added directly to the lysate of ricin-treated cells, suggesting that Zn(2+) blocks the process of the activation of these caspases rather than the direct inhibition of the already activated enzymes. Fluorescence microscopic observation with Zn(2+) specific fluorescent probe dansylaminoethyl-cyclen suggested that there was a substantial increase in probe-detectable Zn(2+) in ricin-treated cells. Since the differences in the total Zn(2+) contents between ricin-treated and -untreated cells as measured with an atomic absorption spectrophotometer were too small to explain the increase in probe fluorescence in ricin-treated cells, it was suggested that release of Zn(2+) from intracellular stores or metalloproteins may occur rather than enhanced uptake from the medium. The Zn(2+) probe fluorescence change was observed prior to the depletion of intracellular glutathione. Carbobenzoxy-Asp-1-yl-[(2,6-dichlorobenzoyl)oxy]methane (Z-Asp-CH(2)-DCB), a caspase family protease inhibitor, prevented ricin-induced increase in Zn(2+) probe fluorescence. These results suggest that redistribution of intracellular Zn(2+) occurs during ricin-induced apoptosis as early apoptotic event, and exogenously added Zn(2+) may prevent such intracellular Zn(2+) redistribution resulting in the inhibition of apoptosis.
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PMID:Role of zinc ions in ricin-induced apoptosis in U937 cells. 1204 48

Neurotrophins support neuronal survival and differentiation via Trk receptors, yet can also induce cell death via the p75 receptor. In these studies, we investigated signaling mechanisms governing p75-mediated death of hippocampal neurons, specifically the role of caspases. Although p75 is structurally a member of the Fas/TNFR1 receptor family, caspase-8 was not required for p75-mediated death, unlike other members of this receptor family. In contrast, p75-mediated neuronal death was associated with mitochondrial loss of cytochrome c and required Apaf-1 and caspase-9, -6, and -3. In particular, caspase-6 plays a central role in mediating neurotrophin-induced death, illuminating a novel role for this caspase. Inhibition of DIABLO/Smac, which blocks inhibitor of apoptosis proteins, protected cells from death, whereas simultaneous inhibition of both DIABLO/Smac and MIAP3 allowed trophin-induced death to proceed. In vivo, pilocarpine-induced seizures, previously shown to up-regulate p75 expression and increase neurotrophin production, caused activation of caspase-6 and -3 and cleavage of poly(ADP-ribose) polymerase in p75-expressing hippocampal neurons. In p75(-/-) mice, no activated caspase-3 was detected, and there was a marked reduction in the number of dying neurons after pilocarpine treatment compared with wild type mice. Neurotrophin-induced p75-mediated death is likely to play an important role in mediating neuronal loss consequent to brain injury.
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PMID:Mechanisms of p75-mediated death of hippocampal neurons. Role of caspases. 1209 34

Recent studies have shown increased levels of cyclooxygenase-2 (COX-2) in a variety of human malignancies, including hepatocellular carcinoma (HCC), but so far it is unknown whether COX-2 contributes to the malignant growth and whether inhibition of COX-2 function modifies the malignant potential of liver tumors. COX-1 and COX-2 expression was determined in 4 liver tumor cell lines (Hep 3B, HuH-7, Hep G2, Sk-hep1) by Northern hybridization and Western immunoblot. The functional effects of the nonselective inhibitor sulindac sulfide and the COX-2 selective inhibitors SC-58635 and meloxicam were examined by 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazoliumbromide (MTT)-assays and BrdU uptake, morphology, and TUNEL analysis of apoptosis. Apoptosis regulating proteins were analyzed by Western immunoblot. COX-1 and COX-2 expression was demonstrable in all tested liver tumor cell lines. Sulindac sulfide (50 to 400 micromol/L), SC-58635 (6,25 to 400 micromol/L), and meloxicam (6.25 to 400 micromol/L) led to a significant time- and dose-dependent reduction of cell numbers of up to 80% (P <.05). At equimolar concentrations the effect was more pronounced when COX-2 was selectively blocked. COX-2 inhibition induced apoptosis and reduced tumor cell proliferation. Apoptosis after COX-2 inhibition with SC-58635 (50 micromol/L) was independent of BCL-2, BAX, and the phosphorylation status of AKT/PKB and BAD, but correlated with activation of caspase-9, caspase-3, and caspase-6. In conclusion, selective inhibition of COX-2 leads to a marked growth inhibition of human liver tumor cells, based on the induction of apoptosis and inhibition of proliferation and, thus, may offer therapeutic and preventive potential in human hepatocarcinogenesis.
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PMID:Proapoptotic and antiproliferative potential of selective cyclooxygenase-2 inhibitors in human liver tumor cells. 1229 35

Smac (second mitochondrial activator of caspases) is released from the mitochondria during apoptosis to relieve inhibition of caspases by the inhibitor of apoptosis proteins (IAPs). The release of Smac antagonizes several IAPs and assists the initiator caspase-9 and effector caspases (caspase-3, caspase-6, and caspase-7) in becoming active, ultimately leading to death of the cell. Translocation of Smac along with cytochrome c and other mitochondrial pro-apoptotic proteins represent important regulatory checkpoints for mitochondria-mediated apoptosis. Whether Smac and cytochrome c translocate by the same mechanism is not known. Here, we show that the time required for Smac efflux from the mitochondria of cells subjected to staurosporine-induced apoptosis is approximately four times longer than the time required for cytochrome c efflux. These results suggest that Smac and cytochrome c may exit the mitochondria by different pathways.
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PMID:The kinetics of translocation of Smac/DIABLO from the mitochondria to the cytosol in HeLa cells. 1236 42

To investigate the mechanisms underlying apoptosis in breast cancer cells, staurosporine was used as an apoptotic stimulus in the human breast cancer cell lines MCF-7 and T47D. Staurosporine induced dose and time dependent increases in DNA fragmentation which was abrogated by z-VAD-fmk. MCF-7 cells did not express caspase-3, suggesting that DNA fragmentation occurred in the absence of caspase-3 and that other caspases may be involved. Staurosporine induced DEVDase activity in T47D cells suggesting the involvement of caspase-3 and/or caspase-7, yet there was no DEVDase activity in MCF-7 cells, probably ruling out the involvement caspase-7. However, staurosporine induced the cleavage of pro-caspase-6 in MCF-7 cells, but not in T47D cells. Caspase dependent PARP cleavage was detected in MCF-7 cells at 3 h, whereas only partial PARP cleavage was detected in T47D cells and then only after 24 h. Moreover, staurosporine led to cytochrome c release at 2 h in MCF-7 cells and 6 h in T47D cells. In addition, a time dependent and caspase-independent reduction of the mitochondrial transmembrane potential was observed; which appeared to occur after the release of cytochrome c. Translocation of Bax from the cytosol to mitochondria was observed in both cell types, and this preceded cytochrome c release in both T47D and MCF-7 cells. Apoptotic events in both cell types differ temporally, involving activation of different caspases and mitochondrial changes.
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PMID:Apoptotic mechanisms in T47D and MCF-7 human breast cancer cells. 1237 8

Caspase-3 is a major cell death effector protease in the adult and neonatal nervous system. We found a greater number and higher density of cells in the cortex of caspase-3(-/-) adult mice, consistent with a defect in developmental cell death. Caspase-3(-/-) mice were also more resistant to ischemic stress both in vivo and in vitro. After 2 h of ischemia and 48 h of reperfusion, cortical infarct volume was reduced by 55%, and the density of terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling-positive cells was decreased by 36% compared with wild type. When subjected to oxygen-glucose deprivation (2 h), cortical neurons cultured from mice deficient in caspase-3 expression were also more resistant to cell death by 59%. Mutant brains showed caspase-specific poly(ADP-ribose) polymerase cleavage product (85-kDa fragment) in vivo and in vitro, suggesting redundant mechanisms and persistence of caspase-mediated cell death. In the present study, we found that caspase-8 mediated poly(ADP-ribose) polymerase cleavage in caspase-3(-/-) neurons in vivo and in vitro. In addition, mutant neurons showed no evidence of compensatory activation by caspase-6 or caspase-7 after ischemia. Taken together, these data extend the pharmacological evidence supporting an important role for caspase-3 and caspase-8 as cell death mediators in mammalian cortex and indicate the potential advantages of targeting more than a single caspase family member to treat ischemic cell injury.
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PMID:Caspase activation and neuroprotection in caspase-3- deficient mice after in vivo cerebral ischemia and in vitro oxygen glucose deprivation. 1241 17

DNA damaging agents up-regulate levels of the Fas receptor or its ligand, resulting in recruitment of Fas-associated death domain (FADD) and autocatalytic activation of caspase-8, consequently activating the executioner caspases-3, -6, and -7. We found that human epidermal keratinocytes exposed to a vesicating dose (300 microm) of sulfur mustard (SM) exhibit a dose-dependent increase in the levels of Fas receptor and Fas ligand. Immunoblot analysis revealed that the upstream caspases-8 and -9 are both activated in a time-dependent fashion, and caspase-8 is cleaved prior to caspase-9. These results are consistent with the activation of both death receptor (caspase-8) and mitochondrial (caspase-9) pathways by SM. Pretreatment of keratinocytes with a peptide inhibitor of caspase-3 (Ac-DEVD-CHO) suppressed SM-induced downstream markers of apoptosis. To further analyze the importance of the death receptor pathway in SM toxicity, we utilized Fas- or tumor necrosis factor receptor-neutralizing antibodies or constructs expressing a dominant-negative FADD (FADD-DN) to inhibit the recruitment of FADD to the death receptor complex and block the Fas/tumor necrosis factor receptor pathway following SM exposure. Keratinocytes pretreated with Fas-blocking antibody or stably expressing FADD-DN and exhibiting reduced levels of FADD signaling demonstrated markedly decreased caspase-3 activity when treated with SM. In addition, the processing of procaspases-3, -7, and -8 into their active forms was observed in SM-treated control keratinocytes, but not in FADD-DN cells. Blocking the death receptor complex by expression of FADD-DN additionally inhibited SM-induced internucleosomal DNA cleavage and caspase-6-mediated nuclear lamin cleavage. Significantly, we further found that altering the death receptor pathway by expressing FADD-DN in human skin grafted onto nude mice reduces vesication and tissue injury in response to SM. These results indicate that the death receptor pathway plays a pivotal role in SM-induced apoptosis and is therefore a target for therapeutic intervention to reduce SM injury.
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PMID:Expression of dominant-negative Fas-associated death domain blocks human keratinocyte apoptosis and vesication induced by sulfur mustard. 1248 51

Caspase-3 is an intracellular cysteine protease, activated as part of the apoptotic response to cell injury. Its interest as a therapeutic target has led many to pursue the development of inhibitors. To date, only one series of nonpeptidic inhibitors have been described, and these have limited selectivity within the caspase family. Here we report the properties of a series of anilinoquinazolines (AQZs) as potent small molecule inhibitors of caspase-3. The AQZs inhibit human caspase-3 with Ki values in the 90 to 800 nM range. A subset of AQZs are equipotent against caspase-6, although most lack activity against this isoform and caspase-1, -2, -7, and -8. The AQZs inhibit endogenous caspase-3 activity toward a cell permeable, exogenously added substrate in staurosporine-treated SH-SY5Y cells. The AQZs reduce biochemical and cellular features of apoptosis that are thought to be a consequence of caspase-3 activation including DNA fragmentation, TUNEL staining, and the various morphological features that define the terminal stages of apoptotic cell death. Moreover, the AQZs also inhibit apoptosis induced by nerve growth factor withdrawal from differentiated PC12 cells. Thus, the AQZs represent a new and structurally novel class of inhibitors, some of which selectively inhibit caspase-3 and will thereby allow evaluation of the role of caspase-3 activity in various cellular models of apoptosis.
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PMID:Novel small molecule inhibitors of caspase-3 block cellular and biochemical features of apoptosis. 1249 Jun 20

Evidence from live cell bioassays shows that the flat mucosa from patients with colon cancer exhibits resistance to bile salt-induced apoptosis. Three independent cell lines derived from the colonic epithelial cell line HCT-116 were selected for resistance to bile salt-induced apoptosis. These cell lines were developed as tissue culture models of apoptosis resistance. Selection was carried out for resistance to apoptosis induced by sodium deoxycholate (NaDOC), the bile salt found in highest concentrations in human fecal water. Cultures of HCT-116 cells were serially passaged in the presence of increasing concentrations of NaDOC. The resulting apoptosis resistant cells were able to grow at concentrations of NaDOC (0.5 mM) that cause apoptosis in a few hours in unselected HCT-116 cells. These cells were then analyzed for changes in gene expression. Observations from cDNA microarray, 2-D gel electrophoresis/MALDI-mass spectroscopy, and confocal microscopy of immunofluorescently stained preparations indicated underexpression or overexpression of numerous genes at either the protein or mRNA level. Genes that may play a role in apoptosis and early stage carcinogenesis have been identified as upregulated in these cell lines, including Grp78, Bcl-2, NF-kappaB(p50), NF-kappaB(p65), thioredoxin peroxidase (peroxiredoxin) 2, peroxiredoxin 4, maspin, guanylate cyclase activating protein-1, PKCzeta, EGFR, Ras family members, PKA, PI(4,5)K, TRAF2 and BIRC1 (IAP protein). Under-expressed mRNAs included BNIP3, caspase-6, caspase-3 and serine protease 11. NF-kappaB was constitutively activated in all three resistant cell lines, and was responsible, in part, for the observed apoptosis resistance, determined using antisense oligonucleotide strategies. Molecular and cellular analyses of these resistant cell lines has suggested potential mechanisms by which apoptosis resistance may develop in the colonic epithelium in response to high concentrations of hydrophobic bile acids that are associated with a Western-style diet. These analyses provide the rationale for the development of hypothesis-driven intermediate biomarkers to assess colon cancer risk on an individual basis.
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PMID:Development and molecular characterization of HCT-116 cell lines resistant to the tumor promoter and multiple stress-inducer, deoxycholate. 1250 30

We investigated through which mechanisms ceramide increased oxidative damage to induce leukemia HL-60 cell apoptosis. When 5 microm N-acetylsphingosine (C(2)-ceramide) or 20 microm H(2)O(2) alone induced little increase of reactive oxygen species (ROS) generation as judged by the 2'-7'-dichlorofluorescin diacetate method, 20 microm H(2)O(2) enhanced oxidative damage as judged by ROS accumulation, and thiobarbituric acid-reactive substance production after pretreatment with 5 microm C(2)-ceramide at least for 12 h. The treatment with a catalase inhibitor, 3-amino-1h-1,2,4-triazole, increased oxidative damage and apoptosis induced by H(2)O(2), and in contrast, purified catalase inhibited the enhancement of oxidative damage by H(2)O(2) in ceramide-pretreated cells, suggesting that the oxidative effect of ceramide is involved in catalase regulation. Indeed, C(2)-ceramide inhibited the activity of immunoprecipitated catalase and decreased the levels of catalase protein in a time-dependent manner. Moreover, acetyl-Asp-Met-Gln-Asp-aldehyde, which dominantly inhibited caspase-3 and blocked the increase of oxidative damage and apoptosis due to C(2)-ceramide-induced catalase depletion at protein and activity levels. In vitro, active and purified caspase-3, but not caspase-6, -8, and -9, inhibited catalase activity and induced the proteolysis of catalase protein whereas these in vitro effects of caspase-3 were blocked by acetyl-Asp-Met-Gln-Asp-aldehyde. Taken together, it is suggested that H(2)O(2) enhances apoptosis in ceramide-pretreated cells, because ceramide increases oxidative damage by inhibition of ROS scavenging ability through caspase-3-dependent proteolysis of catalase.
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PMID:Ceramide increases oxidative damage due to inhibition of catalase by caspase-3-dependent proteolysis in HL-60 cell apoptosis. 1251 68


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