Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.56 (caspase-3)
 35,750 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Whilst the role of ceramide, a second messenger of the sphingolipid family, in the initiation of receptor-mediated apoptosis is controversial, a growing body of evidence is emerging for a role of ceramide in the amplification of apoptosis via mitochondrial perturbations that culminate in the activation of execution caspases. Treatment of Jurkat T cells with the cell-permeable analog, C(2)-ceramide, resulted in the rapid onset of apoptosis as evidenced by Annexin V-FITC staining of externalised phosphatidylserine residues. Cells bearing this early apoptotic marker had a reduced mitochondrial transmembrane potential (Delta(Psi)m) that was preceded by the release of cytochrome c from mitochondria. Subsequent activation of caspase-3 provides the link between these ceramide-induced mitochondrial changes and execution caspases that ultimately result in the physical destruction of the cell. Collectively these results demonstrate that ceramide signalling results in caspase-mediated apoptosis via mitochondrial cytochrome c release and are further supportive of the role of ceramide in the amplification of apoptosis.
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PMID:Mitochondrial cytochrome c release precedes transmembrane depolarisation and caspase-3 activation during ceramide-induced apoptosis of Jurkat T cells. 1220 71

Inhaled nitric oxide (iNO) is used clinically to treat pulmonary hypertension in newborns, often in conjunction with hyperoxia (NO/O2). Prolonged exposure to NO/O2 causes synergistic lung injury and death of lung epithelial cells. To explore the mechanisms involved, oxygen-resistant HeLa-80 cells were exposed to NO +/- O2. Exposure to NO and O2 induced a synergistic cytotoxicity, accompanied with apoptotic characteristics, including elevated caspase-3-like activity, Annexin V incorporation, and nuclear condensation. This apoptosis was associated with a synergistic suppression of NF-kappaB activity. Cells lacking functional NF-kappaB p65 subunit were more sensitive to NO/O2 than their wild type counterparts. This injury was partially rescued by transfection with a p65 expression construct, suggesting an inverse relationship between NF-kappaB and susceptibility to the cytotoxicity of NO/O2. Despite the reduced NF-kappaB activity in cells exposed to NO +/- O2, IkappaBalpha was degraded, suggesting that pathways regulating the steady-state levels of IkappaB were not involved. However, exposure to NO/O2 caused a marked reduction in nuclear localization and an increase in protein carbonyl formation of NF-kappaB p65 subunit. These results suggest that NO/O2-induced apoptosis occurs by suppressing NF-kappaB activity.
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PMID:Suppression of nuclear factor-kappa B activity by nitric oxide and hyperoxia in oxygen-resistant cells. 1221 28

We have previously proposed the horseradish peroxidase (HRP) and the non-toxic plant hormone indole-3-acetic acid (IAA) as a novel system for gene-directed enzyme/prodrug therapy (GDEPT). The cytotoxic potential of HRP/IAA GDEPT and the induction of a bystander effect were demonstrated in vitro under normoxic as well as hypoxic tumour conditions. To date, the chemical agents and the cellular targets involved in HRP/IAA-mediated toxicity have not been identified. In the present work, some of the molecular and morphological features of the cells treated with HRP/IAA gene therapy were analysed. Human T24 bladder carcinoma cells transiently transfected with the HRP cDNA and exposed to the prodrug IAA showed chromatin condensation, formation of apoptotic bodies, DNA fragmentation, and Annexin V binding. Similar effects were observed when the cells were incubated with the apoptotic agent cisplatin. Caspases appeared to be involved as effectors in HRP/IAA-mediated apoptosis, since treatment with a general caspase inhibitor decreased the fraction of cells with micronuclei (MN) by 30%, with fragmented DNA by 50%, and with condensed chromatin by 60%. However, very little degradation of one of the downstream targets of caspase-3, PARP, could be detected, and apoptosis alone did not appear to account for the killing levels measured with a clonogenic assay. The effect of HRP/IAA treatment on cell cycle progression was also investigated, and a rapid cytostatic effect, equally affecting all phases of the division cycle, was observed.
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PMID:Mechanisms of cytotoxicity induced by horseradish peroxidase/indole-3-acetic acid gene therapy. 1224 74

We have recently described a novel retinoid 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalenecarboxylic acid (CD437/AHPN) that induces apoptosis in a number of malignant cell types. We now describe our studies examining the effects of CD437 and a nonretinoidal analog (MM002) on the in vitro proliferation of the ALL-REH cell line, the in vitro and in vivo growth of a novel Epstein-Barr virus-negative (EBV(-)) B-cell chronic lymphocytic leukemia (B-CLL) cell line (WSU-CLL), and primary cultures of human B-CLL and acute lymphoblastic leukemia (ALL) cells. CD437 and MM002 induce apoptosis in both cell lines, as indicated by the activation of caspase-2 and caspase-3, cleavage of poly(adenosine diphosphate-ribose) (poly(ADP-ribose)) polymerase, increase in annexin V binding, and subsequent nuclear fragmentation. CD437-mediated apoptosis was not associated with the modulation of Bcl-2, Bax, or Mcl-1 levels, but was associated with the cleavage of the antiapoptotic protein Bcl-X(L) to a proapoptotic 18-kD form. This cleavage of Bcl-X(L) was dependent on caspase-3 activation since Bcl-X(L) cleavage and apoptosis were inhibited by the caspase-3 inhibitor Z-DVED-fmk. CD437 markedly inhibited the growth of WSU-CLL cells in severe combined immunodeficiency (SCID) mice. Tumor growth inhibition, growth delay, and log cell kill were 85.7%, 21 days, and 2.1, respectively, in the treated mice. Moreover, 1 of the 5 treated mice was tumor-free longer than 150 days and thus was considered cured. Exposure of primary cultures of both B-CLL and ALL cells obtained from patients to CD437 and MM002 resulted in their apoptosis. These results suggest that CD437 and MM002 analogs may have a potential role in the treatment of B-CLL and ALL.
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PMID:Induction of apoptosis of human B-CLL and ALL cells by a novel retinoid and its nonretinoidal analog. 1235 3

Oxidized LDL (oxLDL) may contribute to the accumulation of apoptotic cells in atherosclerotic plaques. Although it is well established in monophasic chemical systems that the highly unsaturated EPA and DHA will oxidize more readily than FA that contain fewer double bonds, our previous studies showed that enrichment of LDL, which has discrete polar and nonpolar phases, with these FA did not increase oxidation. The objective of this study was to compare the extent of apoptosis induced by EPA/DHA-rich oxLDL to that induced by EPA/DHA-non-rich oxLDL in U937 cells. LDL was obtained from one healthy subject three times before and after supplementation for 5 wk with 15 g/d of fish oil (FO), an amount easily obtainable from a diet that contains fatty fish. After supplementation, an EPA/DHA-rich LDL was obtained. Oxidative susceptibility of LDL, as determined by measuring the formation of conjugated dienes and the accumulation of cholesteryl ester hydroperoxides, was not higher in EPA/DHA-rich LDL. The oxLDL-induced cell apoptosis was detected by the activation of caspase-3, the translocation of PS to the outer surface of the plasma membrane using the Annexin V-fluorescein isothiocyanate binding assay, and the presence of chromatin condensation and nuclear fragmentation using the 4,6-diamidino-2-phenylindole staining assay. All three measures showed that after FO supplementation, EPA/DHA-rich oxLDL-induced cell apoptosis decreased. The decrease was not related to the concentration of lipid hydroperoxides. This study suggests that a possible protective effect of EPA/DHA-rich diets on atherosclerosis may be through lessening cell apoptosis in the arterial wall.
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PMID:Enrichment of LDL with EPA and DHA decreased oxidized LDL-induced apoptosis in U937 cells. 1237 50

Eicosapentaenoic acid (EPA; 20:5n-3) may reduce the cell number in cultured leukemia/lymphoma cells owing to reduced cell proliferation, induction of cell death, or a combination of these processes. EPA has been shown to promote apoptosis in Ramos cells, and our present study was focused on a possible cell cycle arrest and the pathways by which the apoptotic process is induced. Apoptosis may proceed along the intrinsic (mitochondrial) or the extrinsic (death receptor) pathway, which are mediated via different caspases. Caspases are a class of homologous cysteine proteases recognized as pivotal mediators of apoptosis. We investigated whether EPA affects progression of the cell cycle or promotes apoptosis directly. By incorporation of [3H]thymidine and [3H]valine, we showed that DNA, as well as protein synthesis, was reduced after incubation of Ramos cells with EPA for 6 h. We monitored cell cycle distribution by 5-bromo-2'-deoxyuridine staining and observed no cell cycle arrest in the EPA-incubated cells. Incubation of cells with EPA caused PS-flipping, as demonstrated by annexin V-binding (flow cytometry), and cleavage of poly(ADP-ribose) polymerase measured by Western blot analysis. Furthermore, we observed increased activity of caspase-3 and -9, but not of caspase-8. Whereas inhibitors of caspase-3 and -9 reduced EPA-induced apoptosis, inhibition of caspase-8 did not. This suggests that EPA may promote apoptosis via the intrinsic pathway in Ramos cells. Thus, the reduction in cell number can be explained by a direct apoptotic effect of EPA rather than via cell cycle arrest.
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PMID:Eicosapentaenoic acid promotes apoptosis in Ramos cells via activation of caspase-3 and -9. 1237 51

The objectives of this study were to determine if human ejaculated sperm exhibit active caspases and if caspase-dependent apoptosis markers are identifiable. Sperm from fertile donors and infertile patients were examined after gradient separation into leukocyte-free fractions of high and low motility. Sperm were evaluated for motion parameters, morphology, caspase activation, and apoptosis markers including phosphatidylserine (PS) translocation (annexin V binding) and DNA fragmentation (TUNEL). Active caspase-3 was detected by immunofluorescent microscopy in a small proportion of sperm in situ, in fractions of high and low motility sperm of patients and donors, but low motility fractions had significantly higher numbers of positive sperm. Immunoblot analysis detected inactive procaspase-3 (32 kDa) in all fractions of low sperm motility from patients and donors, while active caspase-3 (17 kDa) was only detected by immunoblotting in a limited number of low motility fractions from patients and in even fewer fractions from donors. Caspase enzymatic activity, as measured using the fluorogenic substrate DEVD-afc, was higher in patients than in donors in both low and high motility fractions. Annexin V staining and DNA fragmentation were detected in a proportion of sperm, with a higher frequency in the low motility fractions. A significant positive correlation between in-situ active caspase-3 in the sperm midpiece and DNA fragmentation was observed in the low motility fractions of patients, suggesting that caspase-dependent apoptotic mechanisms could originate in the cytoplasmic droplet or within mitochondria and function in the nucleus. These data suggest that in some ejaculated sperm populations, caspases are present and may function to increase PS translocation and DNA fragmentation.
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PMID:Caspase activity and apoptotic markers in ejaculated human sperm. 1239 10

Mycobacterium tuberculosis (MTB) can induce apoptosis in monocytes/macrophages both in vitro and in vivo, and this phenomenon is associated with mycobacterial survival. The present study addresses the possibility that apoptotic and inflammatory pathways could coexist through a caspase-1-mediated mechanism. In this context, a caspase-1 inhibitor (YVAD), but not caspase-3 (DEVD) or caspase-4 (LEVD) inhibitors, was able to strongly inhibit MTB-induced apoptosis. Moreover, caspase-1 activity was confirmed by the increased maturation of interleukin (IL)-1beta. Of interest, IL-1beta and tumor necrosis factor (TNF)-alpha were produced massively in the course of infection, and both were inhibited by YVAD pretreatment. To determine whether TNF-alpha was produced actively by apoptotic cells, the intracytoplasmatic cytokine content and apoptotic phenotype were analyzed at the single-cell level. Results showed a progressive increase of TNF-alpha production in annexin V-positive cells. These results indicate that MTB-induced apoptosis is associated with proinflammatory cytokine production.
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PMID:Proinflammatory cytokines in the course of Mycobacterium tuberculosis-induced apoptosis in monocytes/macrophages. 1240 97

Rad21 is one of the major cohesin subunits that holds sister chromatids together until anaphase, when proteolytic cleavage by separase, a caspase-like enzyme, allows chromosomal separation. We show that cleavage of human Rad21 (hRad21) also occurs during apoptosis induced by diverse stimuli. Induction of apoptosis in multiple human cell lines results in the early (4 h after insult) generation of 64- and 60-kDa carboxy-terminal hRad21 cleavage products. We biochemically mapped an apoptotic cleavage site at residue Asp-279 (D(279)) of hRad21. This apoptotic cleavage site is distinct from previously described mitotic cleavage sites. hRad21 is a nuclear protein; however, the cleaved 64-kDa carboxy-terminal product is translocated to the cytoplasm early in apoptosis before chromatin condensation and nuclear fragmentation. Overexpression of the 64-kDa cleavage product results in apoptosis in Molt4, MCF-7, and 293T cells, as determined by TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) and Annexin V staining, assaying of caspase-3 activity, and examination of nuclear morphology. Given the role of hRad21 in chromosome cohesion, the cleaved C-terminal product and its translocation to the cytoplasm may act as a nuclear signal for apoptosis. In summary, we show that cleavage of a cohesion protein and translocation of the C-terminal cleavage product to the cytoplasm are early events in the apoptotic pathway and cause amplification of the cell death signal in a positive-feedback manner.
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PMID:Linking sister chromatid cohesion and apoptosis: role of Rad21. 1241 29

1. A novel immunosuppressant FTY720 caused a significant decrease in peripheral T lymphocytes, but not in B lymphocytes upon oral administration. This decrease was mainly a result of FTY720-induced apoptosis. In this study, we confirmed FTY720-induced T cell selective apoptosis using lymphoma cell lines in vitro. 2. Viability loss, DNA fragmentation, Annexin V binding, and caspases activation (caspase-3, -8, and -9) were observed in Jurkat cells (T lymphoma cells), but not significantly in BALL-1 cells (B lymphoma cells). These results indicated that FTY720 selectively induced apoptosis in T cell lymphoma to a greater extent than in B cell lymphoma, a finding that is similar to the result observed when FTY720 was treated with T lymphocytes and B lymphocytes in vitro. 3. FTY720 released cytochrome c from mitochondria in Jurkat intact cells as well as from isolated Jurkat mitochondria directly, but not from mitochondria in BALL-1 cells nor from isolated BALL-1 mitochondria. 4. BALL-1 cells and B cells had more abundant mitochondria-localized anti-apoptotic protein Bcl-2 than did Jurkat cells and T cells. 5. FTY720-induced apoptosis is inhibited by the overexpression of Bcl-2, suggesting that the cellular Bcl-2 level regulates the sensitivity to FTY720.
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PMID:T cell selective apoptosis by a novel immunosuppressant, FTY720, is closely regulated with Bcl-2. 1242 67


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