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)

We have studied different biochemical indicators of apoptosis in okadaic acid-treated normal human lung fibroblasts (NHLF). Apoptosis was identified by fluorimetric microplate measurements of DNA content, caspase-3 activation and changes in mitochondrial and plasma membrane after 1-48-h treatments with 1-1000 nM okadaic acid. Cells exposed to okadaic acid showed activation of caspase-3, decreased DNA content (<50% of controls at >100 nM okadaic acid after 12 h of incubation) and translocation of phosphatidylserine to the outer leaflet of the plasma membrane, as indicated by the increase in Merocyanine 540 fluorescence after 4 h of incubation with more than 250 nM okadaic acid. Decreased mitochondrial membrane potential (53-98% of controls) was observed with MitoTracker Red CMXRos in all cases, which indicated an active role of mitochondria during the early phase of apoptosis. However, reactive oxygen species were significantly reduced in okadaic acid-treated fibroblasts (50-70% of controls at 1000 nM after 3 h of incubation), which indicates that ROS cannot be considered as a hallmark of apoptosis in okadaic acid-treated cells. These results provide evidence of apoptotic events induced by okadaic acid in NHLF, which can be detected by means of sensitive and reliable fluorimetric microplate assays.
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PMID:Apoptotic events induced by the phosphatase inhibitor okadaic acid in normal human lung fibroblasts. 1137 92

Methylglyoxal (MG) is a physiological metabolite, but it is known to be toxic, inducing stress and causing apoptosis. Our previous studies demonstrated that MG induced apoptosis in Jurkat cells by activating the c-Jun N-terminal kinase (JNK) signal transduction pathway, which induced an obvious decrease in mitochondrial membrane potential, followed by caspase-3 activation. Here, we observed that MG-induced apoptosis was associated with both rapid production of superoxide anion (O(2)(-)) followed by a marked increase in ROS and striking and temporal activation of ASK1. Overexpression of wild-type ASK1 could enhance the rate of apoptosis induced by MG, whereas the expression of the kinase-inactive form of ASK1 notably prevented cells from MG-induced death. NAC and PDTC blocked the activation of ASK1 and MG-induced apoptosis completely. Moreover, nonthiol antioxidants SOD-mimic MnTBAP and catalase together obviously inhibited MG-induced ASK1 activation and apoptosis induction. Correspondingly, MG-mediated ASK1 activation was enhanced by diethyldithiocarbamate (DDC). Addition of antioxidant into the culture of cells at a later stage (4-8 h after the initial MG treatment) failed to prevent their death. These results suggest that activating ASK1 at the early stage linking to production of O(2)(-) is crucial for subsequent progression of apoptosis in MG-treated Jurkat cells.
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PMID:Superoxide-mediated early oxidation and activation of ASK1 are important for initiating methylglyoxal-induced apoptosis process. 1149 80

Seven structurally related flavonoids including luteolin, nobiletin, wogonin, baicalein, apigenin, myricetin and fisetin were used to study their biological activities on the human leukemia cell line, HL-60. On MTT assay, wogonin, baicalein, apigenin, myricetin and fisetin showed obvious cytotoxic effects on HL-60 cells, with wogonin and fisetin being the most-potent apoptotic inducers among them. The cytotoxic effects of wogonin and fisetin were accompanied by the dose- and time-dependent appearance of characteristics of apoptosis including DNA fragmentation, apoptotic bodies and the sub-G1 ratio. Treatment with an apoptosis-inducing concentration of wogonin or fisetin causes rapid and transient induction of caspase 3/CPP32 activity, but not caspase 1 activity. Further, cleavage of poly(ADP-ribose) polymerase (PARP) and decrease of pro-caspase 3 protein were detected in wogonin- and fisetin-treated HL-60 cells. An increase in the pro-apoptotic protein, bax, and a decrease in the anti-apoptotic protein, Mcl-1, were detected in fisetin- and wogonin-treated HL-60 cells. However, Bcl-2, Bcl-XL, and Bad all remained unchanged in wogonin- and fisetin-treated HL-60 cells. In vitro chromatin digestion revealed that endonuclease activity was profoundly enhanced in wogonin- and fisetin-treated HL-60 cells, and the addition of ethylenediaminetetraacetic acid (EDTA) or ethyleneglycoltetraacetic acid (EGTA) into the reaction blocked endonuclease activation and at an optimum pH of 7.5. The caspase 3 inhibitor, Ac-DEVD-CHO, but not the caspase 1 inhibitor, Ac-YVAD-CHO, attenuated wogonin- and fisetin-induced DNA ladders, PARP cleavage, and endonuclease activation. Pretreatment of HL-60 cells with N-acetyl-cysteine or catalase efficiently inhibited H(2)O(2) (200 microM)-induced apoptosis, but showed no inhibitory effect on wogonin- and fisetin-induced DNA ladders, caspase 3 activation, or bax protein induction. Decrease in endogenous ROS production was detected in wogonin- and fisetin-treated HL-60 cells by DCHF-DA assay. In conclusion, our experiments indicate that a decrease in intracellular peroxide level was involved in wogonin- and fisetin-induced apoptosis; activation of caspase 3 and endonuclease, induction of bax protein and suppression of Mcl-1 protein were detected in the process.
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PMID:Wogonin and fisetin induce apoptosis in human promyeloleukemic cells, accompanied by a decrease of reactive oxygen species, and activation of caspase 3 and Ca(2+)-dependent endonuclease. 1184 97

In an investigation of the antitumor effects of 2-methoxyestradiol (2-ME) in combination with other reactive oxygen generating treatments, 2-ME (0.5 microM) was found to completely inhibit cell proliferation of rat DS-sarcoma cells in vitro, with 71% of cells dying after exposure to 5 microM 2-ME. Concentration-dependent increases in ROS-formation, lipid peroxidation and mitochondrial changes were also observed, and an elevation in caspase-3 activity resulted in DNA fragmentation and apoptosis. Combination of 2-ME with hypoxanthine and xanthine oxidase enhanced in vitro cytotoxicity. In vivo, 2-ME caused a slight inhibition of tumor growth, with no tumors cured. Combination of 2-ME treatment with localized 44 degrees C hyperthermia, respiratory hyperoxia and xanthine oxidase caused a tumor growth delay with 51% of tumors cured. These results suggest that amplifying the levels of reactive oxygen species within tumor tissue with substances such as 2-ME may prove to be a promising strategy for adjuvant treatment of solid tumors.
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PMID:2-Methoxyestradiol enhances reactive oxygen species formation and increases the efficacy of oxygen radical generating tumor treatment. 1243 19

Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is an active constituent of Rheum palmatum, and showed inhibitory activity on lipopolysaccharide-induced NO production in our previous study. However, the apoptosis-inducing activity of emodin has remained undefined. Among three structurally related anthraquinones, including emodin, physcion, and chrysophanol, emodin showed the most potent cytotoxic effects on HL-60 cells, accompanied by the dose- and time-dependent appearance of characteristics of apoptosis including an increase in DNA ladder intensity, morphological changes, appearance of apoptotic bodies, and an increase in hypodiploid cells. Emodin at apoptosis-inducing concentrations causes rapid and transient induction of caspase 3/CPP32 activity, but not caspase 1 activity, according to cleavage of caspase 3 substrates poly(ADP-ribose) polymerase and D4-GDI proteins, the appearance of cleaved caspase 3 fragments being detected in emodin- but not physcion- or chrysophanol-treated HL-60 cells. A decrease in the anti-apoptotic protein, Mcl-1, was detected in emodin-treated HL-60 cells, whereas other Bcl-2 family proteins including Bax, Bcl-2, Bcl-XL, and Bad remained unchanged. The caspase 3 inhibitor, Ac-DEVD-CHO, but not the caspase 1 inhibitor, Ac-YVAD-CHO, attenuated emodin-induced DNA ladders, associated with the blockage of PARP and D4-GDI cleavage. Free radical scavenging agents including NAC, catalase, SOD, ALL, DPI, L-NAME and PDTC showed no preventive effect on emodin-induced apoptotic responses, whereas NAC, CAT and PDTC prevented HL-60 cells from ROS (H(2)O(2))-induced apoptosis through inhibition of caspase 3 cascades. Induction of catalase, but not SOD, activity was detected in emodin-treated HL-60 cells by in gel activity assays, and H(2)O(2)-induced intracellular peroxide level was significantly reduced by prior treatment of emodin in HL-60 cells. Our experiments provide evidence that emodin is an effective apoptosis inducer in HL-60 cells through activation of the caspase 3 cascade, but that it is independent of ROS production.
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PMID:Emodin induces apoptosis in human promyeloleukemic HL-60 cells accompanied by activation of caspase 3 cascade but independent of reactive oxygen species production. 1244 60

It is a known paradox that many TGF beta 1-producing tumor cells are resistant to this, otherwise, inhibitory cytokine. In a lymphoma of B-cell origin exogenous TGF beta 1 was able to induce apoptosis, suggesting that the apoptosis program can be switched on. The apoptosis induction was independent of the death receptors but dependent on mitochondrial pathway and caspase-3. Probably due to the weak starting signal, caspase-3 further activated caspase-8 which, through the Bid cleavage and Bax translocation into the mitochondria, provided an autocatalytic support for the apoptotic program. There is a time-gat between the early activation of Smad-dependent TIEG and the accumulation of ROS, therefore other participants that start the increase in mitochondrial membrane permeability should be identified.
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PMID:TGF beta 1 kills lymphoma cells using mitochondrial apoptotic pathway with the help of caspase-8. 1255 6

A 3:1 combination of 5-chloro-2-methyl-4-isothiazolin-3-one (CMI) and 2-methyl-4-isothiazolin-3-one (MI) is widely used to preserve cosmetic products. We show here that CMI/MI induced apoptosis in normal human keratinocytes (NHK) as at low concentrations (0.001-0.05% documented by subdiploid DNA content and phosphatidylserine exposure, while at the highest concentration (0.1% as supplied, 15 p.p.m.) the response was necrosis. Various molecular events accompanied the cytotoxic effects of CMI/MI. Generation of ROS and hyperpolarization of mitochondrial transmembrane potential (DeltaPsim) were early events, followed by increased Fas expression and activation of caspase-8, and then activation of caspase-3 and -9. The drop in DeltaPsim occurred only later in the cell death pathway, when NHK showed signs of apoptosis. Pretreatment of cells for 2 h with the redox-active agent N-acetyl-L-cysteine conferred complete protection against the CMI/MI-induced cytotoxic effects, DeltaPsim loss, and apoptosis. The pan-caspase inhibitor Z-Val-Ala-Asp(OMe)-CH2F blocked the CMI/MI-induced apoptosis without preventing ROS generation and the drop in DeltaPsim. These results indicate that the generation of ROS plays an important part in mediating apoptosis and necrosis associated with CMI/MI treatment. This new aspect of the in vitro toxicity of CMI/MI may provide important information about the relationship between the preservative's in vitro apoptotic activity and its in vivo toxicity.
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PMID:Involvement of oxidative stress in apoptosis induced by a mixture of isothiazolinones in normal human keratinocytes. 1288 Apr 25

Trichothecene mycotoxins cause immunosuppression by inducing apoptosis in lymphoid tissue. Trichothecene-induced leukocyte apoptosis can be augmented by bacterial lipopolysaccharide (LPS) but the mechanisms involved in this potentiating effect are not completely understood. The objective of this study was to test the hypothesis that the trichothecene deoxynivalenol (DON, vomitoxin) can interact with LPS directly and other mediators or agonists associated with immune/inflammatory responses to induce apoptosis in primary murine leukocyte cultures. Primary leukocyte suspensions were prepared from murine thymus (TH), spleen (SP), bone marrow (BM) and Peyer's patches (PP) and then cultured with DON in the absence or presence of LPS, prostaglandin E2 (PGE2), anti-immunoglobulin (as antigen mimic), dexamethasone, Fas ligand, or TNF-alpha. Cytotoxicity and apoptosis were evaluated by MTT assay and morphologic assays, respectively. DON was found to inhibit LPS-induced proliferation and dexamethasone-induced apoptosis in SP cultures. In contrast, potentiation of DON-induced apoptosis and cytotoxicity was observed in BM cultures treated with anti-Fas and in TH cultures treated with TNF-alpha. When potentiation of DON-induced apoptosis by TNF-alpha was assessed using pharmacological inhibitors, generation of ROS, intracellular Ca2+, p38/SAPK, and caspase-3 activation were found to play roles. Taken together, these data demonstrate that LPS and its downstream mediators can interact with trichothecenes to modulate proliferative, cytotoxic and apoptotic outcomes in leukocytes in a tissue-specific manner.
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PMID:Potentiation of trichothecene-induced leukocyte cytotoxicity and apoptosis by TNF-alpha and Fas activation. 1459 25

C-phycocyanin, which is a major biliprotein of the blue-green algae, has been shown to possess cyclooxygenase-2 inhibitory activity. We have studied the effect of phycocyanin on a rat histiocytic tumor line. AK-5 cells are induced into apoptotic death program when treated with phycocyanin, which involves the activation of caspase-3. Phycocyanin-mediated apoptotic death is induced through the generation of reactive oxygen radicals. Free radical scavengers inhibited phycocyanin-induced apoptotic death in AK-5 cells. Bcl-2, an inhibitor of apoptosis, is shown to regulate ROS generation. Bcl-2 gene-transfected AK-5 cells are resistant to phycocyanin-induced death. Overexpression of Bcl-2 inhibited the production of ROS in phycocyanin-treated AK-5 cells. Thus, our observations demonstrate phycocyanin-induced apoptotic death in AK-5 cells, which is inhibited by Bcl-2 expression through the regulation of free radical generation. Phycocyanin, a natural product, could therefore be a possible chemotherapeutic agent through its apoptotic activity against tumor cells.
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PMID:Phycocyanin-mediated apoptosis in AK-5 tumor cells involves down-regulation of Bcl-2 and generation of ROS. 1461 90

Apoptosis and necrosis are distinct forms of cell death that occur in response to various agents. We studied the action of N-Acetyl-D-sphingosine (C2-ceramide) or N-hexanoyl-D-sphingosine (C6-ceramide) in human hepatoma HepG2 cell line. The cells were treated in vitro for 1-24 h. Cell toxicity was evaluated by MTT assay. DNA content was estimated by gel electrophoresis and flow cytometry. Measurement of mitochondrial respiration, analysis of cytochrome c release and caspase-3 activation were assessed in order to determine if either of these events in the induction of apoptosis and/or necrosis was predominant. We have demonstrated that C2 and C6-ceramide were cytotoxic in a time and dose-dependent manner. After 24 h of treatment with 100 microM of C2 and C6 the morphology (May-Giemsa staining) of treated cells displayed an apoptotic phenotype in C6-treated cells, confirmed by a high (sub-G1 peak > 20%) proportion by flow cytometry while a necrotic morphology was observed after C2-ceramide treatment, confirmed by DNA smearing in DNA electrophoresis. After C6-ceramide incubation, the respiratory chain was functional only slightly inhibited (20%), there was production of ATP, cytochrome c release without ROS production, activation of caspase-3 and induction of apoptosis. On the contrary, C2-ceramide inhibited the respiratory chain more intensely (80%) increased significantly ROS production, which resulted in an arrest of ATP production, no cytochrome c release and absence of caspase-3 activation. Finally after complete exhaustion of intracellular ATP, mitochondrial explosion induced necrotic cell death. In conclusion, evidence suggest that mitochondrial respiratory chain function is essential for controlling the decision of the cell to enter a apoptotic or necrosis process.
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PMID:Commitment to apoptosis by ceramides depends on mitochondrial respiratory function, cytochrome c release and caspase-3 activation in Hep-G2 cells. 1467 99


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