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)

Caspases are key molecules in the control of apoptosis, but relatively little is known about their contribution to eosinophil apoptosis. We examined caspase-3, -8, and -9 activities in receptor ligation-dependent apoptosis induction in the differentiated human eosinophilic cell line EoL-1. Differentiated EoL-1 exhibited bi-lobed nuclei, eosinophil-associated membrane receptors, and basic granule proteins. Annexin-V fluorescein isothiocyanate binding to EoL-1 revealed significant (P<0.01) apoptosis induction in cells cultured for 20 h with monoclonal antibodies (mAb) specific for CD45 (71%+/-4.3), CD45RA (58%+/-2.3), CD45RB (68%+/-2.4), CD95 (47%+/-2.6), and CD69 (52%+/-2.1) compared with control (23%+/-1.6) or CD45RO mAb (27%+/-3.9). The pan-caspase inhibitor Z-Val-Ala-Asp-fluoromethylketone (fmk) and inhibitors of caspase-8 (Z-Ile-Glu-Thr-Asp-fmk) and caspase-9 (Z-Leu-Glu-His-Asp-fmk) significantly inhibited mAb-induced apoptosis of EoL-1 but had no effect on constitutive (baseline) apoptosis at 16 and 20 h. Caspase activity was analyzed using the novel CaspaTag trade mark technique and flow cytometry. EoL-1 treated with pan-CD45, CD45RA, CD45RB, and CD95 mAb exhibited caspase-3 and -9 activation at 12 h post-treatment, which increased at 16 and 20 h. Activated caspase-8 was detected 12 and 16 h after ligation with CD45, CD45RA, CD45RB, and CD95 mAb followed by a trend toward basal levels at 20 h. CD69 ligation resulted in caspase-3 activation, a modest but significant activation of caspase-8, and a loss in mitochondrial transmembrane potential but had no significant effect on activation of caspase-9. Thus, the intrinsic and extrinsic caspase pathways are involved in controlling receptor ligation-mediated apoptosis induction in human eosinophils, findings that may aid the development of a more targeted, anti-inflammatory therapy for asthma.
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PMID:Membrane receptor-mediated apoptosis and caspase activation in the differentiated EoL-1 eosinophilic cell line. 1507 47

In our continuing search to discover bioactive compounds from natural products, we isolated six new clerodane diterpenes, caseamembrins A to F, from Casearia membranacea and examined their antiproliferative activities in human hormone-resistant prostate cancer PC-3 cells. All of these compounds displayed effective antiproliferative activity using sulforhodamine B assays and induced cell apoptosis by a terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL)-reaction technique. The data demonstrated that caseamembrin C was the most effective compound among these clerodane diterpenoids. Caseamembrin C induced down-regulation of Bcl-2 and Bcl-xL expression, while up-regulation of proapoptotic protein Mcl-1S (short chain), suggesting that these Bcl-2 family member proteins may play a role on arbitrating the apoptotic cell death. Caseamembrin C also induced the up-regulation of Fas ligand (FasL) expression, cleavage and activation of caspase-8 and caspase-9, Bid cleavage and activation of executor caspase-3. However, z-IETD-FMK (Z-Ile-Glu-Thr-Asp-fluoromethyl ketone, a selective caspase-8 inhibitor) almost completely inhibited caseamembrin C-induced Bid cleavage without any modification of caspase-9 activation, indicating that the extrinsic pathway of FasL/caspase-8/Bid cascade only played a minor role in the apoptotic signaling. Taken together, it is suggested that caseamembrin C-induced apoptosis is predominantly through the activation of intrinsic apoptosis pathways by causing the down-regulation of Bcl-2 and Bcl-xL expression, up-regulation of Mcl-1S protein and activation of caspase-9 and caspase-3.
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PMID:Investigation of extrinsic and intrinsic apoptosis pathways of new clerodane diterpenoids in human prostate cancer PC-3 cells. 1549 90

Synthetic triptycene analogs (TT code number) mimic the antitumor effects of daunorubicin (DAU) in vitro, but have the advantage of blocking nucleoside transport, inhibiting both DNA topoisomerase I and II activities, and retaining their efficacy in multidrug-resistant (MDR) tumor cells. Since TT bisquinones induce poly(ADP-ribose) polymerase-1 (PARP-1) cleavage at 6 h and internucleosomal DNA fragmentation at 24 h, which are, respectively, early and late markers of apoptosis, these antitumor drugs were tested for their ability to trigger the release of mitochondrial cytochrome c (Cyt c) and the caspase activation cascade in the HL-60 cell system. Based on their ability to reduce the viability of wild-type, drug-sensitive HL-60-S cells in the nanomolar range, six lead antitumor TT bisquinones have been identified so far: TT2, TT13, TT16, TT19, TT24 and TT26. In accord with the fact that effector caspase-3 is responsible for PARP-1 cleavage, 4 microM concentrations of DAU and these TT bisquinones all maximally induce caspase-3 activity at 6 h in HL-60-S cells, an effect which persists when the drugs are removed after a 1-h pulse treatment. Since caspase-3 may be activated by initiator caspase-9 and -8, it is significant to show that such caspase activation cascade is induced by 4 microM DAU and TT bisquinones at 6 h in HL-60-S cells. Although the relationship is not perfect, the ability of TT analogs to induce caspase-3, -8 and -9 activities may be linked to their quinone functionality and cytotoxicity. Interestingly, 4 microM concentrations of TT bisquinones retain their ability to induce caspase-3, -8 and -9 activities at 6 h in the MDR HL-60-RV cell line where 4 microM DAU becomes totally ineffective. The release of mitochondrial Cyt c is also detected within 6 h in HL-60-S cells treated with 4 microM DAU or TT bisquinones, a finding consistent with the fact that Cyt c is the apoptotic trigger that activates caspase-9. Caspase-2 and -8 may both act upstream of mitochondria to promote Cyt c release, but caspase-2 is already maximally activated 6 h after 4 microM DAU or TT13 treatments, whereas DAU- or TT-induced caspase-8 and -9 activities peak at 9 h. Pre-treatments with 15 microM of the caspase-2 inhibitor benzyloxycarbonyl (z)-Val-Asp-Val-Ala-Asp (VDVAD)-fluoromethyl ketone (fmk) totally block DAU- and TT13-induced caspase-2, -8 and -9 activities, whereas pre-treatments with 15 microM of the caspase-8 inhibitor z-Ile-Glu-Thr-Asp (IETD)-fmk prevent DAU and TT13 from inducing caspase-8 activities without affecting their caspase-2- and -9-inducing activities, suggesting that the induction of apical caspase-2 activity by these drugs may be a critical upstream event required for the activation of other downstream caspases, including caspase-9 and the mitochondrial amplification loop through caspase-8. However, the mechanisms by which DAU and TT13 induce the release of mitochondrial Cyt c appear to be caspase-independent since they are both insensitive to similar pre-treatments with 100 microM of these specific caspase-2 and -8 inhibitors. Moreover, pre-treatments with 10 microg/ml of the antagonistic anti-Fas DX2 and ZB4 monoclonal antibodies (mAbs), and the neutralizing anti-Fas ligand (FasL) NOK-1 mAb are all unable to prevent DAU and TT13 from inducing Cyt c release and caspase-2, -8 and -9 activities, suggesting that the Fas-FasL signaling pathway is not involved in the mechanism by which these quinone antitumor drugs trigger apoptosis in HL-60 cells.
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PMID:Antitumor triptycene bisquinones induce a caspase-independent release of mitochondrial cytochrome c and a caspase-2-mediated activation of initiator caspase-8 and -9 in HL-60 cells by a mechanism which does not involve Fas signaling. 1551 62

Many human proteins have homopolymeric amino acid (HPAA) tracts, although the physiological significance or cellular effects of their presence is poorly understood. We previously reported that 20 kinds of HPAAs show characteristic intracellular localization and that among those, hydrophobic HPAAs aggregate strongly and form high molecular weight proteins when expressed in cultured cells. In this study, we investigated the cytotoxicity of 20 kinds of HPAAs. HPAA tracts of approximately 30 residues fused to the C-terminus of YFP were expressed in COS-7 cells. Cells expressing homopolymeric-Cys, -Ile, -Leu, and -Val showed low viability in Trypan Blue assay. Caspase-3 activity, which is usually upregulated in dying cells, was determined by measuring the cleavage of the peptide substrate Ac-DEVD-MCA and by detecting the cleaved active form of the caspase-3 by Western blotting. The activity of caspase-3 was drastically elevated in cells expressing those HPAAs which showed low viability in Trypan Blue assay. Interestingly, it was found that there is a correlation between the hydrophobicity of a single amino acid and the cytotoxicity of the corresponding HPAA as a homopolymer. These results indicate that the hydrophobicity of HPAAs may cause cytotoxicity.
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PMID:Comparative analysis of the cytotoxicity of homopolymeric amino acids. 1576 94

Pituitary adenylate cyclase activating polypeptide (PACAP), vasoactive intestinal peptide (VIP) and peptide histidine-isoleucine (PHI), are structurally related endogenous peptides widely expressed in the central and peripheral nervous system and showing rich profile of biological activities. They act as neurotransmitters, neuromodulators and neurotrophic factors. Recently, their neuroprotective potential has been revealed in numerous in vitro and in vivo models. Thus, PACAP and VIP protected the cells from neurotoxic effects of ethanol, hydrogen peroxide (H2O2, beta-amyloid and glycoprotein 120 (gp120). Moreover, PACAP showed neuroprotection against glutamate, human prion protein fragment 106-126 [PrP(106-126)] and C2-ceramide. Both peptides reduced brain damage after ischemia and ameliorated neurological deficits in a model of Parkinson's disease. Neuroprotective potential of PHI has not been thoroughly investigated yet, but several results obtained in the last years do not exclude it. The mechanism underlying neuroprotective properties of PACAP seems to involve activation of adenylyl cyclase (AC) --> cyclic adenosine 3',5'-mono-phosphate (cAMP) --> protein kinase A (PKA) and mitogen-activated protein (MAP) kinase pathways, and inhibition of caspase-3. PACAP can also, yet indirectly, stimulate astrocytes to release neuroprotective factors, such as regulated upon activation normal T cell expressed and secreted (RANTES) and macrophage inflammatory protein 1 (MIP-1) chemokines. Neuroprotective activity of VIP seems to involve an indirect mechanism requiring astrocytes. VIP-stimulated astrocytes secrete neuroprotective proteins, including activity-dependent neurotrophic factor (ADNF) and activity-dependent neuroprotective protein (ADNP), as well as a number of cytokines. However, in the activated microglia, VIP and PACAP are capable of inhibiting the production of inflammatory mediators which can lead to neurodegenerative processes within the brain. In conclusion, studies carried out on the central nervous system have shown that PACAP, VIP, and likely PHI, are endowed with a neuroprotective potential, which renders them (or their derivatives) promising therapeutic agents in several psychoneurological disorders linked to neurodegeneration.
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PMID:Neuroprotective potential of three neuropeptides PACAP, VIP and PHI. 1598 13

In this study we investigated the mechanisms of neuronal cell death induced by lipoteichoic acid (LTA) and muramyl dipeptide (MDP) from Gram-positive bacterial cell walls using primary cultures of rat cerebellum granule cells (CGCs) and rat cortical glial cells (astrocytes and microglia). LTA (+/- MDP) from Staphylococcus aureus induced a strong inflammatory response of both types of glial cells (release of interleukin-1beta, tumour necrosis factor-alpha and nitric oxide). The death of CGCs was caused by activated glia because in the absence of glia (treatment with 7.5 microm cytosine-d-arabinoside to inhibit non-neuronal cell proliferation) LTA + MDP did not cause significant cell death (less than 20%). In addition, staining with rhodamine-labelled LTA confirmed that LTA was bound only to microglia and astrocytes (not neurones). Neuronal cell death induced by LTA (+/- MDP)-activated glia was partially blocked by an inducible nitric oxide synthase inhibitor (1400 W; 100 microm), and completely blocked by a superoxide dismutase mimetic [manganese (III) tetrakis (4-benzoic acid)porphyrin chloride; 50 microm] and a peroxynitrite scavenger [5,10,15,20-tetrakis (4-sulfonatophenyl) porphyrinato iron (III); 100 microm] suggesting that nitric oxide and peroxynitrite contributed to LTA-induced cell death. Moreover, neuronal cell death was inhibited by selective inhibitors of caspase-3 (z-DEVD-fmk; 50 microm) and caspase-8 (z-Ile-Glu(O-Me)-Thr-Asp(O-Me) fluoromethyl ketone; 50 microm) indicating that they were involved in LTA-induced neuronal cell death.
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PMID:Inflammatory neurodegeneration induced by lipoteichoic acid from Staphylococcus aureus is mediated by glia activation, nitrosative and oxidative stress, and caspase activation. 1614 39

Growth arrest-specific protein 6 (gas6) activity is mediated through the receptor tyrosine kinase family members Axl, Rse, and Mer, all of which are expressed in human oligodendrocytes. In this study, we examined whether recombinant human (rh) gas6 protects oligodendrocytes from growth factor (insulin) withdrawal or tumor necrosis factor-alpha (TNFalpha) cytotoxicity. In addition, we examined whether the effect was caspase-dependent, which receptor mediated the protective effect, and whether survival required Akt1 activation. Oligodendrocyte viability was assessed by O4 staining and terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling. Addition of rhgas6 to insulin-depleted cultures resulted in a significant increase in oligodendrocyte viability. Rhgas6 and caspase inhibitors also reduced active caspase-3 immunoreactivity relative to TNFalpha-only-treated cultures. In cultures treated with TNFalpha (100 ng/ml), the oligodendrocyte survival rate was 18% compared with cultures treated with TNFalpha and rhgas6 (64%) or the caspase inhibitors IETD-fmk [z-Ile-Glu(OMe)-Thr-Asp(OMe)-fluoromethyl ketone] (65%) and zVAD-fmk (N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone) (63%). Increased phosphoAkt (Ser473) immunoreactivity was detected 15 min after administration of gas6 and TNFalpha to oligodendrocyte cultures but not in TNFalpha-treated cultures. The gas6 protective effect was abrogated by the Axl decoy receptor Axl-Fc, by the phosphatidylinositol 3 (PI3) kinase inhibitor LY294002 [2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one], and in Akt1(-/-) oligodendrocytes. Oligodendrocyte cultures established from wild-type and Rse(-/-) mice, but not from Axl(-/-) mice, were also protected from TNFalpha-induced cell death when maintained in rhgas6. We conclude that gas6 signaling through the Axl receptor and the PI3 kinase/Akt1 survival pathway protects oligodendrocytes from growth factor withdrawal and TNFalpha-mediated cell death.
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PMID:Gas6/Axl signaling activates the phosphatidylinositol 3-kinase/Akt1 survival pathway to protect oligodendrocytes from tumor necrosis factor alpha-induced apoptosis. 1672 20

Caspase-3 is a prototypic executioner caspase that plays a central role in apoptosis. Aza-peptide epoxides are a novel class of irreversible inhibitors that are highly specific for clan CD cysteine proteases. The five crystal structures of caspase-3-aza-peptide epoxide inhibitor complexes reported here reveal the structural basis for the mechanism of inhibition and the specificities at the S1' and the S4 subsites. Unlike the clan CA cysteine proteases, the catalytic histidine in caspase-3 plays a critical role during protonation and subsequent ring opening of the epoxide moiety and facilitates the nucleophilic attack by the active site cysteine. The nucleophilic attack takes place on the C3 carbon atom of the epoxide and results in an irreversible alkylation of the active site cysteine residue. A favorable network of hydrogen bonds involving the oxyanion hole, catalytic histidine, and the atoms in the prime site of the inhibitor enhance the binding affinity and specificity of the aza-peptide epoxide inhibitors toward caspase-3. The studies also reveal that subtle movements of the N-terminal loop of the beta-subunit occur when the P4 Asp is replaced by a P4 Ile, whereas the N-terminal loop and the safety catch Asp179 are completely disordered when the P4 Asp is replaced by P4 Cbz group.
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PMID:Exploring the S4 and S1 prime subsite specificities in caspase-3 with aza-peptide epoxide inhibitors. 1686 51

Oxidative stress and apoptosis are considered common mediators of many neurodegenerative disorders including Parkinson's disease (PD). Recently, we identified that PKCdelta, a member of the novel PKC isoform family, is proteolytically activated by caspase-3 to induce apoptosis in experimental models of PD [Eur. J. Neurosci. 18 (6):1387-1401, 2003; Antioxid. Redox Signal. 5 (5):609-620, 2003]. Since caspase-3 cleaves PKCdelta between proline and aspartate residues at the cleavage site 324DIPD327 to activate the kinase, we developed an irreversible and competitive peptide inhibitor, Z-Asp(OMe)-Ile-Pro-Asp(OMe)-FMK (z-DIPD-fmk), to mimic the caspase-3 cleavage site of PKCdelta and tested its efficacy against oxidative stress-induced cell death in PD models. Cotreatment of z-DIPD-fmk with the parkinsonian toxins MPP(+) and 6-OHDA dose dependently attenuated cytotoxicity, caspase-3 activation, and DNA fragmentation in a mesencephalic dopaminergic neuronal cell model (N27 cells). However, z-DIPD-fmk treatment did not block MPP(+)-induced increases in caspase-9 enzyme activity. The z-DIPD-fmk peptide was much more potent (IC50 6 microM) than the most widely used and commercially available caspase-3 inhibitor z-DEVD-fmk (IC50 18 microM). Additionally, z-DIPD-fmk more effectively blocked PKCdelta cleavage and proteolytic activation than the cleavage of another caspase-3 substrate, poly(ADP-ribose) polymerase (PARP). Importantly, the peptide inhibitor z-DIPD-fmk completely rescued TH(+) neurons from MPP(+)- and 6-OHDA-induced toxicity in mouse primary mesencephalic cultures. Collectively, these results demonstrate that the PKCdelta cleavage site is a novel target for development of a neuroprotective therapeutic strategy for PD.
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PMID:A novel peptide inhibitor targeted to caspase-3 cleavage site of a proapoptotic kinase protein kinase C delta (PKCdelta) protects against dopaminergic neuronal degeneration in Parkinson's disease models. 1704 26

The mechanisms by which infections induce diaphragm dysfunction remain poorly understood. The purpose of this study was to determine which caspase pathways (i.e., the extrinsic, death receptor-linked caspase-8 pathway, and/or the intrinsic, mitochondrial-related caspase-9 pathway) are responsible for endotoxin-induced diaphragm contractile dysfunction. We determined 1) whether endotoxin administration (12 mg/kg IP) to mice induces caspase-8 or -9 activation in the diaphragm; 2) whether administration of a caspase-8 inhibitor (N-acetyl-Ile-Glu-Thr-Asp-CHO, 3 mg/kg iv) or a caspase-9 inhibitor (N-acetyl-Leu-Glu-His-Asp-CHO, 3 mg/kg iv) blocks endotoxin-induced diaphragmatic weakness and caspase-3 activation; 3) whether TNF receptor 1-deficient mice have reduced caspase activation and diaphragm dysfunction following endotoxin; and 4) whether cytokines (TNF-alpha or cytomix, a mixture of TNF-alpha, interleukin-1beta, interferon-gamma, and endotoxin) evoke caspase activation in C(2)C(12) myotubes. Endotoxin markedly reduced diaphragm force generation (P < 0.001) and induced increases in caspase-3 and caspase-8 activity (P < 0.03), but failed to increase caspase-9. Inhibitors of caspase-8, but not of caspase-9, prevented endotoxin-induced reductions in diaphragm force and caspase-3 activation (P < 0.01). Mice deficient in TNF receptor 1 also had reduced caspase-8 activation (P < 0.001) and less contractile dysfunction (P < 0.01) after endotoxin. Furthermore, incubation of C(2)C(12) cells with either TNF-alpha or cytomix elicited significant caspase-8 activation. The caspase-8 pathway is strongly activated in the diaphragm following endotoxin and is responsible for caspase-3 activation and diaphragm weakness.
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PMID:The extrinsic caspase pathway modulates endotoxin-induced diaphragm contractile dysfunction. 1721 30


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