Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.22.60 (caspase-7)
920 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the ability of caspases (cysteine proteases with aspartic acid specificity) to induce cytochrome c release from mitochondria. When Jurkat cells were induced to undergo apoptosis by Fas receptor ligation, cytochrome c was released from mitochondria, an event that was prevented by the caspase inhibitor, zVAD-fmk (zVal-Ala-Asp-CH2F). Purified caspase-8 triggered rapid cytochrome c release from isolated mitochondria in vitro. The effect was indirect, as the presence of cytosol was required, suggesting that caspase-8 cleaves and activates a cytosolic substrate, which in turn is able to induce cytochrome c release from mitochondria. The cytochrome c releasing activity was not blocked by caspase inhibition, but was antagonized by Bcl-2 or Bcl-xL. Caspase-8 and caspase-3 cleaved Bid, a proapoptotic Bcl-2 family member, which gains cytochrome c releasing activity in response to caspase cleavage. However, caspase-6 and caspase-7 did not cleave Bid, although they initiated cytochrome c release from mitochondria in the presence of cytosol. Thus, effector caspases may cleave and activate another cytosolic substrate (other than Bid), which then promotes cytochrome c release from mitochondria. Mitochondria significantly amplified the caspase-8 initiated DEVD-specific cleavage activity. Our data suggest that cytochrome c release, initiated by the action of caspases on a cytosolic substrates, may act to amplify a caspase cascade during apoptosis.
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PMID:Caspases induce cytochrome c release from mitochondria by activating cytosolic factors. 1036 79

Tumor necrosis factor-related apoptosis- inducing ligand (TRAIL) -induced apoptosis, in transformed human breast epithelial MCF-7 cells, resulted in a time-dependent activation of the initiator caspases-8 and -9 and the effector caspase-7. Cleavage of caspase-8 and its preferred substrate, Bid, preceded processing of caspases-7 and -9, indicating that caspase-8 is the apical initiator caspase in TRAIL-induced apoptosis. Using transient transfection of COOH-terminal-tagged green fluorescent protein fusion constructs, caspases-3, -7, and -8 were localized throughout the cytoplasm of MCF-7 cells. TRAIL-induced apoptosis resulted in activation of caspases-3 and -7, and the redistribution of most of their detectable catalytically active small subunits into large spheroidal cytoplasmic inclusions, which lacked a limiting membrane. These inclusions, which were also induced in untransfected cells, contained cytokeratins 8, 18, and 19, together with both a phosphorylated form and a caspase-cleavage fragment of cytokeratin 18. Similarly, in untransfected breast HBL100 and lung A549 epithelial cells, TRAIL induced the formation of cytoplasmic inclusions that contained cleaved cytokeratin 18 and colocalized with active endogenous caspase-3. We propose that effector caspase-mediated cleavage of cytokeratins, resulting in disassembly of the cytoskeleton and formation of cytoplasmic inclusions, may be a characteristic feature of epithelial cell apoptosis.
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PMID:Active caspases and cleaved cytokeratins are sequestered into cytoplasmic inclusions in TRAIL-induced apoptosis. 1072 37

We have shown previously that the pathways leading to Fas-mediated apoptosis in prostatic carcinoma cell lines are intact, because apoptosis can be triggered either by Fas ligation alone in the Fas-sensitive cell lines PC3 and ALVA31 or by rendering the Fas-resistant cell lines DU145 and JCA1 Fas-sensitive by combined treatment with anti-Fas monoclonal antibody and cycloheximide (O. W. Rokhlin et al., Cancer Res., 57: 1758-1768, 1997). In this study, we demonstrate that two of the early events after Fas ligation are the release of cytochrome c from the mitochondria and activation of caspase-9. We also found that Bid is processed after Fas ligation and thus might activate the mitochondria-dependent apoptotic cascade. In a cell-free system, cytochrome c induced caspase-3-like activity in cytoplasmic extracts from all four cell lines studied, although differences in the level of enzymatic activity were observed. Western blot analysis revealed that caspase-7 is activated by cytochrome c at the same level in all extracts, whereas expression and activation of caspase-3 varied considerably. Cytochrome c-activated extracts displayed different abilities in the induction of apoptotic features in isolated nuclei such as morphological changes and DNA fragmentation. However, differences in nuclear apoptotic activity induced by cytochrome c did not correlate with the level of caspase-3 like activity in the different extracts. These results suggest that the mitochondrial pathway is involved in Fas-mediated apoptosis in prostatic carcinoma cell lines and that, in addition to caspase-7 and caspase-3, there are other factors that confer nuclear apoptotic activity.
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PMID:Cytochrome c is involved in Fas-mediated apoptosis of prostatic carcinoma cell lines. 1078 80

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis via the death receptors DR4 and DR5 in different transformed cells in vitro and exhibits potent antitumor activity in vivo with minor side effects. The synthetic retinoid CD437 is a potent inducer of apoptosis in cancer cells through increased levels of death receptors. We demonstrate that treatment of human lung cancer cells with a combination of suboptimal concentrations of CD437 and TRAIL enhanced induction of apoptosis in tumor cell lines with wild-type p53 but not in normal lung epithelial cells. CD437 up-regulated DR4 and DR5 expression. The CD437 and TRAIL combination enhanced activation of caspase-3, caspase-7, caspase-8, and caspase-9 and the subsequent cleavage of poly(ADP-ribose) polymerase and DNA fragmentation factor 45. Caspase inhibitors blocked the induction of apoptosis by this combination. Moreover, this combination induced Bid cleavage and increased cytochrome c release from mitochondria. These results suggest that the mechanism of enhanced apoptosis by this combination involves p53-dependent increase of death receptors by CD437, activation of these receptors by TRAIL, enhanced Bid cleavage, release of cytochrome c, and activation of caspase-3, caspase-7, caspase-8, and caspase-9. These findings suggest a novel strategy for the prevention and treatment of human lung cancer with the CD437 and TRAIL combination.
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PMID:Augmentation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis by the synthetic retinoid 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) through up-regulation of TRAIL receptors in human lung cancer cells. 1115 24

Using adenoviral technology, we overexpressed the proapoptotic molecules pro-caspase-3, pro-caspase-7, and Bax to induce therapeutic apoptosis of prostate cancer cell lines growing in vitro and in vivo. Because overexpressed pro-caspase-3 did not undergo autocatalytic activation in any of the five prostate cancer cell lines evaluated, this strategy was unable to engage any component of the apoptotic pathway. Overexpressed pro-caspase-7 was proteolytically cleaved in LNCaP and LnCaP-Bcl-2 cells but not in PC-3, DU-145, or TsuPr(1) cells. Cleavage was associated with engagement of many components of the apoptotic pathway, including DEVDase activity, cleavage of intracellular caspase targets such as the DNA fragmentation factor and the proapoptotic Bid, release of cytochrome c from the mitochondria to the cytoplasm, and terminal deoxynucleotidyl transferase-mediated nick end labeling. No apoptosis was observed in the cells where caspase-7 did not undergo autocatalytic activation. Searching for an approach that would more reliably induce therapeutic apoptosis of prostate cancer cell lines, we used a binary adenoviral system to overexpress the proapoptotic molecule Bax. Bax was dramatically overexpressed and caused apoptosis of every cell line infected by engaging the mitochondrial pathway, including proteolytic cleavage and catalytic activation of the caspases, cleavage of caspase substrates, release of cytochrome c from the mitochondria, and DNA fragmentation. Furthermore, three injections of the Bax overexpression system into PC-3 cell tumors in nude mice in vivo caused a 25% regression in tumor size corresponding to a 90% reduction relative to continued tumor growth in animals that received injections with the control binary system expressing Lac-Z. These experiments show that adenovirus-mediated Bax overexpression is capable of inducing therapeutic programmed cell death in vitro and in vivo by activating the mitochondrial pathway of apoptosis. On the basis of these studies, we conclude that manipulation of Bax expression is an attractive new gene therapy approach for the treatment of prostate cancer.
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PMID:Adenovirus-mediated Bax overexpression for the induction of therapeutic apoptosis in prostate cancer. 1119 58

Apoptosis plays an important role in the pathogenesis of many viral infections. Despite this fact, the apoptotic pathways triggered during viral infections are incompletely understood. We now provide the first detailed characterization of the pattern of caspase activation following infection with a cytoplasmically replicating RNA virus. Reovirus infection of HEK293 cells results in the activation of caspase-8 followed by cleavage of the pro-apoptotic protein Bid. This initiates the activation of the mitochondrial apoptotic pathway leading to release of cytochrome c and activation of caspase-9. Combined activation of death receptor and mitochondrial pathways results in downstream activation of effector caspases including caspase-3 and caspase-7 and cleavage of cellular substrates including PARP. Apoptosis is initiated by death receptor pathways but requires mitochondrial amplification producing a biphasic pattern of caspase-8, Bid, and caspase-3 activation.
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PMID:Reovirus-induced apoptosis requires both death receptor- and mitochondrial-mediated caspase-dependent pathways of cell death. 1218 43

Caspase-11 is an essential mediator of septic shock response and caspase-11-deficient mice are resistant to LPS-induced shock. Here we report that LPS-induced caspase-11 regulates lymphocyte apoptosis by activating both caspase-3 and caspase-7. The activation of caspase-11 preceded that of caspase-1 and caspases-3/-7, and in the absence of caspase-11, the activation of caspases-3/-7 was significantly reduced. The early activation of caspases-3/-7 by caspase-11 was not affected by blocking of caspase-1 activity and IL-1beta release, implying that caspase-11 activates caspases-3/-7 independently of caspase-1 activation. Furthermore, we show that caspase-11-mediated apoptosis under septic condition is Bid-independent. Our work suggests that the human homologue of caspase-11 may be an effective therapeutic target for treatment of septic shock.
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PMID:Distinct downstream pathways of caspase-11 in regulating apoptosis and cytokine maturation during septic shock response. 1223

Histone deacetylase activity is potently inhibited by hydroaximc acid derivatives such as suberoylanilide hydroxamic acid (SAHA) and trichostatin-A (TSA). These inhibitors specifically induce differentiation/apoptosis of transformed cells in vitro and suppress tumor growth in vivo. Because of its low toxicity, SAHA is currently evaluated in clinical trials for the treatment of cancer. SAHA and TSA induce apoptosis, which is characterized by mitochondrial stress, but so far, the critical elements of this apoptotic program remain poorly defined. To characterize in more detail this apoptotic program, we used human cell lines containing alterations in important elements of apoptotic response such as: p53, Bcl-2, caspase-9, and caspase-3. We demonstrate that caspase-9 is critical for apoptosis induced by SAHA and TSA and that efficient proteolytic activation of caspase-2, caspase-8, and caspase-7 strictly depends on caspase-9. Bcl-2 efficiently antagonizes cytochrome c release and apoptosis in response to both histone deacetylase inhibitors. We provide evidences that translocation into the mitochondria of the Bcl-2 family member Bid depends on caspase-9 and that this translocation is a late event during TSA-induced apoptosis. We also demonstrate that the susceptibility to TSA- and SAHA-induced cell death is regulated by p53.
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PMID:Role of caspases, Bid, and p53 in the apoptotic response triggered by histone deacetylase inhibitors trichostatin-A (TSA) and suberoylanilide hydroxamic acid (SAHA). 1255 48

LIGHT is a new member of the tumor necrosis factor superfamily, which binds to lymphotoxin beta receptor, herpes virus entry mediator, or TR6. This work was carried out to elucidate the molecular mechanism of LIGHT-sensitized, interferon gamma (IFNgamma)-mediated apoptosis of MDA-MB-231 cells. It was revealed that LIGHT treatment resulted in down-regulation of anti-apoptosis Bcl-2 family member: Bcl-2, Bcl-X(L), Bag-1, and Mcl-1; up-regulation of pro-apoptosis Bcl-2 family member: Bak and Ser (112)-phosphor-Bad; down-regulation of pro-apoptosis Bcl-2 member Bax; the other pro-apoptosis member Bid remains unaltered. LIGHT treatment also resulted in activation of caspase-3, caspase-6, caspase-7, caspase-8, caspase-9, DFF45, and PARP. However, caspase activation and caspase activity, especially caspase-3 activity, is not required for LIGHT-induced apoptosis of MDA-MB-231 cells, since caspase-3 inhibitor, benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethylketone, and a broad range caspase inhibitor, benzyloxycarbonyl-val-ala-asp-fluoromethylketone failed to block the apoptosis induced by LIGHT and IFNgamma in MDA-MB-231 cells. In summary, LIGHT-sensitized IFNgamma-mediated apoptosis of MDA-MB-231 cells is probably through down-regulation of anti-apoptosis Bcl-2 family members; it could be caspase (especially caspase-3)-independent, even though extensive caspase activation was observed.
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PMID:LIGHT sensitizes IFNgamma-mediated apoptosis of MDA-MB-231 breast cancer cells leading to down-regulation of anti-apoptosis Bcl-2 family members. 1276 29

Sanguinarine, derived from the root of Sanguinaria canadensis and other poppy fumaria species, possesses strong antimicrobial, anti-inflammatory, and antioxidant properties. We earlier showed that sanguinarine kills human epidermoid carcinoma A431 cells via an induction of apoptosis [N. Ahmad et al., Clin. Cancer Res., 6: 1524-1528, 2000]. In this study, using immortalized human keratinocytes (HaCaT cells), we provide information about mechanism of the antiproliferative effect of sanguinarine. Sanguinarine [0.1 (M-2 (M)] treatment to HaCaT cells was found to inhibit in a dose-dependent manner the cell proliferation and induce apoptosis, as measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and ELISA, respectively. Sanguinarine treatment also resulted in a significant cleavage of poly(ADP-ribose) polymerase in HaCaT cells. Because mitochondrial pathway is critical for the regulation of apoptosis, we studied the involvement and regulation of mitochondrial events in sanguinarine-mediated apoptosis of HaCaT cells. As shown by the immunoblot analysis, our data clearly demonstrated that sanguinarine treatment to HaCaT cells resulted in a dose-dependent (a) increase in the level of Bax with a concomitant decrease in Bcl-2 levels and (b) increase in Bax/Bcl-2 ratio. Sanguinarine also resulted in significant increases in the proapoptotic members of Bcl-2 family proteins, i.e., Bak and Bid. This was accompanied by increase in (a) protein expression of cytochrome c and apoptotic protease-activating factor-1 and (b) activity and protein expression of caspase-3, caspase-7, caspase-8, and caspase-9. Taken together, our data showed the involvement of mitochondrial pathway and Bcl-2 family proteins during sanguinarine-mediated apoptosis of immortalized keratinocytes. We suggest that sanguinarine could be developed as a drug for the management of hyperproliferative skin disorders, including skin cancer.
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PMID:Activation of prodeath Bcl-2 family proteins and mitochondrial apoptosis pathway by sanguinarine in immortalized human HaCaT keratinocytes. 1291 70


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