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Query: UNIPROT:P42574 (caspase-3)
 45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The human leukemia cell line, HL60 is very sensitive to various apoptotic stimuli and p53-null. The death-related cysteine proteases of the caspases family play a central role in the execution phase of apoptosis, and we recently reported the importance of serine protease activation in camptothecin-induced apoptotic endonuclease activation in HL60 cells. In the present study, we investigated the role of caspases (ICE/CED-3-related cysteine proteases) and serine proteases in cell death induced by the topoisomerase I inhibitor, camptothecin, in HL60 cells and in a cell-free system. We found that CPP32 is activated during camptothecin-induced apoptosis, and that N-benzyloxycarbony-Val-Ala-Asp (O-methyl) -fluoromethyketone (Z-VAD-fmk), a cell permeable caspase inhibitor blocks all features of apoptosis: morphological changes, cleavage of caspase 3 (CPP32/Yama/Apopain) and poly(ADP-ribose) polymerase, lamin B degradation and DNA fragmentation. However, Z-VAD-fmk and two other ICE/CED-3 inhibitors, YVAD-CHO and DEVD-CHO, were inactive in a cell-free system reconstituted from nuclei of untreated HL60 cells and cytosol from camptothecin-treated cells, suggesting that caspases are not required for endonuclease activation or lamin B cleavage in the cell-free system. By contrast, the serine protease inhibitors, 3,4-dichloroisocoumarin (DCI) and L-1-chloro-3-(4-tosylamido)-4-phenyl-2-butanone tosyl-L-phenylalanine chloromethyl ketone (TPCK), abolished the apoptosis-associated biochemical changes induced by camptothecin both in whole cells and in a cell-free system. DCI also inhibited CPP32 cleavage. Taken together, these results suggest that in HL60 cells, both CPP32 and serine proteases are activated in camptothecin-induced apoptosis.
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PMID:Camptothecin-induced apoptosis in p53-null human leukemia HL60 cells and their isolated nuclei: effects of the protease inhibitors Z-VAD-fmk and dichloroisocoumarin suggest an involvement of both caspases and serine proteases. 926 76

We report here the purification and cDNA cloning of Apaf-1, a novel 130 kd protein from HeLa cell cytosol that participates in the cytochrome c-dependent activation of caspase-3. The NH2-terminal 85 amino acids of Apaf-1 show 21% identity and 53% similarity to the NH2-terminal prodomain of the Caenorhabditis elegans caspase, CED-3. This is followed by 320 amino acids that show 22% identity and 48% similarity to CED-4, a protein that is believed to initiate apoptosis in C. elegans. The COOH-terminal region of Apaf-1 comprises multiple WD repeats, which are proposed to mediate protein-protein interactions. Cytochrome c binds to Apaf-1, an event that may trigger the activation of caspase-3, leading to apoptosis.
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PMID:Apaf-1, a human protein homologous to C. elegans CED-4, participates in cytochrome c-dependent activation of caspase-3. 926 18

Resistance to stress-induced apoptosis was examined in cells in which the expression of hsp70 was either constitutively elevated or inducible by a tetracycline-regulated transactivator. Heat-induced apoptosis was blocked in hsp70-expressing cells, and this was associated with reduced cleavage of the common death substrate protein poly(ADP-ribose) polymerase (PARP). Heat-induced cell death was correlated with the activation of the stress-activated protein kinase SAPK/JNK (c-Jun N-terminal kinase). Activation of SAPK/JNK was strongly inhibited in cells in which hsp70 was induced to a high level, indicating that hsp70 is able to block apoptosis by inhibiting signaling events upstream of SAPK/JNK activation. In contrast, SAPK/JNK activation was not inhibited by heat shock in cells with constitutively elevated levels of hsp70. Cells that constitutively overexpress hsp70 resist apoptosis induced by ceramide, a lipid signaling molecule that is generated by apoptosis-inducing treatments and is linked to SAPK/JNK activation. Similar to heat stress, resistance to ceramide-induced apoptosis occurs in spite of strong SAPK/JNK activation. Therefore, hsp70 is also able to inhibit apoptosis at some point downstream of SAPK/JNK activation. Since PARP cleavage is prevented in both cell lines, these results suggest that hsp70 is able to prevent the effector steps of apoptotic cell death. Processing of the CED-3-related protease caspase-3 (CPP32/Yama/apopain) is inhibited in hsp70-expressing cells; however, the activity of the mature enzyme is not affected by hsp70 in vitro. Caspase processing may represent a critical heat-sensitive target leading to cell death that is inhibited by the chaperoning function of hsp70. The inhibition of SAPK/JNK signaling and apoptotic protease effector steps by hsp70 likely contributes to the resistance to stress-induced apoptosis seen in transiently induced thermotolerance.
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PMID:Role of the human heat shock protein hsp70 in protection against stress-induced apoptosis. 927 9

HL-60 cells differentiating into neutrophil-like cells die an apoptotic death in vitro. Susceptibility to apoptosis is associated with decreased Bcl-2 protein and mRNA expression; however, the effect of differentiation on the expression of pro-apoptotic caspases is unknown. Spontaneous apoptosis occurred 6 days after retinoic acid treatment. Western blotting showed loss of Bcl-2 by day 7, and new expression of ICE (caspase 1) and CPP32 (caspase 3) protein by day 2. Northern analysis demonstrated loss of Bcl-2 mRNA and increases in ICE mRNA by day 2; CPP32 mRNA was unchanged. Differential Bcl-2 and ICE mRNA expression was also found when granulocytic differentiation was stimulated by DMSO. Differentiated HL-60 cell lysates exhibited functional ICE proteolytic activity. De novo caspase expression was responsible for the development of spontaneous apoptosis, since specific inhibitors of ICE (YVAD-CMK) and CPP32 (DEVD-CHO), inhibited retinoic acid induced spontaneous apoptosis. Functional maturation and susceptibility to apoptosis are both inducible and linked in this granulocyte precursor cell line.
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PMID:Granulocytic differentiation of HL-60 cells results in spontaneous apoptosis mediated by increased caspase expression. 927 75

The mdm2 oncogene encodes a 90-kDa protein that can bind to the p53 tumor suppressor protein and negatively regulate its functions in transcription, cell cycle arrest, and apoptosis. The mdm2 gene is frequently amplified in human sarcomas, which may be responsible for the malignant transformations. We present evidence that the mdm2 oncoprotein is cleaved by an interleukin 1beta-converting enzyme-like protease (caspase) during p53-mediated apoptosis. The protease that cleaves mdm2 has a specificity similar to that of CPP32 (caspase-3), and recombinant caspase-3 is able to cleave mdm2 in vitro. The protease cleavage site has been mapped to between residue 361 and 362 of human mdm2. The proteolytic cleavage removes the COOH-terminal RING finger domain of mdm2, resulting in the loss of RNA binding activity. The p53 binding and inhibition functions of mdm2 are not affected by the cleavage. The cleavage site sequence of mdm2 is evolutionarily conserved, suggesting that regulation by caspase cleavage during apoptosis is an important feature of mdm2.
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PMID:Proteolytic cleavage of the mdm2 oncoprotein during apoptosis. 927 61

Hematopoietic cytokines transduce cell survival signals, which are distinct from the signals necessary for the stimulation of DNA synthesis. Recently, the Ras and phosphatidylinositol 3-kinase pathways have been shown to play important roles in preventing apoptosis in various cell types, e.g. hematopoietic cells and neuronal cells. Withdrawal of cytokine(s), in turn, results in rapid inactivation of these survival pathways and eventually leads to cell death accompanied by the hallmarks of apoptosis. However, the mechanism of cell death caused by cytokine deprivation has not been fully elucidated. In this study, we demonstrate that caspase-3/CPP32, a member of the caspase/interleukin-1beta-converting enzyme family, is activated upon interleukin (IL)-3 deprivation in IL-3-dependent cells as well as IL-2 deprivation in IL-2-dependent cells. In addition, poly(ADP-ribose) polymerase, a cellular substrate for the caspase family proteases, was degraded into apoptotic fragments in both cell lines after cytokine removal. Furthermore, inhibition of a caspase family protease by synthetic peptides suppressed apoptotic death. These results indicate that the activation of a caspase-like protease(s) is required for the progression of apoptosis following cytokine deprivation. However, readdition of IL-3 did not restore the proliferative potential of the cells that survived in the presence of the peptide inhibitor after IL-3 depletion. Therefore, cellular commitment to apoptosis appears to precede the activation of a caspase-like protease(s).
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PMID:Requirement of the caspase-3/CPP32 protease cascade for apoptotic death following cytokine deprivation in hematopoietic cells. 928 12

The induction of apoptosis of tumor cells by the colonic fermentation product butyrate is thought to be an important mechanism in protection against colorectal cancer. Because a major action of butyrate is to inhibit histone deacetylase (leading to chromatin relaxation and altered gene expression), butyrate may induce apoptosis by derepression of specific cell death genes. Here we show that butyrate and trichostatin A (a more selective inhibitor of histone deacetylase) induce the same program of apoptosis in Jurkat lymphoid and LIM 1215 colorectal cancer cell lines that is strictly dependent on new protein synthesis (within 10 h) and that leads to the conversion of the proenzyme form of caspase-3 to the catalytically active effector protease (within 16 h) and apoptotic death (within 24 h). Cells primed with a low concentration of butyrate that itself did not induce activation of caspase-3 or apoptosis were, nevertheless, rendered highly susceptible to induction of apoptosis by staurosporine (an agent that has recently been shown to act by causing mitochondrial release of cytochrome c). Synergy between butyrate and staurosporine was due to the presence of a factor in the cytosol of butyrate-primed cells which enhanced over 7-fold the activation of caspase-3 induced by the addition of cytochrome c and dATP to isolated cytosol. We propose that changes at the level of chromatin structure, induced by a physiological substance butyrate, lead to the expression of a protein that facilitates the pathway by which mitochondria activate caspase-3 and trigger apoptotic death of lymphoid and colorectal cancer cells.
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PMID:Induction of caspase-3 protease activity and apoptosis by butyrate and trichostatin A (inhibitors of histone deacetylase): dependence on protein synthesis and synergy with a mitochondrial/cytochrome c-dependent pathway. 928 76

Programmed cell death, or apoptosis, is inhibited by the antiapoptotic oncogene, Bcl-2, and is mediated by a cascade of aspartate-specific cysteine proteases, or caspases, related to interleukin 1-beta converting enzyme. Depending on cell type, apoptosis can be induced by treatment with thapsigargin (TG); a selective inhibitor of the endoplasmic reticulum-associated calcium-ATPase. The role of caspases in mediating TG-induced apoptosis was investigated in the Bcl-2-negative human breast cancer cell line, MDA-MB-468. Apoptosis developed in MDA-MB-468 cells over a period of 24-72 h following treatment with 100 nM TG, and was prevented by Bcl-2 overexpression. TG-induced apoptosis was associated with activation of caspase-3 and was inhibited by stable expression of the baculovirus p35 protein, an inhibitor of caspase activity. Also, TG-induced apoptosis was inhibited by treating cells with Z-VAD-fmk, a cell-permeable fluoromethylketone inhibitor of caspases. These findings indicate that TG-induced apoptosis of MDA-MB-468 breast cancer cells is subject to inhibition by Bcl-2 and is mediated by caspase activity. This model system should be useful for further investigation directed toward understanding the role of calcium in signaling apoptosis, and its relationship to Bcl-2 and the caspase proteolytic cascade.
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PMID:Baculovirus p35 and Z-VAD-fmk inhibit thapsigargin-induced apoptosis of breast cancer cells. 929 14

We examined the temporal profile of apoptosis after fluid percussion-induced traumatic brain injury (TBI) in rats and investigated the potential pathophysiological role of caspase-3-like proteases in this process. DNA fragmentation was observed in samples from injured cortex and hippocampus, but not from contralateral tissue, beginning 4 hr after TBI and continuing for at least 3 d. Double labeling of brain with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) and an antibody directed to neuronal nuclear protein identified apoptotic neurons with high frequency in both traumatized rat cortex and hippocampus. Cytosolic extracts from injured cortex and hippocampus, but not from contralateral or control tissue, induced internucleosomal DNA fragmentation in isolated nuclei with temporal profiles consistent with those of DNA fragmentation observed in vivo. Caspase-3 mRNA levels, estimated by semiquantitative RT-PCR, were elevated fivefold in ipsilateral cortex and twofold in hippocampus by 24 hr after TBI. Caspase-1 mRNA content also was increased after trauma, but to a lesser extent in cortex. Increased caspase-3-like, but not caspase-1-like, enzymatic activity was found in cytosolic extracts from injured cortex. Intracerebroventricular administration of z-DEVD-fmk-a specific tetrapeptide inhibitor of caspase-3-before and after injury markedly reduced post-traumatic apoptosis, as demonstrated by DNA electrophoresis and TUNEL staining, and significantly improved neurological recovery. Together, these results implicate caspase-3-like proteases in neuronal apoptosis induced by TBI and suggest that the blockade of such caspases can reduce post-traumatic apoptosis and associated neurological dysfunction.
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PMID:Activation of CPP32-like caspases contributes to neuronal apoptosis and neurological dysfunction after traumatic brain injury. 929 87

Keratins 8 (K8) and 18 (K18) are major components of intermediate filaments (IFs) of simple epithelial cells and tumors derived from such cells. Structural cell changes during apoptosis are mediated by proteases of the caspase family. During apoptosis, K18 IFs reorganize into granular structures enriched for K18 phosphorylated on serine 53. K18, but not K8, generates a proteolytic fragment during drug- and UV light-induced apoptosis; this fragment comigrates with K18 cleaved in vitro by caspase-6, -3, and -7. K18 is cleaved by caspase-6 into NH2-terminal, 26-kD and COOH-terminal, 22-kD fragments; caspase-3 and -7 additionally cleave the 22-kD fragment into a 19-kD fragment. The cleavage site common for the three caspases was the sequence VEVD/A, located in the conserved L1-2 linker region of K18. The additional site for caspases-3 and -7 that is not cleaved efficiently by caspase-6 is located in the COOH-terminal tail domain of K18. Expression of K18 with alanine instead of serine at position 53 demonstrated that cleavage during apoptosis does not require phosphorylation of serine 53. However, K18 with a glutamate instead of aspartate at position 238 was resistant to proteolysis during apoptosis. Furthermore, this cleavage site mutant appears to cause keratin filament reorganization in stably transfected clones. The identification of the L1-2 caspase cleavage site, and the conservation of the same or very similar sites in multiple other intermediate filament proteins, suggests that the processing of IFs during apoptosis may be initiated by a similar caspase cleavage.
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PMID:Caspase cleavage of keratin 18 and reorganization of intermediate filaments during epithelial cell apoptosis. 929 92


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