Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P42574 (caspase-3)
 45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transduction of cancer cells with herpes simplex virus thymidine kinase gene (HSVtk) followed by prodrug ganciclovir (GCV) treatment has been shown to induce apoptosis. In this study, four murine tumors including B16F10 melanoma, NG4TL4 sarcoma, H6 hepatoma and 1MEA 7R.1 hepatoma were found to vary in sensitivity to this gene therapy strategy in vitro but, at effective doses of GCV, the HSVtk-transduced cells of all four tumors showed similar kinetics of early rise in p53 protein levels, then cell cycle S-/G2-phase arrest and finally signs of apoptosis. Immunoblot analyses revealed that Fas (CD95/APO-1), Fas ligand (FasL) and two downstream mediators, RIP and caspase-3, (CPP32, YAMA, Apopain) were increased in GCV-treated HSVtk-transduced tumor cells the cell cycle arrest and before apoptosis. Increased expression of FasL could also be observed in vivo in HSVtk-transduced tumors induced to regress by GCV treatment. Enzyme measurements using specific substrate showed that the caspase-3 activation followed kinetically the FasL expression. More than half of the HSVtk/GCV-induced cell death could be abrogated by addition to the cell culture medium of a specific antisense oligonucleotide to block FasL synthesis, a recombinant Fas/Fc chimeric protein to compete with Fas receptor for FasL binding, or cell-permeable specific tetrapeptide inhibitors of caspase-3 or caspase-8.
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PMID:Involvement of Fas (CD95/APO-1) and Fas ligand in apoptosis induced by ganciclovir treatment of tumor cells transduced with herpes simplex virus thymidine kinase. 1043 92

Tumor necrosis factor alpha (TNFalpha) generates a potent cytotoxic effect, however many cancer cells are resistant to TNFalpha-mediated killing and the cause of the differential sensitivity remains to be elucidated. In this study, we demonstrated that TNFalpha induced cell death in four different human colon cancer cell lines. The degree of cytotoxic effect was different in each cell line, in that HCT-15 was relatively sensitive, while DLD-1, HT-29 and WiDr were relatively resistant. TNFalpha induced apoptotic changes such as morphological changes, DNA fragmentation and activation of caspase-3 in HCT-15, but to a lesser degree in the others. Transcriptional expression of TNFR1(p55), as well as that of FLICE, Fas, FADD, DR3, FAF, TRADD, and RIP was similar in these cell lines, indicating that the susceptibility to TNFalpha-induced apoptosis may not be determined by the constitutive expression level of these factors. Interestingly, the cytotoxic effect of TNFalpha was well correlated with the DNA binding activity of NF-kappaB in the colon cancer cell lines. Further, the overexpression of a non-phosphorylated mutant form of IkappaBalpha enhanced the cytotoxicity of TNFalpha in the resistant cell line, DLD-1, indicating that NF-kappaB activity may determine the sensitivity of colon cancer cells to TNFalpha-induced apoptosis. Thus, our results indicate that modulation of NF-kappaB activity may provide a useful tool to sensitize colon cancer cells to TNFalpha treatment.
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PMID:Activation of NF-kappaB determines the sensitivity of human colon cancer cells to TNFalpha-induced apoptosis. 1078 20

A RIP-like protein, RIP3, has recently been reported that contains an N-terminal kinase domain and a novel C-terminal domain that promotes apoptosis. These experiments further characterize RIP3-mediated apoptosis and NF-kappaB activation. Northern blots indicate that rip3 mRNA displays a restricted pattern of expression including regions of the adult central nervous system. The rip3 gene was localized by fluorescent in situ hybridization to human chromosome 14q11.2, a region frequently altered in several types of neoplasia. RIP3-mediated apoptosis was inhibited by Bcl-2, Bcl-x(L), dominant-negative FADD, as well as the general caspase inhibitor Z-VAD. Further dissection of caspase involvement in RIP3-induced apoptosis indicated inhibition by the more specific inhibitors Z-DEVD (caspase-3, -6, -7, -8, and -10) and Z-VDVAD (caspase-2). However, caspase-1, -6, -8 and -9 inhibitors had little or no effect on RIP3-mediated apoptosis. Mutational analysis of RIP3 revealed that the C-terminus of RIP3 contributed to its apoptotic activity. This region is similar, but distinct, to the death domain found in many pro-apoptotic receptors and adapter proteins, including FAS, FADD, TNFR1, and RIP. Furthermore, point mutations of RIP3 at amino acids conserved among death domains, abrogated its apoptotic activity. RIP3 was localized by immunofluorescence to the mitochondrion and may play a key role in the mitochondrial disruptions often associated with apoptosis.
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PMID:The RIP-like kinase, RIP3, induces apoptosis and NF-kappaB nuclear translocation and localizes to mitochondria. 1081 27

Despite Fas expression, many cells resist Fas-induced apoptosis. Although differences in surface Fas expression can explain Fas resistance, multiple proteins below receptor level also inhibit Fas-induced apoptosis. To examine the mechanism of Fas resistance, we studied Fas-induced apoptosis in human medial vascular smooth muscle cells (VSMCs) from healthy coronary arteries. VSMCs showed marked heterogeneity to Fas-induced apoptosis, exhibiting both Fas-resistant (98.1+/-2.3% viable, n = 4, P = NS) and Fas-sensitive (31.3+/-2.6% viable, n = 3, P<0.01) cells. Fas-resistant VSMCs expressed surface Fas and could recruit RIP, indicating that functional receptor complexes were formed. However, Fas-resistant cells showed reduced expression of FADD, Fas ligand, and caspases 3, 7, and 8 and increased expression of FLIP and c-IAP-1. Fas-induced apoptosis was associated with cleavage of caspase 3 and blocked by inhibitors of caspase 3 or 8 but not caspase 1, 6, or 7. Selective inhibition of caspase 3 or 8 by antisense transfection inhibited Fas-induced apoptosis, but their reexpression could not rescue the Fas-resistant phenotype. In vivo, medial VSMCs showed marked heterogeneity of expression of caspase 3. We conclude that Fas sensitivity is determined not only by expression of surface Fas but by differential expression of Fas-signaling proteins below receptor level. Subpopulations of cells within the same tissue have different sensitivities to apoptosis, determined by expression of specific death-signaling proteins.
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PMID:Sensitivity to Fas-mediated apoptosis is determined below receptor level in human vascular smooth muscle cells. 1082 27

A novel human inhibitor of apoptosis protein (IAP) family member termed Livin was identified, containing a single baculoviral IAP repeat (BIR) domain and a COOH-terminal RING finger domain. The mRNA for livin was not detectable by Northern blot in most normal adult tissues with the exception of the placenta, but was present in developmental tissues and in several cancer cell lines. Highest levels were observed in two melanoma-derived cell lines, G361 and SK-Mel29. Transfection of livin in HeLa cells resulted in protection from apoptosis induced by expression of FADD, Bax, RIP, RIP3, and DR6. Similar to other IAP family members, the anti-apoptotic activity of Livin was dependent on the BIR domain. Livin was also capable of inhibiting DEVD-like caspase activity triggered by tumor necrosis factor-alpha. In vitro binding studies demonstrated a direct interaction between Livin and the active form of the downstream caspases, caspase-3 and -7, that was dependent on the BIR domain of Livin. In addition, the unprocessed and cleaved forms of caspase-9 co-immunoprecipitated with Livin in vivo, and recombinant Livin could inhibit the activation of caspase-9 induced by Apaf-1, cytochrome c, and dATP. The subcellular distribution of the transfected Livin was analyzed by immunofluorescence. Both Livin and Survivin were expressed in the nucleus and in a filamentous pattern throughout the cytoplasm. In contrast to the apoptotic activity, the COOH-terminal RING domain mediated its subcellular localization patterning. Further studies found that transfection of an antisense construct against livin could trigger apoptosis specifically in cell lines expressing livin mRNA. This was associated with an increase in DNA fragmentation and in DEVD-like caspase activity. Thus, disruption of Livin may provide a strategy to induce apoptosis in certain cancer cells.
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PMID:Livin, a novel inhibitor of apoptosis protein family member. 1102 45

HIV-1 induces apoptosis and leads to CD4+ T-lymphocyte depletion in humans. It is still unclear whether HIV-1 kills infected cells directly or indirectly. To elucidate the mechanisms of HIV-1-induced apoptosis, we infected human CD4+ T cells with HIV-1. Enzymatic analysis with fluorometric substrates showed that caspase 2, 3, and 9 were activated in CD4+ T cells with peak levels 48 h after infection. Immunoblotting analysis confirmed the cleavage of pro-caspase 3 and 9, and of specific caspase substrates. Release of cytochrome c and apoptosis-inducing factor (AIF) from mitochondria was observed in HIV-infected cells. The cytochrome c and AIF release preceded the reduction of the mitochondrial transmembrane potential and nuclear chromatin condensation. H IV infection led to phosphorylation of p53 at the Ser15 residue, detectable as early as 24 h after infection. The p53 phosphorylation was followed by increased mRNA and protein expression of p21, Bax, HDM2, and p53. Up-regulation of surface FasL expression, accompanied by a down-regulation of Fas-associated proteins (FADD, DAXX, and RIP), was observed 72 h after infection. Our results suggest that HIV activates the p53 pathway, leading to cytochrome c and AIF release with ensuing caspase activation.
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PMID:HIV induces lymphocyte apoptosis by a p53-initiated, mitochondrial-mediated mechanism. 1109 84

We recently reported that butyrate, an inhibitor of histone deacetylases, is capable of inducing Fas-independent apoptosis in the acute lymphoblastic leukemia cell line CCRF-CEM. Here we demonstrate that butyrate enhances Fas-induced apoptosis in this cell line. The application of different histone deacetylase inhibitors revealed that tetra-acetylated histone H4 is associated with the amplifying effect of butyrate on Fas-induced cell death. FasL, Fas, FADD, RIP, caspase-8, caspase-3, Bid, FLIP(S+L), FLASH and FAP-1, proteins known to act within the Fas-apoptosis cascade, showed no changes in their expression levels in cells treated with butyrate compared with untreated cells. Analyses of Fas-oligomerization and Western blotting as well as enzyme activity assays of caspase-2, caspase-3 and caspase-8 suggest that butyrate enhances Fas-induced apoptosis downstream of Fas but upstream of caspase-8 activation. In immunoprecipitation experiments a 37 kD butyrate-regulated protein was detected which specifically interacts with caspase-8.
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PMID:Inhibition of histone deacetylase activity enhances Fas receptor-mediated apoptosis in leukemic lymphoblasts. 1159 99

Two ovarian cancer cell lines named NOS4 and SKOV-3 have been shown to have different sensitivities to a cytotoxic anti-Fas antibody, CH-11. Although both cell lines express Fas molecules on the cell surfaces at the same intensities, apoptosis is induced by CH-11 in NOS4 cells but not in SKOV-3 cells. In this study, the different apoptosis-sensitivities of these cells were assessed. Both cell lines express almost the same levels of FADD, RIP, c-FLIP, FAP-1, Bax, Bcl-2 and Bcl-XL. Evidence of caspase-8, caspase-9 and caspase-3 activation and of cleavage of PARP and Bid was obtained in NOS4 cells but not in SKOV-3 cells. When triggered by FasL protein, DNA fragmentation and caspase-8 activation were observed in SKOV-3 cells, though they were not as clear as in NOS4 cells. All the anti-Fas antibody-mediated signals for apoptosis induction in NOS4 cells were completely blocked by a caspase-8-specific inhibitor, Z-IETD-FMK. These results indicate that the different sensitivities to the anti-Fas antibody are solely dependent on the activation of caspase-8, which could be influenced by yet unknown qualitative or quantitative abnormalities in molecules involved in DISC formation.
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PMID:Activation of caspase-8 is critical for sensitivity to cytotoxic anti-Fas antibody-induced apoptosis in human ovarian cancer cells. 1186 94

Signal transduction induced by tumor necrosis factor (TNF) family members and their receptors has been an intensive area of research for several years. The major impact of these studies has been the delineation of apoptotic and cell survival signaling pathways. These discoveries, coupled with major advances in the study of mammalian apoptotic machinery, constitute a promising blueprint of the molecular network governing the fate of all living cells. In this review, we concentrate on the fate of cells in the immune system, where regulation of cell death and cell survival is a frequent and important exercise. A small imbalance in favor of either fate can result in disastrous pathological outcomes, such as cancer, autoimmunity or immune deficiency. It is an insurmountable task to discuss all molecules reported in the literature that are implicated in lymphocyte death or survival. We have therefore focused on discoveries made by mouse gene targeting, as these studies provide the most physiologically relevant information on each molecule. We begin with a description of signaling channels initiated by TNF receptor type 1 engagement, which can lead to either cell survival or to cell death. The point of bifurcation of this pathway and the decision-making molecules FADD, TRAF2 and RIP are discussed. We then follow apoptotic and survival pathways from upstream to downstream, describing many important players involved in signal transduction. Molecules important for NF-kappaB and JNK/stress-activated protein kinase activation such as IKKbeta, NEMO, MAP3K and TRAF6 are discussed, as is the impact of BAFF and its receptors on B-cell survival. Mouse mutants that have helped to define the mammalian apoptosis execution machinery, including animals lacking Apaf-1, caspase-3 and caspase-9, are also described. We conclude with a brief analysis of the potential therapeutic options arising from this body of work.
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PMID:Signaling for survival and apoptosis in the immune system. 1211 Jan 44

Death receptors, such as Fas and tumor necrosis factor-related apoptosis-inducing ligand receptors, recruit Fas-associated death domain and pro-caspase-8 homodimers, which are then autoproteolytically activated. Active caspase-8 is released into the cytoplasm, where it cleaves various proteins including pro-caspase-3, resulting in apoptosis. The cellular Fas-associated death domain-like interleukin-1-beta-converting enzyme-inhibitory protein long form (FLIP(L)), a structural homologue of caspase-8 lacking caspase activity because of several mutations in the active site, is a potent inhibitor of death receptor-induced apoptosis. FLIP(L) is proposed to block caspase-8 activity by forming a proteolytically inactive heterodimer with caspase-8. In contrast, we propose that FLIP(L)-bound caspase-8 is an active protease. Upon heterocomplex formation, a limited caspase-8 autoprocessing occurs resulting in the generation of the p43/41 and the p12 subunits. This partially processed form but also the non-cleaved FLIP(L)-caspase-8 heterocomplex are proteolytically active because they both bind synthetic substrates efficiently. Moreover, FLIP(L) expression favors receptor-interacting kinase (RIP) processing within the Fas-signaling complex. We propose that FLIP(L) inhibits caspase-8 release-dependent pro-apoptotic signals, whereas the single, membrane-restricted active site of the FLIP(L)-caspase-8 heterocomplex is proteolytically active and acts on local substrates such as RIP.
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PMID:The long form of FLIP is an activator of caspase-8 at the Fas death-inducing signaling complex. 1221 47


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