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)

Caspases are a family of cysteine proteases implicated in the biochemical and morphological changes that occur during apoptosis (programmed cell death). The loop domain of Bcl-2 is cleaved at Asp34 by caspase-3 (CPP32) in vitro, in cells overexpressing caspase-3, and after induction of apoptosis by Fas ligation and interleukin-3 withdrawal. The carboxyl-terminal Bcl-2 cleavage product triggered cell death and accelerated Sindbis virus-induced apoptosis, which was dependent on the BH3 homology and transmembrane domains of Bcl-2. Inhibitor studies indicated that cleavage of Bcl-2 may further activate downstream caspases and contribute to amplification of the caspase cascade. Cleavage-resistant mutants of Bcl-2 had increased protection from interleukin-3 withdrawal and Sindbis virus-induced apoptosis. Thus, cleavage of Bcl-2 by caspases may ensure the inevitability of cell death.
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PMID:Conversion of Bcl-2 to a Bax-like death effector by caspases. 939 3

Ectopic overexpression of Apaf-1 (2.5-fold) in human acute myelogenous leukemia HL-60 cells (HL-60/Apaf-1 cells) induced apoptosis and sensitized HL-60/Apaf-1 cells to etoposide- and paclitaxel-induced apoptosis (C. Perkins et al., Cancer Res., 58: 4561-4566, 1998). In this report, we demonstrate that in HL-60/Apaf-1 cells, the activity of caspase-9 and -3 induced by Apaf-1 overexpression was associated with a significant increase (5-fold) in the cytosolic accumulation of cytochrome c (cyt c), loss of mitochondrial membrane potential (deltapsim), and an increase in the reactive oxygen species. These were also associated with the processing of procaspase-8 and Bid (cytosolic, proapoptotic BH3 domain containing protein). Transient transfection of Apaf-1 into the Apaf-1-containing mouse embryogenic fibroblasts (MEFs; Apaf-1+/- MEFs) or Apaf-1-/- MEFs also induced the processing of procaspase-9 and procaspase-8, Bid cleavage, and apoptosis. These events were secondary to the activity of the downstream caspases induced by Apaf-1. This conclusion is supported by the observation that in HL-60/Apaf-1 cells, ectopic expression of dominant negative caspase-9, its inhibitory short isoform caspase-9b, or XIAP or treatment with the caspase inhibitor zVAD (50 microM) inhibited Apaf-1-induced caspase-8 and Bid cleavage, mitochondrial deltapsim, release of cyt c, and apoptosis. In contrast, a transient transfection of dominant negative caspase-8 or CrmA or exposure to caspase-8 inhibitor zIETD-fmk inhibited the processing of procaspase-8 and Bid but did not inhibit the cytosolic accumulation of cyt c in either the untreated HL-60/Apaf-1 cells or the etoposide-treated HL-60/Apaf-1 and HL-60/neo cells. These results indicate that Apaf-1 overexpression lowers the apoptotic threshold by activating caspase-9 and caspase-3. This triggers the mitochondrial deltapsim and cyt c release into the cytosol through a predominant mechanism other than cleavage of caspase-8 and/or Bid. This mechanism may involve a cytosolic mitochondrial permeability transition factor, which may be processed and activated by the downstream effector caspases, thereby completing an amplifying feedback loop, which triggers the mitochondrial events during apoptosis.
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PMID:The role of Apaf-1, caspase-9, and bid proteins in etoposide- or paclitaxel-induced mitochondrial events during apoptosis. 1074 35

Engagement of the plasma membrane receptor Fas can induce apoptosis of leukemic cells. Signaling through Fas requires the formation of a death-inducing signaling complex (DISC) that involves the cytoplasmic domain of Fas, the adaptor molecule FADD/MORT-1, and procaspase-8. The present study investigated whether another caspase, known as procaspase-2L, played a role in Fas-mediated cell death. A series of human leukemic variant cells was derived by stable transfection with a CASP2L antisense construct (CASP2L/AS). Specific down-regulation of procaspase-2L decreased the sensitivity of these cells to apoptosis induced by an agonistic anti-Fas antibody (Ab, clone CH11), as determined by studying DNA fragmentation, chromatin condensation, and externalization of phosphatidylserine on the plasma membrane. In leukemic cells transfected with an empty vector, anti-Fas Ab treatment activated caspase-8, decreased the expression of the BH3 domain-only protein Bid, triggered the release of cytochrome c from the mitochondria to the cytosol, and activated caspase-3. All these events could not be observed when CASP2L/AS cells were similarly treated with anti-Fas Abs. CASP2L/AS transfection did not inhibit the formation of the DISC and no direct interaction between procaspase-2L and either Fas or FADD or procaspase-8 was identified. Down-regulation of procaspase-2L inhibited anti-Fas Ab-mediated cleavage of c-FLIP (FLICE-inhibitory protein), a protein that interferes with the formation of a functional DISC. These results suggest that the long isoform of caspase-2 plays a role in the Fas-mediated pathway to cell death by contributing to caspase-8 activation at the DISC level.
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PMID:Involvement of caspase-2 long isoform in Fas-mediated cell death of human leukemic cells. 1123 27

Critical issues in apoptosis include the importance of caspases versus organelle dysfunction, dominance of anti- versus proapoptotic BCL-2 members, and whether commitment occurs upstream or downstream of mitochondria. Here, we show cells deficient for the downstream effectors Apaf-1, Caspase-9, or Caspase-3 display only transient protection from "BH3 domain-only" molecules and die a caspase-independent death by mitochondrial dysfunction. Cells with an upstream defect, lacking "multidomain" BAX, BAK demonstrate long-term resistance to all BH3 domain-only members, including BAD, BIM, and NOXA. Comparison of wild-type versus mutant BCL-2, BCL-X(L) indicates these antiapoptotics sequester BH3 domain-only molecules in stable mitochondrial complexes, preventing the activation of BAX, BAK. Thus, in mammals, BH3 domain-only molecules activate multidomain proapoptotic members to trigger a mitochondrial pathway, which both releases cytochrome c to activate caspases and initiates caspase-independent mitochondrial dysfunction.
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PMID:BCL-2, BCL-X(L) sequester BH3 domain-only molecules preventing BAX- and BAK-mediated mitochondrial apoptosis. 1158 31

Platelet transfusion is widely used to prevent bleeding in patients with severe thrombocytopenia. The maximal storage duration of platelet concentrates is usually 5 days, due to the platelet storage lesion that impairs their functions when stored for longer times. Some of the morphological and biochemical changes that characterize this storage lesion are reminiscent of cell death by apoptosis. The present study analyzed whether proteins involved in nucleated cell apoptosis could play a role in the platelet storage lesion. Storage of leukocyte-depleted platelets obtained by apheresis is associated with a late and limited activation of caspases, mainly caspase-3. This event correlates with an increased expression of the pro-apoptotic BH3-only protein Bim in the particulate fraction and a slight and late release of the pro-apoptotic mitochondrial protein Diablo/Smac in the cytosol. Platelets do not express the death receptors Fas, DR4 and DR5 on their plasma membrane, while the expression of the decoy receptor DcR2 increases progressively during platelet storage. Addition of low concentrations of the cryoprotector dimethylsulfoxide accelerates platelet caspase activation during storage, an effect that is partially prevented by the caspase inhibitor z-VAD-fmk. Altogether, DcR2 expression on the plasma membrane is an early event while caspase activation is a late event during platelet storage. These observations suggest that caspases are unlikely to account for the platelet storage lesion. As a consequence, addition of caspase inhibitors may not improve the quality of platelet concentrates stored in standard conditions.
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PMID:Early increase in DcR2 expression and late activation of caspases in the platelet storage lesion. 1158 15

By GenBank database searches and PCR, we have identified a novel human Bcl2-like gene, Bcl2-L-10, which contains conserved BH4, BH1 and BH2 domains but lacks BH3 domain. The Bcl2-L-10 gene has been assigned to chromosome 15q21.2. Transfection experiments demonstrated that Bcl2-L-10 can block apoptosis induced by interleukin-3 withdrawal and Bax expression, by prevention of cytochrome C release, caspase-3 activation and mitochondrial membrane potential collapse. Bcl2-L-10 cannot block TNFalpha-induced apoptosis. Furthermore, both the BH4 domain and the transmembrane domain of Bcl2-L-10 are necessary for its suppressive action on cell death. Our results demonstrated that Bcl2-L-10 is a newly detected anti-apoptotic member of the Bcl-2 family and that it blocks apoptosis in the mitochondrial death pathway but not in the death receptor pathway.
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PMID:Bcl2-L-10, a novel anti-apoptotic member of the Bcl-2 family, blocks apoptosis in the mitochondria death pathway but not in the death receptor pathway. 1168 80

We previously demonstrated that the forced expression of pro-caspase-3 can revert acquired chemoresistance in MT1-Adr breast cancer cells which show a defective activation of the mitochondrial pathway of apoptosis. We now asked whether the manipulation of mitochondrial apoptosis signaling can revert different types of drug resistance, i.e. the resistance due to impaired mitochondrial activation in the MT1-Adr cells and the resistance in MT3-Adr cells which is caused by increased expression of the Mdr-1/p-glycoprotein ABC transporter. Here we show that Bcl-2 overexpression is the underlying cause for the resistant phenotype in the MT1-Adr cells. Overexpression of the apoptosis-promoting Bax homologue Bak or the BH3 only protein Nbk/Bik reverts, as expected, acquired drug resistance in the MT1-Adr cells as recently demonstrated for pro-caspase-3. Moreover, we show that both apoptosis-promoters, Nbk/Bik and Bak, antagonize acquired chemoresistance for epirubicin-mediated apoptosis in MT3-Adr breast cancer cells. Neither drug uptake nor drug efflux were influenced by Bak or Nbk/Bik. Thus, our data show that manipulation of the downstream apoptosis signaling cascade by Bak and Nbk/Bik can overcome not only drug resistance due to mitochondrial apoptosis deficiency (in the MT1-Adr cells) but also classical, i.e. efflux-mediated, resistance for drug-induced cell death in the MT3-Adr cell line. Nbk/Bik and Bak could therefore be target genes to increase chemosensitivity and overcome different types of drug resistance.
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PMID:The apoptosis promoting Bcl-2 homologues Bak and Nbk/Bik overcome drug resistance in Mdr-1-negative and Mdr-1-overexpressing breast cancer cell lines. 1180 66

The involvement of p53, Bax, cytochrome C and CPP-32 (caspase-3) in the molecular mechanism ofTGF-beta1-induced apoptosis in HC11 mouse mammary epithelial cells (MEC) was examined. Laser scanning cytometry (LSC) was applied for the quantitative analysis of expression and distribution of examined apoptosis-related proteins in the cytoplasmic (Cf) and nuclear (Nf) area. Maximal pixel of fluorescence (MP) parameter corresponding to aggregation of molecules in the cell was also measured. Confocal and immunoelectron microscopy were used as a complementary methods. Apoptosis induced by TGF-beta1 (2 ng/ml) was associated with the increase of Bax MP observed within 60 min. after cytokine administration, indicating aggregation of Bax in the cell. Immunoelectron microscopy revealed Bax aggregation on mitochondrial membranes, rough endoplasmic reticulum, Golgi apparatus, cytoskeleton, nuclear envelope and inside of nucleus. The accumulation of Bax in the nucleus was confirmed by compartmental Bax analysis, showing the increase of cell number with elevated Bax Nf in 2 hr after TGF-beta1 administration to the culture. The redistribution of Bax within the cell was dependent on its activation occurring by the cleavage at N-terminal epitope and exposure of BH3 domain. Bax aggregation on organelles was completely abolished by prolactin or IGF-I. TGF-beta1 increased p53 MP, evidently after 4 hr of cell culture exposure to this cytokine. p53 was accumulated first of all in the nucleus, which was shown by significant increase of p53 Nf/Cf ratio and increase of p53-related nuclear fluorescence on confocal images. TGF-beta1 decreased cytochrome C MP, which corresponded to its release from mitochondria and dissipation in the cytosol. It was accompanied by the increase of CPP-32 MP and concentration of 89 kDa product of PARP degradation in the nucleus. In conclusion, TGF-beta1 triggers apoptosis in MEC through mitochondrial pathway involving: activation and translocation of Bax to mitochondrial membranes, release of cytochrome C from mitochondria, activation of CPP-32 and degradation of its substrate - PARP in the nucleus. Activation and subcellular redistribution of Bax is inhibited by lactogenic hormones: prolactin and IGF-I.
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PMID:Molecular mechanism of TGF-beta1-induced apoptosis in HC11 mouse mammary epithelial cells (MEC). 1193 68

Mitochondria act as a focal point for upstream apoptosis signals by releasing cytochrome c into the cytosol, leading to the activation of caspases and subsequent cell death. Members of the Bcl-2 protein family regulate this phenomenon by heterodimerization via the BH3 domain of proapoptotic members opposing their pro- and antiapoptotic functions. The mechanism of cytochrome c release from mitochondria and of its regulation remains controversial. In vitro binding studies of purified and biologically active proteins should help in understanding the molecular mechanism of interactions and protein functions. In this work, the Bcl-2-related antiapoptotic chicken protein Nr-13 was overexpressed as a highly soluble recombinant protein which showed correct folding as judged by circular dichroism and fluorescence spectroscopy. Purified Nr-13 inhibits caspase-3 activation in a Xenopus egg-derived cell-free system, and neutralizes the proapoptotic activity of a synthetic peptide containing the BH3 domain of Bax. The latter effect correlates with the high-affinity binding of the BH3 peptide to Nr-13 as monitored by the intrinsic tryptophan fluorescence. On the basis of the structural similarity with Bcl-x(L), putative residues involved in this interaction were identified. Nr-13 exhibits a high-affinity interaction with cytochrome c which is prevented by preincubation with the BH3-Bax peptide. These findings are discussed with respect to a model for the regulation of apoptosis in which a direct interaction between the antiapoptotic protein and cytochrome c may prevent the apoptosis.
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PMID:Interaction between the antiapoptotic protein Nr-13 and cytochrome c. Antagonistic effect of the BH3 domain of Bax. 1209 70

We have investigated the role of the BH3-only pro-death Bcl-2 family protein, Bid, in ischemic neuronal death in a murine focal cerebral ischemia model. Wild-type and bid-deficient mice of inbred C57BL/6 background were subjected to 90-min ischemia induced by left middle cerebral artery occlusion followed by 72-h reperfusion. The volume of ischemic infarct was significantly smaller in the bid-deficient brains than in the wild-type brains, suggesting that Bid participated in the ischemic neuronal death. Indeed, following the ischemic treatment there was a significant reduction of apoptosis in the ischemic areas, particularly in the inner infarct border zone (the penumbra), of the bid-deficient brains. In addition, activation of Bid in the wild-type brains could be readily detected at approximately 3 h after ischemia, as evidenced by its proteolytic cleavage and translocation to the mitochondria as determined using Western blot analysis and immunofluorescence staining. Correspondingly, mitochondrial release of cytochrome c could be detected around the same time Bid was cleaved in the wild-type brains. However, no significant cytochrome c release was detected in the bid-deficient brains until 24 h later. This suggests that, although the mitochondrial apoptosis pathway might be activated by multiple mechanisms during focal cerebral ischemia, Bid is critical to its early activation. This notion was further supported by the finding that caspase-3 activation was severely impaired in the bid-deficient brains, whereas activation of caspase-8 was much less affected. Taken together, these data suggest that Bid is activated early in neuronal ischemia in a caspase-8-dependent fashion and that Bid is perhaps one of the earliest and most potent activators of the mitochondrial apoptosis pathway. Thus, the role of Bid in the induction of ischemic neuronal death may render this molecule an attractive target for future therapeutic intervention.
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PMID:Bid-mediated mitochondrial pathway is critical to ischemic neuronal apoptosis and focal cerebral ischemia. 1220 Apr 26


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