Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.4.2.30 (PARP)
 13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Rad51 gene of Saccharomyces cerevisiae is required for genetic recombination and recombinational repair of DNA strand breaks. In higher eukaryotes Rad51 is essential for embryonic development, and is involved in cell proliferation and DNA repair. Here we show that human Rad51 (HsRad51) is proteolytically cleaved during apoptosis in two T-lymphocyte cell lines, Jurkat and PFI-285. Apoptosis was induced by camptothecin or anti-Fas monoclonal antibody (anti-Fas mAb). HsRad51 was cleaved with similar kinetics as human poly(ADP-ribose) polymerase (HsPARP) after treatment with either agent. The time course of cleavage coincided with internucleosomal DNA fragmentation. The HsRad51 fragments observed in apoptotic cells were identical to those generated from in vitro translated (IVT) HsRad51 exposed to activated Jurkat S-100 extract in a cell-free system. In each case, cleavage of HsRad51 was abolished by acetyl-Asp-Glu-Val-Asp-aldehyde (Ac-DEVD-CHO). However, cleavage of IVT HsRad51 could not be demonstrated using purified caspase-2, -3 or -6 to -10, and the identity of the responsible protease thus remains to be determined. In summary, we have shown that HsRad51 belongs to a group of repair proteins, including PARP and DNA-dependent protein kinase, which are specifically cleaved during the execution phase of apoptosis.
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PMID:Proteolytic cleavage of HsRad51 during apoptosis. 960 20

We have attempted to elucidate the mechanism of apoptotic cell death induced by hypoxia (very low oxygen conditions) in neuronal cells. Human neuroblastoma SK-N-MC cells under hypoxic conditions resulted in apoptosis in a time-dependent manner estimated by DNA fragmentation assay and nuclear morphology stained with fluorescent chromatin dye. Pretreatment with Z-Asp-CH2-DCB, a caspase inhibitor, suppressed the DNA ladder in response to hypoxia in a concentration-dependent manner. An increase in caspase-3-like protease (DEVDase) activity was observed during apoptosis, but no caspase-1 activity (YVADase) was detected. To confirm the involvement of caspase-3 during apoptosis, Western blot analysis was performed using anti-caspase-3 antibody. The 20- and 17-kDa proteins, corresponding to the active products of caspase-3, were generated in hypoxia-challenged lysates in which processing of the full length form of caspase-3 was evident. With a time course similar to this caspase-3 activation, hypoxic stress caused the cleavage of PARP, yielding an 85-kDa fragment typical of caspase activity. In addition, caspase-2 was also activated by hypoxia, and the stress elicited the release of cytochrome c into the cytosol during apoptosis. These results suggest that caspase activation and cytochrome c release play roles in hypoxia-induced neuronal apoptosis.
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PMID:Hypoxia induces apoptosis in human neuroblastoma SK-N-MC cells by caspase activation accompanying cytochrome c release from mitochondria. 984

It is well known that caspases are produced as proforms, which are proteolytically cleaved and activated during apoptosis or programmed cell death. We report here that caspases are activated during apoptosis by treatment with NOC18, a nitric oxide (NO) donor. Our present experiments have examined the way in which NO induces neuronal cell death, using a new type of NO donor that spontaneously releases only NO without enzymatic metabolism. NOC18 induced apoptosis in human neuroblastoma SH-SY5Y cells in a concentration- and time-dependent manner as estimated by DNA fragmentation assay, FACScan analysis, and nuclear morphology. Oxyhemoglobin, an NO trapper, suppressed NOC18-triggered DNA fragmentation, indicating that NO from NOC18 is a real activator in this study. Upon the induction of apoptosis, an increase in caspase-3-like protease activity, but not caspase-1, was observed. Procaspase-2 protein, an inactive form of caspase-2, decreased dramatically. In addition, NOC18 also resulted in poly (ADP-ribose) polymerase (PARP) cleavage, yielding an 85-kDa fragment typical of caspase activity. Oxyhemoglobin blocked the decrease of procaspase-2 and the cleavage of PARP by NOC18 in a concentration-dependent manner. Moreover, NO elicited the release of cytochrome c into the cytosol during apoptosis. These results suggest that both stimulation of caspase activity and cytochrome c release are partly involved in NO-induced neuronal apoptosis.
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PMID:Caspase activation accompanying cytochrome c release from mitochondria is possibly involved in nitric oxide-induced neuronal apoptosis in SH-SY5Y cells. 988 70

We here report involvement of caspases in NO-induced neuronal apoptosis. Our experiments were designed to elucidate how NO induces neuronal cell death using NOC18, a new type of NO donor that spontaneously releases NO alone, without enzymatic metabolization. NOC18 induced apoptosis in human neuroblastoma SH-SY5Y cells in a concentration- and time-dependent manner estimated with DNA fragmentation assay, FACScan analysis, and nuclear morphology. In this study, oxyhemoglobin, an NO trapper, suppressed NOC18-triggered DNA fragmentation, indicating that NO from NOC18 is an apoptosis-inducer. An increase in caspase-3-like protease activity was observed in parallel with the induction of apoptosis, but no caspase-1-like protease activity was detected. The level of pro-caspase-2 protein, a precursor of caspase-2, was decreased dramatically. In addition, NOC18 also caused the cleavage of PARP, yielding an 85 kDa protein, a typical fragment of the caspases reaction. Oxyhemoglobin blocked the decrease in pro-caspase-2 and the cleavage of PARP by NOC18. Moreover, NO elicited the release of cytochrome c into the cytosol from mitochondria during apoptosis. These results suggest that activation of caspases by cytochrome c released from mitochondria is involved in neuronal apoptosis induced by NO.
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PMID:[Possible involvement of caspase activation in nitric oxide-induced neuronal apoptosis in SH-SY5Y cells]. 1019 Jan 47

Cell death is an early and common event in the pathogenesis associated with the abnormal development induced by a variety of teratogens. Previously, we showed that the cell death induced in day 9 mouse embryos by three teratogens, hyperthermia (HS), 4-hydroperoxycyclophosphamide (4-CP), and sodium arsenite (As), is apoptotic in nature involving the activation of caspase-3, cleavage of poly(ADP-ribose) polymerase (PARP), and DNA fragmentation. We now show that HS, 4-CP, and staurosporine (ST) induce the release of cytochrome c from mitochondria with kinetics suggesting a causal relationship with the activation of caspase-3 and caspase-2. This causal relationship is supported by data showing that procaspase-3 and -2 can be activated in vitro by the addition of cytochrome c to a S-100 fraction prepared from control day 9 embryos. Together, these data support the notion that these three teratogens induce changes in embryonic mitochondria resulting in the release of cytochrome c and the subsequent activation of caspase-9, the upstream activator of caspase-3. Previously, we also showed that cells within the day 9 mouse embryo are differentially sensitive/resistant to the cell death-inducing potential of HS, 4-CP, and As. The most dramatic example of this differential sensitivity is the complete resistance of heart cells, characterized by the lack of caspase-3 activation, PARP cleavage, and DNA fragmentation. We now show that this block in the terminal phase of the apoptotic pathway in heart cells is associated with a lack of teratogen-induced release of cytochrome c. Together, our data indicate that mitochondria play a pivotal role in cell death during the early phases of teratogenesis.
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PMID:Cytochrome c release from mitochondria of early postimplantation murine embryos exposed to 4-hydroperoxycyclophosphamide, heat shock, and staurosporine. 1065 48

The recognized role of caspases as executioners of apoptosis, led us to investigate their involvement in death responses induced by okadaic acid (OA) in HeLa S(3) and MCF-7 cells. A one-day treatment with OA induced accumulation of the 85kDa poly(ADP-ribose) polymerase (PARP) fragment in cell lysates but the response was prevented if cells were treated with OA in the presence of the caspase inhibitors Z-VAD-FMK and Z-DEVD-FMK. The HeLa S(3) and MCF-7 cells were found to contain measurable levels of the intact caspase-2, -7, -8 and -9 zymogens, whereas caspase-3 was found only in HeLa cells. After one day of OA treatment, pro-caspase-2, -3, -7 and -9 isoforms were found processed in HeLa cells, whereas only pro-caspase-2 was processed in MCF-7 cells. Pro-caspase-8, in turn, was mostly unprocessed in both cell lines. The possible interference of caspase inhibitors on cell death was also evaluated, and we found that both Z-VAD-FMK and Z-DEVD-FMK could contribute different extents of protection of MCF-7 and HeLa cells from toxic effects caused by OA. We concluded that OA triggers multiple pathways of caspase processing, contributing to death responses triggered by OA in HeLa S(3) and MCF-7 cells.
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PMID:The toxic responses induced by okadaic acid involve processing of multiple caspase isoforms. 1113 34

Apoptotic cell death is induced in SH-SY5Y neuroblastoma cells following exposure to the protein kinase inhibitors staurosporine (100 nM) and 1-(5-Isoquinolinesulfonyl)-2-methylpiperazine: H-7 (100 microM). This is associated with reduced levels of PARP 117 kDa and with the concomitant formation of PARP-cleaved products of 89 kDa that result from caspase-3 activation. The process is inhibited with DEVD-fmk, a potent caspase-3 (and caspase-8) inhibitor, thus indicating that staurosporine- and H-7-induced cell death in SH-SY5Y is mediated by caspase activation. Increased caspase-2- and caspase-3-like activities, but not caspase-9-like activity, were demonstrated by monitoring proteolysis of the corresponding colorimetric substrates. Caspase-2 activity peaked at 6 h, whereas caspase-3 peaked at 12 h in parallel with the maximal loss of cell viability. No modifications in the expression levels of Fas and Fas-L were observed by Western blotting. Furthermore, no activation of caspase-8 was elicited by colorimetric assays through the process of apoptosis of neuroblastoma cells. These findings indicate that the Fas/Fas-L-caspase-8 pathway of cell death signaling is not involved in staurosporine- and H-7-induced apoptosis in SH-SY5Y neuroblastoma cells.
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PMID:Staurosporine- and H-7-induced cell death in SH-SY5Y neuroblastoma cells is associated with caspase-2 and caspase-3 activation, but not with activation of the FAS/FAS-L-caspase-8 signaling pathway. 1114 7

Garcinol, a polyisoprenylated benzophenone, was purified from Garcinia indica fruit rind. The effects of garcinol and curcumin on cell viability in human leukemia HL-60 cells were investigated. Garcinol and curcumin displayed strong growth inhibitory effects against human leukemia HL-60 cells, with estimated IC(50) values of 9.42 and 19.5 microM, respectively. Garcinol was able to induce apoptosis in a concentration- and time-dependent manner; however, curcumin was less effective. Treatment with garcinol caused induction of caspase-3/CPP32 activity in a dose- and time-dependent manner, but not caspase-1 activity, and induced the degradation of poly(ADP-ribose) polymerase (PARP). Pretreatment with caspase-3 inhibitor inhibited garcinol-induced DNA fragmentation. Treatment with garcinol (20 microM) caused a rapid loss of mitochondrial transmembrane potential, release of mitochondrial cytochrome c into cytosol, and subsequent induction of procaspase-9 processing. The cleavage of D4-GDI, an abundant hematopoietic cell GDP dissociation inhibitor for the Ras-related Rho family GTPases, occurred simultaneously with the activation of caspase-3 but preceded DNA fragmentation and the morphological changes associated with apoptotic cell death. Of these, Bcl-2, Bad, and Bax were studied. The level of expression of Bcl-2 slightly decreased, while the levels of Bad and Bax were dramatically increased in cells treated with garcinol. These results indicate that garcinol allows caspase-activated deoxyribonuclease to enter the nucleus and degrade chromosomal DNA and induces DFF-45 (DNA fragmentation factor) degradation. It is suggested that garcinol-induced apoptosis is triggered by the release of cytochrome c into the cytosol, procaspase-9 processing, activation of caspase-3 and caspase-2, degradation of PARP, and DNA fragmentation caused by the caspase-activated deoxyribonuclease through the digestion of DFF-45. The induction of apoptosis by garcinol may provide a pivotal mechanism for its cancer chemopreventive action.
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PMID:Induction of apoptosis by garcinol and curcumin through cytochrome c release and activation of caspases in human leukemia HL-60 cells. 1131 81

It has been known for some time that ablation of the neural tube and/or the notochord in the chick embryo leads to a massive wave of cell death in the adjacent somites. It is postulated that in the normal embryo, survival signals emanate from the neural tube and/or notochord that suppress apoptosis in the cells of the somites, except for a small population of sclerotome cells that are programmed to die naturally. In this study we show that axial ablation results in the death of sclerotome and not somitic neural crest cells, and we have examined the apoptotic response of these cells to the ablation. We show that several elements of the apoptotic cascade become detectable in somite cells in response to the withdrawal of survival signals. We demonstrate the down-regulation of bcl-2 protein in the somites adjacent to, and caudal to, the site of ablation, corresponding to the region that displays an elevated level of cell death. Although caspase-9 appeared to be activated in somites at all levels of the trunk, caspase-2 showed a clear response to the ablation of the axial structures. Removal of the neural tube and notochord produced an up-regulation of caspase-2 activity in somites in the region of the operation. Cleavage of two down-stream substrates of these caspases was examined. The cleavage of poly (ADP-ribose) polymerase (PARP) was apparent in somites at all levels of the trunk, and showed only a modest up-regulation after ablation. By contrast, the cleavage of DNA fragmentation factor (DFF45) showed a marked up-regulation in response to ablation, suggesting that this is a primary substrate for a caspase-dependent apoptotic mechanism. Evidence was also found for a caspase-independent mechanism, since the expression of apoptosis-inducing factor (AIF) was found to be very sensitive to, and up-regulated in somites by, axial ablation. Because the wave of apoptosis that is precipitated in somites by removal of the axial structures may be mediated by BMP-4, we examined the levels of BMP-4 in somites in response to axial ablation. BMP-4 expression was clearly up-regulated in somites adjacent to, or close to, the site of operation.
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PMID:Ablation of axial structures activates apoptotic pathways in somite cells of the chick embryo. 1178 86

Continuous and long-lasting exposure to tert-butylhydroperoxide (t-BOOH) increased the number of apoptotic SH-SY5Y human neuroblastoma cells both in the presence and in the absence of the intracellular Ca(2+) ion chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA). In addition, t-BOOH exposure induced activation of CPP32, as demonstrated by poly-(ADP-ribose) polymerase (PARP) cleavage, and of ICH-1L caspases. Exposure to t-BOOH also induced a time-dependent release of cytochrome c. Interestingly, in the presence of BAPTA, CPP32 activation still occurred, whereas ICH-1L activation was blocked. Ac-DEVD-CHO, an inhibitor of CPP32 activity, prevented the appearance of apoptotic cells, whereas the inhibitor of ICH-1L activity Z-VDVAD-FMK did not. Collectively, these findings demonstrate that in SH-SY5Y neuroblastoma cells exposure to continuous and long-lasting oxidative stress induced activation of caspase-3 that was independent of intracellular Ca(2+) ion concentration ([Ca(2+)](i)) elevation but led to cell apoptosis. In contrast, caspase-2 activation was dependent on [Ca(2+)](i) increase but did not result in apoptosis.
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PMID:Ca(2+)-independent caspase-3 but not Ca(2+)-dependent caspase-2 activation induced by oxidative stress leads to SH-SY5Y human neuroblastoma cell apoptosis. 1199 72


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