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)

Many anticancer drugs are able to induce apoptosis in tumor cells but the mechanisms underlying this phenomenon are poorly understood. Some authors reported that the p53 tumor suppressor gene may be responsible for drug-induced apoptosis; however, chemotherapy-induced apoptosis can also be observed in p53 negative cells. Recently, doxorubicin (DXR) was reported to induce CD95L expression to mediate apoptosis through the CD95/CD95L system. Thus, an impairment of such a system may be involved in drug resistance. We evaluated the in vitro antitumor activity of several cytotoxic drugs on two human p53-negative T-cell lymphoma cell lines, the HUT78-B1 CD95L-resistant cell line and the HUT78 parental CD95L-sensitive cell line. We demostrated by Western blotting assay that DXR and etoposide (VP-16) were able to induce CD95L expression after 4 h of treatment. In contrast, they were unable to induce the expression of p53. DXR, at concentrations ranging from 0.001 - 1 microg/ml, and VP16, at concentrations ranging from 0.05 - 1 microg/ml, were equally cytotoxic and induced apoptosis in both cell lines as assessed by fluorescence microscopy and flow cytometry analyses. Although we observed a slightly reduced percentage of apoptotic cells in HUT78B1 when compared with the parental HUT78 cells after few hours of drug exposure, this difference was no longer evident at 48 or 72 h. Similarly, the exposure of HUT78 cells to a CD95-blocking antibody partially reduced early apoptosis (24 h) without affecting the long-term effects of the drugs including cytotoxicity. Furthermore, as observed with DXR and VP-16, both the CD95L-sensitive and the CD95L-resistant cell lines resulted equally sensitive to the cytotoxic effects of a number of different cytotoxic drugs (vincristine, camptothecin, 5-fluorouracil and methotrexate). The treatment with the Caspase-3 tetrapeptide aldehyde inhibitor, Ac-DEVD-CHO, did not affect the DXR-induced apoptosis whereas it only modestly inhibited apoptosis and cytotoxicity of VP-16, while Z-VAD.FMK, a Caspase inhibitor that prevents the processing of Caspase-3 to its active form, was able to block DXR-induced apoptosis at 24 h but not at 48 h. Thus, our results do not confirm a crucial role for the CD95/CD95L system in drug-induced apoptosis and suggest the involvement of alternative p53-independent pathways at least in this experimental model system.
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PMID:The CD95/CD95 ligand system is not the major effector in anticancer drug-mediated apoptosis. 1020 May 32

In this study, we show that N-acetylcysteine (NAC), a precursor of glutathione and an intracellular free radical scavenger, almost completely prevented hepatocyte growth factor (HGF)-suppressed growth of Sarcoma 180 and Meth A cells, and HGF-induced apoptosis, assessed by DNA fragmentation, and increase in caspase-3 activity, in Sarcoma 180 cells. The reduced form of glutathione also prevented HGF-suppressed growth of the cells as effective as NAC. Ascorbic acid partially prevented the effect of HGF, but other antioxidants such as superoxide dismutase, catalase, and vitamin E, and the free radical spin traps N-t-butyl-alpha-phenylnitrone and 3,3,5, 5-tetramethyl-1-pyrroline-1-oxide did not have protective effects. HGF caused morphological changes of the cells, many cells showing condensation and rounding, and enhanced the generation of intracellular reactive oxygen species (ROS) as judged by flow cytometric analysis using 2',7'-dichlorofluorescein diacetate. NAC completely prevented both HGF-induced morphological changes and the enhancement of ROS generation in the cells. However, NAC did not prevent the HGF-induced scattering of Madin-Darby canine kidney cells. To our knowledge, this is the first report that HGF stimulates the production of ROS, and our results suggest the involvement of oxidative stress in the mechanism by which HGF induces growth suppression of tumor cells.
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PMID:Involvement of oxidative stress in tumor cytotoxic activity of hepatocyte growth factor/scatter factor. 1022 23

Fas and Fas ligand (FasL) have been found both in lymphoid and in non-lymphoid malignancies, and are thought to play a role in the interplay between tumors and the immune system. Here we investigated Fas/FasL expression, function and intracellular signalling pathways in human melanomas. Of 5 melanoma cell lines, 3 expressed Fas at their surface, and all of them expressed FasL. FasL was functional, since it triggered Fas-induced apoptosis of human T lymphocytes clones. Conversely, cross-linking of Fas molecule with a specific monoclonal antibody failed to induce apoptosis in any of the melanomas tested, or ceramide intracellular accumulation or caspase-3 activation, pointing to an early alteration in the Fas-triggered signaling cascade. All melanomas retained the ability to undergo apoptosis induced by cytotoxic lymphocytes, which was mediated by the granule exocytosis mechanism. This suggests that melanoma cells evade immune-mediated Fas-triggered apoptosis via a selective blockade of the Fas apoptotic pathway. Cytotoxic lymphocytes, however, may circumvent tumor resistance to Fas-induced death via granzyme-mediated apoptosis, further supporting the development of immunotherapeutic strategies in the treatment of cancer.
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PMID:Blockade of the Fas-triggered intracellular signaling pathway in human melanomas is circumvented by cytotoxic lymphocytes. 1022 47

Aging is associated with altered immune function. We previously reported that splenocytes and thymocytes undergo apoptosis with aging in rats. In the present study, we examined the expression of genes associated with apoptosis in splenocytes and thymus in aging rats. We evaluated the expression of bax, interleukin 1-beta-converting enzyme (ICE)/ced-3 protease family, caspase-3 and tumor suppressor gene p53. Rats in age groups of 6, 24, 48, and 96 weeks were sacrificed; thymocytes and splenocytes were isolated followed by lysis in a modified RIPA buffer containing protease inhibitors. Western blot analysis of proteins was performed by probing immunoblots with antibodies against p53, bax and PARP (poly ADP-ribose polymerase). Increased aging was associated with enhanced expression of bax, p53 and cleavage of PARP by Caspase-3. The expression of p53 and cleavage of PARP indicates the presence of damaged DNA; nevertheless, the cleavage of PARP or activation of caspase-3 may be playing an important role in the initiation of early events in apoptosis. These results suggest that aging of splenocytes and thymocytes is associated with the expression of cell death genes. The present study provides an insight into age-associated altered immune function.
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PMID:Aging splenocyte and thymocyte apoptosis is associated with enhanced expression of p53, bax, and caspase-3. 1032 82

Apoptosis (programmed cell death) serves an important role in the normal morphogenesis, immunoregulation, and homeostatic mechanisms in both normal and neoplastic cells. Caspase-3/CPP32, a member of the ICE/Ced-3-family of cysteine proteases, is an important downstream mediator of several complex proteolytic cascades that result in apoptosis in both hematopoietic and nonhematopoietic cells. Previous studies have demonstrated that caspase-3 is commonly expressed in classical Hodgkin's disease (CHD); however, the biological significance of its expression in Hodgkin's disease is unknown. In this report, the expression of caspase-3 in nodular lymphocyte predominance Hodgkin's disease (NLPHD) was evaluated by immunohistochemistry; in addition, we investigated the role of caspase-3 in CD95 (Fas)-mediated apoptosis in three CHD cell lines. Formalin-fixed, paraffin-embedded tissue sections from 11 cases of NLPHD were immunostained for caspase-3 using a polyclonal rabbit antibody that detects both the 32-kd zymogen and the 20-kd active subunit of the caspase-3 protease. Only 1/11 cases of NLPHD demonstrated caspase-3 immunopositivity in lymphocytic/histiocytic cells. Caspase-3 expression was also evaluated in three CHD cell lines, HS445, L428, and KMH2. Whereas caspase-3 expression was detected in HS445 and L428 cell lines, no expression was found in KMH2 cells by immunohistochemical staining. Treatment of HS445 and L428 cell lines for 72 hours with agonistic CD95 monoclonal antibody induced marked apoptosis that was significantly inhibited by pretreatment with the caspase-3 inhibitor, DEVD-FMK, as determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay and flow cytometric analysis of 7-amino-actinomycin D staining. In addition, a significant increase in caspase-3 activity as determined by an enzyme colorimetric assay was detected in HS445 and L428 cells after 48 hours of CD95 stimulation. In marked contrast, treatment of caspase-3-deficient KMH2 cells with anti-CD95 mAb did not demonstrate an increase in caspase-3 activity or induce apoptosis. These data demonstrate caspase-3 is important for CD95-mediated apoptosis in CHD cell lines. In addition, the majority of NLPHD cases examined in this study failed to express detectable levels of caspase-3, suggesting these tumor cells may be resistant to apoptotic stimuli dependent on caspase-3 activity. Furthermore, these data suggest the differential expression of caspase-3 noted between NLPHD and CHD may provide additional evidence that each is a unique disease entity.
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PMID:Characterization of the interleukin-1beta-converting enzyme/ced-3-family protease, caspase-3/CPP32, in Hodgkin's disease: lack of caspase-3 expression in nodular lymphocyte predominance Hodgkin's disease. 1032 97

By using the amino acid sequence motif of tumor necrosis factor (TNF), we searched the expressed sequence tag data base and identified a novel full-length cDNA encoding 285 amino acid residues and named it THANK. THANK is a type II transmembrane protein with 15-20% overall amino acid sequence homology to TNF, LT-alpha, FasL, and LIGHT, all members of the TNF family. The mRNA for THANK was expressed at high levels by peripheral blood leukocytes, lymph node, spleen, and thymus and at low levels by small intestine, pancreas, placenta, and lungs. THANK was also prominently expressed in hematopoietic cell lines. The recombinant purified protein expressed in the baculovirus system had an approximate molecular size 20 kDa with amino-terminal sequence of AVQGP. Treatment of human myeloid U937 cells with purified THANK activated nuclear transcription factor-kappaB (NF-kappaB) consisting of p50 and p65. Activation was time- and dose-dependent, beginning with as little as a 1 pM amount of the cytokines and as early as 15 min. Under the same conditions, THANK also activated c-jun NH2-terminal kinase (JNK) in U937 cells. THANK also strongly suppressed the growth of tumor cell lines and activated caspase-3. Although THANK had all the activities and potency of TNF, it did not bind to the TNF receptors. Thus our results indicate that THANK is a novel cytokine that belongs to the TNF family and activates apoptosis, NF-kappaB, and JNK through a distinct receptor.
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PMID:Identification and characterization of a novel cytokine, THANK, a TNF homologue that activates apoptosis, nuclear factor-kappaB, and c-Jun NH2-terminal kinase. 1034 44

The Deleted in Colorectal Cancer gene (DCC) encodes a cell surface receptor that belongs to the Ig superfamily. Inactivation of the DCC gene has been implicated in human tumor progression. However, little is known about the biological function of the DCC protein. In the present study, we demonstrated that expression of DCC activated caspase-3 and programmed cell death, or induced G2/M cell cycle arrest in tumor cells. In some cell lines, apoptosis was evident within 24 h of DCC expression. Timing of the appearance of apoptotic cells coincided with that of the cleavage of poly (ADP-ribose) polymerase, a substrate of caspase-3. Expression of the apoptosis inhibitory gene Bcl-2 was not able to abrogate the DCC-induced apoptosis. In the G2/M cycle arrest cells, cdk1 activity was inhibited. Our results suggest that the DCC protein may transduce signals resulting in activation of caspases or inhibition of Cdk1. These data provide a possible mechanism by which DCC suppresses tumorigenesis.
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PMID:Induction of apoptosis and G2/M cell cycle arrest by DCC. 1034 49

Nitric oxide (NO) is a potent inhibitor of apoptosis in many cell types, including hepatocytes. We and others have described NO-dependent decreases in caspase activity in cells undergoing apoptosis. However, previous work has not determined whether NO disrupts the proteolytic processing and thus the activation of pro-caspases. Here we report that NO suppresses proteolytic processing and activation of multiple pro-caspases in intact cells, including caspase-3 and caspase-8. We found that both exogenous NO as well as endogenously produced NO via adenoviral inducible NO synthase gene transfer protected hepatocytes from tumor necrosid factor (TNF) alpha plus actinomycin D (TNFalpha/ActD)-induced apoptosis. Affinity labeling with biotin-VAD-fmk of all active caspase species in TNFalpha-mediated apoptosis identified four newly labeled spots (activated caspases) present exclusively in TNFalpha/ActD-treated cells. Both NO and the caspase inhibitor, Ac-DEVD-CHO, prevented the appearance of the four newly labeled spots or active caspases. Immunoanalysis of affinity labeled caspases demonstrated that caspase-3 was the major effector caspase. Western blot analysis also identified the activation of caspase-8 in the TNFalpha/ActD-treated cells, and the activation was suppressed by NO. Furthermore, NO inhibited several other events associated with caspase activation in cells, including release of cytochrome c from mitochondria, decrease in mitochondrial transmembrane potential, and cleavage of poly(ADP-ribose) polymerase in TNFalpha/ActD-treated cells. These findings indicate the involvement of multiple caspases in TNFalpha-mediated apoptosis in hepatocytes and establish the capacity of NO to inhibit not only active caspases but also caspase activation.
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PMID:Nitric oxide suppresses apoptosis via interrupting caspase activation and mitochondrial dysfunction in cultured hepatocytes. 1035 93

If the interplay between caspase proteases and mitochondria decide the fate of the cell during apoptosis, they may constitute useful molecular targets for novel drug design. We have shown that photoactivated merocyanine 540 (pMC540) triggers caspase-mediated apoptosis in HL60 leukemia and M14 melanoma cells. Because pMC540 is a mixture of photoproducts, we set out to purify the biologically active component(s) from this mixture and to investigate their ability to directly activate intracellular caspases and/or trigger mitochondrial events associated with apoptosis. Two photoproducts, namely C1 and C2, purified and characterized by mass spectroscopy and nuclear magnetic resonance (NMR) analysis, effectively induced apoptosis in HL60 and M14 cells. Interestingly, both C1 and C2 induced non-receptor-dependent activation of caspase 8, which was responsible for the downstream activation of caspase 3 and cell death. Both compounds induced the release of cytochrome C from mitochondria of tumor cells and from purified rat liver mitochondria; however, different mechanisms were operative in cytochrome C translocation in response to C1 or C2. C1-induced cytochrome C release was mediated by the mitochondrial permeability transition (MPT) pore and accompanied by a decrease in mitochondrial transmembrane potential (triangle uppsim), whereas cytochrome C release in response to C2 was independent of MPT pore opening. These findings do not exclude the possibility that changes in mitochondrial triangle uppsim are critical for apoptosis in some instances, but support the notion that this may not be a universal step in the apoptotic process. Thus, identification of two novel anticancer agents that directly activate effector components of the apoptotic pathway could have potential implications for the development of newer chemotherapeutic drugs.
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PMID:Purified photoproducts of merocyanine 540 trigger cytochrome C release and caspase 8-dependent apoptosis in human leukemia and melanoma cells. 1036 Nov 6

Activation of caspases is required in Fas receptor mediated apoptosis. Maintenance of a reducing environment inside the cell has been suggested to be necessary for caspase activity during apoptosis. We explored the possibility to potentiate Fas mediated killing of tumor cells by alpha-lipoic acid (LA), a redox-active drug and nutrient that is intracellularly reduced to a potent reductant dihydrolipoic acid. Treatment of cells with 100 microM LA for 72 h markedly potentiated Fas-mediated apoptosis of leukemic Jurkat cells but not that of peripheral blood lymphocytes from healthy humans. In Jurkat, Fas activation was followed by rapid loss of cell thiols, decreased mitochondrial membrane potential, increased [Ca2+]i and increased PKC activity; all these responses were potentiated in LA pretreated cells. PKCdelta played an important role in mediating the effect of LA on Fas-mediated cell death. In response to Fas activation LA treatment potentiated caspase 3 activation by over 100%. The ability of LA to potentiate Fas mediated killing of leukemic cells was abrogated by a caspase 3 inhibitor suggesting that increased caspase 3 activity in LA-treated Fas-activated cells played an important role in potentiating cell death. This work provides first evidence showing that inducible caspase 3 activity may be pharmacologically up-regulated by reducing agents such as dihydrolipoic acid.
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PMID:Fas mediated apoptosis of human Jurkat T-cells: intracellular events and potentiation by redox-active alpha-lipoic acid. 1038 41


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