Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.22.56 (caspase-3)
 35,750 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interferon gamma (IFNgamma) induces apoptosis in purified human erythroid colony-forming cells (ECFC) and inhibits cell growth. Fas (APO-1; CD95) and Fas ligand (FasL) mediate apoptosis induced by IFNgamma, because Fas is significantly upregulated by IFNgamma, whereas Fas ligand is constitutively present in the ECFC and neutralization of FasL greatly reduces the apoptosis. Because conversion of caspases from their dormant proenzyme forms to active enzymes has a critical role in transducing a cascade leading to apoptosis, we performed further studies of the expression and activation of caspases in normal human and IFNgamma-treated day-6 ECFC to better understand the mechanism of IFNgamma action in producing this cell death. RNase protection assays showed that the caspase-1, -2, -6, -8, and -9 mRNAs were upregulated by IFNgamma, whereas the caspase-5 and -7 mRNAs were not increased. Western blots showed that FLICE/caspase-8 was upregulated and activated by 24 hours of incubation with IFNgamma. FADD was not similarly altered by incubation with IFNgamma. Western blots of ICE/caspase-1, which might be required for amplification of the initial FLICE activation signal, showed that pro-ICE expression significantly increased after treatment with IFNgamma for 24 hours and cleavage of pro-ICE also increased. CPP32/apopain/caspase-3, responsible for the proteolytic cleavage of poly (ADP) ribose polymerase (PARP), was also studied and treatment of ECFC with IFNgamma resulted in an increased concentration of caspase-3 by 24 hours and a clear induction of enzyme activation by 48 hours, which was identified by the appearance of its p17-kD peptide fragment. The cleavage of PARP was demonstrated by an obvious increase of the 89-kD PARP cleavage product, which was observed at almost the same time as caspase-3 activation in the IFNgamma-treated cells, whereas untreated ECFC showed little change. Peptide inhibitors of the caspase proteins, DEVD-fmk, DEVD-cho, YVAD-cho, and IETD-fmk, were incubated with the ECFC to obtain further evidence for the involvement of caspases in IFNgamma-induced apoptosis. The activation of FLICE/caspase-8 and CPP32/caspase-3 and cleavage of PARP clearly were inhibited, but the reduction of cell growth due to apoptosis, induced by IFNgamma, was only partially blocked by the presence of the inhibitors. These results indicate that IFNgamma acts on ECFC not only to upregulate Fas, but also to selectively upregulate caspases-1, -3, and -8, which are activated and produce apoptosis, whereas the concentrations of FasL and FADD are not demonstrably changed.
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PMID:Interferon gamma induces upregulation and activation of caspases 1, 3, and 8 to produce apoptosis in human erythroid progenitor cells. 1023 83

Cytotoxic endoribonucleases (RNases) possess a potential for use in cancer therapy. However, the molecular determinants of RNase-induced cell death are not well understood. In this work, we identify such determinants of the cytotoxicity induced by onconase, an amphibian cytotoxic RNase. Onconase displayed a remarkable specificity for tRNA in vivo, leaving rRNA and mRNA apparently undamaged. Onconase-treated cells displayed apoptosis-associated cell blebbing, nuclear pyknosis and fragmentation (karyorrhexis), DNA fragmentation, and activation of caspase-3-like activity. The cytotoxic action of onconase correlated with inhibition of protein synthesis; however, we present evidence for the existence of a mechanism of onconase-induced apoptosis that is independent of inhibition of protein synthesis. The caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp(OMe) fluoromethyl ketone (zVADfmk), at concentrations that completely prevent apoptosis and caspase activation induced by ligation of the death receptor Fas, had only a partial protective effect on onconase-induced cell death. The proapoptotic activity of the p53 tumor suppressor protein and the Fas ligand/Fas/Fas-associating protein with death domain (FADD)/caspase-8 proapoptotic cascade were not required for onconase-induced apoptosis. Procaspases-9, -3, and -7 were processed in onconase-treated cells, suggesting the involvement of the mitochondrial apoptotic machinery in onconase-induced apoptosis. However, the onconase-induced activation of the caspase-9/caspase-3 cascade correlated with atypically little release of cytochrome c from mitochondria. In turn, the low levels of cytochrome c released from mitochondria correlated with a lack of detectable translocation of proapoptotic Bax from the cytosol onto mitochondria in response to onconase. This suggests the possibility of involvement of a different, potentially Bax- and cytochrome c-independent mechanism of caspase-9 activation in onconase-treated cells. As one possible mechanism, we demonstrate that procaspase-9 is released from mitochondria in onconase-treated cells. A detailed understanding of the molecular determinants of the cytotoxic action of onconase could provide means of positive or negative therapeutic modulation of the activity of this potent anticancer agent.
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PMID:Molecular determinants of apoptosis induced by the cytotoxic ribonuclease onconase: evidence for cytotoxic mechanisms different from inhibition of protein synthesis. 1076 89

One of the main functions of the tumor suppressor p53 is the induction of programmed cell death. Here we investigated in detail the molecular mechanisms that underlay p53 transactivation-dependent apoptosis in the human colon cancer cell line DLD-1. Although p53 upregulated the death receptors Fas, TRAIL-R1 and TRAIL-R2 in this cell line, p53-induced cell death occurred without detectable caspase-8 activation whereas, activation of caspase-9 and caspase-3 was readily observed. In addition to the upregulation of death receptors, p53 induced the pro-apoptotic Bcl-2 family members Bik and Bak and downregulated the anti-apoptotic Bcl-xL protein. Moreover, in RNase protection assay analyses as well as in reporter gene analyses we found a p53-dependent upregulation of the death receptor-inhibitory protein cFLIP. Together, these data argue for a p53-mediated activation of the mitochondrial pathway of apoptosis. In contrast to recently published data obtained in different cellular systems, there was no evidence for an essential role of NF-kappaB in p53-induced cell death. Moreover, induction of p53 interfered with TNF-induced NF-kappaB activation independently from apoptosis-induction.
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PMID:p53 upregulates cFLIP, inhibits transcription of NF-kappaB-regulated genes and induces caspase-8-independent cell death in DLD-1 cells. 1131 89

In Huntington's Disease (HD), the huntingtin protein (Htt) includes an expanded polyglutamine domain. Since mutant Htt concentrates in the nucleus of affected neurons, we have inquired whether normal Htt (Q16--23) is also able to access the nucleus. We observe that a major pool of normal full-length Htt of HeLa cells is anchored to endosomes and also detect RNase-sensitive nuclear foci which include a 70-kDa N-terminal Htt fragment. Agents which damage DNA trigger caspase-3-dependent cleavage of Htt and dramatically relocate the 70 kDa fragment to the nucleoplasm. Considering that polyglutamine tracts stimulate caspase activation, mutant Htt is therefore poised to enter the nucleus. These considerations help rationalize the nuclear accumulation of Htt which is characteristic of HD and provide a first example of involvement of caspase cleavage in release of membrane-bound proteins which subsequently enter the nucleus.
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PMID:Nuclear relocation of normal huntingtin. 1138 66

Rana catesbeiana ribonuclease (RC-RNase) and onconase were proven to own anti-tumor activity. While molecular determinants of onconase-induced cell death have become more explicit, the RC-RNase-induced death pathway remains presently unknown. Here we demonstrated that RC-RNase-induced molecular cascades in caspase-3-deficient MCF-7 cells did not include activation of initiation caspase-8 and -9. Cleavage timing suggested that procaspase-2 and -6 might be processed by active caspase-7 in MCF-7 cells. Caspase-7 was also responsible for cleavage of the poly(ADP-ribose) polymerase. Furthermore, we reported that overexpression of Bcl-X(L) could raise the survival rates of MCF-7 cells treated with RC-RNase and onconase.
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PMID:Caspase activation in response to cytotoxic Rana catesbeiana ribonuclease in MCF-7 cells. 1151 56

Rana catesbeiana ribonuclease (RC-RNase) exerted strong anti-tumor activity and its cytotoxicity was shown to correlate with differentiation stages of three different hepatoma cell lines. In this study, we demonstrate different RC-RNase cytotoxicity in undifferentiated HL-60 cells and in those that had been induced to differentiate by retinoic acid or dimethylsulfoxide. RC-RNase showed cytotoxicity in undifferentiated HL-60 cells, but not in HL-60 cells undergoing terminal differentiation. Furthermore, the caspase-9/caspase-3 pathway was activated when RC-RNase induced death in undifferentiated HL-60 cells and induction of differentiation led to a reversal of the caspase activation pathway.
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PMID:Induction of differentiation rescues HL-60 cells from Rana catesbeiana ribonuclease-induced cell death. 1243 86

4-phenylbutyrate (triButyrate trade mark, PB) a derivative of the short-chain fatty acid, butyrate, possesses anti-tumor activity in vitro in different tumor cell lines. Unlike most cytostatic compounds, PB possesses low toxicity. In order to evaluate possible clinical use of PB in cancer therapy, hepatocarcinoma (Hep3B) and hepatoblastoma (HepT1) cell lines, as well as xenografts derived from those in nude rats, were treated with PB in different dose (1-100 mM) and time regimens. Treatment with 10 mM of PB for 24 h (or 5 mM for 48 h) was shown to significantly inhibit Hep3B cell growth in vitro. The HepT1 cell line was more sensitive to PB treatment: already 1 mM of PB for 24 h significantly inhibited the growth of the cells. PB also resulted in regression of xenografts derived from these cell lines in vivo, when administrated by mini-pump with an intratumor catheter, yielding 20 micro mol of PB per cm3 of tumor volume per day. TUNEL assay and caspase-3 activity measurements suggested apoptosis to be the cell death mechanism in both cell lines and xenografts. Increased histones H3 and H4 acetylation was shown in both cells and xenografts, and the inhibition of histone deacetylase is proposed as the main trigger for the anti-tumor action of PB. Concomitant induction of p21Waf1/Cip1 expression was detected by RNase protection assay and Western blotting. Reduction in expression of alpha-fetoprotein was found both in Hep3B cells and xenografts, suggesting also a differentiation effect by PB.
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PMID:Apoptosis and tumor remission in liver tumor xenografts by 4-phenylbutyrate. 1257 11

Bovine seminal ribonuclease (BS-RNase), a natural dimeric homolog of bovine pancreatic RNase (RNase A), and HHP2-RNase, an engineered dimeric form of human pancreatic RNase (HP-RNase), are endowed with powerful antitumor effects. Here we show that BS- and HHP2-RNases, but not monomeric RNase A, induce apoptosis of human thyroid carcinoma cell lines. RNase-induced apoptosis was associated with activation of initiation caspase-8 and -9. This was followed by activation of executioner caspase-3, leading to the proteolytic cleavage of poly(ADP-ribose) polymerase. The caspase inhibitor Z-Val-Ala-Asp-(OMe)-fluoromethylketone protected thyroid cancer cells from BS-RNase-induced apoptosis. RNase-triggered apoptosis and caspase activation were accompanied by reduced phosphorylation of Akt/protein kinase B (PKB), a serine-threonine kinase that when phosphorylated is able to deliver survival signals to cancer cells. BS-RNase antitumor effects in nude mice were accompanied by caspase activation and apoptosis. Because of the high selectivity of apoptotic effects for malignant cells, BS- and HHP2-RNase are promising tools for the treatment of aggressive thyroid cancer.
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PMID:Antineoplastic ribonucleases selectively kill thyroid carcinoma cells via caspase-mediated induction of apoptosis. 1278 4

Following Gram-negative bacterial infection there is a reduction in matrix-producing cells. The goal of the present study was to examine the apoptotic effects of lipopolysaccharide (LPS) on fibroblastic cells and to investigate the role that the host response plays in this reaction. This was accomplished in vivo by subcutaneous inoculation of LPS in wild type and TNFR1(-/-)R2(-/-) mice. The direct effects of LPS on fibroblast apoptosis was studied in vitro with normal diploid human fibroblasts. The results indicate that LPS in vivo induces apoptosis of fibroblasts. By RNA profiling we demonstrated that LPS stimulates global expression of apoptotic genes and down-regulates anti-apoptotic genes. Fluorometric studies demonstrated that LPS in vivo significantly increased caspase-8 and caspase-3 activity and by use of specific inhibitors, the activation of caspase-3 was shown to be initiated by caspase-8 with no contribution from caspase-9. In vitro studies demonstrated that LPS did not induce apoptosis of fibroblasts, whereas tumor necrosis factor (TNF) did. In addition, the pattern of apoptotic gene expression induced by TNF in vitro was nearly identical to that induced by LPS in vivo, as measured by RNase protection assay. Moreover, pre-treatment of cells with TNF greatly enhanced apoptosis induced by a second stimulation with TNF 24 h later, suggesting that the global induction of pro-apoptotic genes was functionally significant. Thus, LPS acts to modulate the expression of a large number of genes that favor apoptosis of fibroblastic cells that is dependent upon activation of caspase-8 and is largely mediated by TNF.
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PMID:Lipopolysaccharides indirectly stimulate apoptosis and global induction of apoptotic genes in fibroblasts. 1455 Dec 16

Using morphological and molecular approaches, we characterized cisplatin-induced cell necrosis and apoptosis in rat kidney. Male Sprague-Dawley rats ( n=5 per group) received a single intraperitoneal injection of either cisplatin (5 mg/kg) or saline, and were killed on day 5. Functionally, cisplatin-treated rats developed polyuric acute renal failure. Morphologically, kidneys of cisplatin-treated rats showed overt tubular necrosis associated with apoptosis in the corticomedullary junction. Cell necrosis was segment-specific and was distributed in radial fashion at the corticomedullary junction. The apoptosis was limited to discrete cells in apparently intact tubules in the vicinity of the necrosed tubules. The apoptotic changes were confirmed by TUNEL (TdT-mediated deoxyuridine triphosphate nick-end labeling) and staining for cleaved caspase-3. Analysis of outer medullary tissue for apoptosis-related molecules by RNase protection assay revealed a significant increase in the expression of pro-apoptotic mRNAs (caspases 1, 2, and 8, and Bax) in cisplatin-treated rats. On the other hand, the expression of mRNA for the anti-apoptotic Bcl-2 did not change, resulting in a decrease in relative ratio of Bcl-2/Bax, and thus favoring apoptosis. The above changes were paralleled by a marked increase in caspase-3 precursor, the executioner protease. Furthermore, these pro-apoptotic molecular changes were associated with a 3-fold increase in the activity of JNK1 in the outer medulla, but not in the cortex, of cisplatin-treated rat kidneys, localizing to the site of maximal apoptosis. Upregulation of JNK1 activity in the outer medulla was not accompanied by changes in the activities of ERK or p38 kinase. In conclusion, these data suggest that cisplatin-induced apoptotic cell death in native kidney may be mediated by cooperative activation of the JNK1 pathway and Bax in the outer medulla.
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PMID:Cellular and molecular studies on cisplatin-induced apoptotic cell death in rat kidney. 1455 73


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