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)

We investigated the potential role of the ubiquitin proteolytic system in the death of cerebellar granule neurons induced by reduction of extracellular potassium. Inhibitors of proteasomal function block apoptosis if administered at onset of this process, but they do not exert such effect when added 2-3 hr later. The same inhibitors also prevent caspase-3 activity and calpain-caspase-3-mediated processing of tau protein, suggesting that proteasomes are involved upstream of the caspase activation. Although the proteasomes seem to play an early primary role in programmed cell death, we found that with progression of apoptosis, during the execution phase, a perturbation in normal ubiquitin-proteasome function occurs, and high levels of ubiquitinated proteins accumulate in the cytoplasm of dying cells. Such accumulation correlates with a progressive decline of proteasome chymotrypsin and trypsin-like activities and, to a lower extent, of postacidic-like activity. Both intracytoplasmic accumulation of ubiquitinated proteins and decline of proteasome function are reversed by the pan-caspase inhibitor Z-VAD-fmk. The decline in proteasome function is accompanied by, and likely attributable to, a marked and progressive decline of deubiquitinating activities. The finding that the proteasomes are early involved in apoptosis and that ubiquitinated proteins accumulate during this process prospect granule neurons as a model system aimed at correlating these events with neurodegenerative diseases.
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PMID:Proteasome involvement and accumulation of ubiquitinated proteins in cerebellar granule neurons undergoing apoptosis. 1063 88

MNEI (monocyte/neutrophil elastase inhibitor) is a 42 kDa serpin superfamily protein characterized initially as a fast-acting inhibitor of neutrophil elastase. Here we show that MNEI has a broader specificity, efficiently inhibiting proteases with elastase- and chymotrypsin-like specificities. Reaction of MNEI with neutrophil proteinase-3, an elastase-like protease, and porcine pancreatic elastase demonstrated rapid inhibition rate constants >10(7) M(-1) s(-1), similar to that observed for neutrophil elastase. Reactions of MNEI with chymotrypsin-like proteases were also rapid: cathepsin G from neutrophils (>10(6) M(-1) s(-1)), mast cell chymase (>10(5) M(-1) s(-1)), chymotrypsin (>10(6) M(-1) s(-1)), and prostate-specific antigen (PSA), which had the slowest rate constant at approximately 10(4) M(-1) s(-1). Inhibition of trypsin-like (plasmin, granzyme A, and thrombin) and caspase-like (granzyme B) serine proteases was not observed or highly inefficient (trypsin), nor was inhibition of proteases from the cysteine (caspase-1 and caspase-3) and metalloprotease (macrophage elastase, MMP-12) families. The stoichiometry of inhibition for all inhibitory reactions was near 1, and inhibitory complexes were resistant to dissociation by SDS, further indicating the specificity of MNEI for elastase- and chymotrypsin-like proteases. Determination of the reactive site of MNEI by N-terminal sequencing and mass analysis of reaction products identified two reactive sites, each with a different specificity. Cys(344), which corresponds to Met(358), the P(1) site of alpha1-antitrypsin, was the inhibitory site for elastase-like proteases and PSA, while the preceding residue, Phe(343), was the inhibitory site for chymotrypsin-like proteases. This study demonstrates that MNEI has two functional reactive sites corresponding to the predicted P(1) and P(2) positions of the reactive center loop. The data suggest that MNEI plays a regulatory role at extravascular sites to limit inflammatory damage due to proteases of cellular origin.
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PMID:The serpin MNEI inhibits elastase-like and chymotrypsin-like serine proteases through efficient reactions at two active sites. 1174 53

A trypsin inhibitor (PDTI) was isolated from Peltophorum dubium seeds by affinity chromatography on a thyroglobulin-agarose or a trypsin-agarose column. In both cases, SDS-PAGE showed two bands of M(r) 20,000 and 22,000, which could not be resolved. Their amino-terminal sequences were identical and similar to that of Kunitz-type soybean trypsin inhibitor (SBTI). Mass spectrometry analysis of tryptic digests of both bands showed 16 coincident peaks, suggesting that they are closely related proteins. The K(i)s for trypsin and chymotrypsin inhibitory activity of PDTI were 1.6 x 10(-7) and 1.3 x 10(-5)M, respectively. Lectin-like activity of PDTI and SBTI, detected by hemagglutination of rabbit erythrocytes, was inhibited by sialic acid-containing compounds. PDTI and SBTI caused apoptosis of Nb2 rat lymphoma cells, demonstrated by decrease of viability, DNA hypodiploidy, DNA fragmentation, and caspase-3-like activity. They had no effect on normal mouse splenocytes or lymphocytes, whereas they caused apoptosis of concanavalin A-stimulated mouse lymphocytes.
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PMID:A novel trypsin inhibitor from Peltophorum dubium seeds, with lectin-like properties, triggers rat lymphoma cell apoptosis. 1259 Sep 27

Streptococcus pneumoniae is the major pathogen of community-acquired pneumonia and one of the most common causes of death due to infectious diseases in industrialized countries. Lung epithelium lines the airways and constitutes the first line of innate defense against respiratory pathogens. Little is known about the molecular interaction of pneumococci with lung epithelial cells. Apoptosis of lung epithelium is involved in some bacterial lung infections. In this study different pneumococcal strains specifically induced either apoptotic or necrotic death of human alveolar and bronchial epithelial cells. Pneumococcus-induced apoptosis did not depend on the virulence factors pneumolysin and H(2)O(2). Apoptotic cells showed increased activity of caspases 6, 8, and 9 but not increased activity of caspase 3. Moreover, programmed cell death could be strongly reduced by a caspase 6 inhibitor and a pan-caspase inhibitor. Inhibitors of calpain and chymotrypsin- and trypsin-like proteases also reduced pneumococcus-induced apoptosis. Furthermore, pneumococcus-infected human alveolar epithelial cells showed Bid cleavage and reduced levels of Bcl2 and Bax. Overexpression of Bcl2 in these cells reduced apoptosis significantly. Thus, pneumococci induced apoptosis of human alveolar and bronchial epithelial cells. Programmed cell death was executed by caspase 6 and noncaspase proteases, but not by caspase 3, and could be blocked by overexpression of Bcl2.
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PMID:Streptococcus pneumoniae-induced caspase 6-dependent apoptosis in lung epithelium. 1532 85

Mutations in familial Parkinson's disease (PD) have been associated with the failure of protein degradation through the ubiquitin-proteasome system (UPS). Impairment of proteasome function has also been suggested to play a role in the pathogenesis of sporadic PD. We examined the proteasome activity in PC12 cells treated with 6-hydroxydopamine (6-OHDA), the dopamine synthetic derivate used in models of PD. We found that 6-OHDA treatment increased protein oxidation, as indicated by carbonyl group accumulation, and increased caspase-3 activity. In addition, there was an increase in trypsin-, chymotrypsin-, and postacidic-like proteasome activities in cells treated with 10-100 microM 6-OHDA, whereas higher doses caused a marked decline. 6-OHDA exposure also increased mRNA expression of the 19S regulatory subunit in a dose-dependent manner, whereas the expression of 20S- and 11S-subunit mRNAs did not change. Administration of the antioxidant N-acetylcysteine to 6-OHDA-treated cells prevented the alteration in proteasome functions. Moreover, reduction in cell viability owing to administration of proteasome inhibitor MG132 or lactacystin was partially prevented by the endogenous antioxidant-reduced glutathione. In conclusion, our data indicate that mild oxidative stress elevates proteasome activity in response to increase in protein damage. Severe oxidative insult might cause UPS failure, which leads to protein aggregation and cell death. Moreover, in the case of UPS inhibition or failure, the blockade of physiological reactive oxygen species production during normal aerobic metabolism is enough to ameliorate cell viability. Control of protein clearance by potent, brain-penetrating antioxidants might act to slow down the progression of PD.
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PMID:Oxidative stress, induced by 6-hydroxydopamine, reduces proteasome activities in PC12 cells: implications for the pathogenesis of Parkinson's disease. 1565 61

It has been shown that proteasome activity is required for cancer cell survival and consumption of fruits and vegetables is associated with decreased cancer risk. Previously, we reported that grape extract could inhibit proteasome activity and induce apoptosis in tumor cells. In this study, we examined the flavonoids apigenin, quercetin, kaempferol and myricetin for their proteasome-inhibitory and apoptosis-inducing abilities in human tumor cells. We report that apigenin and quercetin are much more potent than kaempferol and myricetin at: (i) inhibiting chymotrypsin-like activity of purified 20S proteasome and of 26S proteasome in intact leukemia Jurkat T cells; (ii) accumulating putative ubiquitinated forms of two proteasome target proteins, Bax and Inhibitor of nuclear factor kappabeta-alpha in Jurkat T cells and (iii) inducing activation of caspase-3 and cleavage of poly(ADP-ribose) polymerase in Jurkat T cells. The proteasome-inhibitory abilities of these compounds correlated with their apoptosis-inducing potencies. Results from computational modeling of the potential interactions of these flavonoids to the chymotrypsin site (beta5 subunit) of the proteasome were consistent with the obtained proteasome-inhibitory activities. We found that the C(4) carbon may be a site of nucleophilic attack by the OH group of N-terminal threonine of proteasomal beta5 subunit and that the C(3) hydroxyl may alter the ability of these flavonoids to inhibit the proteasome. Finally, apigenin neither effectively inhibited the proteasome activity nor induced apoptosis in non-transformed human natural killer cells. Our results suggested that the proteasome may be a target of these dietary flavonoids in human tumor cells and that inhibition of the proteasome by flavonoids may be one of the mechanisms responsible for their cancer-preventive effects.
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PMID:Dietary flavonoids as proteasome inhibitors and apoptosis inducers in human leukemia cells. 1585 6

Twenty-six trihaloacetylazulene derivatives were investigated for their tumor-specific cytotoxicity and apoptosis-inducing activity against three human normal cells (HGF, HPC, HPLF) and four human tumor cell lines (HSC-2, HSC-3, HSC-4, HL-60). The trichloroacetylazulenes [1b-13b] generally showed higher cytotoxicity as compared to the corresponding trifluoroacetylazulenes [1a-13a]. The trichloroacetylazulenes [1b-13b] also showed higher tumor-specific cytotoxicity (expressed as TS value) than the corresponding trifluoroacetylazulenes [1a-13a]. Especially, 2,3-dimethyl-1-trichloroacetylazulene [5b] and 1,3-ditrichloroacetyl-4,6,8-trimethylazulene [11b] showed the highest cytotoxicity and tumor specificity (TS > 35.6 and > 44.1, respectively). These compounds induced internucleosomal DNA fragmentation in HL-60 cells, but not in HSC-2 and HSC-3 cells, but activated caspase-3, -8 and -9 in all of these cells, suggesting the activation of both mitochondria-independent (extrinsic) and dependent (intrinsic) pathways. Western blot analysis showed that two compounds [5b, 11b] slightly increased the intracellular concentration of pro-apoptotic proteins (Bad, Bax) in HSC-2 cells. None of the 26 compounds showed anti-HIV activity. These results suggest [5b] and [11b] as possible candidates for future cancer chemotherapy.
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PMID:Apoptosis-inducing activity of trihaloacetylazulenes against human oral tumor cell lines. 1682 25

We have developed a high throughput assay for the measurement of protease activity in solution. This technology will accelerate research in functional proteomics and enable biologists to streamline protease substrate evaluation and optimization. The peptide sequences that serve as protease substrates in this assay are labeled on the carboxy terminus with a biotin moiety and a fluorescent tag is attached to the amino terminus. Protease cleavage causes the biotin containing fragment to be detached from the labeled peptide fragment. Following the protease treatment, all biotin containing species (uncleaved substrates and the cleaved carboxy terminal fragment of the substrate) are removed by incubation with streptavidin beads. The cleaved fluorescently labeled amino terminal part of the substrate remains in solution. The measured fluorescence intensity of the solution is directly proportional to the activity of the protease. This assay was validated using trypsin, chymotrypsin, caspase-3, subtilisin-A, enterokinase and tobacco etch virus protease.
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PMID:A method for rapid protease substrate evaluation and optimization. 1684 30

As previously suggested, codeinone (oxidation product of codeine) induces non-apoptotic cell death, characterized by marginal caspase activation and the lack of DNA fragmentation in HL-60 human promyelocytic leukemia cells, which was inhibited by N-acetyl-L-cysteine. Whether, morphinone, an oxidative metabolite of morphine, also induced a similar type of cell death in HL-60 cells was investigated. Morphinone showed slightly higher cytotoxic activity against human tumor cell lines (oral squamous cell carcinoma HSC-2, HSC-3, HSC-4, NA, Ca9-22, promyelocytic leukemia HL-60, cervical carcinoma HeLa) than against normal oral human cells (gingival fibroblast HGF, pulp cells HPC, periodontal ligament fibroblast HPLF). Morphinone also induced an almost undetectable level of internucleosomal DNA fragmentation in the HL-60 cells. Morphinone did not activate caspase-8 or -9 in these cells. Morphinone dose-dependently activated caspase-3 in both HL-60 and HSC-2 cell lines, but to a much lesser extent than actinomycin D. Electron microscopy demonstrated that morphinone induced mitochondrial shrinkage, vacuolization and production of autophagosome and the loss of cell surface microvilli, without destruction of cell surface and nuclear membranes in the HL-60 cells. The autophagy inhibitor 3-methyladenine (0.3-10 mM) slightly inhibited the morphinone-induced cytotoxicity, when corrected for its own cytotoxicity. These data suggest that morphinone induces non-apoptotic cell death in HL-60 cells.
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PMID:Induction of non-apoptotic cell death by morphinone in human promyelocytic leukemia HL-60 cells. 1709 51

Three antitumor antibiotics, mitomycin C, bleomycin sulfate and peplomycin sulfate, were compared for their tumor-specific cytotoxicity, using human oral squamous cell lines (HSC-2, HSC-3, HSC-4, Ca9-22 and NA), human promyelocytic leukemic cell line HL-60 and human normal oral cell types (gingival fibroblast HGF, pulp cell HPC and periodontal ligament fibroblast HPLF). Among these three compounds, mitomycin C showed the highest tumor-specificity, due to its higher cytotoxic activity against human oral tumor cell lines than bleomycin and peplomycin. However, there was considerable variation of drug sensitivity among the six tumor cell lines. Mitomycin C induced internucleosomal DNA fragmentation and caspase-3, -8 and -9 activation in HL-60 cells only after 24 h. On the other hand, mitomycin C induced no clear-cut DNA fragmentation in HCS-2 cells, although it activated caspase-3, -8 and -9 to a slightly higher extent. Western blot analysis demonstrated that mitomycin C did not induce any apparent change in the intracellular concentration of anti-apoptotic protein (Bcl-2) and pro-apoptotic proteins (Bax, Bad). Electron microscopy of mitomycin C-treated HL-60 cells showed intact mitochondria (as regards to integrity and size) and cell surface microvilli, without production of an apoptotic body or autophagosome, at an early stage after treatment. The present study suggests the incomplete induction of apoptosis or the induction of another type of cell death by mitomycin C treatment.
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PMID:Re-evaluation of tumor-specific cytotoxicity of mitomycin C, bleomycin and peplomycin. 1709 55


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