Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P08758 (annexin V)
 9,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The small, basic, and cysteine-rich antifungal protein PAF is abundantly secreted into the supernatant by the beta-lactam producer Penicillium chrysogenum. PAF inhibits the growth of various important plant and zoopathogenic filamentous fungi. Previous studies revealed the active internalization of the antifungal protein and the induction of multifactorial detrimental effects, which finally resulted in morphological changes and growth inhibition in target fungi. In the present study, we offer detailed insights into the mechanism of action of PAF and give evidence for the induction of a programmed cell death-like phenotype. We proved the hyperpolarization of the plasma membrane in PAF-treated Aspergillus nidulans hyphae by using the aminonaphtylethenylpyridinium dye di-8-ANEPPS. The exposure of phosphatidylserine on the surface of A. nidulans protoplasts by Annexin V staining and the detection of DNA strand breaks by TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) gave evidence for a PAF-induced apoptotic-like mechanism in A. nidulans. The localization of reactive oxygen species (ROS) by dichlorodihydrofluorescein diacetate and the abnormal cellular ultrastructure analyzed by transmission electron microscopy suggested that ROS-elicited membrane damage and the disintegration of mitochondria played a major role in the cytotoxicity of PAF. Finally, the reduced PAF sensitivity of A. nidulans strain FGSC1053, which carries a dominant-interfering mutation in fadA, supported our assumption that G-protein signaling was involved in PAF-mediated toxicity.
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PMID:Antifungal protein PAF severely affects the integrity of the plasma membrane of Aspergillus nidulans and induces an apoptosis-like phenotype. 1591 45

A novel endothelial cell apoptosis inducing metalloprotease (VLAIP) was found in the snake venom of Vipera lebetina. This metalloprotease is a heterodimeric glycoprotein with molecular mass of about 106 kDa. The protease hydrolyzes azocasein, fibrinogen and oxidized insulin B-chain. The enzyme readily hydrolyzes the Aalpha-chain and more slowly Bbeta-chain of fibrinogen. VLAIP does not cleave fibrin. The complete amino acid sequences of the two different monomers of VLAIP are deduced from the nucleotide sequences of cDNAs encoding these proteins. The full-length cDNA sequences of the VLAIP-A and VLAIP-B encode open reading frames of 616 and 614 amino acids that include signal peptide, propeptide and mature metalloproteinase with disintegrin-like and cysteine-rich domains. VLAIP belongs to the metalloprotease/disintegrin family of reprolysins and has high identity with the proteins that induce apoptosis of endothelial cells. Treatment of HUVEC cells with VLAIP induces changes in the attachment of cells to the substrate and causes cell death. We demonstrated that VLAIP inhibits endothelial cell adhesion to extracellular matrix proteins: fibrinogen, fibronectin, vitronectin, collagen I, and collagen IV. The induction of apoptosis by VLAIP was shown by means of a typical DNA fragmentation pattern of apoptotic cells as well as by monitoring phosphatidylserine externalization using annexin V-FITC staining and flow cytometric analysis.
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PMID:A novel metalloprotease from Vipera lebetina venom induces human endothelial cell apoptosis. 1592 94

A prominent feature of glioblastoma is its resistance to death from Fas pathway activation. In this study, we explored the modulation of Fas-induced glioblastoma death with chemotherapeutic agents. Camptothecin significantly increased the glioblastoma cell death response to Fas receptor activation regardless of p53 status. Sublethal concentrations of camptothecin reduced the IC50 of agonistic anti-Fas antibody (CH-11) 10-fold, from 500 to 50 ng/mL, in human U87 glioblastoma cells (p53 wild-type). Cell viability in response to camptothecin, CH-11 alone, and the combination of camptothecin + CH-11 was found to be 84%, 85%, and 47% (P < 0.001), respectively. A similar pattern of relative cytotoxicity was found in U373 cells (p53 mutant). We further examined the pathways and mechanisms involved in this apparent synergistic cytotoxic response. Cell death was found to be predominantly apoptotic involving both extrinsic and intrinsic pathways as evidenced by annexin V staining, cleavage of caspases (3, 8, and 9), increased caspase activities, Smac release, and cytoprotection by caspase inhibitors. Expression of Fas-associated death domain, and not Fas, Fas ligand, or caspase proteins, increased following cell treatment with camptothecin + CH-11. Camptothecin treatment enhanced c-jun-NH2-kinase activation in response to CH-11, but inhibition of c-jun-NH2-kinase did not prevent cell death induced by the combination treatment. Reactive oxygen species, especially H2O2, were elevated following camptothecin treatment; and H2O2 enhanced cell death induced by CH-11. The antioxidants glutathione and N-acetyl-cysteine prevented cell death induced by camptothecin + CH-11. These findings show that camptothecin synergizes with Fas activation to induce glioblastoma apoptosis via a mechanism involving reactive oxygen species and oxidative stress pathways.
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PMID:Sensitization of glioma cells to Fas-dependent apoptosis by chemotherapy-induced oxidative stress. 1595 70

Phenylethyl isothiocyanate (PEITC) is a well recognized potential chemopreventive compound against human cancers. In this study, the molecular mechanism of PEITC-induced apoptosis was examined with two antioxidants (N-acetyl-cysteine and vitamin E) and a caspase-3 inhibitor (z-DEVD-fmk). Results demonstrated that PEITC significantly induced human hepatoma PLC/PRF/5 (CD95-negative) cells undergoing apoptosis. Treatment with 0 approximately 10 microM PEITC-triggered cell apoptosis as revealed by the externalization of annexin V-targeted phosphatidylserine and the subsequent appearance of sub-G1 population. Results also displayed that PEITC-induced apoptosis involves the up-regulation of p53 and Bax protein, down-regulation of the XIAP, Bcl-2, Bcl-(XL) and Mcl-1 proteins, cleavage of Bid, and the release of cytochrome c and Smac/Diablo, which were accompanied by the activation of caspases -9, -3 and -8. PEITC-induced the generation of reactive oxygen species and the decrease of mitochondrial membrane potential (Deltapsim) in a time-dependent pattern. N-acetyl-cysteine and vitamin E at 100 microM, and z-DEVD-fmk at 50 microM markedly blocked PEITC-induced apoptosis, which was demonstrated by a decline in the reactive oxygen species generation and the release of the cytochrome c and Smac/Diablo from mitochondria to the cytosol. N-acetyl-cysteine, vitamin E and z-DEVD-fmk also prevented the PEITC in inducing the loss of Deltapsim. They also affected the activity of XIAP and Bax proteins. Taken together, these studies suggest that PEITC is an apoptotic inducer that acts on the mitochondria and the feedback amplification loop of caspase-8/Bid pathways in PLC/PRF/5 cells.
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PMID:Effects of antioxidants and caspase-3 inhibitor on the phenylethyl isothiocyanate-induced apoptotic signaling pathways in human PLC/PRF/5 cells. 1605 26

Various physical and psychological stressors can cause thymocyte apoptosis and cell loss in rodents. Although glucocorticoids (GC) are commonly implicated, oxidative stress may also play a role. The purpose of this study was to examine the effect of an acute bout of strenuous treadmill running, and the antioxidant N-acetyl-L-cysteine (NAC) on thymocyte loss and apoptosis. Eighty-eight female C57BL/6 mice were given NAC (1 g/kg, i.p.) or saline (SAL) 30 min before 90 min of treadmill exercise at a 2 degrees slope (EX; 30 min at 22 m/min; 30 min at 25 m/min; and 30 min at 28 m/min) and sacrificed immediately (Imm) or 24 h following EX. Control mice (NonEX) were exposed to treadmill noise and vibration without running. Thymocytes were isolated and analyzed for phosphatidylserine (PS) externalization (Annexin V), loss of membrane integrity, mitochondria membrane depolarization, intracellular hydrogen peroxide (H(2)O(2)) production, and intracellular glutathione (GSH) as well as protein levels of caspase 3, Bcl-2, and cytosolic cytochrome c. Blood was analyzed for corticosterone (CORT) concentrations by radioimmunoassay. Exercise stress caused a significant increase in plasma CORT concentrations in EX + SAL + Imm and EX + NAC + Imm groups compared to NonEX mice. Relative to NonEX mice, thymocytes isolated from EX + SAL + Imm mice showed signs of an early apoptotic profile as indicated by decreased GSH stores and increased mitochondrial membrane depolarization. These effects were followed by a 50% reduction in thymocyte numbers 24 h post-exercise (EX + SAL + 24 h). Alterations in GSH levels, mitochondrial membrane depolarization, and thymocyte loss were not observed in mice receiving NAC. These results suggest that exercise-induced thymocyte apoptosis and cell loss may be mediated via an oxidative stress pathway.
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PMID:Mouse thymocyte apoptosis and cell loss in response to exercise and antioxidant administration. 1606 Nov 51

Fungicide thiram, which is also known as an inducer of allergic contact dermatitis (ACD), was used as a model compound of thiuram chemicals, and its cellular effects were investigated in cultured Chinese hamster V79 cells. The level of intracellular reduced glutathione (GSH), protein sulfhydryl (PSH) groups, protein carbonyls (PC), membrane lipid peroxidation reflected by enhanced thiobarbituric acid reactive substrates (TBARS) production, as well as apoptotic effect were determined. The apoptosis induction was determined by assessing DNA fragmentation by TUNEL, annexin V binding, and caspases activation assays, using fluorescent microscope or flow cytometry, respectively. The concentrations of thiram required to induce cellular GSH depletion (by 40-50%), protein, and membrane lipid peroxidation (2-fold, and 1.7-fold, respectively), as well as to induce apoptosis in V79 Chinese hamster fibroblasts without causing necrosis through cytotoxic effects were between 50-100 microM. To investigate the role of decreased GSH content in the toxicity of thiram, GSH level was modified prior to exposure. Pretreatment of V79 cells with N-acetyl-L-cysteine (NAC), a GSH biosynthesis precursor, prevented GSH decrease, PC and TBARS production, as well as caspases activation induced by thiram exposure. On the other hand, thiram effects were enhanced by the previous depletion of cellular GSH by L-buthionine-(S,R)-sulfoximine (BSO).
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PMID:Effect of glutathione depletion on apoptosis induced by thiram in Chinese hamster fibroblasts. 1627 29

Previous investigations have shown that 2-hydroxyethyl methacrylate (HEMA) causes reactive oxygen species (ROS) production, which in turn affects cell survival and cell death. The purpose of this study was to evaluate the effects of the antioxidant N-acetyl-L-cysteine (NAC) on HEMA-induced toxicity in human primary gingival fibroblasts (HGF). HGF were treated with various concentrations of HEMA (0-12 mm) in the absence and presence of NAC (1, 5, and 10 mm). The 3-(4,5 dimethyiazol-2-1)-2-5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate the mitochondrial dehydrogenase activity after HEMA exposure. Viability and cell death were determined by flow cytometry using Annexin V and PI staining. ROS production was detected by the increasing fluorescence of the oxidation-sensitive dye 2',7'-dichlorofluorescein diacetate (DCFH-DA) after HEMA treatment. After a 24h incubation period, HEMA concentrations higher then 10mm caused a decrease of cell viability, mitochondrial activity, and an increase of cell death. HEMA concentrations of 4-12 mm markedly increased ROS levels in a dose-dependent manner. High NAC concentrations (5 and 10 mm) significantly reduced cell death, and restored the mitochondrial activity after a 24 h co-treatment, but 1 mm NAC increased HEMA toxicity (p<0.05). All NAC concentrations significantly reduced ROS levels induced by HEMA after a 2 h exposure (p<0.05), but no such reduction was observed after a 4 h treatment. Furthermore, treatment with 10 mm HEMA and 1 mm NAC for 6h caused an increase in ROS levels compared to 10 mm HEMA alone (p<0.05). In conclusion, our results suggest that high NAC concentrations protect HGF against HEMA cytotoxicity by reducing the induced ROS levels.
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PMID:Effect of N-acetyl-L-cysteine on ROS production and cell death caused by HEMA in human primary gingival fibroblasts. 1628 59

Cytotoxici and alpha-diisoeugenol were investigated. The cytotoxicity of curcumin and a-diisoeugenol against human promyelocytic leukemia cells (HL-60 cells) and human submandibular cancer cells (HSG cells) was similar (CC50 1-3 microM). However, curcumin induced much more apoptosis, particularly in HL-60 cells compared with HSG cells, as revealed by measurement of the sub-G1/G0 DNA fraction in flow cytometric histograms. Treatment with 15 microM curcumin increased the number of cells with a sub-G1/G0 DNA fraction from control levels of <5% to 55% in HL-60 cells and 30% in HSG cells. Flow cytometry, after staining with annexin V-FITC/PI (the exposure of phosphatidylserine (PS) on the surface of apoptotic cells), showed a dose-dependent induction of early apoptosis by curcumin, which reached about 65% in HL-60 cells and about 20% in HSG cells after treatment with 10 microM curcumin. In contrast, alpha-diisoeugenol failed to induce apoptosis in either cell type. For both cell types, the proportion of late apoptotic/necrotic cells increased rapidly at concentrations of curcumin and a-diisoeugenol greater than 10 microM. The generation of intracellular reactive oxygen species (ROS) in curcumin-treated HL-60 cells was greater than that in HSG cells, as judged by CDFH-DA staining. In both cell types, ROS generation by a-diisoeugenol was at control levels. ROS generation by curcumin was suppressed by antioxidants such as N-acetyl-L-cysteine (NAC) and glutathione (GSH) and by scavengers of hydroxy radicals such as mannitol, but, conversely, was promoted by prooxidants such as the transition metal ions Cu(II) and Zn(II). ROS generation may play a part in the exposure of PS. Curcumin, but not a-diisoeugenol, at 10 microM inhibited LPS (lipopolysaccharide)-induced COX-2 gene expression in RAW 264.7 cells. Semiempirical PM 3 calculations suggested that this activity of curcumin, in which it behaves as a non-steroidal anti-inflammatory drug (NSAID)-like compound, is dependent on its phenolic function, which is more pronounced than that of alpha-diisoeugenol. Taken together, our results suggest that the bioactivity of curcumin is a result of its ability to act as both a prooxidant and an antioxidant.
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PMID:Induction of cytotoxicity and apoptosis and inhibition of cyclooxygenase-2 gene expression, by curcumin and its analog, alpha-diisoeugenol. 1630 95

Caspase-independent cell death has drawn increasing attention. In the present study, we found that lipopolysaccharide (LPS) accelerated spontaneous death of human lung epithelial A549 cells in a serum- and cell density-dependent manner: while serum starvation has been demonstrated to induce apoptosis in the same cell line, LPS-induced cell death was only observed in the presence of serum; in addition, the cell death was not observed when the cells were seeded at 10- or 100-fold lower density. The apoptotic features were demonstrated by TUNEL assay, DNA laddering and Annexin V staining. However, treatment of cells with two commonly used pan-caspase inhibitors, zVAD.fmk or BOC-D.fmk, failed to block cell death. In contrast, two cathepsin B inhibitors, Ca074-Me or N-1845, reduced cell death significantly. A time-dependent activation of cathepsin B, but not caspase 3, was observed in both control and LPS-treated cells. Although LPS did not further activate cathepsin B or its release, it increased expression and translocation of apoptosis inducing factor from mitochondria to the nucleus, and increased release of cytochrome c from mitochondria. LPS-induced cell death was significantly attenuated by either N-acetyl-L-cysteine or pyrrolidine-dithiocarbamate, both free radical scavengers. Disruption of lipid raft formation with filipin or methyl-beta-cyclodextrin also reduced apoptosis significantly, suggesting that lipid raft-dependent signaling is essential. These data imply that confluent cells undergo spontaneous cell death mediated by cathepsin B; LPS may accelerate this caspase-independent cell death through release of mitochondrial contents and reactive oxygen species.
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PMID:Lipopolysaccharide accelerates caspase-independent but cathepsin B-dependent death of human lung epithelial cells. 1689 74

A large number of methods devoted to the identification of apoptotic cells and the analysis of the morphological, biochemical, and molecular changes that take place during this universal biological process have been developed. Apoptotic cells are recognized on the basis of their reduced DNA content and morphological changes that include nuclear condensation and which can be detected by flow cytometry (sub-G1 DNA content), Trypan Blue, or Hoechst staining. Changes in plasma membrane composition and function are detected by the appearance of phosphatidylserine on the plasma membrane, which reacts with Annexin V-fluorochrome conjugates. Combined with propidium iodide (PI) staining, this method can distinguish between the early and late apoptotic events. The best-recognized biochemical hallmarks of apoptosis are the activation of cysteine proteases (caspases), condensation of chromatin, and fragmentation of genomic DNA into nucleosomal fragments. Recognized by a variety of assays, activated caspases cleave many cellular proteins and the resulting fragments may serve as apoptosis markers. Finally, the mitochondria and the Bcl-2 family proteins play an important role in this process that can be recognized by translocation of apoptogenic factors, such as Bax and cytochrome c, in and out of mitochondria.
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PMID:Apoptosis assays. 1708 18


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