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 mechanism of arachidonic acid (AA)-induced apoptosis in vascular smooth muscle cells (VSMCs) was studied in the A-10 rat aortic smooth muscle cell line. Treatment of serum-deprived VSMCs with 50 microM AA for 24 h resulted in a loss of cell viability. The apoptotic effect of AA was characterized by annexin V binding, sub-G1 population of cells, cell shrinkage and chromatin condensation. AA-induced VSMC death was attenuated by antioxidants alpha-tocopherol and glutathione, the hydrogen peroxide (H2O2) scavenger catalase and by serum proteins, albumin and gamma globulins. Moreover, the AA peroxidation products, 12(S)-hydroperoxyeicosatetraenoic acid (HPETE), 15(S)-HPETE, 4-hydroxy-2-nonenal (HNE) and malondialdehyde (MDA) caused VSMC apoptosis. These data suggest an oxidative mechanism of AA-induced VSMC death. The apoptotic effect of AA was pH-dependent, being inhibited by extracellular alkalinization to pH 8.0. AA inhibited serum-stimulated cell cycle progression in quiescent cells, but not in proliferating cells. In conclusion, AA, through its oxidation products causes VSMC apoptosis. Antioxidants, by inhibiting VSMC apoptosis, may prevent consequent pathological events such as atherosclerotic plaque rupture.
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PMID:Arachidonic acid-derived oxidation products initiate apoptosis in vascular smooth muscle cells. 1242 75

A cationic steroid with a hydrogen-bonding pocket that has an affinity for anionic phospholipid headgroups was synthesized and shown to strongly promote the translocation or flip-flop of a fluorescent, C(6)NBD-labeled phosphatidylserine probe (C(6)NBD-PS) across vesicle membranes. In addition, the synthetic PS scramblase increases the levels of endogenous PS on the surface of erythrocytes as monitored by flow cytometry analysis of annexin V-FITC binding. The PS scrambling effect is enhanced when the cells are pretreated with N-ethylmaleimide (NEM), an inhibitor of the endogenous aminophospholipid flippase. The combination of NEM and synthetic PS scramblase enhances the ability of erythrocytes to promote the conversion of prothrombin to thrombin by a factor of 4. An analogous cationic steroid with a smaller binding pocket has no measurable PS translocation activity, a result that is attributed to its inability to sufficiently diminish the hydrophilicity of the multiply charged PS headgroup.
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PMID:Facilitated phosphatidylserine (PS) flip-flop and thrombin activation using a synthetic PS scramblase. 1283 89

Exponentially growing cultures of human bladder tumor cells (T24) were treated with Vitamin C (VC) alone, Vitamin K(3) (VK(3)) alone, or with a VC:VK(3) combination for 1, 2, or 4hr. Flow cytometry of T24 cells exposed to the vitamins for 1h revealed a growth arrested population and a population undergoing cell death. Cells in G(1) during vitamin treatment arrested in G(1) while those in S phase progressed through S phase and arrested in G(2)/M. DNA synthesis decreased to 14 to 21% of control levels which agreed with the percent of cells in S phase during treatment. Annexin V labeling demonstrated the majority of the cells died by autoschizis, but necrosis and apoptosis also were observed. Catalase treatment abrogated both cell cycle arrest and cell death which implicated hydrogen peroxide (H(2)O(2)) in these processes. Redox cycling of VC and VK(3) increased H(2)O(2) production and decreased cellular thiol levels and DNA content, while increasing intracellular Ca(2+) levels and lipid peroxidation. Feulgen staining of treated cells revealed a time-dependent decrease in tumor cell DNA, while electrophoresis revealed a spread pattern. These results suggest that Ca(2+) disregulation activates at least one DNase which degrades tumor cell DNA and induces tumor cell death.
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PMID:Cell cycle arrest and autoschizis in a human bladder carcinoma cell line following Vitamin C and Vitamin K3 treatment. 1469 46

Heme oxygenase-1 (HO-1), an inducible enzyme that catalyzes oxidative degradation of heme to form biliverdin, carbon monoxide and free iron, may protect tumor cells against oxidative stress, thus contributing to rapid tumor growth in vivo. Here, we discuss whether pegylated zinc protoporphyrin (PEG-ZnPP), a potent HO inhibitor, modulates the chemotherapeutic response of tumor cells to treatment that generates reactive oxygen species (ROS). PEG-ZnPP is a water-soluble HO inhibitor that accumulates in tumor tissues after intravenous administration. Cytotoxicity of antitumor agents in vitro was determined by means of MTT and annexin V assays using human colon carcinoma SW480 cells. Mice bearing sarcoma 180 tumors were used as an in vivo model. Pegylated D-amino acid oxidase (PEG-DAO), which behaves as an oxidative chemotherapeutic agent by generating toxic oxidants at tumor tissues, was administered with its substrate D-proline to mice with or without PEG-ZnPP pretreatment. PEG-ZnPP-treated SW480 cells became vulnerable to insults caused by various cytotoxic agents; the 50% lethal doses were reduced by 25%, 39%, 83%, and 61% for hydrogen peroxide, t-butyl hydroperoxide, camptothecin and doxorubicin, respectively. Cells treated with PEG-ZnPP plus cytotoxic oxidants exhibited marked production of intracellular ROS, which paralleled the incidence of apoptosis. PEG-ZnPP pretreatment significantly reduced tumor growth in mice receiving PEG-DAO/D-proline compared to no PEG-ZnPP pretreatment. These findings suggest that HO-1 may become an attractive target for chemotherapeutic intervention. Further study of the effect of PEG-ZnPP plus conventional anticancer drugs that generate ROS, such as cisplatin, camptothecin, doxorubicin, mitomycin C and etoposide, is warranted.
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PMID:Enhancement of chemotherapeutic response of tumor cells by a heme oxygenase inhibitor, pegylated zinc protoporphyrin. 1473 61

When protoplasts of the opportunistic fungal pathogen Aspergillus fumigatus were treated with low but toxic levels of hydrogen peroxide (0.1 mM) or amphotericin B (0.5 microg ml(-1)), loss of cell viability and death were associated with a number of phenotypic changes characteristic of apoptosis. The percentage of protoplasts staining positive with annexin V-FITC, an indicator of the externalization of phosphatidylserine and an early marker of apoptosis, rose to approximately 55 % within 1 h. This was followed by a similar increase in apoptotic DNA fragmentation detected by the TUNEL assay, and led to a loss of cell permeability and death in approximately 90 % of protoplasts, as indicated by the uptake of propidium iodide. The development of an apoptotic phenotype was blocked when protoplasts were pre-treated with the protein synthesis inhibitor cycloheximide, indicating active participation of the cell in the process. However, no significant activity against synthetic caspase substrates was detected, and the inclusion of the cell-permeant broad-spectrum caspase inhibitor Z-VAD-fmk did not block the development of the apoptotic-like phenotype. Higher concentrations of H(2)O(2) (1.8 mM) and amphotericin B (1 microg ml(-1)) caused protoplasts to die without inducing an apoptotic phenotype. As predicted, the fungistatic antifungal agent itraconazole, which inhibits growth without causing immediate cell death, did not induce an apoptotic-like phenotype.
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PMID:Oxidative and amphotericin B-mediated cell death in the opportunistic pathogen Aspergillus fumigatus is associated with an apoptotic-like phenotype. 1518 79

Oxidative stress and apoptosis are implicated in tendon degeneration. Peroxiredoxin 5 (PRDX5) is a novel thioredoxin peroxidase recently identified in mammals, participating directly in eliminating hydrogen peroxide (H(2)O(2)) and neutralizing other reactive oxygen species (ROS). We have previously reported that PRDX5 is upregulated in degenerative human tendon. However, the effects of this upregulation on human tendon cell function remain unknown, in particular, with regards to oxidative stress conditions. Here we report that exposure of human tendon cells to 50 microM H(2)O(2) for 24 h (in vitro oxidative stress) caused a significant increase in the percentage of apoptotic cells (P<0.05) as assessed by flow cytometric analysis of Annexin V binding, accompanied by increased PRXD5 mRNA and protein expression. Overexpression of PRDX5 in human tendon cells via transfection inhibited H(2)O(2)-induced tendon cell apoptosis by 46% (P<0.05), and prevented the decrease in tendon cell collagen synthesis which occurs under H(2)O(2) challenge, although the decrease in collagen synthesis was small. Results from our study indicate that the antioxidant enzyme PRDX5 plays a protective role in human tendon cells against oxidative stress by reducing apoptosis and maintaining collagen synthesis.
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PMID:Overexpression of antioxidant enzyme peroxiredoxin 5 protects human tendon cells against apoptosis and loss of cellular function during oxidative stress. 1527 23

Bovine serum amine oxidase (BSAO) oxidatively deaminates polyamines containing primary amine groups, spermidine and spermine, to form the cytotoxic products hydrogen peroxide and aldehyde(s). Polyamines are present at elevated levels in many tumor tissues. The aims of the study were to evaluate the anti-tumoral activities of native and immobilized BSAO in mouse melanoma and also to determine the mechanism of tumor cell death. C57BL mice received a subcutaneous injection of B16 melanoma cells to induce formation of tumors, prior to antitumor treatments with native and immobilized BSAO. The enzyme was immobilized in a poly(ethylene glycol) (PEG) biocompatible matrix. Antitumor treatments consisted of a single injection of enzyme into the tumor. When immobilized BSAO (2.5mU) was injected into the tumor, there was a marked decrease of 70% of the tumor growth. This was compared with a decrease of only 32% of tumor size when the same amount of native BSAO was administered. The type of cell death was analysed in tumors that were treated with native or immobilized BSAO. When tumors were treated with immobilized BSAO, there was induction of a high level of apoptosis (around 70%), compared to less than 10% with the native enzyme. Apoptotic cell death was assessed by nuclear chromatin condensation using Hoechst staining and labelling of externalized phosphatidylserine using Annexin V. However, native BSAO, probably due to a burst of cytotoxic products, induced a high level of necrosis of about 40%, compared to less than 10% with immobilized BSAO. In conclusion, the advantage is that immobilized BSAO can act by allowing the slow release of cytotoxic products, which induces tumor cell death by apoptosis rather than necrosis.
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PMID:Anti-tumoral effect of native and immobilized bovine serum amine oxidase in a mouse melanoma model. 1593 45

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

The mechanisms underlying the cytotoxic action of pure fullerene suspension (nano-C60) and water-soluble polyhydroxylated fullerene [C60(OH)n] were investigated. Crystal violet assay for cell viability demonstrated that nano-C60 was at least three orders of magnitude more toxic than C60(OH)n to mouse L929 fibrosarcoma, rat C6 glioma, and U251 human glioma cell lines. Flow cytometry analysis of cells stained with propidium iodide (PI), PI/annexin V-fluorescein isothiocyanate, or the redox-sensitive dye dihydrorhodamine revealed that nano-C60 caused rapid (observable after few hours), reactive oxygen species (ROS)-associated necrosis characterized by cell membrane damage without DNA fragmentation. In contrast, C60(OH)n caused delayed, ROS-independent cell death with characteristics of apoptosis, including DNA fragmentation and loss of cell membrane asymmetry in the absence of increased permeability. Accordingly, the antioxidant N-acetylcysteine protected the cell lines from nano-C60 toxicity, but not C60(OH)n toxicity, while the pan-caspase inhibitor z-VAD-fmk blocked C60(OH)n-induced apoptosis, but not nano-C60-mediated necrosis. Finally, C60(OH)n antagonized, while nano-C60 synergized with, the cytotoxic action of oxidative stress-inducing agents hydrogen peroxide and peroxynitrite donor 3-morpholinosydnonimine. Therefore, unlike polyhydroxylated C60 that exerts mainly antioxidant/cytoprotective and only mild ROS-independent pro-apoptotic activity, pure crystalline C60 seems to be endowed with strong pro-oxidant capacity responsible for the rapid necrotic cell death.
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PMID:Distinct cytotoxic mechanisms of pristine versus hydroxylated fullerene. 1647 88

The main purpose of this study was to determine whether enhancement of repair capacity would attenuate mitochondrial DNA oxidative damage and result in greater cell survival under stressful conditions. The repair of oxidative damage is initiated by DNA glycosylases, which catalyze the excision of oxidized bases, such as 8-hydroxydeoxyguanosine (8-oxodG). Drosophila DNA glycosylases, dOgg1 and RpS3, were ectopically expressed within the mitochondrial matrix in Drosophila S2 cells, causing a severalfold decrease in the levels of 8-oxodG in mitochondrial DNA. Unexpectedly, cells did not show increased resistance to oxidative stress, but instead became more susceptible to treatment with hydrogen peroxide or paraquat. Even in the absence of oxidative challenge, cells expressing RpS3 or dOgg1 in mitochondria exhibited increased apoptosis relative to controls, as determined by flow-cytometric analysis of Annexin V and DNA degradation measured by the Comet assay. Another notable finding was that ectopic expression of either dOgg1 or RpS3 in mitochondria increased cell survival after exposure to the nitric oxide donor SNAP. These results suggest that ectopic expression of one of the constituents of the DNA repair system in mitochondria may cause a perturbation in the base excision repair pathway and lower, rather than enhance, survivability.
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PMID:Effects of ectopic expression of Drosophila DNA glycosylases dOgg1 and RpS3 in mitochondria. 1689 96


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