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)

We investigated the relationship between drug resistance and Bcl-2/Bax in B-cell chronic lymphocytic leukaemia (B-CLL). Apoptosis was induced in vitro with chlorambucil and cell death was monitored by dual-labelled FACS analysis using Annexin V and propidium iodide. Bcl-2 and Bax protein expression was quantified using FACS and a correlation between drug-induced apoptosis and Bcl-2/Bax was established. Cells were then sorted into viable and nonviable populations according to their forward and side-scatter characteristics and re-analysed for Bcl-2/Bax. The most resistant cells had elevated Bcl-2 levels and low Bax expression. Furthermore, those cells which were undergoing apoptosis showed only a marginal reduction in Bcl-2 expression, but significantly elevated Bax expression following exposure to chlorambucil. The Bcl-2/Bax was significantly greater in the cell fractions resistant to chlorambucil-induced apoptosis. This observation further supports the suggestion that Bax is the pivotal protein in determining the fate of cells following apoptotic signals.
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PMID:Elevated Bcl-2/Bax are a consistent feature of apoptosis resistance in B-cell chronic lymphocytic leukaemia and are correlated with in vivo chemoresistance. 951 6

Understanding the dynamics of cell death in conjunction with those of cell cycle can be illuminating in the investigation of various cellular behaviors. Robust assays for measuring such parameters are invaluable. Many assays of apoptosis and/or cell cycle use flow cytometry. This chapter describes two different assays to measure apoptosis and cell cycle simultaneously using flow cytometry. The first involves the use of terminal transferase (the "TUNEL" assay) together with propidium iodide for identification of cell cycle. The second uses fluorescently labeled annexin V, together with propidium iodide as an indicator of cell membrane integrity; and additionally Hoechst 33342 for determination of cell cycle. Each assay has positive and negative attributes. The terminal transferase assay is performed using fixed cells and is therefore useful in the analysis of samples collected over time. The annexin V assay is performed using unfixed cells, and thus provides information regarding membrane integrity. Other practical aspects of both assays are discussed.
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PMID:Simultaneous measurement of cell cycle and apoptotic cell death. 964 10

Cell surface exposure of phosphatidylserine (PS) during apoptosis serves recognition and removal of the dying cell by phagocytes. Loss of phospholipid asymmetry and PS exposure is investigated by immunocytochemistry and related to morphological changes. Loss of membrane asymmetry was determined on dexamethasone-treated rat thymocytes using the PS specific probe annexin V. Thymocytes incubated in the presence of dexamethasone were studied in time series during the execution of the apoptotic program. Thymocytes first start to expose PS at their cell surface. At this initial stage the barrier function of the plasma membrane remains intact. At a later stage the plasma membrane becomes leaky for compounds like propidium iodide and subsequently the cell disintegrates into apoptotic bodies. Microscopical evaluation of dexamethasone-treated thymocytes showed that the cells with an apoptotic morphology all bound annexin V. The cells with a normal viable morphology lacked annexin V binding except for those cells that started to shed small vesicles. These vesicles were positive for annexin V, indicating a local disturbance of the phospholipid asymmetry. The local exposure of PS is considered to be a very early event of apoptosis, preceding the full sequence of morphological changes at the ultrastructural level.
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PMID:Surface exposure of phosphatidylserine during apoptosis of rat thymocytes precedes nuclear changes. 965 Jul 85

Chemoprevention of colorectal cancer using aspirin has been demonstrated in rodents and has been suggested by data from epidemiological studies. The mechanism that accounts for this prevention is unknown, but it is thought to relate to an irreversible inhibition of cyclooxygenase and, subsequently, prostaglandin production. The effect of aspirin on the growth of human colonic tumor cells was determined in an effort to gain insight into a possible mechanism of action. In the two cell lines studied, SW 620 and HT-29, we observed a significant dose- and time-dependent increase in aspirin toxicity in a concentration range of 1.25-10 mM. This result was independent of prostaglandin production, because there was no measurable prostaglandin E2 in cell culture medium. As compared with controls, cells in cultures that contained aspirin were not detached, which suggests that the mechanism of cell death was not apoptosis. Flow cytometric analysis revealed an increase in S phase and G2-M populations as well as the number of subdiploid nuclei in cultures treated with high-dose aspirin. Confirmation that cells were undergoing necrosis in response to aspirin was evident from the presence of cells that bound annexin V and accumulated propidium iodide in the absence of a population that bound annexin alone. The results suggest that aspirin induces cell cycle arrest and causes necrosis at high concentrations in vitro, but does not induce apoptosis. Collectively, these two events, necrosis and cell cycle arrest, may contribute to the chemopreventive effect that seems to result from long-term administration of aspirin in vivo.
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PMID:Aspirin toxicity for human colonic tumor cells results from necrosis and is accompanied by cell cycle arrest. 966 90

Upon transforming growth factor-beta (TGF-beta) treatment, Ramos cells, a B-cell lymphoma cell line, undergo apoptosis, as measured by annexin V labeling, DNA fragmentation, and propidium iodide staining. Apoptosis could be observed by 24 h after TGF-beta exposure and occurred before the development of a significant blockage of cell cycle progression. TGF-beta-mediated apoptosis was also accompanied by a strong induction of caspase-3 subfamily activity. Incubation of cells with the caspase inhibitor Z-VAD.FMK at 20 microM, but not at 10 microM, prevented TGF-beta-induced apoptosis from occurring. By comparison, caspase-3 subfamily activity was 87% inhibited at 10 microM Z-VAD.FMK and completely inhibited at 20 microM. Because of TGF-beta's well-established role of regulating gene transcription, the mRNA levels for proteins associated with apoptosis (Fas- and Fas-associated proteins, Bcl-2 family members, IAP proteins, and I kappa B) were also studied. After 24 h of TGF-beta treatment, the most significant mRNA changes occurred with Bcl-XL (two-fold decrease) and Bik (twofold increase). TGF-beta treatment also resulted after 48 h in a fivefold decrease in Bcl-XL protein levels, based on immunoblotting analysis. Therefore, TGF-beta-mediated apoptosis involves the activation of caspases. In addition, TGF-beta transcriptionally regulates Bcl-2 family members, Bcl-XL and Bik, to further influence the apoptosis process.
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PMID:Transforming growth factor-beta-mediated apoptosis in the Ramos B-lymphoma cell line is accompanied by caspase activation and Bcl-XL downregulation. 966 22

Apoptosis (AO) is a process by which cells typically undergo a form of nonnecrotic cellular suicide. AO normally allows the host to selectively delete cells from a given tissue site without producing bystander injury associated with necrosis. However, inappropriate induction of AO has been associated with a variety of acute as well as chronic pathological states and may contribute to the therapeutic nonresponsiveness frequently encountered in the septic animal/patient's organ function. In this respect, while AO has been demonstrated in a variety of immune cell tissues of septic animals it is unclear if it is present in the septic liver. Therefore, it was the aim of our study to determine if AO is evident in hepatocytes of polymicrobial septic animals. To assess this, C3H/HeN male mice were subjected to polymicrobial sepsis (cecal ligation and puncture) or sham- CLP (Sham). Hepatocytes were then harvested at 4 h (early hyperdynamic phase) or 24 h (late hypodynamic state) later, and indices of AO were assessed [cell cycle analysis of Annexin V/propidium iodide (PI) staining for flow cytometric analysis, DNA extracted, and cell death ELISA]. Plasma glutamic pyruvic transaminase (GPT) was also colorimetrically assessed as well as total viable cell yield as an index of hepatocellular necrosis. The results indicate that indices of hepatocellular AO, as determined by cell cycle analysis and cell death ELISA, were markedly increased in polymicrobial septic mice at 24 h. However, while an increase in DNA fragmentation/degradation could be consistently detected, the pattern was typically faint. Similarly, although there was an increase in Annexin V staining it was not dissociated from that of PI (necrotic index). Alternatively, necrosis (as evidenced by increased GPT levels at both 4 and 24 h) preceded the induction of all the indices of AO. Taken together, these data suggest a role for both necrosis and apoptosis in the evolution of hepatocellular injury encountered in the polymicrobial septic animal/patient which may represent a unique pattern of cell death under such conditions.
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PMID:Does hepatocellular injury in sepsis involve apoptosis? 969 18

Challenge of elicited peritoneal macrophages with lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) was followed by an apoptotic response. These cells expressed cytokine-inducible nitric oxide synthase (iNOS) in response to these stimuli, and the NO released contributed markedly to the apoptotic death, as deduced from the increased viability observed when iNOS activity was inhibited. The antiviral type I IFN (IFN-alpha/beta) down-regulated the high levels of NO produced when cells were stimulated with suboptimal doses of LPS and IFN-gamma. Moreover, IFN-alpha/beta also decreased cell death in LPS/IFN-gamma-activated cells, as determined by the reduction in the content of oligonucleosomal DNA fragments, in the binding of annexin V to the plasma membrane, and in the amount of hypodiploid cells when analyzed by flow cytometry after in vivo staining with propidium iodide. Kinetic analysis of the protection exerted by IFN-alpha/beta) against the apoptosis induced by treatment with LPS and IFN-gamma showed that type I IFNs were very effective when added up to 1 h after IFN-gamma/LPS stimulation. Addition of IFN-alpha/beta 4 h after stimulation with IFN-gamma/LPS failed completely to prevent apoptosis. This inhibition of apoptosis elicited by IFN-alpha/beta suggests the existence of a mechanism intended to improve macrophage viability in the course of certain viral infections.
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PMID:Interferon-alpha/beta inhibits the apoptosis induced by lipopolysaccharide and interferon-gamma in murine peritoneal macrophages. 971 61

Vinorelbine (NVB) is a novel vinca alkaloid FDA approved for use in some advanced carcinomas. However, its role in non-Hodgkin's lymphoma (NHL) is still not well defined. NVB is an antimicrotubule agent, but as yet, it is not known whether it induces apoptosis. By flow cytometry using nuclear staining (propidium iodide) and annexin V, we demonstrated that NVB and vincristine (VCR) induced both mitotic arrest and apoptosis in leukemia and lymphoma cells, in a drug exposure time dependent manner. Cell cycle kinetics in 3 different cell lines varied during vinca alkaloid treatment. The annexin V method showed that apoptosis, as opposed to necrosis, was the dominant mode of cell kill of chemosensitive leukemia and lymphoma cells. Phosphatidylserine expression on the cell surface was detectable as a hallmark of apoptosis at earlier drug exposure when compared to conventional flow cytometry with PI staining. By Western blot analysis, we demonstrated that CPP32 or caspase-3, a critical apoptosis inducer, and its active subunits p20 and p11 were upregulated in chemo- and apoptosis-sensitive lymphoma and leukemia cells treated with NVB. Our data contributes to the emerging hypothesis suggesting that widely divergent exogenous stimuli and chemotherapeutic agents can effect apoptosis in cancer cells via different pathways involving the caspases. We believe that vinorelbine may be a potentially important drug in the treatment of NHL in the future.
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PMID:Vinorelbine induces apoptosis and caspase-3 (CPP32) expression in leukemia and lymphoma cells: a comparison with vincristine. 972 Jul 29

1. House dust mite (HDM) allergens with cysteine and serine proteinase activity are risk factors for allergic sensitization and asthma. A simple method to fractionate proteinase activity from HDM faecal pellets into cysteine and serine class activity is described. 2. Both proteinase fractions increased the permeability of epithelial cell monolayers. The effects of the serine proteinase fraction were inhibited by 4-(2-aminoethyl)-benzenesulphonyl fluoride hydrochloride (AEBSF) and soybean trypsin inhibitor (SBTI). The effects of the cysteine proteinase fraction could be inhibited by E-64. No reciprocity of action was found. 3. Treatment of epithelial monolayers with either proteinase fraction caused breakdown of tight junctions (TJs). AEBSF inhibited TJ breakdown caused by the serine proteinase fraction, whereas E-64 inhibited the cysteine proteinase fraction. 4. Agarose gel electrophoresis revealed that the proteinases induced DNA cleavage which was inhibited by the matrix metalloproteinase inhibitor BB-250. Compound E-64 inhibited DNA fragmentation caused by the cysteine proteinase fraction, but was without effect on the serine proteinase fraction. Staining of proteinase-treated cells with annexin V (AV) and propidium iodide (PI) revealed a diversity of cellular responses. Some cells stained only with AV indicating early apoptosis, whilst others were dead and stained with both AV and PI. 5. HDM proteinases exert profound effects on epithelial cells which will promote allergic sensitization; namely disruption of intercellular adhesion, increased paracellular permeability and initiation of cell death. Attenuation of these actions by proteinase inhibitors leads to the conclusion that compounds designed to be selective for the HDM enzymes may represent a novel therapy for asthma.
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PMID:Class specific inhibition of house dust mite proteinases which cleave cell adhesion, induce cell death and which increase the permeability of lung epithelium. 972 Jul 72

Exposure to ultraviolet (UV) radiation and photochemotherapy induces apoptotic cell death in epidermal cells. In this study annexin V binding and propidium iodide (PI) uptake have been measured by flow cytometry to evaluate UV-induced cell death in the human squamous cell carcinoma-derived cell line A 431. Physiological and therapeutical relevant doses of UVA, UVA1, UVB, narrow-band UVB (311 nm) and photochemotherapy using 100 ng/ml of 8-methoxypsoralen (8-MOP) with UVA or UVA1 (PUVA or PUVA1) have been applied. Doses ranged from 8 to 96 J/cm2 for UVA1 and UVA, from 8 to 128 mJ/cm2 for UVB, from 256 to 4096 mJ/cm2 for narrow-band UVB (311 nm) and from 1 to 16J/cm2 for photochemotherapy. Results show that the amount of annexin V binding, a measure of early apoptosis, as well as PI uptake, a parameter of ultimate cell death, are strictly correlated with the applied UV dose. Peak values of annexin V-positive cells are noted 12 h after UV exposure in all protocols and are followed by an increase of PI-uptaking cells with peak values at 24 h after UVA and UVA1, and 48 h after PUVA, PUVA1, UVB and narrow-band UVB. To compare the effect of different wavelengths and light sources, dose equivalents are calculated based on the induction of 50% cell death (as determined by PI uptake). The equivalents are 96 J/cm2 for UVA and UVA1, 16 J/cm2 for PUVA and PUVA1, 256 mJ/cm2 for UVB and 2048 mJ/cm2 for narrow-band UVB. Our results establish annexin V/PI double staining as an appropriate method for the quantification of UV-induced cell death. Moreover, they provide a basis for further investigations concerning mechanisms and modifications of UV-induced apoptosis.
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PMID:Flow cytometric quantification of UV-induced cell death in a human squamous cell carcinoma-derived cell line: dose and kinetic studies. 975 90


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