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)

PD180970 is a novel pyrido[2,3-d]pyrimidine class of ATP-competitive inhibitor of protein tyrosine kinases. We found that PD180970 inhibited in vivo tyrosine phosphorylation of p210Bcr-Abl (IC50 = 170 nM) and the p210BcrAbl substrates Gab2 and CrkL (IC50 = 80 nM) in human K562 chronic myelogenous leukemic cells. In vitro, PD180970 potently inhibited autophosphorylation of p210Bcr-Abl (IC50 = 5 nM) and the kinase activity of purified recombinant Abl tyrosine kinase (IC50 = 2.2 nM). Incubation of K562 cells with PD180970 resulted in cell death. Results of nuclear staining, apoptotic-specific poly(ADP-ribose) polymerase cleavage, and annexin V binding assays indicated that PD180970 induced apoptosis of K562 cells. In contrast, PD180970 had no apparent effects on the growth and viability of p210Bcr-Abl-negative HL60 human leukemic cells. Thus, PD180970 is among the most potent inhibitors of the p210Bcr-Abl tyrosine kinase, which is present in almost all cases of human chronic myelogenous leukemia. These findings indicate that PD180970 is a promising candidate as a novel therapeutic agent for Bcr-Abl-positive leukemia.
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PMID:The pyrido[2,3-d]pyrimidine derivative PD180970 inhibits p210Bcr-Abl tyrosine kinase and induces apoptosis of K562 leukemic cells. 1086 98

We are interested in the cytotoxic and proinflammatory effects of particulate pollutants in the respiratory tract. We demonstrate that methanol extracts made from diesel exhaust particles (DEP) induce apoptosis and reactive oxygen species (ROS) in pulmonary alveolar macrophages and RAW 264.7 cells. The toxicity of these organic extracts mimics the cytotoxicity of the intact particles and could be suppressed by the synthetic sulfhydryl compounds, N-acetylcysteine and bucillamine. Because DEP-induced apoptosis follows cytochrome c release, we studied the effect of DEP chemicals on mitochondrially regulated death mechanisms. Crude DEP extracts induced ROS production and perturbed mitochondrial function before and at the onset of apoptosis. This mitochondrial perturbation follows an orderly sequence of events, which commence with a change in mitochondrial membrane potential, followed by cytochrome c release, development of membrane asymmetry (annexin V staining), and propidium iodide uptake. Structural damage to the mitochondrial inner membrane, evidenced by a decrease in cardiolipin mass, leads to O-*2 generation and uncoupling of oxidative phosphorylation (decreased intracellular ATP levels). N-acetylcysteine reversed these mitochondrial effects and ROS production. Overexpression of the mitochondrial apoptosis regulator, Bcl-2, delayed but did not suppress apoptosis. Taken together, these results suggest that DEP chemicals induce apoptosis in macrophages via a toxic effect on mitochondria.
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PMID:The role of a mitochondrial pathway in the induction of apoptosis by chemicals extracted from diesel exhaust particles. 1094 1

The occurrence of a pleiomorphic population of cytoplasmic fragments is a common characteristic of early human embryos fertilized in vitro. Here, temporal, spatial, fine structural, and biochemical aspects of fragmentation were examined in fragmented monospermic and dispermic pronuclear to early cleavage stages human embryos classified as stage-appropriate during the first 3.5 days of culture. The morphodynamics of certain common patterns of fragmentation and the movement and composition of fragments were analysed by time-lapse video, mitochondrial fluorescent probes, and transmission electron microscopy. Plasma membrane and nuclear DNA integrity were assessed by annexin V staining, and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling (TUNEL) and single-cell alkaline gel electrophoresis ('comet') assays respectively. Developmental competence for affected embryos was related to outcome after embryo transfer. The results demonstrate that certain common forms of spontaneous fragmentation affecting early human embryos are not lethal, and that clusters of apparent fragments are often transient structures, which disappear by resorption or lysis. The findings suggest that the occurrence and fate of fragments characteristic of these phenotypes may be related to oncosis-like processes associated with transient and focal ATP deficiencies in blastomeres and mitochondrial deficiencies or absence in extracellular fragments.
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PMID:A microscopic and biochemical study of fragmentation phenotypes in stage-appropriate human embryos. 1127 25

Treatment of hormone refractory prostate cancer requires new treatment strategies. Genetic prodrug activation therapy (GPAT) may provide a new therapeutic avenue. In this study the antitumour efficacy of the gene encoding herpes simplex virus thymidine kinase (HSVtk) activating the prodrug ganciclovir (GCV) was compared in two models of ectopic (subcutaneous) rat prostate cancer. Both models, which differ in their characteristics, were previously shown to be weakly immunogenic but susceptible to immunotherapy. Tumour cell lines were stably transfected with HSVtk and were rendered highly sensitive to GCV. Little or no bystander killing effect was observed by tk-transfected cells on wild-type cells in vitro. However, a significant in vivo bystander effect was observed suggesting an immune-mediated response. Indeed, such an immune response was capable of slowing the growth of distant wild-type tumours and increased overall animal survival. A T helper 1 immune response was generated as a result of GCV activation and cell kill, demonstrated by the secretion of IFNgamma by cultured splenocytes in response to tumour cells. BrDU staining of tk-transfected cells treated with GCV in vitro suggested apoptotic cell death, but Annexin V staining was less marked for one of the cell lines. Serial in vivo monitoring by non-invasive magnetic resonance spectroscopy (MRS) of the tk-transfected MATLyLu tumours demonstrated a decreased ATP/Pi ratio (a measure of cell energy status) during growth and an increase in the ATP/Pi ratio during regression initiated by treatment with GCV. Further, significant differences were found in the phosphomonester (PME) to total phosphate (SigmaP) ratios in treated compared with untreated tumours, a result rarely seen in animal models, but commonly observed in patients. This study showed that a Th1-biased immune response generated by killing prostate tumour cells with tk/GCV can kill distant as well as local wild-type tumour cells. These findings suggest that GPAT may have a potential application in patients with both confined and metastatic prostate cancer and MRS may provide a method of monitoring response to treatment.
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PMID:Genetic prodrug activation therapy (GPAT) in two rat prostate models generates an immune bystander effect and can be monitored by magnetic resonance techniques. 1131 23

Cyclin-dependent kinases (cdk's) have recently been suggested to regulate human immunodeficiency virus type 1 (HIV-1) transcription. Previously, we have shown that expression of one cdk inhibitor, p21/Waf1, is abrogated in HIV-1 latently infected cells. Based on this result, we investigated the transcription of HIV-1 in the presence of chemical drugs that specifically inhibited cdk activity and functionally mimicked p21/Waf1 activity. HIV-1 production in virally integrated lymphocytic and monocytic cell lines, such as ACH(2), 8E5, and U1, as well as activated peripheral blood mononuclear cells infected with syncytium-inducing (SI) or non-syncytium-inducing (NSI) HIV-1 strains, were all inhibited by Roscovitine, a purine derivative that reversibly competes for the ATP binding site present in cdk's. The decrease in viral progeny in the HIV-1-infected cells was correlated with a decrease in the transcription of HIV-1 RNAs in cells treated with Roscovitine and not with the non-cdk general cell cycle inhibitors, such as hydroxyurea (G(1)/S blocker) or nocodazole (M-phase blocker). Cyclin A- and E-associated histone H1 kinases, as well as cdk 7 and 9 activities, were all inhibited in the presence of Roscovitine. The 50% inhibitory concentration of Roscovitine on cdk's 9 and 7 was determined to be approximately 0.6 microM. Roscovitine could selectively sensitize HIV-1-infected cells to apoptosis at concentrations that did not impede the growth and proliferation of uninfected cells. Apoptosis induced by Roscovitine was found in both latent and activated infected cells, as evident by Annexin V staining and the cleavage of the PARP protein by caspase-3. More importantly, contrary to many apoptosis-inducing agents, where the apoptosis of HIV-1-infected cells accompanies production and release of infectious HIV-1 viral particles, Roscovitine treatment selectively killed HIV-1-infected cells without virion release. Collectively, our data suggest that cdk's are required for efficient HIV-1 transcription and, therefore, we propose specific cdk inhibitors as potential antiviral agents in the treatment of AIDS.
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PMID:Inhibition of human immunodeficiency virus type 1 transcription by chemical cyclin-dependent kinase inhibitors. 1146 99

Platelet shape change represents an early response to activating agents. Whereas the PAR-1-activating peptide SFLLRN induces a total platelet activation, YFLLRNP brings the process only to the shape change step in a process independent of the cytosolic Ca2+ concentration. In this paper, the YFLLRNP-induced shape change has been observed in human citrated platelet-rich plasma (PRP). Scanning electron microscopy of platelets activated by 300 microM YFLLRNP showed platelets that had changed shape and extended long pseudopods. The protein content of the material sedimenting at 13,000 x g from 1% Triton X-100 extracts increased during the shape change, indicating a reorganization of the cytoskeleton. This was supported by electrophoresis. The GP IIb-IIIa complex was not activated, however, and the platelets that had undergone shape change did not support clot retraction. As no increase in binding of FITC-labeled annexin V (FITC-annexin V) was observed, the extensive shape change was not associated with a disturbance of the membrane phospholipid asymmetry. Platelet aggregation was never observed with 300 microM YFLLRNP, but could be seen at much higher concentrations, neither was secretion from dense granules observed at 300 microM as no extracellular ATP could be observed. These studies confirm and extend the concept of the Ca2+-independent shape change as a distinct and sharply delineated process that, in itself, may be of little pathophysiological importance if such "partly activated" platelets occur in the circulation.
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PMID:Platelet shape change induced by the peptide YFLLRNP. 1155 73

Placental trophoblasts undergo apoptosis as part of normal epithelial turnover and placental ageing. Classically, the induction of apoptosis in in vitro preparations has utilized the cytokines TNFalpha and IFNgamma and has been measured using the TUNEL technique. The aim of this study was to compare apoptotic susceptibility of mononucleated and differentiated trophoblasts using a range of cytotoxic agents. To achieve this, an in vitro model of syncytialization was used, along with isolated placental cytotrophoblasts and an extravillous cytotrophoblast derived cell line (SGHPL-4). Cytotrophoblasts from term placentae (n=12), syncytiotrophoblasts (n=12) and SGHPL-4s (n=8) were cultured under reduced oxygen or with TNFalpha/IFNgamma, dexamethasone or staurosporine. Apoptosis assessments were made using TUNEL, Annexin V binding, fluorescence microscopy and ATP/ADP measurements. Each cytotoxic agent increased apoptosis in all three cell populations. For untreated cells, cytotrophoblasts showed the greatest levels of apoptosis in culture. With stimulation, these levels were significantly elevated using dexamethasone, TNFalpha/IFNgamma and staurosporine and further raised under hypoxic conditions. SGHPL-4 cells showed similar trends to those of cytotrophoblasts, however the syncytiotrophoblasts, although responsive to dexamethasone and TNFalpha/IFNgamma, showed lower levels of apoptosis with staurosporine and hypoxia. ADP : ATP measurements gave similar results to the other techniques and ratios of less than 1.0 were correlated with Annexin V measurements on the flow cytometer (P< 0.001). The typical morphological features of apoptosis i.e. chromatin margination, membrane blebbing and apoptotic body formation were detected in cytotrophoblasts and SGHPL-4 cells. However, only chromatin condensation could be recognized in syncytiotrophoblast preparations. Necrotic cell numbers were also increased under all cytotoxic conditions. Although elevated with dexamethasone, staurosporine and hypoxia, these levels were markedly raised in cytotrophoblasts and SGHPL-4 cells following incubations with TNFalpha/IFNgamma. These observations show variations in apoptosis between mononuclear trophoblasts and differentiated multinucleated syncytiotrophoblasts. Differential effects of stimuli may suggest disparate apoptotic pathways. These variations may reflect functional differences between placental cellular and syncytial components and may highlight the importance of exogenous stimulation in various stages of placental development.
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PMID:The in-vitro characterization of induced apoptosis in placental cytotrophoblasts and syncytiotrophoblasts. 1171 69

1. Cell death mode switch of cortical neurons from E17 rats was studied. Cells rapidly died under the serum-free condition. The time-course of cell death was markedly delayed by increasing cell density for primary culture in the trypan blue exclusion, LDH release, and MTT assays. 2. By analyzing cell death by the use of double staining using PI/TUNEL and PI/Annexin V combinations, the mode in the low density culture was found to be necrosis, while that in the high density culture was apoptosis. 3. The intracellular ATP level after the start of serum-free culture rapidly decline to 25% of 0-time level in the low density culture, but it was 60% in the high density culture. Both oligomycin and zVAD-fmk markedly decreased ATP levels and the population of TUNEL-positive neurons, while 3-aminobenzamide slightly increased these indices. 4. Thus. it is strongly suggested that the cell death mode switch from necrosis to apoptosis is closely related to intracellular ATP levels, and some conditioned medium factors observed in the high density culture may affect both ATP level and cell death mode switch.
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PMID:Cell density-dependent death mode switch of cultured cortical neurons under serum-free starvation stress. 1177 63

The chemotherapeutic cisplatin causes renal dysfunction and renal proximal tubular cell (RPTC) apoptosis. The goal of these studies was to examine the role of p53, caspase 3, 8, and 9, and mitochondria in the signaling of cisplatin-induced apoptosis. Cisplatin (50 microM) produced time-dependent apoptosis in RPTCs, causing cell shrinkage, a 50-fold increase in caspase 3 activity, a 4-fold increase in phosphatidylserine externalization, and 5- and 15-fold increases in chromatin condensation and DNA hypoploidy, respectively. Mitochondrial membrane potential and ATP levels did not change at any time during cisplatin exposure. Caspase 8 and 9 activities also did not increase during treatment. Cisplatin increased nuclear p53 expression 4 h after treatment, preceding both caspase 3 activation and chromatin condensation. Treatment with the p53 inhibitor alpha-2-(2-imino-4,5,6,7-tetrahydrobenzothiazol-3-yl)-1-p-tolylethanone (PFT) before cisplatin exposure inhibited p53 nuclear expression at 4, 8, and 12 h and inhibited phosphatidylserine externalization and caspase 3 activation at 12 h. Neither DEVD-fmk nor ZVAD-fmk inhibited cisplatin-induced p53 nuclear expression. Both DEVD-fmk and ZVAD-fmk completely inhibited caspase 3 activity but, like PFT, partially inhibited cisplatin-induced chromatin condensation, annexin V labeling, and DNA hypoploidy after 24 h. These data demonstrate that at least 50% of cisplatin-induced apoptosis in RPTC is mediated by p53 and that p53 activates caspase 3 independently of either caspase 9 or 8 or mitochondrial dysfunction. Furthermore, 50% of cisplatin-induced RPTC apoptosis is independent of p53 and caspases 3, 8, and 9.
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PMID:Cisplatin-induced renal cell apoptosis: caspase 3-dependent and -independent pathways. 1206 94

The binding of extracellular ATP to the P2X(7) receptor opens an integral cation-permeable channel; it also leads to membrane blebbing and, in certain immune cells, interleukin-1beta secretion and eventual death. The latter three effects are unique to the P2X(7) receptor; also unique among P2X receptors is the long intracellular C terminus of the protein. We have shown that the C-terminal domain of the P2X(7) receptor is responsible for the cell blebbing phenotype. A screen for proteins that associate with the C-terminal domain of the P2X(7) receptor and might mediate the blebbing phenotype, identified epithelial membrane protein 2 (EMP-2). The interaction between EMP-2 and P2X(7) was confirmed biochemically by co-immunoprecipitation, co-purification, and glutathione S-transferase pull-down assays, and this interaction was entirely dependent on the C-terminal domain of P2X(7). The P2X(7) receptor also interacted with the other members of the epithelial membrane protein family (EMP-1, EMP-3, and PMP-22). All four EMPs were found to be expressed in HEK-293 cells and in THP-1 monocytes, which express P2X(7) receptors. Interestingly, the constitutive overexpression of any of the EMPs in HEK-293 cells led to cell blebbing, annexin V binding, and cell death, by a caspase-dependent pathway. These findings suggest that the P2X(7) C-terminal domain associates with EMPs, and this interaction may mediate some aspects of the downstream signaling following P2X(7) receptor activation.
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PMID:Epithelial membrane proteins induce membrane blebbing and interact with the P2X7 receptor C terminus. 1210 82


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