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)

ZD2767P is a phenol mustard glutamate prodrug which is currently being developed for Antibody Directed Enzyme Prodrug Therapy (ADEPT). In ZD2767 ADEPT an active bi-functional alkylating drug, ZD2767D (4-[N,N-bis(2-iodoethyl)amino]phenol), is generated following cleavage of ZD2767P by the bacterial enzyme carboxypeptidase G2 (CPG2) which is targeted to the tumour by conjugation to the F(ab')(2)fragment of the anti-CEA antibody A5B7. The aim of the studies described here was to identify the mode of cell death induced by ZD2767P + CPG2 in comparison to the established nitrogen mustard chlorambucil. The contribution of bifunctional and monofunctional ZD2767 DNA lesions to cell death induction was investigated using a monofunctional ZD2767D analogue. Apoptosis in LoVo tumour cells was studied by three different methods (nuclear morphology, annexin V staining and TUNEL). Levels of apoptosis detected using the three assays were similar, and each drug treatment produced apoptosis at levels above those in control cells at concentrations which resulted in tumour cell growth inhibition. The bi-functional compounds, ZD2767P + CPG2 and chlorambucil, induced apoptosis in a concentration and time dependent manner, with equitoxic concentrations producing equivalent levels of apoptosis. In contrast, the mono-functional ZD2767D analogue at 100 microM resulted in the maximal level of apoptosis at 25 h with no further increase over the following 72 h. These studies have demonstrated that apoptosis is the mechanism of cell death induced by the ZD2767 ADEPT system, and that levels of apoptosis produced by ZD2767 are similar to those observed at equitoxic concentrations of the classical nitrogen mustard chlorambucil. The mono-functional ZD2767 analogue also induced apoptosis, but with a different time course and characteristics. In conjunction with previous data, these studies have shown that the potent activity of ZD2767 can be attributed to the ability of the compound to induce bifunctional DNA lesions and engage apoptosis.
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PMID:Induction of apoptosis by the ADEPT agent ZD2767: comparison with the classical nitrogen mustard chlorambucil and a monofunctional ZD2767 analogue. 1153 Dec 65

Annexins are a superfamily of calcium-dependent membrane-associated proteins which interact with phospholipids. The primary structure of Annexins I, III, VII, VIII and XI contain a region enriched in proline, glutamate, serine and threonine (PEST sequences) towards the N-terminal end while annexins II, V and VI possess PEST regions somewhat distal to the N-terminus. These PEST sequences are believed to be the signals for rapid intracellular degradation. Annexin I is known to be cleaved by calpain near its PEST region suggesting that its PEST region might be a possible calpain recognition site. Western blot analysis of annexins V and XI in rat lung homogenates suggest that these proteins are resistant to proteolysis by calpain. Annexin V was found to be stable to intrinsic lung proteases in the presence of either Ca2+ or EGTA while annexin XI was found to be partially degraded by intrinsic lung proteases in the presence of EGTA. Eight of the 10 known mammalian annexins also contain a pentapeptide sequence that is biochemically related to the KFERQ motif which is a known signal that targets protein for lysosomal proteolysis. Our data suggest that the annexins may be regulated by limited proteolysis, most likely at their N-terminal end, while most, if not all, of them might be degraded by the lysosomal pathway.
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PMID:Proteolytic signals in the primary structure of annexins. 1195 51

High concentrations of intracellular glutathione (GSH) enhance in vitro production of porcine embryos. Objectives were: (1) to determine the effects of gamma-glutamyl cycle compound supplements to the IVM medium on IVF and IVC; and (2) to evaluate embryo viability. Porcine oocytes were matured in NCSU 23 medium supplemented with either l-cysteine (3.3 mM), l-cysteamine (150 P < 0.05microM), l-cysteine and l-cystemaine, l-glycine (1, 2.5, or 5 mM), l-glutamate (1, 2.5, or 5 mM), l-alpha-aminobutyrate (3.3mM), beta-mercaptoethanol (BME) (25 microM), l-cysteine and BME, or l-alpha-aminobutyrate and BME. Increases (P < 0.05) in GSH concentrations were observed using l-cysteine, 1.0 mM l-glutamate, l-alpha-aminobutyrate, and l-alpha-aminobutyrate with BME. Oocytes matured with l-alpha-aminobutyrate and BME had a lower (P < 0.05) occurrence of polyspermy during IVF compared to controls and a greater percentage (P < 0.05) of embryos reaching the blastocyst stage compared to other treatment groups. For Objective 2, oocytes were matured in NCSU 23 or NCSU 23 supplemented with l-alpha-aminobutyrate with BME. Embryo cell death was determined using an Annexin V-FITC assay. Supplementation had no effect on the time of cell death. Embryo mortality was increased (P < 0.05) from 24 to 42 h post-IVF, with the greatest occurrence around 36 h. In conclusion, supplementing l-alpha-aminobutyrate and BME into the IVM medium increased intracellular GSH concentrations, decreased the occurrence of polyspermy during IVF, and increased embryo development parameters during IVC, but did not affect cell death during embryo development. The onset of cell death occurred from 24 to 42 h post-IVF, with the greatest occurrence around 36 h post-IVF.
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PMID:Exogenous gamma-glutamyl cycle compounds supplemented to in vitro maturation medium influence in vitro fertilization, culture, and viability parameters of porcine oocytes and embryos. 1515 23

Excessive stimulation of the NMDA receptor by glutamate induces cell death and has been implicated in the development of several neurodegenerative diseases. While apoptosis plays a role in glutamate-mediated toxicity, the mechanisms underlying this process have yet to be completely determined. Recent evidence has shown that exposure to excitatory amino acids regulates the expression of the antiapoptotic protein, Bcl-2, and the proapoptotic protein, Bax, in neurons. Since it has been suggested that the ratio of Bax to Bcl-2 is an important determinant of neuronal survival, the reciprocal regulation of these Bcl-2 family proteins may play a role in the neurotoxicity mediated by glutamate. Here, we have used a differentiable neuronal cell line, N1E-115, to investigate the molecular properties of glutamate-induced cell death. Annexin V staining was used to determine apoptotic cell death between 0 and 5 days differentiation with DMSO/low serum. Immunoblot analysis was used to determine whether the expression of Bcl-2 or Bax was modulated during the differentiation process. Bcl-2 protein levels were increased during maturation while Bax expression remained unchanged. Maximum Bcl-2 expression was observed following 5 days of differentiation. Examination of Bcl-2 and Bax following glutamate treatment revealed that the expression of these proteins was inversely regulated. Exposure to glutamate (0.001-10 mM) for 20+/-2 h resulted in a dose-dependent decrease in cell survival (as measured by MTT analysis) that was maximal at 10 mM. These results further support the role of apoptosis in glutamate-mediated cell death. Furthermore, a significant decrease in Bcl-2 levels was observed at 1 mM and 10 mM glutamate (32.1%+/-4.8 and 33.7+/-12.8%, respectively) while a significant upregulation of Bax expression (88.2+/-17.9%) was observed at 10 mM glutamate. Interestingly, Bcl-2 and Bax levels in cells treated with glutamate from 12-24 h were not significantly different from those of control. Taken together, these findings provide additional evidence for the reciprocal regulation of Bcl-2 and Bax expression by glutamate and suggest that neuronal excitotoxicity may, in part, result from the inverse regulation of these proteins.
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PMID:Glutamate mediates cell death and increases the Bax to Bcl-2 ratio in a differentiated neuronal cell line. 1536 91

Accumulating evidence suggests that glutamate plays a key role in the proliferation and invasion of glioblastoma tumors. Astrocytic tumors have been shown to release glutamate at high levels, which may stimulate tumor cell proliferation and motility via activation of glutamate receptors. Excess glutamate has also been found to facilitate tumor invasion by causing excitotoxic damage to normal brain thereby paving a pathway for tumor migration. Results from tissue microarray analyses showed decreased excitatory amino acid transporter-2 (EAAT-2) expression in high-grade glial tumors compared with low-grade astrocytomas and normal brain. EAAT-2 expression was inversely correlated with tumor grade, implicating its potential role in glial tumor progression, which was reflected by an undetectable level of EAAT-2 protein in glioma cell lines. In this study, we sought to investigate the effect of reconstituted EAAT-2 on glioma cell growth in vitro and in vivo by adenoviral-mediated gene transfer. Infection of glioma cells with Ad-EAAT-2 resulted in a physiologic level of functional EAAT-2, and a subsequent dose-dependent reduction in cell proliferation in all glioma cell lines tested compared with controls. Interestingly, results from analyses of Annexin V staining, detection of poly(ADP-ribose)polymerase cleavage and caspase-3 activation all indicated that Ad-EAAT-2 infection elicited apoptosis in glioma cells. Ex vivo experiments in nude mice showed a total suppression of tumor growth at sites that received Ad-EAAT-2-infected cells. Collectively, our results uncovered a new function of EAAT-2 in controlling glioma proliferation. Further studies will improve our knowledge of the role of glutamate in glioma growth and may provide useful prognostic information and alternative therapeutic targets for the treatment of glioma.
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PMID:The excitatory amino acid transporter-2 induces apoptosis and decreases glioma growth in vitro and in vivo. 1575 93

Nitric oxide (NO) is a molecule that plays a prominent role in neurotoxic as well as neuroprotective pathways. Here, we investigated the effects of NO on potentially excitotoxic glutamate-induced intracellular calcium ([Ca2+]i) dynamics. Our hypothesis was that pre- and coexposure to NO in conjunction with glutamate receptor stimulation modulates [Ca2+]i responses differentially. [Ca2+]i transients, assessed by the fluorescent cytosolic Ca2+ indicator dye fluo-4, were elicited in mouse striatal neurons by consecutive NMDA applications (200 microM for 100 s each). Subgroups of neuronal cultures were additionally exposed to a NO donor (S-nitroso-N-acetyl-d,l-penicillamine, SNAP, 50-500 microM), either by pre- (for 6 h prior to NMDA) or cotreatment (for 30 min during NMDA). Pretreatment with NO led to dramatically decreased NMDA-evoked [Ca2+]i rises in comparison to controls (NMDA alone). Annexin V/propidium iodide staining showed consistently that NO pretreatment is protective against NMDA-induced cell death. In contrast, NO/NMDA cotreatment caused a potentiation of [Ca2+]i rises, whereby the duration of [Ca2+]i transients following NMDA application was prolonged and remained at an increased plateau level. Simultaneous application of the mitochondrial permeability transition pore (mtPTP) blocker cyclosporin A (2 microM) during the NO/NMDA cotreatment prevented the deregulation of [Ca2+]i. The observed [Ca2+]i deregulation was accompanied by a decrease in the mitochondrial membrane potential as indicated by tetramethylrhodamine methylester (TMRM) fluorescence. These findings suggest that NO can act in a protective way due to preconditioning or can have a possibly detrimental impact in case of acute release. They provide a possible explanation for the ambivalence of NO in neurodegenerative processes where glutamate receptor stimulation and mitochondrial [Ca2+]i sequestration are causally involved.
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PMID:Nitric oxide applications prior and simultaneous to potentially excitotoxic NMDA-evoked calcium transients: cell death or survival. 1619 18

Glutamate cytotoxicity contributes to neuronal degeneration in many central nervous system (CNS) diseases, such as epilepsy and ischemia. We previously reported that a high-fat and low-carbohydrate diet, the ketogenic diet (KD), protects against kainic acid-induced hippocampal cell death in mice. We hypothesized based on these findings that ketosis resulting from KD might inhibit glutamate cytotoxicity, resulting in inhibition of hippocampal neuronal cell death. Therefore, we investigated the role of ketone bodies [acetoacetate (AA) and beta-hydroxybutyrate (beta-OHB)] both in a mouse hippocampal cell line (HT22) and in rat primary hippocampal neurons. As a result, we found that pretreatment with 5 mM lithium AA and 4 mM Na beta-OHB protected the HT22 hippocampal cell line and primary hippocampal neuronal culture against 5 mM glutamate toxicity and that up to 2 hr of pretreatment with 5 mM AA had a protective effect against 5 mM glutamate toxicity in the HT22 cell line. Pretreatment with 5 mM AA decreased ROS production of HT22 cell line at 2 and 8 hr exposure of glutamate, and it decreased the appearance of annexin V-positive HT22 cells, which are indicative of an early stage of apoptosis, and propidium iodide-positive HT22 cells, which are indicative of necrosis.
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PMID:Acetoacetate protects neuronal cells from oxidative glutamate toxicity. 1643 89

1. The effects of L-glutamate on activation-induced cell death (AICD) of human activated (1 microg ml(-1) phytohemagglutinin plus 2 U ml(-1) interleukin-2; 8 days) T lymphocytes were studied by measuring anti-CD3 monoclonal antibody (10 microg ml(-1); 18 h)-induced cell apoptosis (Annexin V and propidium iodide staining). 2. L-Glutamate (1 x 10(-8)-1 x 10(-4) M) significantly (P < or = 0.01) inhibited AICD in a concentration-dependent manner (EC50=6.3 x 10(-8) M; maximum inhibition 54.8+/-6.3% at 1 x 10(-6) M). 3. The L-glutamate inhibitory effect was pharmacologically characterized as mediated by group I mGlu receptors, since mGlu receptor agonists reproduced this effect. The EC50 values were: 3.2 x 10(-7) M for (1S,3R)-ACPD; 4.5 x 10(-8) M for quisqualate; 1.0 x 10(-6) M for (S)-3,5-DHPG; 2.0 x 10(-5) M for CHPG. 4. Group I mGlu receptor antagonists inhibited the effects of quisqualate 1.0 x 10(-6) M. The IC50 values calculated were: 8.7 x 10(-5), 4.3 x 10(-6) and 6.3 x 10(-7) M for AIDA, LY 367385 and MPEP, respectively. 5. L-Glutamate (1 x 10(-6) M; 18 h) significantly (P < or = 0.05) inhibited FasL expression (40.8+/-11.3%) (cytofluorimetric analysis), whereas it did not affect Fas signalling. 6. Expression of both mGlu1 and mGlu5 receptor mRNA by T lymphocytes and T-cell lines, as demonstrated by reverse transcriptase-PCR analysis, suggests that L-glutamate-mediated inhibition of AICD was exerted on T cells. 7. These data depict a novel role for L-glutamate in the regulation of the immune response through group I mGlu receptor-mediated mechanisms.
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PMID:Group I mGlu receptor stimulation inhibits activation-induced cell death of human T lymphocytes. 1675 98

Monosodium glutamate (MSG), the sodium salt of glutamate, is commonly used as a flavor enhancer in modern nutrition. Recent studies have shown the existence of glutamate receptors on lymphocytes, thymocytes and thymic stromal cells. In this study, we evaluated the in vitro effect of different MSG concentrations on rat thymocyte apoptosis and expression of two apoptosis-related proteins, Bcl-2 and Bax. Rat thymocytes, obtained from male Wistar rats, were exposed to increasing concentrations of MSG (ranging from 1 mM to 100 mM) for 24 h. Apoptosis was detected using the Annexin V-FITC/PI apoptosis detection kit and cells were analyzed using a flow cytometer. Expression of Bcl-2 and Bax proteins were determined with flow cytometry using respective monoclonal antibodies. Exposure to MSG resulted in a dose-dependent decrease in cell survival (as determined by trypan blue exclusion method). Annexin V-FITC/PI also confirmed that MSG increased, in a dose-dependent manner, apoptotic cell death in rat thymocyte cultures. MSG treatment induced downregulation of Bcl-2 protein, while Bax protein levels were not significantly changed. Our data showed that MSG significantly modulates thymocyte apoptosis rate in cultures. The temporal profile of Bcl-2 and Bax expression after MSG treatment suggests that downregulation of Bcl-2 protein and the resulting change of Bcl-2/Bax protein ratio may be an important event in thymocyte apoptosis triggered by MSG.
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PMID:Effect of monosodium glutamate on apoptosis and Bcl-2/Bax protein level in rat thymocyte culture. 1718 47

The aim of this study was to investigate the effects of breviscapine on cultured rat hippocampal neuronal toxicity induced by glutamate. Primary hippocampal neurons were prepared from 2 day-old SD rats. After 8 days cultured in vitro, the cultures subjected to 30 min treatment of 0.1, 0.5 and 1.0 mmol x L(-1) L-glutamate, separately. Breviscapine (10, 20 and 40 micromol x L(-1)) was added into the cultures during 30 min treatment of L-glutamate and for the following 24 h respectively. After 24 h of L-glutamate treatment, flow cytometric analysis of Annexin V (marks apoptosis) and PI (propidium iodide, marks necrosis) labeling cells showed that L-glutamate dose-dependently induced hippocampal neuronal apoptosis and necrosis. In agreement with these results, RT-PCR experiments indicated a biphasic regulation of X-chromosome-linked inhibitor of apoptosis protein (XIAP) mRNA after L-glutamate treatment, i. e up-regulation by 0.1 mmol x L(-1) L-glutamate and down-regulation by 0.5 and 1.0 mmol x L(-1) L-glutamate. However, breviscapine markedly reduced apoptosis and necrosis due to toxicity of 0.5 mmol L(-1) L-glutamate. Compared with the vehicle-treated L-glutamate group, the apoptosis was reduced by 30.4% and 40.1%, and necrosis was reduced by 32.5% and 38.8%, after treatment by breviscapine of 20 and 40 micromol x L(-1). Meanwhile, breviscapine obviously reversed the down-regulation of XIAP expression induced by L-glutamate (up-regulation by 45.1% and 54.9% when compared with that of the vehicle-treated glutamate group). The results from the detection of confocal laser scanning microscopy with Fluo-3, a Ca2+ probe showed an obvious increase in intracellular Ca2+ during L-glutamate treatment; and breviscapine of 20 or 40 micromol x L(-1) significantly slowed down glutamate-induced Ca2+ influx and lowered the intracellular Ca2+ peak in hippocampal neurons (P < 0.01). These results suggest that neuroprotective effect of breviscapine against glutamate excitotoxicity was associated with inhibition of the accumulation of intracellular Ca2+ and up-regulation of XIAP expression in hippocampal neurons.
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PMID:[Protective effects of breviscapine against cultured rat hippocampal neuronal toxicity induced by glutamate]. 1770 92


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