Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.4.2.30 (PARP)
13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The site and mechanisms by which meningococci gain access to the CNS are unclear. In this study we determined whether production of nitric oxide (NO) is part of the host (endothelial cell) response to meningococcal cell lysate, and the consequences for endothelial cell viability. Expression of NO synthase type II (NOS-2) mRNA, protein and enzyme activity were investigated in mouse cerebrovascular endothelial cells exposed to sonicated Neisseria meningitidis. The production of nitrite peaked after 48 h of incubation, and this reflected transcriptional activation of the NOS-2 gene and increased expression of the NOS-2 protein. This endothelial response was independent of meningococcal lipopolysaccharide production. Endothelial cell death occurred as a result of NO production, and addition of a NOS inhibitor prevented cell death, but the cells did not exhibit features of apoptosis. However, inhibition of poly (ADP-ribose) polymerase (PARP) decreased the rate of cell death by more than 40%. These data indicate that N. meningitidis increases expression of NOS-2 in endothelial cells and causes cell death. Such an effect could contribute to meningococcal entry into the CNS in situ.
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PMID:Transcriptional activation of nitric oxide synthase-2, and NO-induced cell death, in mouse cerebrovascular endothelium exposed to Neisseria meningitidis. 1206 73

Pancreatic cancer is often resistant to conventional chemotherapy. In this study, we examined the role of adenovirus-mediated overexpression of E2F-1 in inducing apoptosis and increasing the sensitivity of pancreatic cancer cells to chemotherapeutic agents. MIA PaCa-2 pancreatic head exocrine adenocarcinoma cells (mutant p53) were treated by mock infection or adenoviruses expressing beta-galactosidase or E2F-1 (Ad-E2F-1) alone or in combination with sublethal concentrations of each chemotherapeutic drug. Cell growth and viability were assessed at selected time points. Apoptosis was evaluated by flow cytometry, characteristic changes in cell morphology and poly (ADP-ribose) polymerase (PARP) cleavage. Western blot analysis was used to examine the expression of E2F-1 and Bcl-2 family member proteins and PARP cleavage. Western blot analysis revealed marked overexpression of E2F-1 at a multiplicity of infection (MOI) of 20 and 70. By 3 days after infection, Ad-E2F-1 treatment at an MOI of 70 resulted in approximately a 20-fold reduction in cell growth and 60% reduction in cell viability as compared to mock-infected cells. Cell cycle analysis, PARP cleavage and changes in cell morphology supported apoptosis as the mechanism of cell death in response to E2F-1. In order to test the efficacy of treatment with a combination of gene therapy and chemotherapy, we utilized concentrations of Ad-E2F-1 which reduced viability to 50% in combination with each chemotherapeutic agent. Cotreatment of the cells with E2F-1 virus and roscovitine (ROS) or etoposide resulted in an additive effect on cell growth inhibition and induction of apoptosis. Interestingly, 5-fluorouracil did not cooperate with Ad-E2F-1 in the mediation of tumor death or inhibition of cell growth. Immunoblotting for Bcl-2 family members revealed no significant changes in the expression levels of Bcl-2, Bcl X(L), Bax or Bak following gene or 'chemogene' therapy with E2F-1. However, a Bax cleavage product was noted which was substantially increased by cotreatment with ROS or etoposide. E2F-1 overexpression initiates apoptosis and suppresses growth in pancreatic MIA PaCa-2 cells in vitro. E2F-1-mediated apoptosis was not associated with significant changes in the expression of Bcl-2 family member proteins in these pancreatic cancer cells. ROS and etoposide, when combined with E2F-1 overexpression, induce apoptosis in an additive manner. This chemogene combination may provide a potentially useful therapeutic strategy for advanced pancreatic cancer.
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PMID:E2F-1 gene therapy induces apoptosis and increases chemosensitivity in human pancreatic carcinoma cells. 1206 45

Preeclampsia is a severe disorder of human pregnancy characterized by generalized activation of maternal endothelial cells. Oxidative stress of the placenta is considered a key intermediary step, precipitating deportation of apoptotic fragments into the maternal circulation, but the cause remains unknown. We hypothesize that intermittent placental perfusion, secondary to deficient trophoblast invasion of the endometrial arteries, leads to an ischemia-reperfusion-type insult. We therefore tested whether hypoxia-reoxygenation (H/R) in vitro stimulates apoptosis in human placental tissues compared with controls kept hypoxic or normoxic throughout. After H/R, release of cytochrome c from mitochondria was significantly increased and was associated with intense immunolabeling for active caspase 3 in the syncytiotrophoblast and fetal endothelial cells. There was also increased labeling of syncytiotrophoblastic nuclei for cleaved poly (ADP-ribose) polymerase (PARP), and higher cytosolic concentrations of cleaved PARP fragment were detected by Western blot. Syncytiotrophoblastic nuclei displayed increased chromatin condensation, and a significantly greater percentage was TUNEL positive. These changes were accompanied by increased lactate dehydrogenase release into the medium. Preadministration of the free radical scavenger, desferrioxamine, reduced cytochrome c release and the TUNEL-positive index, suggesting generation of hydroxyl radicals mediates these processes. By contrast, hypoxia alone caused a smaller increase in the TUNEL-positive index, and the majority of syncytiotrophoblastic nuclei displayed karyolysis, whereas normoxic controls remained euchromatic. We conclude that H/R stimulates apoptotic changes within the syncytiotrophoblast, whereas hypoxia principally induces necrosis. The quality of placental perfusion may therefore be a more important factor in the pathophysiology of preeclampsia than the absolute quantity.
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PMID:Hypoxia-reoxygenation: a potent inducer of apoptotic changes in the human placenta and possible etiological factor in preeclampsia. 1208 65

Neuronal apoptosis is one of the pathological features of Alzheimer's disease (AD). Morphological pathology reveals that neuronal apoptosis is associated with senile plaques containing amyloid-beta peptide (Abeta) in AD brains. Reactive oxygen species (ROS) has been proposed to be involved in the apoptotic mechanism of Abeta-mediated neurotoxicity. In the present study, using a rat pheochromocytoma (PC12) cell line, we investigated the effect of Pycnogenol (PYC), a potent antioxidant and ROS scavenger, on Abeta(25-35)-induced apoptosis and ROS generation. We used vitamin E, a known antioxidant agent, to verify the effect of PYC. Abeta(25-35)-induced apoptosis in PC12 cells was demonstrated by: (1) a dose-dependent loss of cell viability; (2) a time- and dose-dependent increase in the apoptotic cells; (3) an induction of DNA fragmentation; and (4) an increase in caspase-3 activity and cleavage of poly (ADP-ribose) polymerase (PARP). Our data showed that a significant increase in ROS formation preceded apoptotic events after PC12 cells were exposed to Abeta(25-35). We further found that PYC not only suppressed the generation of ROS but also attenuated caspase-3 activation, DNA fragmentation, PARP cleavage, and eventually protected against Abeta-induced apoptosis. Vitamin E also suppressed cell death and caspase-3 activation induced by Abeta(25-35). Taken together, these results suggest that ROS may be involved in Abeta-induced apoptosis in PC12 cells. They further suggest that PYC can reduce apoptosis, possibly by decreasing free radical generation in PC12 cells.
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PMID:Pycnogenol protects neurons from amyloid-beta peptide-induced apoptosis. 1211 51

Nucleated cells are more resistant to complement-mediated cell death than anucleated cells such as erythrocytes. There are few reports concerning the metabolic response of nucleated cells subjected to sub-lethal complement attack. It is possible that the rate of utilization of specific metabolic fuels by the cell is increased to enhance cell defence. We have measured the maximum activity of hexokinase, citrate synthase, glucose 6-phosphate dehydrogenase and glutaminase in rat mesenteric lymphocytes exposed to sub-lethal concentrations of activated complement (present in zymosan-activated serum, ZAS). These enzymes were carefully selected as they indicate changes of flux in glycolysis, TCA cycle, pentose phosphate pathway and glutaminolysis, respectively. The only enzyme activity to change on exposure of lymphocytes to ZAS was glutaminase, which was enhanced approximately by two-fold. Although rates of both glutamine and glucose utilization were enhanced by exposure to ZAS, only the rate of oxidation of glutamine was increased. Complement kills anucleated cells by simple osmotic lysis. However, it is likely that some nucleated cells will display characteristics of an ordered death mechanism and we have demonstrated that the concentration of lymphocyte ATP is dramatically decreased by activated complement. Nevertheless, the extent of cell death could be significantly reduced by the addition of inhibitors of the nuclear enzyme poly (ADP-ribose) polymerase (PARP). We conclude that glutamine metabolism is not only important for lymphocyte proliferative responses but is also important for cell defence from sub-lethal concentrations of activated complement. The rapid rate of complement-induced lymphocyte death reported here is suggested to be a consequence of over-activation of the nuclear enzyme PARP and ATP depletion.
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PMID:Sub-lethal concentrations of activated complement increase rat lymphocyte glutamine utilization and oxidation while lethal concentrations cause death by a mechanism involving ATP depletion. 1212 93

Interleukin-6 (IL-6) exerts a wide spectrum of regulatory activities during immune and inflammatory responses. The aim of this study was to investigate the role of endogenous IL-6 in the inflammatory response associated with acute pancreatitis. Acute pancreatitis was induced by hourly (x5) i.p. injections of cerulein (50 microg/kg, suspended in saline solution) in IL-6 deficient mice (IL-6-KO) and wild-type (IL-6WT) littermates. IL-6KO mice exhibited a more severe tissue injury and a higher rate of mortality and when compared to IL-6WT mice. Acute pancreatitis was characterized by edema, neutrophil infiltration, tissue hemorrhage and cell necrosis, upregulation of P-selectin and intercellular adhesion molecule-1 (ICAM-1), as well as increases in the serum levels of amylase and lipase. The degree of oxidative and nitrosative tissue damage was significantly greater in IL-6KO mice than in wild-type littermates, as indicated by higher tissue levels of malondialdehyde and nitrosylated proteins. Plasma levels of the inflammatory cytokines tumour necrosis factor-alpha and interleukin-1beta were also greatly enhanced in IL-6KO mice when compared to wild-type mice. These events were correlated with an increase in the staining (immunoreactivity) for poly (ADP-ribose) polymerase (PARP) in the pancreas of cerulein-treated IL-6WT. The staining for PARP was more pronounced in IL-6KO mice subjected to acute pancreatitis than in the corresponding WT mice. These data demonstrate that endogenous IL-6 exerts an anti-inflammatory role during acute pancreatitis, possibly by regulating the expression of adhesion molecules, the subsequent adhesion and activation of neutrophils and finally the generation of cytokine and reactive oxygen or nitrogen species.
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PMID:Absence of endogenous interleukin-6 enhances the inflammatory response during acute pancreatitis induced by cerulein in mice. 1216 Nov 3

Using a binary co-transfection strategy of Ad/GT Bax and Ad/PGK-GV16, we have succeeded in inducing overexpression of Bax protein in three prostate cell lines (androgen-insensitive DU145 and PC3, and androgen-sensitive LNCaP). The expression of Bax protein by this system was sufficient to induce all three prostate lines to undergo apoptosis. The fact that DU145 cells which have a p53 mutation and are deficient in Bax, responded to this treatment, suggests that this effect is independent of these pathways. Initiation of the cleavage of Caspase-3 (CPP32/Yama/apopain) and PARP (poly (ADP-ribose) polymerase) by the introduction of Bax were confirmed by western blot analysis. Bcl-2 expression is relevant in the progression of prostate cancer and contributes to an androgen, apoptotic-resistant phenotype in the advanced stages. We examined stable Bcl-2 overexpressing DU145, PC3 and LNCaP cell lines as models of advanced prostate cancer. The adenoviral co-transfection system induced Bax protein expression and apoptosis even in these Bcl-2 transfected cell lines. Taken together, our results suggest that this Bax expression system might represent a useful gene therapy strategy when applied to the treatment of prostate cancer and its efficacy would be independent of the Bcl-2 status and androgen sensitivity of these cancers.
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PMID:A recombinant adenovirus expressing wild-type Bax induces apoptosis in prostate cancer cells independently of their Bcl-2 status and androgen sensitivity. 1217 Jul 76

Malignant transformation of cells is associated with changes in gene expression. Gross alterations in chromatin organization may be involved in such gene dysregulation, as well as the involvement of specific transcription factors. Specialized genomic DNA segments that exhibit high affinity to the nuclear matrix in vitro have been designated as matrix/scaffold attachment regions (MARs/SARs). MARs are postulated to anchor chromatin onto the nuclear matrix, thereby organizing genomic DNA into topologically distinct loop domains that are important in replication and transcription. In support of this notion, MARs often colocalize or exist in close proximity to regulatory sequences including enhancers. Base unpairing regions (BURs) are typically 100-150 bp regions within MARs, possess an intrinsic propensity to unwind under negative superhelical strain, and are considered to be hallmark of MARs. To investigate a potential mechanism that could lead to significant alterations in gene expression in cancer cells, this review focuses on a group of chromatin-associated proteins that specifically recognize double stranded BURs. Several important proteins have been identified from cancer cells as BUR-binding proteins, including poly (ADP-ribose) polymerase (PARP-1), Ku autoantigen, SAF-A, HMG-I(Y), nucleolin and p53. Many of these proteins are dramatically upregulated in malignancy of the breast. Increase in the amount of these BUR-binding proteins, some of which are known to interact with each other, may not only provide an architectural core but also recruit functional multi-molecular complexes at the base of chromatin loops to affect multiple distant genes. Experimental strategies by which these proteins can be exploited as carcinoma-specific diagnostic markers and as targets for antineoplastic therapy are discussed.
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PMID:Chromatin (dis)organization and cancer: BUR-binding proteins as biomarkers for cancer. 1218 16

Bile acid-induced apoptosis plays an important role in the pathogenesis of cholestatic liver disease, and its prevention is of therapeutic interest. The effects of betaine were studied on taurolithocholate 3-sulfate (TLCS) and glycochenodeoxycholate (GCDC)-induced apoptosis in rat hepatocytes in vitro and in vivo. Hepatocyte apoptosis, caspase activation, and poly (ADP-ribose) polymerase (PARP) cleavage, which are normally observed in response to both bile acids, were largely prevented after preincubation of hepatocytes with betaine. Betaine uptake was required for this protective effect, which was already observed at betaine concentrations of 1 mmol/L. Betaine did not affect the TLCS-induced membrane trafficking of CD95 and tumor necrosis factor-related apoptosis inducing ligand (TRAIL) receptor 2 to the plasma membrane or the TLCS-induced recruitment of Fas-associated death domain (FADD) and caspase 8 to the CD95 receptor. However, betaine largely prevented cytochrome c release and oxidative stress exerted otherwise by TLCS. Inhibition of caspase 9 strongly blunted TLCS-induced caspase-8 activation. Further betaine did not prevent the TLCS-induced c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (Erk), and p38 mitogen-activated protein kinase (p38(MAPK)) activation or TLCS-induced protein kinase B (PKB) dephosphorylation. The protective betaine effect was insensitive to inhibition of Erks by PD089059, of p38(MAPK) by SB203580, or of phosphatidylinositol 3-kinase (PI3-kinase) by LY294002. Betaine supplementation in the drinking water significantly ameliorated in vivo hepatocyte apoptosis following bile duct ligation. In conclusion, this study identifies betaine as a potent protectant against bile acid-induced apoptosis in vivo and in vitro, and its antiapoptotic action largely resides on an inhibition of the proapoptotic mitochondrial pathway.
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PMID:Prevention of bile acid-induced apoptosis by betaine in rat liver. 1229 30

3-Aminobenzamide (3AB) is an inhibitor of poly (ADP-ribose) polymerase (PARP), an enzyme implicated in the maintenance of genomic integrity, which is activated in response to radiation-induced DNA strand breaks. cDNA macroarray membranes containing 1536 clones were used to characterize the gene expression profiles displayed by mouse BALB/3T3 fibroblasts (A31 cell line) in response to ionizing irradiation alone or in combination with 3AB. A31 cells in exponential growth were pre-treated with 3AB 4mM 1h before gamma-irradiation (4Gy), remaining in culture during 6h until harvesting time. A31 cells treated with 3AB alone presented a down-regulation in genes involved in protein processing and cell cycle control, while an up-regulation of genes involved in apoptosis and related to DNA/RNA synthesis and repair was verified. A31 cells irradiated with 4Gy displayed 41 genes differentially expressed, being detected a down-regulation of genes involved in protein processing and apoptosis, and genes controlling the cell cycle. Concomitantly, another set of genes for protein processing and related to DNA/RNA synthesis and repair were found to be up-regulated. A positive or negative interaction effect between 3AB and radiation was verified for 29 known genes. While the combined treatment induced a synergistic effect on the expression of LCK proto-oncogene and several genes related to protein synthesis/processing, a negative interaction effect was found for the expression of genes related to cytoskeleton and extracellular matrix assembly (SATB1 and Anexin III), cell cycle control (tyrosine kinase), and genes participating in DNA/RNA synthesis and repair (RNA helicase, FLAP endonuclease-1, DNA-3 glycosylase methyladenine, splicing factor SC35 and Soh1). The present data open the possibility to investigate the direct participation of specific genes, or gene products acting in concert in the mechanism underlying the cell response to radiation-induced DNA damage under the influence of PARP inhibitor.
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PMID:Differential gene expression in gamma-irradiated BALB/3T3 fibroblasts under the influence of 3-aminobenzamide, an inhibitior of parp enzyme. 1237 59


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