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Pivot Concepts:
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Target Concepts:
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Query: UNIPROT:P04040 (
Catalase
)
3,577
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Hypoxia-inducible factor 1 (HIF-1) is a heterodimeric basic helix-loop-helix transcription factor composed of HIF-1 alpha and HIF-1 beta that is the central regulator of responses to hypoxia. The specific binding of HIF-1 to the hypoxia-responsive element (HRE) induces the transcription of genes that respond to hypoxic conditions, including vascular endothelial growth factor (VEGF). Here we report that expression of HIF-1 alpha is increased in diverse Epstein-Barr virus (EBV)-infected type II and III cell lines, which express EBV latent membrane protein 1 (LMP1), the principal EBV oncoprotein, as well as other latency proteins, but not in the parental EBV-negative cell lines. We show first that transfection of an LMP1 expression plasmid into Ad-AH cells, an EBV-negative nasopharyngeal epithelial cell line, induces synthesis of HIF-1 alpha protein without increasing its stability or mRNA level. The mitogen-activated protein kinase (MAPK) kinase inhibitor PD98059 markedly reduces induction of HIF-1 alpha by LMP1.
Catalase
, an H(2)O(2) scavenger, strongly suppresses LMP1-induced production of H(2)O(2), which results in a decrease in the expression of HIF-1 alpha induced by LMP1. Inhibition of the NF-kappa B, c-jun N-terminal kinase, p38 MAPK, and phosphatidylinositol 3-kinase pathways did not affect HIF-1 alpha expression. Moreover, LMP1 induces HIF-1 DNA binding activity and upregulates HRE and VEGF promoter transcriptional activity. Finally, LMP1 increases the appearance of VEGF protein in extracellular fluids; induction of VEGF is suppressed by PD98059 or catalase. These results suggest that LMP1 increases HIF-1 activity through induction of HIF-1 alpha protein expression, which is controlled by p42/
p44
MAPK activity and H(2)O(2). The ability of EBV, and specifically its major oncoprotein, LMP1, to induce HIF-1 alpha along with other invasiveness and angiogenic factors reported previously discloses additional oncogenic properties of this tumor virus.
...
PMID:Epstein-Barr virus latent membrane protein 1 induces synthesis of hypoxia-inducible factor 1 alpha. 1516 87
Previous microarray expression analyses have indicated autocrine human growth hormone (hGH) regulation of genes involved in the oxidative stress response. Expression analysis of antioxidant enzymes revealed that autocrine hGH increased both the mRNA and protein levels of catalase, superoxide dismutase 1 (SOD1), glutathione peroxidase and glutamylcysteine synthetase but not that of SOD2. As a consequence, autocrine hGH increased the antioxidant capacity of mammary carcinoma cells and protected against oxidative stress-induced apoptosis.
Catalase
activity was increased by autocrine production of hGH in mammary carcinoma cells and a catalase inhibitor abrogated protection from oxidative stress afforded by autocrine hGH. Autocrine hGH transcriptionally regulated catalase gene expression in a
p44
/42 MAP kinase-dependent manner and inhibition of MEK concordantly abrogated the protective effect of autocrine hGH against oxidative stress-induced apoptosis. Given that increased cellular oxidative stress is a key effector mechanism of specific chemotherapeutic agents, we propose that antagonism of autocrine hGH will improve the efficacy of chemotherapeutic regimes utilized for human mammary carcinoma.
...
PMID:p44/42 MAP kinase-dependent regulation of catalase by autocrine human growth hormone protects human mammary carcinoma cells from oxidative stress-induced apoptosis. 1578 23
Cardiac hypertrophy, a major determinant of morbidity and mortality in hypertrophic cardiomyopathy (HCM), is considered a secondary phenotype and potentially preventable. To test this hypothesis, we screened 30 5- to 6-month-old beta-myosin heavy chain Q403 transgenic rabbits by echocardiography and selected 26 without cardiac hypertrophy. We randomized the transgenic rabbits to treatment with atorvastatin (2.5 mg/Kg/d), known to block hypertrophic signaling or a placebo. We included 15 nontransgenic rabbits as controls. Cardiac phenotype was analyzed serially before, 6 and 12 months after randomization. Serum total cholesterol levels were reduced by 49% with atorvastatin administration. Left-ventricular mass, wall thickness; myocyte size, myocardial levels of molecular markers of hypertrophy, lipid peroxides, and oxidized mitochondrial DNA; and the number of terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL)-positive myocytes were increased significantly in the placebo but not in the atorvastatin group. Myocardium catalase mRNA levels were decreased by 5-fold in the placebo but were normal in the atorvastatin group.
Catalase
protein level and activity were not significantly changed. Levels of membrane-bound Ras and phospho-
p44
/42 mitogen-activated-protein kinase (MAPK) were increased in the placebo group (approximately 2.5 fold) but were reduced in the atorvastatin group. Levels of GTP- and membrane-bound RhoA and Rac1, phospho-p38, and phospho-c-Jun NH2-terminal kinases were unchanged. Thus, atorvastatin prevented development of cardiac hypertrophy; determined at organ, cellular, and molecular levels, partly through reducing active Ras and
p44
/42 MAPK. The results indicate potential beneficial effects of atorvastatin in prevention of cardiac hypertrophy, a major determinant of morbidity in all forms of cardiovascular diseases, and beckon clinical studies in humans with HCM.
...
PMID:Prevention of cardiac hypertrophy by atorvastatin in a transgenic rabbit model of human hypertrophic cardiomyopathy. 1602 Jul 56
Toosendanin (Tsn), a triterpenoid extracted from Melia toosendan Sieb et Zucc, possesses different pharmacological effects in human and important values in agriculture. However, liver injury has been reported when toosendanin or Melia-family plants, which contain toosendanin are applied. The mechanism by which toosendanin induces liver injury remains largely unknown. Here we reported that toosendanin induced primary rat hepatocytes death by mitochondrial dysfunction and caspase activation. Toosendanin led to decrease of mitochondrial membrane potential, fall in intracellular ATP level, release of cytochrome c to cytoplasm, activation of caspase-8, 9, and 3 and ultimately cell death. Level of reactive oxygen species (ROS) was also increased in hepatocytes after incubation with toosendanin.
Catalase
, the H2O2-decomposing enzyme, can prevent the reduction in ATP level and protect hepatocytes from toosendanin-induced death. The ERK1/2 (
p44
/42 MAP kinases) and JNK (c-Jun N-terminal kinase) were activated, but p38 MAPK was not activated by toosendanin. Inhibition of ERK1/2 activation sensitized hepatocytes to death and increased activity of caspase-9 and 3 in response to toosendanin. Inhibition of JNK attenuated toosendanin-induced cell death. These results suggested that toosendanin causes death of primary rat hepatocytes by mitochondrial dysfunction and caspase activation. Generation of ROS and MAP kinases activation might be involved in this process.
...
PMID:Roles of reactive oxygen species and MAP kinases in the primary rat hepatocytes death induced by toosendanin. 1849 25