Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role of oxidative metabolism in the up-regulation/activation of stress-induciblesignaling pathways as well as induction of micronucleus formation in bystander cells was investigated. By immunoblotting and in situ immunofluorescence, active Cu-Zn superoxide dismutase (SOD) enzyme and active catalase enzyme were shown to inhibit the up-regulation of p21(Waf1) as well as the induction of micronucleus formation in bystander cells from confluent cultures of normal human diploid fibroblasts irradiated with 0.3-3 cGy of alpha-particles. Enzyme activity assays indicated that exogenous SOD became significantly associated with the cells. Reactive oxygen species apparently derived from a flavin-containing oxidase enzyme [presumably an NAD(P)H-oxidase] appeared to be major contributors to the bystander-induced up-regulation of p53 and p21(Waf1) as well as micronucleus formation, as evidenced by the inhibition of these effects with diphenyliodonium. Rapid activation of nuclear factor kappaB, Raf-1, extracellular signal-regulated kinase 1/2, c-Jun NH2-terminal kinase, and p38 mitogen-activated protein kinase and their downstream effectors activator protein 1, ELK-1, p90RSK, and activating transcription factor 2 was also observed in cultures exposed to very low fluences of alpha-particles. Significant attenuation in the activation of these kinases and transcription factors occurred in irradiated cultures treated with either SOD or catalase. Overall, these results support the hypothesis that superoxide and hydrogen peroxide produced by flavin-containing oxidase enzymes mediate the activation of several stress-inducible signaling pathways as well as micronucleus formation in bystander cells from cultures of human cells exposed to low fluences of alpha-particles.
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PMID:Oxidative metabolism modulates signal transduction and micronucleus formation in bystander cells from alpha-particle-irradiated normal human fibroblast cultures. 1235 50

Neurotoxic properties of L-dopa and dopamine (DA)-related compounds were assessed in human neuroblastoma SH-SY5Y cells with reference to their structural relationship. L-Dopa and its metabolites containing two free hydroxyl residues on their benzene ring showed toxicity in the cell, which was prevented by superoxide dismutase (SOD) and reduced glutathione (GSH), but not by catalase. Furthermore, a synthetic derivative of DA, 3-hydroxy-4-methoxyphenethylamine (HMPE) containing methoxy residue at position 4 in the benzene ring, exerted partial cytotoxicity, which was not prevented by SOD, GSH or catalase. However, the metabolites containing methoxy residue at position 3 failed to show a toxic effect in the SH-SY5Y cells. Moreover, DA induced apoptotic cell death, which was observed by nuclear and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining and measurement of caspase-3 activity; this compound up-regulated apoptotic factor p53 while down-regulating anti-apoptotic factor Bcl-2. In the cell-free in vitro electron spin resonance (ESR) spectrometry, DA possessing two hydroxyl groups showed generation of DA-semiquinone radicals, which were markedly prevented by addition of SOD or GSH but not by catalase. On the other hand, methylation of one of the hydroxyl residues on the benzene ring of DA converted DA to an unoxidizable compound (3-MT or HMPE), and caused it to lose the property to produce semiquinone radicals. It has been previously reported that SOD acting as a superoxide:semiquinone oxidoreductase prevents quinone formation, and that reduced GSH through forming a complex with DA-quinone prevents quinone binding to the thiol group of the intact protein. Therefore, the present results suggest that DA and its metabolites containing two hydroxyl residues exert cytotoxicity mainly due to generation of highly reactive quinones.
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PMID:Apoptosis-inducing neurotoxicity of dopamine and its metabolites via reactive quinone generation in neuroblastoma cells. 1249 14

Advances of molecular biology have provided a great variety of new approaches to research on human disorders. This article gives an outline of molecular biological approaches to analysis of neurological disorders such as giant cell glioblastoma (GGBM) and amyotrophic lateral sclerosis (ALS), and their respective animal models: p53 knockout mice for GGBM and mutant superoxide dismutase-1 transgenic mice for ALS. Genomic DNA extracted from fresh-frozen tissue is examined by Southern blotting for screening mutations in a certain gene. Polymerase chain reaction (PCR) products of a gene in genomic DNA are examined by single-stranded conformation polymorphism, sequencing and agarose gel electrophoresis for identifying mutations, and for preparing and evaluating DNA probes used in Southern blotting and DNA in situ hybridization (ISH). Total RNA from tissue is examined by northern blotting for quantifying and verifying a certain mRNA. Reverse transcription-PCR products of a certain mRNA in total RNA are examined by sequencing and agarose gel electrophoresis for preparing and evaluating cDNA probes used in northern blotting and mRNA ISH. Tissue total protein is immunoblotted for quantifying and verifying a certain protein, and for evaluating the specificity of antibodies used in western blotting and immunohistochemistry. Immunoprecipitates are immunoblotted for evaluating a profile of protein or other substances. Enzyme-linked immunosorbent assay is used for measuring tissue concentration of protein or other substances, and for determining titers of specific antibodies. By these procedures, chronological analysis of animal models for human diseases contribute to elucidating pathogenic mechanisms and exploiting new therapies. Noticing both the similarity and difference between human and animal disorders will help understand the nature of disease.
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PMID:Molecular biological approaches to neurological disorders including knockout and transgenic mouse models. 1256 75

Antigenic stimuli increase ROS that influence T-cell activation by interfering with the oxidant-antioxidant balance. Oxidative stress takes place when excess of ROS production is not counterbalanced by antioxidant mechanisms and bcl-2 gene product that inhibits apoptosis by interacting with mitochondrial superoxide dismutase. ROS Excess induces apoptosis both by activation of NF-kB-dependent genes and DNA damage. The latter has been shown to elicit the activation of poly-ADP-ribose transferase and the accumulation of p53, thus determining apoptosis. Additionally, oxidative stress may induce formation of cell membrane oxidized lipids, potent inducers of apoptosis. Oxidative stress is also involved in immune diseases. In AIDS, ROS excess and deficiency of antioxidants lead to apoptosis and virus activation. ROS produced at sites of chronic inflammation, have genotoxic effects. As a consequence, abnormalities of the p53 genes might explain the conversion from an inflammatory phase into autonomous progression of rheumatoid arthritis or other chronic inflammatory disorders.
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PMID:Oxidative stress and apoptosis in immune diseases. 1257 15

In this study, inducible nitric oxide synthase (iNOS) expression in a series of 158 human primary brain tumors was analyzed. To gain some insight into the biological significance of iNOS expression in tumor cells, comparative immunohistochemical analyses were employed to characterize the expression of iNOS, superoxide dismutase (SOD) proteins (SOD1 and SOD2), Ki-67 antigen (MIB-1) and p53 protein in these cells. Sixteen (39.0%) of the 41 glioblastoma multiforme (GBM) specimens showed iNOS immunoreactivity. Positive immunoreactions with iNOS were also detected in 2/8 anaplastic astrocytomas, 1/17 astrocytomas, 1/14 medulloblastomas and 1/11 primitive neuroectodermal tumors, but no positive reactions were observed in oligodendrogliomas (0/11), ependymomas (0/5), schwannomas (0/21), meningiomas (0/23) or pituitary adenomas (0/7). The MIB-1 labeling index of GBMs that expressed iNOS was significantly higher than that of GBMs that did not (0.025< P <0.05, Wilcoxon rank-sum test). Unlike iNOS-negative tumors, all iNOS-positive tumors coexpressed SOD1 or SOD2. In particular, there was a significant correlation between iNOS induction and SOD1 expression (P =1.65x10(-10), Fisher's exact test) in GBM specimens. There was no significant relationship between iNOS and p53 protein in any type of primary brain tumor (P >0.05, Fisher's exact test). No significant immunohistochemical reactions with iNOS, MIB-1 or p53 protein were observed in normal brain tissue sections. We conclude that primary brain tumors express iNOS, and that iNOS expression in brain tumor cells may depend, in part, on cellular proliferation potential. Based on the fact that SOD1 scavenges oxidative-stress species originating from large amounts of nitric oxide (NO) produced by iNOS, iNOS-expressing brain tumor cells may protect themselves against NO cytotoxicity by overinducing SOD1.
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PMID:Immunohistochemical expression of inducible nitric oxide synthase (iNOS) in human brain tumors: relationships of iNOS to superoxide dismutase (SOD) proteins (SOD1 and SOD2), Ki-67 antigen (MIB-1) and p53 protein. 1262 86

The mechanisms of injury- and disease-associated apoptosis of neurons within the CNS are not understood. We used a model of cortical injury in rat and mouse to induce retrograde neuronal apoptosis in thalamus. In this animal model, unilateral ablation of the occipital cortex induces apoptosis of corticopetal projection neurons in the dorsal lateral geniculate nucleus (LGN), by 7 days post-lesion, that is p53 modulated and Bax dependent. We tested the hypothesis that this degenerative process is initiated by oxidative stress and early formation of DNA damage and is accompanied by changes in the levels of pro-apoptotic mediators of cell death. Immunoblotting revealed that the protein profiles of Bax, Bak and Bad were different during the progression of neuronal apoptosis in the LGN. Bax underwent a subcellular redistribution by 1 day post-lesion, while Bak increased later. Bad showed an early sustained increase. Cleaved caspase-3 was elevated maximally at 5 and 6 days. Active caspase-3 underwent a subcellular translocation to the nucleus. A dramatic phosphorylation of p53 was detected at 4 days post-lesion. DNA damage was assessed immunocytochemically as hydroxyl radical adducts (8-hydroxy-2-deoxyguanosine) and single-stranded DNA. Both forms of DNA damage accumulated early in target-deprived LGN neurons. Transgenic overexpression of superoxide dismutase-1 provided significant protection against the apoptosis but antioxidant pharmacotreatments with trolox and ascorbate were ineffective. We conclude that overlapping and sequential signaling pathways are involved in the apoptosis of adult brain neurons and that DNA damage generated by superoxide derivatives is an upstream mechanism for p53-regulated, Bax-dependent apoptosis of target-deprived neurons.
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PMID:Early events of target deprivation/axotomy-induced neuronal apoptosis in vivo: oxidative stress, DNA damage, p53 phosphorylation and subcellular redistribution of death proteins. 1264 45

The evidence for a role of apoptosis in the neurodegenerative diseases, Alzheimer's disease (AD), Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS), and in the more acute conditions of cerebral ischemia, traumatic brain injury (TBI), and spinal cord injury (SCI) is reviewed with regard to potential intervention by means of small antiapoptotic molecules. In addition, the available animal models for these diseases are discussed with respect to their relevance for testing small antiapoptotic molecules in the context of what is known about the apoptotic pathways involved in the diseases and the models. The principal issues related to pharmacotherapy by apoptosis inhibition, i.e., functionality of rescued neurons and potential interference with physiologically occurring apoptosis, are pointed out. Finally, the properties of a number of small antiapoptotic molecules currently under clinical investigation are summarized. It is concluded that the evidence for a role of apoptosis at present is more convincing for PD and ALS than for AD. In PD, damage to dopaminergic neurons may occur through oxidative stress and/or mitochondrial impairment and culminate in activation of an apoptotic, presumably p53-dependent cascade; some neurons experiencing energy failure may not be able to complete apoptosis, end up in necrosis and give rise to inflammatory processes. These events are reasonably well reflected in some of the PD animal models, notably those involving 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and rotenone. In sporadic ALS, an involvement of pathways involving p53 and Bcl-2 family members appears possible if not likely, but is not established. The issue is important for the development of antiapoptotic compounds for the treatment of this disease because of differential involvement of p53 in different mutant superoxide dismutase (SOD) mice. Most debated is the role of apoptosis in AD; this implies that little is known about potentially involved pathways. Moreover, there is a lack of suitable animal models for compound evaluation. Apoptosis or related phenomena are likely involved in secondary cell death in cerebral ischemia, TBI, and SCI. Most of the pertinent information comes from animal experiments, which have provided some evidence for prevention of cell death by antiapoptotic treatments, but little for functional benefit. Much remains to be done in this area to explore the potential of antiapoptotic drugs. There is a small number of antiapoptotic compounds in clinical development. With some of them, evidence for maintenance of functionality of the rescued neurons has been obtained in some animal models, and the fact that they made it to phase II studies in patients suggests that interference with physiological apoptosis is not an obligatory problem. The prospect that small antiapoptotic molecules will have an impact on the therapy of neurodegenerative diseases, and perhaps also of ischemia and trauma, is therefore judged cautiously positively.
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PMID:Prospects for antiapoptotic drug therapy of neurodegenerative diseases. 1265 69

The cytotoxic effects of menadione and hydrogen peroxide were examined in two hepatic stellate cell lines derived from normal or cirrhotic rat liver. The cirrhotic fat-storing cells (CFSC) were found more resistant than the normal fat-storing cells (NFSC) to menadione cytotoxicity. No significant differences were observed in hydrogen peroxide toxicity in these two cell lines. Although protein levels and enzymatic activities of catalase, Cu,Zn-SOD, Mn-SOD, and NADPH cytochrome c reductase were similar in these cell lines, 20-fold increases of NAD(P)H:quinone oxidoreductase 1 (NQO1) enzymatic activity and protein levels were detected in CFSC compared to those of NFSC. Gel mobility shift assays and functional analysis using transient transfection experiments indicated the involvement of the electrophile responsive element (EPRE) in the up-regulation of the NQO1 expression. Antibody supershift analysis revealed that, although Nrf2 is a member of the EPRE-binding complex in both NFSC and CFSC, Nrf1 was identified as a part of the protein/DNA complex only in CFSC. Expression of p53 tumor suppressor gene was found in higher levels in CFSC than in NFSC. We conclude that activation of the EPRE-signaling pathway, which up-regulates several phase II genes and affects p53 stabilization, may offer resistance to hepatic stellate cells against oxidative damage during hepatic injury. This resistance may be a part of the activation process of the hepatic stellate cells and could contribute to their increased proliferation and production of extracellular matrix.
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PMID:Involvement of the electrophile responsive element and p53 in the activation of hepatic stellate cells as a response to electrophile menadione. 1272 13

Oxidative damage to DNA is thought to play a significant role in mutagenesis, aging, and cancer. Sensitivity to oxidative DNA damage and DNA repair efficiency were examined using a series of human breast epithelial cell lines-MCF-10A, MCF-10AT, and MCF-10ATG3B-with progressively elevated Ras protein. Breast epithelial cells were treated with H2O2, in the absence and presence of the DNA-repair inhibitors hydroxyurea (HU) and cytosine arabinoside (Ara-C). DNA strand breaks were assessed by the mean olive tail moment (microm) using the alkaline single-cell gel electrophoresis (Comet) assay. In untreated cells, the mean olive tail moment values were 4.3 +/- 0.7, 8.3 +/- 1.1, and 7.1 +/- 0.6 microm in the MCF-10A, MCF-10AT, and MCF-10ATG3B cells, respectively. Five min H2O2 treatment produced concentration-dependent DNA damage, with the MCF-10A cells most susceptible and the tumorigenic MCF-10ATG3B cells the least susceptible. Treatment with 100 microM H2O2 resulted in approximately 17-, 6-, and 4.5-fold increases in mean olive tail moment values in the MCF-10A, MCF-10AT, and MCF-10ATG3B cells, respectively, compared to untreated cells. The HCC1937 tumor cell line responded in a manner comparable to the MCF-10ATG3B cells treated with H2O2, HU/Ara-C pre-treatment resulted in a approximately 1.5-fold increase in olive tail moment values in all three cell lines. Protein levels of antioxidant enzymes, including catalase, copper/zinc superoxide dismutase (Cu/Zn SOD), and manganese SOD (MnSOD) were determined in order to examine a potential mechanism for increased resistance to H2O2-mediated DNA damage. Levels of these enzymes increased progressively, with highest expression in MCF-10ATG3B cells. Increased cellular resistance also coincided with marked decreases in p53 protein levels. These results demonstrate that, in this cell lineage, sensitivity to oxidative DNA damage by H2O2 decreases with tumorigenicity (i.e., MCF-10A vs. MCF-10ATG3B), and show that DNA repair, altered Ras, and p53 expression, or compensatory mechanisms involving elevated antioxidant enzymes are involved in mediating these effects.
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PMID:Oxidative DNA damage and repair in a cell lineage model of human proliferative breast disease (PBD). 1280 49

The mutagenic and carcinogenic potency of betel-nut components is well established. This study was undertaken to determine the genotoxic potency of an aqueous extract of raw betel nut (AEBN) in relation to the endogenous glutathione (GSH) level in mouse bone marrow cells (BMC) and human peripheral blood lymphocytes (PBLs), and to find out whether arecoline (ARC), an alkaloid of betel nut, could generate reactive oxygen species (ROS) in these cells. It was observed that AEBN has genotoxic properties, which is further enhanced by depletion of endogenous GSH levels. However, the degree of enhancement varies with the type of parameter and cell system studied. The present data indicate that the generation of ROS by ARC could partially contribute to the induction of chromosomal aberrations (CAs), since the frequency of ARC-induced CAs was reduced either by post-treatment with superoxide dismutase (SOD) or in anoxic conditions. However, the induction of sister chromatid exchanges (SCEs) probably involves p53-dependent changes in cell proliferation and allowing some repair of DNA damage. The extent of damage for each parameter was higher when the mice were exposed to AEBN for 30 days than 5 days. Longer exposure showed higher level of p53 expression in mouse BMC, which could block the damaged cells from proliferation and allow the cells to repair the DNA damage.
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PMID:Genotoxic effect of raw betel-nut extract in relation to endogenous glutathione levels and its mechanism of action in mammalian cells. 1283 49


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