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)

Hepatocyte growth factor (HGF) is one of the prospective agents for therapy against a variety of neurologic and neurodegenerative disorders, although the precise mechanisms for the effect of HGF remain to be elucidated. We showed that treatment with HGF protected hippocampal cornu ammonis (CA) subregion 1 neurons from apoptotic cell death after transient forebrain ischemia. Accumulating evidence indicates that ischemia-induced neuronal damage occurs via caspase-independent pathways. In the present study, we focused on the localization of apoptosis-inducing factor (AIF), which is an important protein in the signal-transduction system through caspase-independent pathways, to investigate the possible mechanism for the protective effect of HGF after transient forebrain ischemia. Hepatocyte growth factor attenuated the increase in the expression of AIF protein in the nucleus after transient forebrain ischemia. We further explored the upstream components of AIF translocation. Primary DNA damage induced by Ca(2+) influx and subsequent NO formation are thought to be the initial events for AIF translocation, which results in the subsequent DNA damage by AIF. Hepatocyte growth factor prevented the primary oxidative DNA damage, as was estimated by using anti-8-OHdG (8-hydroxy-2'-deoxyguanosine) antibody. Oxidative DNA damage after ischemia is known to lead to the activation of poly(ADP-ribose) polymerase (PARP) and p53, resulting in AIF translocation. Marked increases in the PAR polymer formation and the expression of p53 protein after ischemia were effectively prevented by HGF treatment. In the present study, we first showed that HGF was capable of preventing neuronal cell death by inhibiting the primary oxidative DNA damage and then preventing the activation of the PARP/p53/AIF pathway.
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PMID:Prevention of apoptosis-inducing factor translocation is a possible mechanism for protective effects of hepatocyte growth factor against neuronal cell death in the hippocampus after transient forebrain ischemia. 1651 2

Maternal diet during pregnancy has been proposed to modify female offspring's later susceptibility to develop breast cancer; however, most of the dietary factors identified thus far have led to increased risk. To identify dietary factors that might reduce offspring's breast cancer risk, pregnant rat dams were fed diets containing 6% fiber originating either from cellulose (control), or oat, whole wheat or defatted flax flour. At birth, dams were switched to the AIN93 semi-purified diet. Mammary tumor incidence and multiplicity, induced by administering the offspring 5 mg 7,12-dimethylbenz[a]anthracene (DMBA) at the age of 50 days, was reduced in the whole wheat flour-exposed offspring and increased in the defatted flax-exposed offspring. To identify the mechanisms mediating the effects of in utero dietary exposures, changes in mammary gland morphology and gene expression were assessed before puberty onset (3 weeks of age) and at the time rats are most susceptible to malignant transformation (8 weeks of age). The number of terminal end buds (TEBs), i.e., the targets of malignant transformation, was reduced in the mammary glands of whole wheat- and oat flour-exposed offspring, as compared to the controls. Further, the number of apoptotic epithelial cells (based on ISOL assay) was elevated in the whole wheat flour offspring, but no changes in cell proliferation (PCNA), estrogen receptor alpha (ER-alpha) or cyclin D1 mRNA or protein levels were seen. The mRNA and/or protein levels of BRCA1 and p53 were significantly increased in the mammary glands of whole wheat flour offspring. Further, the levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of DNA damage, were significantly reduced in these rats, suggesting that maternal dietary exposure to whole wheat during pregnancy may reduce offspring's breast cancer risk by improving DNA damage repair mechanisms.
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PMID:Maternal dietary exposure to fiber during pregnancy and mammary tumorigenesis among rat offspring. 1692 99

Cerebellar hypoplasia in experimental fetal alcohol syndrome (FAS) is associated with impaired insulin-stimulated survival signaling. In vitro studies demonstrated that ethanol inhibition of neuronal survival is mediated by apoptosis and mitochondrial dysfunction. Since insulin and insulin-like growth factors (IGFs) regulate energy metabolism, and ethanol can exert its toxic effects by causing oxidative damage to DNA and proteins, we further characterized the effects of chronic gestational exposure to ethanol on mitochondrial gene expression, and the degree to which ethanol inhibition of mitochondrial function is mediated by impaired insulin/IGF responsiveness. Pregnant Long-Evans rats were fed isocaloric liquid diets containing 0, 2, 4.5, 6.5, or 9.25% v/v ethanol from gestation day 6 through delivery. Cerebella harvested on postnatal day 1 were examined for indices of oxidative stress, and mRNA levels of mitochondrial, pro-oxidant, and pro-apoptosis gene expression. Rat primary cerebellar neuron cultures were used to characterize the effects of ethanol (50 mM for 96 h) on insulin and IGF stimulated mitochondrial function and ATP production. Ethanol-exposed cerebella had significantly reduced mRNA levels of mitochondrial genes encoding Complexes II-A, IV, and V, increased expression of p53 and NADPH oxidase (NOX) 1 and 3, and increased immunoreactivity for 4-hydroxy-2,3-nonenal (HNE) and 8-OHdG in cerebellar granule cells. The activations of p53 and NOX genes were highest in cerebella from pups exposed to the 6.5 or 9.25% ethanol containing diet, whereas the impairments in mitochondrial Complex IV and V expression were similar at low and high levels of ethanol exposure. In vitro experiments confirmed that ethanol treatment reduces neuronal expression of mitochondrial genes encoding Complexes IV and V, impairs mitochondrial function and ATP production, and increases HNE and 8-OHdG immunoreactivity, but they also showed that these effects were not insulin- or IGF-dependent. Together, the results suggest that mitochondrial dysfunction, oxidative stress, and DNA damage in FAS may be largely due to the toxic effects of ethanol rather than specific impairments in insulin or IGF signaling.
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PMID:Chronic ethanol exposure causes mitochondrial dysfunction and oxidative stress in immature central nervous system neurons. 1743 46

In addition to the direct effect of estrogen on mitochondria and the redox cycling of catechol estrogen, estrogen-induced proinflammatory cytokines, such as interleukin-1 beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha), also generate reactive oxygen and nitrogen species (RO/NS). Different cellular signaling pathways may operate in response to varying levels of estrogen-induced RO/NS, leading to genotoxic damage, cell apoptosis, or cell growth. At high levels of RO/NS, cells receiving genotoxic insults, if not repaired, may engage the apoptotic pathways. There is increasing evidence supporting that estrogen-induced alterations in the genome of cells is produced by oxidative attack. Furthermore, ROS generated by estrogen exposure and/or active metabolites of estrogen in combination with receptor-mediated proliferation of genetically damaged cells may be involved in tumor development. This view is supported by the findings of DNA modifications produced in vitro or in vivo by natural and synthetic estrogens in the target organs of cancer both in experimental models and in humans. Interaction of estrogen-induced oxidants and estrogen metabolites with DNA was shown to generate mutations in genes. Cotreatment with an inhibitor of IL-1beta and TNF-alpha synthesis, pentoxifylline, decreased stilbene estrogen-induced levels of myeloperoxidase (MPO), 8-hydroxydeoxyguanosine formation, and gene mutations, and prevented stilbene estrogen-induced lesions. Stable MCF-7 clones overexpressing IL-1beta resulted in a high level of IL-1beta peptide secretion undergoing cell apoptosis, and an elevated level of p53 protein in response to high oxidative stress when compared to nontransfected cells, whereas MCF-7 clones overexpressing IL-1beta that resulted in a moderate level of IL-1beta secretion stimulated the clonal expansion of MCF-7 and TM3 cells. Estrogen-induced MCF-7 cell growth and cyclin D1 expression were suppressed by antioxidants and mitochondrial blockers. These studies support that in addition to ovarian estrogen-mediated ER signaling, mitogenic signals may also come from estrogen-induced RO/NS. Further validation of this concept that the concentration of the RO/NS within the cellular microenvironment determines its stimulatory or inhibitory growth signals as well as its genotoxic effects regulating the growth of estrogen-dependent tumors may result in novel preventive strategies.
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PMID:Estrogen-induced generation of reactive oxygen and nitrogen species, gene damage, and estrogen-dependent cancers. 1762 Feb 1

Ultraviolet radiation is known to cause oxidative DNA damage and is thought to be a major factor implicated in the pathogenesis of pterygium. Among all the photo-oxidative DNA products, the 8-hydroxydeoxyguanosine (8-OHdG) is regarded a sensitive and stable biomarker for evaluating the degree of DNA damage. The protein p53 is a major cell stress regulator that acts to integrate signals from a wide range of cellular stresses. UV radiation has a carcinogenic effect resulting in DNA damaged cells with loss of normal growth control. This assumption is supported by the association between UV-B exposure and activation of survivin, a member of the inhibitor of apoptosis protein family (IAP), highly up-regulated in almost all types of human malignancy. In this study we demonstrate, for the first time in pterygium, the immunohistochemical presence of survivin, and investigate the correlation between survivin, p53 and 8-OHdG. Our results demonstrate that oxidative stress could lead to a significant activation of survivin expression, suggesting that this might be an important event in the development of pterygium, inducing and supporting a hyperproliferative condition. Survivin expression in pterygium would counteract UV-B-induced apoptosis and would cooperate with loss of p53. The co-operation between survivin and functional loss of p53 might provide a general mechanism for aberrant inhibition of apoptosis that could be responsible for the development of pterygium and its possible progression to neoplasia.
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PMID:Expression of survivin protein in pterygium and relationship with oxidative DNA damage. 1826 76

Interferon (IFN) is a multifunctional cytokine which works as a suppressor of hepatocarcinogenesis. Pegylated interferon (PEG-IFN) is a modified form of IFN with different pharmacokinetics. We evaluated the anti-tumor effect of PEG-IFN using a rat hepatocarcinogenesis model. Male Fisher Rats were treated using the Solt and Faber model to induce liver cancer. IFN and PEG-IFN were administered from chemical initiation, and pre-neoplastic foci and neoplastic hepatocellular carcinoma (HCC) were examined at 4 and 40 weeks after chemical initiation, respectively. Apoptosis-related molecules such as p53 and Fas-L, proliferating cell nuclear antigen (PCNA), and oxidative stress-related molecules such as 8-hydroxydeoxyguanosine (8-OHdG) and thioredoxin (TRX) were assessed by immunohistochemical analysis and reverse transcriptase-polymerase chain reaction (RT-PCR). The expression of Notch-1, a molecule related to the regenerative and oncogenic processes was also examined. The generation of foci and HCC were significantly suppressed in IFN and PEG-IFN groups compared with the control group. Whereas PCNA and Notch-1 were strongly expressed in the foci and HCC, Fas-L was mainly detected in the surrounding hepatocytes. 8-OHdG and TRX were also detected in the foci. Although PCNA and Notch-1 were down-regulated in IFN- and PEG-IFN-treated groups, Fas-L was up-regulated in those groups. The activation of Notch-1 signaling and the accumulation of oxidative stress in the pre-neoplastic foci might be associated with the progression of HCC in the DEN-induced hepatocarcinogenesis model. The inhibitory effect of the PEG-IFN and IFN on hepatocarcinogenesis was almost the same, and this might be induced by the Fas-related apoptosis in the surrounding tissues.
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PMID:Anti-tumor effect of pegylated interferon in the rat hepatocarcinogenesis model. 1829 37

Mutagenesis is a multistage process. Substitution mutations can be induced by base modified through alteration of pairing property. Mutations of exon 5 and 8 of p53 gene have been found in most arsenicosis patients with precarcinomas and carcinomas, but never in arsenicosis individuals without precarcinomas and carcinomas. This study investigates whether base modification exists in exon 5 and 8 of p53 gene, and explores the dose-effect relationship between damage of exon 5 of p53 gene and urinary arsenic. Concentrations of urinary 8-hydroxydeoxyguanine (8-OHdG) are analyzed to identify the occurrence of DNA damage. The real-time PCR developed by Sikorsky et al. is applied to detect base modification in exon 5 and 8 of p53 gene for apparently healthy participants. Our results show that the mean total arsenic concentrations of two exposed groups from an arsenic plant are significantly elevated compared with the control group, and the damage level of exon 5 of the high-exposed group is significantly higher than that of the control group, but which does not happen in exon 8. The closely correlation between the damage index of exon 5 and urinary organic arsenic concentration are found. Concentration of 8-OHdG of the high-exposed group is significantly higher than that of the control group. These results imply that base modification in exon 5 of p53 gene can be induced by arsenic. In addition, our study suggests that the damage level of exon 5 is a useful biomarker to assess adverse health effect levels caused by chronic exposure to arsenic.
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PMID:Increased damage of exon 5 of p53 gene in workers from an arsenic plant. 1862 Oct 66

Cancer has been suggested to result from interactions between genetic and environmental factors, and certain subgroups in the general population may be at increased risk because of their relatively higher susceptibility to environmental carcinogens. The current study, part of a large biomonitoring study conducted in Flanders from 2002 to 2006 (The Flanders Environment and Health Survey), aims to determine these susceptible subpopulations based on multiple genotypic differences between individuals. A random selection of 429 adolescents and 361 adults was genotyped for 36 polymorphisms in 23 genes selected because of their known role in carcinogen metabolism, DNA repair, and oxidative stress. In both age groups, relationships between endogenous exposure to organochloride substances (polychlorinated biphenyl, hexachlorobenzene, dichlorodiphenyl dichloroethane), metals (cadmium, lead), and urinary metabolites (1-hydroxypyrene, trans-trans muconic acid) versus genotoxic effects (Comet assay and micronuclei in lymphocytes, and urinary 8-hydroxydeoxyguanosine) were investigated. In addition, in the study among adults, the relationship of these exposures with several tumor markers (prostate-specific antigen, carcinoembryonic antigen, and p53) was tested. The impact of the genotype on established exposure-effect relationships was evaluated. Eight exposure-effect relationships were found, including three novel associations, with an impact of various genotypes, predominantly affecting biotransformation and oxidative stress response. This study shows that at least part of the interindividual differences in relationships between carcinogen exposure and genotoxic effect can be explained by genotypic differences, enabling the identification of more susceptible subgroups for environmental cancer risks. This may be of relevance for environmental health policy setting.
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PMID:Multiplex genotyping as a biomarker for susceptibility to carcinogenic exposure in the FLEHS biomonitoring study. 1870 79

The present study was undertaken to examine whether lycopene is able to counteract 7-ketocholesterol (7-KC)-induced oxidative stress and apoptosis in human macrophages. Human THP-1 macrophages were exposed to 7-KC (10-25 microM) alone and in combination with lycopene (0.5-2 microM), and we monitored changes in cell oxidative status [reactive oxygen species (ROS) production, NOX-4, hsp70 and hsp90 expressions, 8-OHdG formation] and in cell proliferation and apoptosis. After 24 h of treatment, lycopene significantly reduced the increase in ROS production and in 8-OHdG formation induced by the oxysterol in a dose-dependent manner. Moreover, the carotenoid strongly prevented the increase of NOX-4, hsp70 and hsp90 expressions as well as the phosphorylation of the redox-sensitive p38, JNK and ERK1/2 induced by the oxysterol. The attenuation of 7-KC-induced oxidative stress by lycopene coincided with a normalization of cell growth in human macrophages. Lycopene prevented the arrest in G0/G1 phase of cell cycle induced by the oxysterol and counteracted the increased expression of p53 and p21. Concomitantly, it inhibited 7-KC-induced apoptosis, by limiting caspase-3 activation and the modulatory effects of 7-KC on AKT, Bcl-2, Bcl-xL and Bax. Comparing the effects of lycopene, beta-carotene and (5Z)-lycopene on ROS production, cell growth and apoptosis show that lycopene and its isomer were more effective than beta-carotene in counteracting the dangerous effects of 7-KC in human macrophages. Our study suggests that lycopene may act as a potential antiatherogenic agent by preventing 7-KC-induced oxidative stress and apoptosis in human macrophages.
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PMID:Lycopene prevents 7-ketocholesterol-induced oxidative stress, cell cycle arrest and apoptosis in human macrophages. 1915 29

Irradiation with ultraviolet-A (UVA) ray at doses of 20-100 J/cm(2) diminished the cell viability of human keratinocytes HaCaT and human melanoma cells HMV-II, both of which were protected by pre-irradiational administration with the ascorbic acid (Asc) derivative, VC-IP (2,3,5,6-O-tetra-2'-hexyldecanoyl-L-ascorbic acid; vitamin C-isopalmityl tetraester), which is the first lipoidic-liquiform pro-vitamin C by itself that is materialized by esterization of all four intramolecular hydroxyl groups of an Asc molecule with branched chain fatty groups, resulting in molecular fluidity higher than that of the corresponding straight chains. Irradiation with UVA to HaCaT keratinocytes was shown to cause the formation of 8-hydroxydeoxyguanosine (8-OHdG), translocation of phosphatidylserine in the inner layer into the outer layer of cell membrane, and lowering of a mitochondrial membrane potential, all of which were repressed by pre-irradiational administration with VC-IP. Expression of p53 gene, another hallmark of UV-induced DNA damages, was promoted by UVA irradiation to the keratinocytes but also repressed by VC-IP. Administration with VC-IP of 10-50 microM to human fibroblasts NHDF achieved the enhancement of collagen synthesis, repression of matrix metalloprotease-2/9 activity, and increasing of intracellular Asc contents more markedly than that with Asc itself of the same concentrations. Thus UVA-induced diverse harmful effects could be prevented by VC-IP, which was suggested to ensue intrinsically from the persistent enrichment of intracellular Asc, through esterolytic conversion of VC-IP to a free-form Asc molecule, resulting in relief to UVA-caused oxidative stress.
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PMID:Cytoprotective effects of the lipoidic-liquiform pro-vitamin C tetra-isopalmitoyl-ascorbate (VC-IP) against ultraviolet-A ray-induced injuries in human skin cells together with collagen retention, MMP inhibition and p53 gene repression. 1916 21


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