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 alpha-class mammalian glutathione S-transferases (GSTs) in the protection of many cell types, including vascular smooth muscle cells, against oxidant damage has been demonstrated, but the role of GSTs in the endothelial cell is not well studied. In order to examine the role of GSTs in the endothelial cell, a stable transfection of mouse pancreatic islet endothelial cells (MS1) with cDNA of mGSTA4-4, mouse isozyme of GSTs with activity in vascular wall, was established. Transfected cells demonstrated significantly higher GSTs enzyme activity and expressed significantly increased resistance to the cytotoxicity of allylamine, acrolein, 4-hydroxy-2-nonenal (4-HNE), and H(2)O(2) (P < 0.05). A significantly higher rate of proliferation and lower baseline level of intracellular malondialdehyde (MDA) and 4-HNE were present when compared to wild-type or vector-transfected MS1 endothelial cells (P < 0.05). Transfection protected MS1 endothelial cells from 4-HNE and H(2)O(2) induced apoptosis by inhibiting phosphorylation of c-Jun N-terminal kinases (p-JNK) and consequent activation of p53 and Bax. In early human fibrous atherosclerotic plaques, immunohistochemical studies demonstrated marked induction of hGSTA4-4 in endothelial cells overlying plaque, and in proliferating plaque vascular smooth muscle cells. Our results indicate that endothelial cell mGSTA4-4 can play a key role in protecting blood vessels against oxidative stress and, thus, is likely to be a critical defense mechanism against oxidants that act as atherogens.
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PMID:Glutathione-S-transferase A4-4 modulates oxidative stress in endothelium: possible role in human atherosclerosis. 1506 94

4-Hydroxy-2-trans-nonenal (4-HNE), one of the major end products of lipid peroxidation, has been shown to induce apoptosis in a variety of cell lines. It appears to modulate signaling processes in more than one way because it has been suggested to have a role in signaling for differentiation and proliferation. We show for the first time that incorporation of 4-HNE-metabolizing glutathione S-transferase (GST) isozyme, hGSTA4-4, into adherent cell lines HLE B-3 and CCL-75, by either cDNA transfection or microinjection of active enzyme, leads to their transformation. The dramatic phenotypic changes due to the incorporation of hGSTA4-4 include rounding of cells and anchorage-independent rapid proliferation of immortalized, rounded, and smaller cells. Incorporation of the inactive mutant of hGSTA4-4 (Y212F) in cells by either microinjection or transfection does not cause transformation, suggesting that the activity of hGSTA4-4 toward 4-HNE is required for transformation. This is further confirmed by the fact that mouse and Drosophila GST isozymes (mGSTA4-4 and DmGSTD1-1), which have high activity toward 4-HNE and subsequent depletion of 4-HNE, cause transformation whereas human GST isozymes hGSTP1-1 and hGSTA1-1, with minimal activity toward 4-HNE, do not cause transformation. In cells overexpressing active hGSTA4-4, expression of transforming growth factor beta1, cyclin-dependent kinase 2, protein kinase C betaII and extracellular signal regulated kinase is upregulated, whereas expression of p53 is downregulated. These studies suggest that alterations in 4-HNE homeostasis can profoundly affect cell-cycle signaling events.
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PMID:Transfection with 4-hydroxynonenal-metabolizing glutathione S-transferase isozymes leads to phenotypic transformation and immortalization of adherent cells. 1509 8

The morbidity and mortality experienced by cancer patients is mainly due to the invasion and metastasis of the primary tumor. Recently, a potential metastasis-associated gene and its product, the metastatic tumor antigen 1 (MTA1), were identified; this gene has been found to be overexpressed in a variety of cancers. MTA1 is also known as a potent co-repressor of estrogen receptor element transcription in breast cancer cells. The expression of MTA1 in hepatocellular carcinoma (HCC) and its potential relationship to metastasis and to estrogen receptor alpha (ER-alpha) expression has not been examined, forming the basis for this study. Paraffin sections of 45 HCC specimens, 4 different HCC cell lines, and normal hepatocyte cell line (h NHeps) were immunostained with MTA1 and ER-alpha antibodies. In addition, we examined, by Western blotting, the MTA1 and ER-alpha expression levels in 4 human HCC lines (HepG2 [wild p53], HLE, HLF, and HuH-7 [mutant p53]). MTA1 was overexpressed in HCC cells versus nonmalignant hepatocytes in 31 of 45 HCC specimens (69%). Its expression was predominantly localized to the nucleus or cytoplasm of HCC cells. Nineteen of 20 HCC (95%) specimens with vascular invasion displayed strong MTA1 expression. Overexpression of MTA1 also significantly correlated with large tumor size. The cytoplasmic and nuclear immunoreactivity for ER-alpha was present in HCC specimens in 46% and 12%, respectively. Expression of MTA1 inversely correlated with the nuclear localization of ER-alpha. There was no marked difference in MTA1 and ER-alpha expression levels between HCC cell line expressing wild-type p53 and cell line with mutated p53 HCC. In conclusion, these findings indicate that overexpression of MTA1 is associated with HCC growth and vascular invasion. Nuclear translocation of ER-alpha inversely correlated with MTA1 expression, suggesting negative regulatory mechanisms.
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PMID:Overexpression of metastatic tumor antigen 1 in hepatocellular carcinoma: Relationship to vascular invasion and estrogen receptor-alpha. 1511 22

Lipid peroxidation (LPO) is a cellular process that commonly takes place under normal physiological conditions. Under excessive oxidative stress, the level of LPO becomes very significant, and a growing body of evidence has shown that excessive LPO may be involved in carcinogenesis. Trans-4-hydroxy-2-nonenal (4-HNE) is a major product of LPO, and its level becomes relatively high in cells under oxidative stress. 4-HNE is able to react readily with various cellular components, including DNA and proteins. We previously found that the 4-HNE-DNA adduct is a potent mutagen in human cells and is preferentially formed at codon 249 of the p53 gene, a mutational hotspot in human cancers. To further understand the role of 4-HNE in carcinogenesis, we addressed the question of whether 4-HNE affects DNA repair in human cells. We found that the repair capacity for benzo[a]pyrene diol epoxide and UV light-induced DNA damage was greatly compromised in human cells or human cell extracts treated with 4-HNE, which is mainly through interaction of 4-HNE with cellular repair proteins. We also found that 4-HNE greatly sensitizes cells to benzo[a]pyrene diol epoxide- and UV-induced killing. Together these results strongly suggest that this LPO metabolite damages not only DNA but also DNA repair mechanisms in human cells. We propose that these two detrimental effects of LPO may contribute synergistically to human carcinogenesis.
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PMID:Trans-4-hydroxy-2-nonenal inhibits nucleotide excision repair in human cells: a possible mechanism for lipid peroxidation-induced carcinogenesis. 1518 27

Previously, we have shown that overexpression of 4-hydroxy-2-nonenal (HNE)-detoxifying enzyme glutathione S-transferase A4-4 (hGSTA4-4) in human lens epithelial cells (HLE B-3) leads to pro-carcinogenic phenotypic transformation of these cells [R. Sharma, et al. Eur. J. Biochem. 271 (2004) 1960-1701]. We now demonstrate that hGSTA4-transfection also causes a profound change in the expression of genes involved in cell adhesion, cell cycle control, proliferation, cell growth, and apoptosis, which is consistent with phenotypic changes of the transformed cells. The expression of p53, p21, p16, fibronectin 1, laminin gamma1, connexin 43, Fas, integrin alpha6, TGFalpha, and c-jun was down-regulated, while the expression of protein kinase C beta II (PKCbetaII), c-myc, cyclin-dependent kinase 2 (CDK2), and TGFbeta was up-regulated in transfected cells. These results demonstrate that HNE serves as a crucial signaling molecule and, by modulating the expression of genes, can influence cellular functions.
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PMID:Depletion of 4-hydroxynonenal in hGSTA4-transfected HLE B-3 cells results in profound changes in gene expression. 1600 54

A systemic vitamin K analog, compound 5 (Cpd 5), possesses the ability to inhibit cell growth of tumor cells. Therefore, we investigated the effect of Cpd 5 in human hepatocellular carcinoma (HCC) cell lines and evaluated its role in apoptosis. Human HCC cell lines were cultured and treated with Cpd 5. Apoptosis was assessed using DAPI staining and Annexin-V membrane staining. The expression of caspases, XIAP and Bcl-xL was also investigated. Cpd 5 decreased cell viability in a dose-dependent manner in two HCC cells (HLE and SK-Hep1) containing mutant p53, but not in the HepG2 cell line, which contained wild-type p53. Cpd 5-treated HLE and SK-Hep1 cells showed typical apoptotic features, nuclear condensation and nuclear fragmentation upon DAPI staining. Positive membranous staining for Annexin-V was also seen in these cells. Both caspase-8 and caspase-3 activities were up-regulated slightly. Pro-caspase-8 protein levels decreased slightly in both cells. Although the expression of Bcl-xL was not influenced by Cpd 5, that of XIAP decreased in HLE cells. However, the pan-caspase inhibitor, zVAD, could not significantly prevent Cpd 5-induced apoptosis and Cpd 5 could not augment TRAIL-induced apoptosis. These results demonstrate that Cpd 5 induced apoptosis in human HCC cell lines, mainly independently of caspase activities. This may contribute to its highly potent cytotoxicity toward HCC cells.
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PMID:Vitamin K analog (compound 5) induces apoptosis in human hepatocellular carcinoma independent of the caspase pathway. 1609 31

The 14-3-3 protein family consists of seven isoforms, most of which are expressed abundantly in neurons and glial cells, although the sigma isoform, a p53 target gene originally identified as an epithelium-specific marker, has not been identified in the human central nervous system. Here, we show that human astrocytes in culture expressed 14-3-3sigma under stress conditions. By Western blot, the expression of 14-3-3sigma, p53 and p21 was coordinately upregulated in astrocytes following exposure to hydrogen peroxide, 4-hydroxy-2-nonenal (4-HNE) or etoposide, a topoisomerase II inhibitor. 14-3-3sigma was induced by treatment with 5-aza-2'-deoxycytidine, suggesting a hypermethylated status of the gene promoter in astrocytes. In vivo, a small subset of hypertrophic reactive astrocytes, often showing a multinucleated morphology, expressed 14-3-3sigma in active demyelinating lesions of multiple sclerosis (MS) and ischemic lesions of cerebral infarction, where the expression of 4-HNE and 8-hydroxy-2'-deoxyguanosine was enhanced in reactive astrocytes. Microarray analysis of etoposide-treated astrocytes verified upregulation of p53-responsive genes and concurrent downregulation of mitotic checkpoint-regulatory genes. These observations suggest that 14-3-3sigma might serve as a marker of oxidative and DNA-damaging stresses inducing the mitotic checkpoint dysfunction in reactive astrocytes under pathological conditions.
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PMID:Human astrocytes express 14-3-3 sigma in response to oxidative and DNA-damaging stresses. 1679 59

While interferon-alpha (IFN-alpha) subtypes share a common specific receptor composed of two subunits, interferon-alpha receptor (IFNAR)-1 and IFNAR-2, their subtype activities are exhibited via several intracellular signaling pathways and thus subsequently show different biological effects. Anti-proliferative effects of single treatment with IFN-alpha subtypes or 5-fluorouracil (FU), and of combined treatment with each IFN-alpha subtype and 5-FU were examined on three hepatocellular carcinoma cell lines, HepG2, HLE and PLC/PRF/5. HepG2 and PLC/PRF/5 cells were susceptible to the combination treatment, but HLE cells were not. Proliferation of PLC/PRF/5 cells was also inhibited by the IFN-alpha subtypes singly. In addition, apoptosis was observed in HepG2 cells upon treatment with 5-FU alone and with the combination treatment, and in PLC/PRF/5 cells after single treatment with the IFN-alpha subtypes and after the combination treatment. IFN-alpha subtypes induced cell cycle arrest in the G2/M phase in HepG2 and PLC/PRF/5. Analyses by Western blotting and immunoprecipitation revealed increased p53 phosphorylation in HepG2 and PLC/PRF/5 cells but not in HLE cells after combined treatment. Single treatment with IFN-alpha subtypes promoted p53 activation only in PLC/PRF/5 cells. These results propose that IFN-alpha subtypes induce cells to undergo apoptosis through p53 activation directly and indirectly, in collaboration with 5-FU, further suggesting the presence of distinct signal pathways for IFN-alpha-induced apoptosis.
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PMID:Role of p53 in the inhibitory effects of interferon-alpha subtypes on proliferation of hepatocellular carcinoma cells. 1709 86

Antineoplaston A10 (3-phenylacetylamino-2,6-piperidinedion) is a naturally occurring substance and was the first antineoplaston in the human body to be chemically identified. The effect of antineoplaston A10 on human hepatocellular carcinoma cell lines HepG2 and HLE has been examined. Antineoplaston A10 displayed anti-proliferative action inhibiting cell growth in a dose- and time-dependent manner in vitro as measured by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) and clonogenic assays. Incubation with antineoplaston A10 for 48 h induced apoptotic events such as a typical apoptotic morphology, formation of a characteristic ladder pattern of DNA migration and accumulation of sub-G1 phase cells. Next, hepatoma xenografts in nude mice were employed to study the antitumor effects of antineoplaston A10 in vivo. Oral administration of antineoplaston A10 delayed the growth of HepG2 and HLE cells in the mice without a reduction in body weight. A higher proportion of apoptotic cells in xenografts was observed by means of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining. In addition, the level of expression of apoptotic marker p53 increased while that of anti-apoptotic protein bcl-2 decreased, as evaluated with immunohistochemical staining in the xenografts. These results suggested that antineoplaston A10 may inhibit the growth of human hepatoma cells through the induction of apoptosis.
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PMID:Induction of apoptosis in human hepatocellular carcinoma cells by synthetic antineoplaston A10. 1769 34

To identify positive or negative factors for HIV-1 infectivity, clones from the U937 promonocytic cell line that express similar levels of CD4 and CXCR4, but differ in HIV-1 susceptibility, were compared. In contrast to HIV-1 permissive clone 10 (plus), nonpermissive clone 17 (minus) was adherent to coverslips coated with chemokines, was phagocytic, killed bacteria, and expressed human leukocyte elastase (HLE) in a granule-like compartment (HLEG) that was never detected at the cell surface (HLECS). In contrast to the minus clone, the plus clone expressed HLE on the cell surface and was adherent to coverslips coated with the HLECS ligands alpha1proteinase inhibitor (alpha1PI, alpha1antitrypsin) and the HIV-1 fusion peptide. The phosphorylation status of several important signaling proteins was studied at the single cell level. Tumor suppressor p53, NF-kappaB p65, and Akt were constitutively phosphorylated in the plus clone, but not in the minus clone. Surprisingly, both alpha1PI and LPS induced phosphorylation of NF-kappaB p65 Ser-536 in both clones, but induced dephosphorylation of Ser-529 in the plus clone only. HIV-1 permissivity was conferred to the minus clone in a manner that required stimulation by both alpha1PI and LPS and was coincident to NF-kappaB p65 phosphorylation/dephosphorylation events as well as translocation of HLE to the cell surface. Even when stimulated, the minus clone exhibited greater reverse transcriptase activity, but less p24, than the plus clone. Results presented suggest that HIV-1 uptake and production efficiency are influenced by signaling profiles, receptor distribution, and the phagocytic capacity specific to the stage of differentiation of the CD4+ target cell.
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PMID:NF-kappaB signaling, elastase localization, and phagocytosis differ in HIV-1 permissive and nonpermissive U937 clones. 1809 51


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