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)

Autosomal recessive juvenile parkinsonism (AR-JP), a common familial form of Parkinson's disease, is caused by mutations of human Parkin. To deepen the understanding of Parkin biology in an in vivo model of Drosophila, we attempted to characterize the function of Drosophila melanogaster Parkin and found that D. melanogaster Parkin exhibited UbcH8-dependent E3 ubiquitin-protein ligase activity. Using E2 binding and in vitro ubiquitination assays, UbcH8 preferentially was found to bind to Parkin mutants harboring functional RING1 domains, but failed to bind to mutants harboring point mutants with complete loss of function. This inability of UbcH8 binding to such mutants was accompanied by abrogation of an E3 ligase activity, indicating that D. melanogaster Parkin as an E3 ligase interacts with UbcH8 through its RING1 domain. An in vivo ubiquitination assay revealed that D. melanogaster Parkin existed in ubiquitinated form in vivo. Moreover, peanut and septin1, D. melanogaster septin proteins, were also ubiquitinated by D. melanogaster Parkin. Co-immunoprecipitation with membrane protein Syntaxin indicated direct binding of septin proteins to syntaxin, implicating their relevance in the exocytosis of dopamine in cells. Western blot analysis and DNA fragmentation indicated that the rate and efficiency of p53-dependent apoptosis were significantly higher in the presence of dopamine than without the septin proteins. Therefore, our findings in the present study demonstrate that Parkin possibly influences septin protein effects on p53-mediated apoptosis, helping to extend the utility of Drosophila as a model system for the study of neurodegeneration.
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PMID:Drosophila melanogaster Parkin ubiquitinates peanut and septin1 as an E3 ubiquitin-protein ligase. 1745 38

We have previously demonstrated that epigenetic silencing of occludin, a tight junction-associated membrane protein, results in the acquisition of apoptotic resistance to various apoptogenic stimuli, causally contributing to the enhanced tumorigenicity of cancer cells. However, it remains to be examined whether occludin expression in transformed cells has an alternative impact that is important for cancer progression. Here we show that forced expression of occludin induces anoikis and promotes oxidative stress-induced premature senescence in breast carcinoma cells, which is accompanied by upregulation of negative cell cycle regulators such as p16(INK4A), p21(Waf1/Cip1) and p27(Kip1) but not p53. The senescent phenotype is reversed by specific inhibition of mitogen-activated protein kinase. Endogenous reexpression of occludin mediated by a synergistic effect with a demethylator and histone deacetylase inhibitor or retinoids that stimulate retinoic acid receptor alpha is also sufficient for provoking the senescent phenotype. In addition, tumors that developed from occludin-expressing cells in mice showed a feature of cellular senescence that has not been described as a consequence of occludin signaling. These findings suggest that the loss of occludin expression is at least partially involved in the senescence-escape program during mammary tumorigenesis.
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PMID:Occludin-mediated premature senescence is a fail-safe mechanism against tumorigenesis in breast carcinoma cells. 1745 53

The Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1), an oncogenic protein, plays an important role in the carcinogenesis of nasopharyngeal carcinoma (NPC). Phosphorylation of p53 protein is likely to play the key role in regulating its activity. p53 protein accumulates but mutation of p53 gene is not common in NPC. The molecular mechanisms of p53 augmentation have not been completely elucidated. Here, the role of MAP kinases in the phosphorylation of p53 modulated by LMP1 was determined. p53 could be activated and phosphorylated clearly at Ser15, Ser20, Ser392, and Thr81 modulated by LMP1. Furthermore, LMP1-induced phosphorylation of p53 at Ser15 was directly by ERKs; at Ser20 and Thr81 by JNK, at Ser 15 and Ser392 by p38 kinase. The phosphorylation of p53 was associated with its transcriptional activity and stability modulated by LMP1. These results strongly suggest that MAP kinases have a direct role in LMP1-induced phosphorylation of p53 at multiple sites, which provide a novel view for us to understand the mechanism of the activation of p53 in the carcinogenesis of nasopharyngeal carcinoma.
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PMID:Latent membrane protein 1 of Epstein-Barr virus regulates p53 phosphorylation through MAP kinases. 1758 79

The aim of study was to investigate the mechanism of N, N'-di-(m-methylphenyl)-3, 6-dimethyl-1, 4-dihydro-1, 2, 4, 5-tetrazine-1, 4-dicarboamide (ZGDHu-1) inducing apoptosis in SHI-1 human leukemia cell line. Different concentrations of ZGDHu-1 and different times of culture were used to treat SHI-1 cells; the apoptosis of SHI-1 cells was analyzed by morphology, DNA agarose gel electrophoresis, DNA content detection, Annexin-V/PI and Hoechst33258 labeling method, the mitochondrial transmembrane potential (Delta Psi m) were measured by dihydrorhodamin 123, and expressions of bcl-2, bax, Fas, p53 and mitochondrial membrane protein were analyzed by flow cytometry, while the bcl-2, bax and p53 gene were analyzed by RT-PCR. The transcriptional level of hTERT-mRNA was measured by real-time fluorescence quantitative RT-PCR. The results showed that after exposure to ZGDHu-1, SHI-1 cells were induced to apoptosis in a time-and does-dependent manner. SHI-1 cell apoptosis was confirmed by typical cell morphology, DNA fragmentation, sub-G(1) phase, Hoechst33258 and Annexin-V/PI labeling etc. The expression of bax, bax/bcl-2, p53 and Fas gene significantly increased and bcl-2 slightly decreased. ZGDHu-1 could increased the expression of mitochondrial membrane protein in a dose-dependent manner while Delta Psi m reduced. The expression of hTERT-mRNA significantly decreased. It is concluded that ZGDHu-1 can up-regulate the expression of p53, bax and bax/bcl-2. The mitochondrial pathway mediated by descent of mitochondrial transmembrane potential may be one of the mechanisms inducing apoptosis by ZGDHu-1, in which Fas gene also participates. Telomerase may be an effective gene target for anti-tumour effect of ZGDHu-1.
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PMID:[ZGDHu-1-inducing apoptosis of SHI-1 leukemia cells and its molecular mechanism]. 1760 50

Previous studies found that kainic acid (KA)-induced apoptosis involved the lysosomal enzyme cathepsin B, suggesting a possible mechanism of autophagy in excitotoxicity. The present study was sought to investigate activation and contribution of autophagy to excitotoxic neuronal injury mediated by KA receptors. The formation of autophagosomes was observed with transmission electron microscope after excitotoxin exposure. The contribution of autophagic mechanisms to KA-induced upregulation of microtubule-associated protein 1A/1B light chain 3 (LC3), lysosome- associated membrane protein 2 (LAMP2) and cathepsin B, release of cytochrome c, activation of caspase-3, down-regulation of Bcl-2, upregulation of Bax, p53, puma and apoptotic death of striatal neurons were assessed with co-administration of the autophagy inhibitor 3-methyladenine (3-MA). These studies showed that KA brought about an increase in the formation of autophagosomes and autolysosomes in the cytoplasm of striatal cells. KA-induced increases in the ratio of LC3-II/LC3-I, LAMP2, cathepsin B, release of cytochrome c and activation of caspase-3 were blocked by pre-treatment with 3-MA. 3-MA also reversed KA-induced down-regulation of Bcl-2 and upregulation of Bax protein levels, LC3, p53 and puma mRNA levels in the striatum. KA-induced internucleosomal DNA fragmentation and loss of striatal neurons were robustly inhibited by 3-MA. These results suggest that over-stimulation of KA receptors can activate autophagy. The autophagic mechanism participates in programmed cell death through regulating the mitochondria-mediated apoptotic pathway.
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PMID:An autophagic mechanism is involved in apoptotic death of rat striatal neurons induced by the non-N-methyl-D-aspartate receptor agonist kainic acid. 1809 25

The Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1) plays an important role in the carcinogenesis of nasopharyngeal carcinoma (NPC). The tumor suppressor p53 is an important transcription factor. The mutation of the p53 gene is the frequent alteration in most of tumors, but nearly 100% wild-type p53 gene is found in NPC biopsy. Here, our study testified that SV40 T-antigen transformed nasopharyngeal epithelial cells contained free, wild-type p53. Moreover, LMP1 regulated p53 both at transcriptional and translational level. Furthermore, the mechanism of p53 accumulation mediated by LMP1 from post-translational level-phosphorylation and ubiquitination were determined. Therefore, the effects of EBV LMP1 on p53 may potentially contribute to EBV-associated pathogenesis.
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PMID:The activation of p53 mediated by Epstein-Barr virus latent membrane protein 1 in SV40 large T-antigen transformed cells. 1824 76

Many studies have shown that the activation of beta-catenin signaling can promote oncogenesis, and it is therefore of interest to find agents that modulate this pathway. Recent work has shown using B lymphoma cells that infection by Epstein-Barr virus (EBV) and expression of its latent membrane protein (LMP)-1, cause increases in the expression of beta-catenin and cellular transformation. Conversely, results from cell-based small molecule screening studies have shown that the antibiotic hexachlorophene can down-regulate beta-catenin in colon cancer cells. Here we report that hexachlorophene also counteracts the elevated beta-catenin levels in EBV-infected B lymphomas. This is associated with restoration in levels of Siah-1 (an E3 ubiquitin ligase that is active in beta-catenin regulation) which had been diminished by LMP-1. Our results suggest that Siah-1 is targeted by both LMP-1 and hexachlorophene with opposite effects. The hexachlorophene modulation of Siah-1 and beta-catenin is independent of p53 and results in reduced expression of cyclin-D1 and c-Myc (target genes of beta-catenin), leading to the growth arrest of B lymphoma cells. From these results we propose that hexachlorophene may provide a novel therapeutic strategy for EBV-infected B lymphoma cells by reducing beta-catenin levels via the restoration of Siah-1.
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PMID:Hexachlorophene suppresses beta-catenin expression by up-regulation of Siah-1 in EBV-infected B lymphoma cells. 1909 60

In this report, we summarized the clinicopathologic features of 5 cases of lymphoepithelioma-like carcinoma of the prostate, a rare variant of prostate cancer characterized by a malignant epithelial component densely infiltrated by lymphoid cells. In all 5 patients, there were obstructive symptoms and elevated prostate-specific antigen; one patient had also hematuria. Their ages ranged from 69 to 82 years (mean age, 76 years). The initial diagnosis of lymphoepithelioma-like carcinoma of the prostate was made on transurethral resection in 3 cases and radical prostatectomy in 2 others. In one case the diagnosis of lymphoepithelioma-like carcinoma admixed with conventional acinar adenocarcinoma was an unexpected finding at time of transurethral resection for benign prostatic hyperplasia. Three patients had clinical stage T3 tumors and another had stage T4 disease; stage T1b was present in the remaining case. Microscopically, all tumors contained lymphoepithelioma-like carcinoma, which comprised 10% to 90% of the entire tumor. All cases were associated with adenocarcinoma, either as the sole pattern in 5 cases or with an additional ductal component in 3 cases. One case had additional features of adenosquamous carcinoma. The lymphoepithelioma-like carcinoma component was characterized by indistinct cytoplasmic borders and a syncytial growth pattern. The stroma was densely infiltrated by lymphoid cells admixed with some plasma cells and neutrophils; one case had a prominent infiltration of eosinophils. Immunohistochemical staining demonstrated that lymphoepithelioma-like carcinoma was positive for prostate-specific antigen, prostate acid phosphatase, alpha-methylacyl coenzyme A racemase, and epithelial membrane antigen; several cytokeratins (AE1/AE3, 7, 8, and 20 [rare cells]) were also immunoreactive. The mean Ki-67 labeling index was 53% (range, 40%-70%), and the p53 expression in all cases was low (10%-20%). The lymphoid component was mainly composed of T with a minor subset of B cells, admixed with some dendritic cells and histiocytes as seen by S100 and CD68 immunoreactivity. Latent membrane protein 1 immunostaining and in situ hybridization for Epstein-Barr virus were negative in all 5 lymphoepithelioma-like carcinoma cases. DNA ploidy of lymphoepithelioma-like carcinoma tumors gave DNA histograms with aneuploid peaks. DNA ploidy of the concurrent adenocarcinoma gave DNA aneuploid peaks except in one DNA diploid case. Four patients died of disease from 8 to 26 months; one patient was lost to follow-up. In summary, lymphoepithelioma-like carcinoma of the prostate arise in aggressive prostate cancers at advanced clinical stage. Morphologic recognition and distinction from other prostatic lesions and tumors with prominent lymphoid stroma is critical for its clinical management.
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PMID:Lymphoepithelioma-like carcinoma of the prostate. 1926 13

Mycotoxins produced by the Fusarium molds can cause a variety of human diseases and economic losses in livestock. Fusaria produce predominantly two types of mycotoxins: the nonestrogenic trichothecenes including T-2 toxin and the mycoestrogens such as zearalenone (ZEN). In a previous report, we demonstrated that the hepatotoxicity of these mycotoxins involves the mitochondrial pathway of apoptosis. Here, we observed that both fusarotoxins induced cell death by a mitochondria-dependent apoptotic process which includes opening of the mitochondrial permeability transition pore complex (PTPC), loss of mitochondrial transmembrane potential, increase in O(2)(.-) production, mitochondrial relocalization of Bax, cytochrome c release, and caspase activation. Studies performed on isolated mouse liver mitochondria showed that both ZEN and T-2 toxin might act directly on mitochondria to induce a PTPC-dependent permeabilization of mitochondrial membranes. Moreover, they may target different members of PTPC. Indeed, although the inner membrane protein adenine nucleotide translocase could be the target of T-2 toxin, ZEN seems to target the outer membrane protein voltage-dependent anion channel. Cells pretreatment with the p53 inhibitor pifithrin-alpha suggested that ZEN but not T-2 toxin triggered a p53-dependent mitochondrial apoptotic pathway. Finally, mitochondrial alterations induced by ZEN and T-2 toxin are mediated by Bcl-2 family proteins, such as Bax, and prevented by Bcl-x(L) and to a lesser extent by Bcl-2. Taken together, these data indicate that mitochondria play a pivotal role in both ZEN- and T-2 toxin-induced apoptosis and that PTPC members and proteins of Bcl-2 family should be interesting targets to overcome fusarotoxin toxicity.
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PMID:Fusarial toxin-induced toxicity in cultured cells and in isolated mitochondria involves PTPC-dependent activation of the mitochondrial pathway of apoptosis. 1954 94

Focal adhesion kinase (FAK) is a 125-kDa non-receptor and non-membrane protein tyrosine. FAK can function with integrins and growth factor receptors to promote cell survival dependent kinase activity and nuclear FAK promotes cell proliferation and survival through FERM (FAK, ezrin, radixin, moesin) domain-enhanced p53 degradation independent kinase activity. Many previous studies have indicated that FAK plays a critical role in the biological processes of normal and cancer cells and FAK has been proposed as a potential target in cancer therapy. Small molecule inhibitors (PF-573,228; PF-562,271 and NVP-226) for use as potential cancer therapies have been developed. However, the detailed mechanism of the role for FAK in tumor cell generation and progression remain unclear, so future work is needed to explore these issues. New inhibitors that can be effectively inhibit the function of FAK still need to be explored due to the low specificity, and resistance.
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PMID:Focal adhesion kinase as potential target for cancer therapy (Review). 1978 9


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