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

Ulcerative colitis and Crohn's disease (together known as Inflammatory Bowel Disease or IBD) are both associated with increased risk for colorectal cancer. Although it is conventional to emphasise differences between IBD-associated and sporadic colon cancer, such as a lower rate of Adenomatosis Polyposis Coli mutations and earlier p53 mutations, IBD-associated cancer has a similar dysplasia-cancer sequence to sporadic colon cancer, similar frequencies of major chromosomal abnormalities and of microsatellite instability and similar glycosylation changes. This suggests that IBD-associated colon cancer and sporadic colon cancer might have similar pathogenic mechanisms. Because the normal colon is arguably in a continual state of low-grade inflammation in response to its microbial flora, it is reasonable to suggest that both IBD-associated and sporadic colon cancer may be the consequence of bacteria-induced inflammation. We have speculated that the glycosylation changes might result in recruitment to the mucosa of bacterial and dietary lectins that might otherwise pass harmlessly though the gut lumen. These could then lead to increased inflammation and/or proliferation and thence to ulceration or cancer. The glycosylation changes include increased expression of onco-fetal carbohydrates, such as the galactose-terminated Thomsen-Friedenreich antigen (Gal beta1,3GalNAc alpha-), increased sialylation of terminal structures and reduced sulphation. These changes cannot readily be explained by alterations in glycosyltransferase activity but similar changes can be induced in vitro by alkalinisation of the Golgi lumen. Consequences of these changes may be relevant not only for cell-surface glycoconjugates but also for intracellular glycoconjugates.
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PMID:Altered glycosylation in inflammatory bowel disease: a possible role in cancer development. 1282 Jul 18

Senescence limits cellular proliferation, and therefore might be a mechanism which could suppress the progression of cancer. Herein we show that E2F1, a transcription factor essential to a cell cycle progress and a main target of tumor suppressor Rb, is a critical barrier for the induction of senescence. Human cancer cells transfected with siE2F1 were shown to express replicative senescence markers, in addition to yielding positive results upon SA-beta-Gal staining. Consistent with the notion of the critical role in senescence of E2F1, cells which overexpressed E2F1 proved to be immune to the induction of senescence. Importantly, it appears that E2F1 depletion-induced cancer cell senescence is not reliant on the integrity of either Rb or p53. Our results provide a molecular explanation for the selectivity with which senescence induction occurs, and also provides insights into the possibility of using E2F1 as a therapeutic target in the treatment of cancer.
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PMID:E2F-1 is a critical modulator of cellular senescence in human cancer. 1659 52

Galectin 3 (Gal-3), a member of the beta-galactoside binding lectin family, exhibits antiapoptotic functions, and its aberrant expression is involved in various aspects of tumor progression. Here we show that p53-induced apoptosis is associated with transcriptional repression of Gal-3. Previously, it has been reported that phosphorylation of p53 at Ser46 is important for transcription of proapoptotic genes and induction of apoptosis and that homeodomain-interacting protein kinase 2 (HIPK2) is specifically involved in these functions. We show that HIPK2 cooperates with p53 in Gal-3 repression and that this cooperation requires HIPK2 kinase activity. Gene-specific RNA interference demonstrates that HIPK2 is essential for repression of Gal-3 upon induction of p53-dependent apoptosis. Furthermore, expression of a nonrepressible Gal-3 prevents HIPK2- and p53-induced apoptosis. These results reveal a new apoptotic pathway induced by HIPK2-activated p53 and requiring repression of the antiapoptotic factor Gal-3.
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PMID:Repression of the antiapoptotic molecule galectin-3 by homeodomain-interacting protein kinase 2-activated p53 is required for p53-induced apoptosis. 1673 36

Galectin-3 (Gal-3), a member of a beta-galactoside-binding protein family, is involved in RNA processing and cell cycle regulation through activation of transcription factors when translocated to the nucleus. We have previously shown that Gal-3 can import into the nucleus through at least two pathways; via passive diffusion and/or active transport (Nakahara, S., Oka, N., Wang, Y., Hogan, V., Inohara, H, and Raz, A. (2006) Cancer Res. 66, 9995-10006). Here, we investigated the process mediated by the active nuclear transport of Gal-3 and have identified a nuclear localization signal (NLS)-like motif in its protein sequence, (223)HRVKKL(228), that resembles p53 and c-Myc NLSs ((378)SRHKKL(383), (322)AKRVKL(327)), respectively. Moreover, trimers of enhanced green fluorescence protein (3xGFP) fused with this NLS-like sequence, which is too large to passively diffuse through the nuclear pores, accumulated in the cell nuclei. To gain insights into this newly identified nuclear import mechanism, the interaction between Gal-3 and importins (importins alpha and beta) that carry the NLS harboring nuclear proteins into the nucleus, was investigated. Pull-down assays and bimolecular fluorescence complementation (BiFC) analysis revealed that wild-type Gal-3, but not mutant Gal-3 (R224A), binds to importin-alpha. Down-regulation of importin-beta by RNA interference (RNAi) efficiently abrogates its nuclear accumulation. Furthermore, we provide evidence that impaired nuclear translocation of mutant Gal-3 protein (R224A) results in accelerated degradation compared with the wild-type protein. Thus, these results suggest that Gal-3 is translocated to the nucleus, in part, via the importin-alpha/beta route and that Arg(224) amino acid residue of human Gal-3 is essential for its active nuclear translocation and its molecular stability.
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PMID:Importin-mediated nuclear translocation of galectin-3. 1705 90

The cellular DNA damage response (DDR) entails the activation of ATM, ATR and/or DNA PK protein kinases that causes modifications of proteins including Chk1, Chk2 and 53BP1, aggregation of DDR proteins into foci, and activation of p53. The DDR is thought to be required for initiation and maintenance of cellular senescence. Potentially senescent cells with DNA damage foci occur in large numbers in vivo with many diseases, but, with the exception of mammalian dermis, there is little evidence for that with normal aging. After experimental induction of cellular senescence in the livers of juvenile mice, there was robust expression of DDR markers in hepatocytes at 1 week; however, by 7 weeks, activation of ATM/ATR kinase targets was limited, although cells with DNA damage foci were present. An analysis of hepatocytes of aged, 22-month-old mice, not experimentally exposed to genotoxins, showed limited activation of ATM/ATR targets, though high numbers of cells with DNA damage foci were found, similar to that seen many weeks after artificial senescence induction in young mice. Based on senescence heterochromatin and SA ss Gal assays of the 22-month-old mouse liver, more than 20% of hepatocytes were potentially senescent, though only some components of the DDR were enriched.
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PMID:Modification of the ATM/ATR directed DNA damage response state with aging and long after hepatocyte senescence induction in vivo. 1844 May 96

The unicellular eukaryote Entamoeba histolytica is a human parasite that causes amebic dysentery and liver abscess. A genome-wide analysis of gene expression modulated by intestinal colonization and invasion identified an upregulated transcript that encoded a putative high-mobility-group box (HMGB) protein, EhHMGB1. We tested if EhHMGB1 encoded a functional HMGB protein and determined its role in control of parasite gene expression. Recombinant EhHMGB1 was able to bend DNA in vitro, a characteristic of HMGB proteins. Core conserved residues required for DNA bending activity in other HMGB proteins were demonstrated by mutational analysis to be essential for EhHMGB1 activity. EhHMGB1 was also able to enhance the binding of human p53 to its cognate DNA sequence in vitro, which is expected for an HMGB1 protein. Confocal microscopy, using antibodies against the recombinant protein, confirmed its nuclear localization. Overexpression of EhHMGB1 in HM1:IMSS trophozoites led to modulation of 33 transcripts involved in a variety of cellular functions. Of these, 20 were also modulated at either day 1 or day 29 in the mouse model of intestinal amebiasis. Notably, four transcripts with known roles in virulence, including two encoding Gal/GalNAc lectin light chains, were modulated in response to EhHMGB1 overexpression. We concluded that EhHMGB1 was a bona fide HMGB protein with the capacity to recapitulate part of the modulation of parasite gene expression seen during adaptation to the host intestine.
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PMID:Characterization of an Entamoeba histolytica high-mobility-group box protein induced during intestinal infection. 1865 54

Galectin-3 (Gal-3) is an anti-apoptotic molecule of the beta-galactoside-binding lectin family. Gal-3 is down-regulated by wt-p53 and this repression is required for p53-induced apoptosis. Since poorly differentiated thyroid carcinomas (PDTCs) and anaplastic thyroid carcinomas (ATCs) frequently harbour p53 mutations, we asked whether Gal-3 expression and activity could be influenced by such mutations in these tumours. We found a positive correlation between Gal-3 expression and p53 mutation in human thyroids and in thyroid carcinoma cell lines (TCCLs) harbouring different p53 mutations. Gal-3 was over-expressed in most ATCs and TCCLs, especially those with the most frequently detected p53 mutation (p53(R273H)). Over-expression of p53(R273H) in two p53-null cells (SAOS-2 and SW-1736) as well as in two wt-p53-carrying TCCLs (TPC-1 and K1), stimulated Gal-3 expression, while interference with p53(R273H) endogenous expression in ARO cells down-regulated Gal-3 expression. Conversely, over-expression of wt-p53 in ARO cells restored the inhibitory effect on Gal-3 expression. ARO cells are highly resistant to apoptosis and express both p53 and Gal-3, which are increased upon cisplatin treatment. Interference with Gal-3 expression in these cells stimulated their chemosensitivity. In conclusion, gain-of-function p53 mutant acquires the de novo ability to stimulate Gal-3 expression and to increase chemoresistance in ATCs.
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PMID:Gal-3 is stimulated by gain-of-function p53 mutations and modulates chemoresistance in anaplastic thyroid carcinomas. 1919 18

Induction of cellular senescence by various antitumour agents is a promising strategy of cancer treatment. We assessed the ability of sodium butyrate (NaB), a histone deacetylase inhibitor (HDACi), to reactivate the cellular senescence program in either E1A + cHa-Ras-transformed rat embryo fibroblasts with wild-type p53 (ERas(WT)) and in the isogenic cell line where p53 was inactivated due to expression of the potent genetic suppressor element GSE56 (ERas(GSE56)). NaB treatment increased p53 transcriptional activity and induced an irreversible G1/S cell cycle arrest in ERas(WT), but not in ERas(GSE56) cells. By the transient transfections method using reporter luciferase (p53-LUC) constructions, it was shown that p53-LUC activity as a marker of p53 transactivation function did not increase after X-rays exposure of transformants ERas(GSE56). p53 activity in transformants ERas(WT) increased both after irradiation or upon NaB treatment. Interestingly, the expression of senescence-associated beta-galactosidase (SA-beta-Gal), widely used as a marker of senescence, as well as loss of clonogenic ability, were observed in both cell lines following NaB treatment. Thus, our results suggest that induction of p53 transcription activity could be the key determinant of HDACi-induced cell cycle arrest and senescence in transformed cells and provide an additional evidence of SA-beta-Gal invalidity as a sufficient senescence marker.
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PMID:[Effect of histone deacetylases inhibitor sodium butyrate (NaB) on transformants E1A + cHa-Ras expressing wild type p53 with supressed transactivation function]. 1979 55

Fibroblast growth factor 18 (FGF18) is one of the genes downstream of Wnt, one of the most important signaling pathways activated in colon cancer. An FGF18 promoter containing a single T-cell factor/lymphocyte enhancing factor 1 (TCF/LEF1) binding site was inserted upstream of a thymidine kinase (TK) suicide gene module, while a bacterial beta-Gal (LacZ) element served as the reporter gene. Following transient transfection with pUCFGF18LacZ, beta-Gal staining showed that 5% of SW480, 10% of HCT116, 0% of human umbilical vein endothelial cells (HUVECs) and 0% of normal colon cells (NCCs) had expressed LacZ. beta-Gal enzyme-linked immunosorbent assay revealed that the ratio of pUCFGF18LacZ activity to that of positive control was 0.09 and 0.25 in SW480 and HCT116, respectively (significantly higher than mock plasmid), while there were no significant changes in the beta-Gal expression in HUVEC and NCC cells transfected with pUCFGF18LacZ or mock plasmid. Following transfection with pUCFGF18TK and pUCCMVTK (positive control), cytotoxicity analysis of transfected cells showed that treatment with ganciclovir (GCV) significantly decreased SW480 and HCT116 cell survival at GCV concentrations above 20 microg/mL. An inverse correlation between GCV concentration and cell viability was evident in both colon cancer cell lines following transfection with these suicide plasmids. pUCFGF18TK and pUCCMVTK induced apoptosis after the administration of GCV in HCT116, but not in SW480, as demonstrated by M30 cytodeath antibody. This discrepancy may stem from differences in the mechanisms of TK/GCV-induced apoptosis in p53-proficient (HCT116) and -deficient (SW480) cells. The specific activity of the FGF18 promoter in HCT116 and SW480 may reflect the advantage of this promoter over artificial promoters containing artificial TCF/LEF binding sites.
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PMID:Selective suicide gene therapy of colon cancer cell lines exploiting fibroblast growth factor 18 promoter. 2018 3

The neuropeptide galanin and its receptors are found to be upregulated in brain associated with Alzheimer's disease (AD), while the role of galanin in AD is still unclear. The present study was performed to explore the neuroprotective role of galanin both in vitro and in vivo. Our results demonstrated that galanin inhibited the neurotoxicity induced by amyloid-beta(25-35) (Abeta(25-35)) or Abeta(1-42) in primary cultured hippocampal neurons of rats. Moreover, Gal(2-11) (an agonist of GalR(2/3)) also inhibited the neurotoxicity induced by Abeta(25-35) in the cultured neurons. We further found that galanin inhibited the activation of p53, Bax, and caspase-3 induced by Abeta(25-35) in the cultured hippocampal neurons. Moreover, galanin reversed the down regulation of Bcl-2 induced by Abeta(25-35) in the cultured neurons. Interestingly, in the Morris water maze task we found that intra-CA1 injection of Abeta(25-35)-induced spatial learning deficits in rats were blocked by galanin. In addition, galanin inhibited the Abeta(25-35)-induced dysregulation of p53, Bax, and MAP2 in rat hippocampus. Our results strongly demonstrate that galanin plays neuroprotective roles in nerve cells and in AD-induced learning and memory deficits.
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PMID:Galanin protects amyloid-beta-induced neurotoxicity on primary cultured hippocampal neurons of rats. 2041 91


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