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)

Mechanisms underlying multidrug resistance (MDR), one of the major causes of cancer treatment failure, are still poorly understood. We selected the osteosarcoma MDR HosDXR150 cell line by culturing Hos cells in the presence of increasing doxorubicin doses and showed that it is crossresistant to vinblastine. Similarly to the Hos parental cell line, HosDXR150 cells present mutated p53, functionally inactivated pRb/p105 and wild-type pRb2/p130. Owing to p53 mutation, MDR-1 gene, codifying for P-glycoprotein, is upregulated. Evasion of apoptosis in HosDXR150 cells is only partially explained by drug extrusion because of P-glycoprotein overexpression. Analysis of gene expression level profiles showed that parental cell line undergoes apoptosis through an E2F1/p73-dependent pathway while its resistant variant evades it. This result can be explained by the presence of distinct E2Fs-pRb2/p130 complexes on the p73 promoter. Namely, in Hos p73 transcription is activated by E2F1-Rb2/p130-p300 complexes, while in HosDXR150 it is kept repressed by E2F4-Rb2/p130-HDAC1 complexes.
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PMID:Triggering of p73-dependent apoptosis in osteosarcoma is under the control of E2Fs-pRb2/p130 complexes. 1278 60

Che-1 is a recently identified human RNA polymerase II binding protein involved in the regulation of gene transcription and cell proliferation. We previously demonstrated that Che-1 inhibits the Rb growth-suppressing function by interfering with Rb-mediated HDAC1 recruitment on E2F target gene promoters. By hybridization of cancer profile arrays, we found that Che-1 expression is strongly down-regulated in several tumors, including colon and kidney carcinomas, compared with the relative normal tissues. Consistent with these data, Che-1 overexpression inhibits proliferation of HCT116 and LoVo human colon carcinoma cell lines by activation of the cyclin-dependent kinase inhibitor p21WAF1/Cip1 in a p53-independent manner and by promoting growth arrest at the G1 phase of the cell cycle. Che-1 activates p21WAF1/Cip1 by displacing histone deacetylase (HDAC)1 from the Sp1 binding sites of the p21WAF1/Cip1 gene promoter and accumulating acetylated histone H3 on these sites. Accordingly, Che-1-specific RNA interference negatively affects p21WAF1/Cip1 transactivation and increases cell proliferation in HCT116 cells. Taken together, our results indicate that Che-1 can be considered a general HDAC1 competitor and its down-regulation is involved in colon carcinoma cell proliferation.
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PMID:Che-1 arrests human colon carcinoma cell proliferation by displacing HDAC1 from the p21WAF1/CIP1 promoter. 1284 90

One mechanism by which a cell affords protection from the transforming effects of oncogenes is via the action of the tumor suppressor, ARF, which activates p53 by inactivating Mdm2. Many oncogenes have also been shown to activate the transcription factor NF-kappa B, which can contribute toward the malignant phenotype in many ways, including an ability to antagonize p53. Here we find that ARF inhibits NF-kappa B function and its antiapoptotic activity independent of Mdm2 and p53. ARF represses the transcriptional activation domain of the NF-kappa B family member RelA by inducing its association with the histone deacetylase, HDAC1. Further, we show that the response of NF-kappa B to the oncogene Bcr-Abl is determined by the ARF status of the cell. These results reveal an important function of ARF that can regulate the NF-kappa B response to oncogene activation.
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PMID:p53- and Mdm2-independent repression of NF-kappa B transactivation by the ARF tumor suppressor. 1288 89

The ING family of proteins is involved in the regulation of diverse processes ranging from cell cycle and cellular senescence to apoptosis. These effects are most likely through activation of acetylation-dependent pathways that ultimately alter gene expression. Despite reports linking ING to p53 activation, the molecular basis of how ING activates p53 function has not been elucidated. In this study, we found that a subset of ING family members strongly repressed human alpha-fetoprotein (AFP) promoter activity but stimulated the p21(WAF1) promoter in parallel experiments in the same cell type, similar to the effects of p53. The p47(ING1a) isoform also repressed AFP promoter activity, but in contrast to other ING isoforms, it repressed the p21(WAF1) promoter. p47(ING3) up-regulated p21(WAF1) promoter activity, but it did not have any effect on the AFP promoter. ING1b and ING2 also repressed the AFP promoter in Hep3B p53-null cell lines, and p53 coexpression enhanced this transcriptional repression. Suppression of AFP gene transcription by ING was strongly dependent on AT-motifs that bind to the hepatocyte nuclear factor 1 (HNF1) transcription factor. Indeed, electrophoretic mobility shift assays confirmed that HNF1 binds to AT-motifs, but we found, surprisingly, that the ING1 complexes binding to these AT-motifs were devoid of HNF1 protein. Both ING1 and p53 were able to suppress AFP transcription and cause p21 induction; hSIR2, a negative regulator of the p53 protein, showed the opposite effects on the AFP promoter and, like HDAC1, repressed p21 promoter activity. In addition, we found that p33(ING1b) physically interacts with hSIR2, reverses its ability to induce the AFP promoter, and induces acetylation of p53 residues at Lys(373) and/or Lys(382). These findings provide novel evidence that p33(ING1b) represses AFP transcription by at least two mechanisms, one of which includes p53. The first is by binding to the AT-motif and excluding HNF1 binding while possibly targeting HAT activity to promoter regions, and the second is by increasing the levels of active, acetylated p53 via binding and inhibiting the ability of hSIR2 to deacetylate p53 protein.
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PMID:ING1 represses transcription by direct DNA binding and through effects on p53. 1452

The balance between acetylation and deacetylation of histone and nonhistone proteins controls gene expression in a variety of cellular processes, with transcription being activated by acetyltransferases and silenced by deacetylases. We report here the formation and enzymatic characterization of a complex between the acetyltransferase p300 and histone deacetylases. The C/H3 region of p300 was found to co-purify deacetylase activity from nuclear cell extracts. A prototype of class I histone deacetylases, HDAC1, interacts with p300 C/H3 domain in vitro and in vivo. The p300-binding protein E1A competes with HDAC1 for C/H3 binding; and, like E1A, HDAC1 overexpression interferes with either activation of Gal4p300 fusion protein or p300-dependent co-activation of two C/H3-binding proteins, MyoD and p53. The exposure to deacetylase inhibitors could reverse the dominant-negative effect of a C/H3 fragment insulated from the rest of the molecule, on MyoD- and p53-dependent transcription, whereas inhibition by E1A was resistant to trichostatin A. These data support the hypothesis that association between acetyltransferases and deacetylases can control the expression of genes implicated in cellular growth and differentiation, and suggest that the dominant-negative effect of the p300 C/H3 fragment relies on deacetylase recruitment.
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PMID:Deacetylase recruitment by the C/H3 domain of the acetyltransferase p300. 1496 10

This paper was designed to investigate the expression of p53, p21 of A549 cell strains under hypoxic condition and the effect of trichostatin A (TSA), the inhibitor of histone deacetylasel (HDAC1) on their expression. The authors designed 1 normoxia group (control group) and 6 hypoxia groups (experimental group): hypoxia 6 h group (A), TSA+hypoxia 6 h (B), hypoxia 12 h group (C), hypoxia 24 h group (D), TSA+hypoxia 24 h (E), hypoxia 48 h group (F). The expression of HDAC1 in A549 cells was examined by using Western blot and the expression of p53, p21 in A549 cells and the effect of TSA on them were determined by using immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). The A value expressed by HDAC1 in A549 cell strains was 138+/-11 in the control group, 78+/-4, 86+/-5, 124+/-3, 120+/-9 in experimental groups A, C, D, F, respectively. The A value of the expression of the protein and mRNA of p53 in A549 cell strains were 0.12+/-0.02, 0.62+/-0.02 in the control group, 0.10+/-0.03, 0.32 +/-0.03; 0.11+/-0.01, 0.33+/-0.02; 0.13+/-0.03, 0.58+/-0.01; 0.12+/-0.02, 0.56+/-0.02 in experimental group A, B, D, E, respectively. The A value of the expression of the protein and mRNA of p21 in A549 cell strains were 0.17+/-0.03, 0.62+/-0.03 in the control group, 0.16+/-0.02, 0.50+/-0.02; 0.14+/-0.02, 0.36+/-0.02; 0.15+/-0.03, 0.49+/-0.03; 0.13+/-0.02, 0.33+/-0.02 in experimental groups A, B, D, E, respectively. These results indicate that the expression of HDAC1 is regulated by hypoxia and the effect of TSA is closely related to the expression of P21 under hypoxia condition.
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PMID:Expression of P53, P21 in human lung adenocarcinoma A549 cell strains under hypoxia conditions and the effect of TSA on their expression. 1501 35

Histone deacetylase (HDAC) inhibitors induce an intrinsic type of apoptosis in human papillomavirus (HPV)-positive cells by disrupting the mitochondrial transmembrane potential (deltapsim). Loss of deltapsim was only detected in E7, but not in E6 oncogene-expressing cells. HDAC inhibition led to a time-dependent degradation of the pocket proteins pRb, p107 and p130, releasing 'free' E2F-1 following initial G1 arrest. Inhibition of proteasomal proteolysis, but not of caspase activity rescued pRb from degradation and functionally restored its inhibitory effect on the cyclin E gene, known to be suppressed by pRb-E2F-1 in conjunction with HDAC1. Using siRNA targeted against p53, E2F-1 still triggered apoptosis by inducing the E2F-responsive proapoptotic alpha- and beta-isoforms of p73. These data may determine future therapeutic strategies in which HDAC inhibitors can effectively eliminate HPV-positive cells by an apoptotic route that does not rely on the reactivation of the 'classical' p53 pathway through a preceding shut-off of viral gene expression.
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PMID:HDAC inhibitors trigger apoptosis in HPV-positive cells by inducing the E2F-p73 pathway. 1507 64

Histone deacetylases (HDACs) such as HDAC1 and HSIR2 have been known to be involved in the regulation of life-span extension. However, its underlying mechanism remains unclear in human. Using the primary human gingival fibroblasts (HGFs) derived from donors of different ages, which exhibit clear features of senescence in aged HGFs, we demonstrated that histone deacetylase, HDAC1 and HSIR2, repressed the ageing through the transcriptional inactivation of p53 and p21 promoters. These results suggest that primary HGFs can be a useful human ageing model, and HDAC1, HSIR2, p53 and p21 may play an important role in ageing process of human beings.
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PMID:Histone deacetylases, HDAC1 and HSIR2, act as a negative regulator of ageing through p53 in human gingival fibroblast. 1513 Jul 52

The p53 tumour suppressor exerts anti-proliferative effects, including growth arrest, apoptosis and cell senescence, in response to various types of stress. However, p53 is a short-lived protein and its activity is maintained at low levels in normal cells. Numerous studies indicate that CBP/p300-mediated acetyl-transferase activity is critical for its role in both catalysing p53 acetylation and activating p53-mediated function during stress response. Interestingly, two additional regulators have also been identified in the p53 acetylation pathway. PID/MTA2 is a p53-interacting protein that induces p53 deacetylation by recruiting the HDAC1 complex. Subsequent work has also identified Sir2alpha, a NAD-dependent histone deacetylase that can attenuate p53 transcriptional activity through deacetylation. The prominence of deacetylase activity on p53 certainly raises the defining question of its physiological purpose. It is likely that deacetylation proxides a quick acting mechanism to stop p53 function once transcriptional activation of target genes is no longer needed. We present data indicating that both HDAC1 and Sir2alpha are critical for p53-dependent stress response. Furthermore, we also try to define the functional consequence of p53 acetylation at the molecular level. Finally, we propose a model regarding the differential roles of HDAC1 and Sir2alpha in the regulation of p53 function.
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PMID:Dynamics of the p53 acetylation pathway. 1517 Dec 55

Melanoma cells typically express wild-type p53, yet they are notoriously resistant to DNA-damaging agents. Here, we show that sodium butyrate (NaB), a histone deacetylase (HDAC) inhibitor, induced apoptosis in human melanoma cells in a dose- and time-dependent manner. Apoptosis was associated with HDAC1-dependent induction of Bax and acetylation of p53. Down-regulation of HDAC1 by an antisense vector sensitized the cells to NaB-induced apoptosis, whereas its overexpression conferred resistance to this agent. Increased HDAC1 levels and activity impaired NaB-mediated activation of Bax promoter and Bax protein levels. Finally, using p53-null melanoma cell line and RNA interference in cells expressing wild-type p53 protein, we show that Bax induction and NaB-mediated apoptosis is p53 dependent.
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PMID:Overexpression of histone deacetylase 1 confers resistance to sodium butyrate-mediated apoptosis in melanoma cells through a p53-mediated pathway. 1552 Jan 74


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