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 biological functions of the tumor suppressor ING1 have been studied extensively in the past few years since it was cloned. It shares many biological functions with p53 and has been reported to mediate growth arrest, senescence, apoptosis, anchorage-dependent growth, chemosensitivity, and DNA repair. Some of these functions, such as cell cycle arrest and apoptosis, have been shown to be dependent on the activity of both ING1 and p53 proteins. Two recent reports by Scott and colleagues demonstrate that p33(ING1) (one of the ING1 isoforms) translocates to the nucleus and binds to PCNA upon UV irradiation. Here we report that p33(ING1) mediates UV-induced cell death in melanoma cells. We found that overexpression of p33(ING1) increased while the introduction of an antisense p33(ING1) plasmid reduced the apoptosis rate in melanoma cells after UVB irradiation. We also demonstrated that enhancement of UV-induced apoptosis by p33(ING1) required the presence of p53. Moreover, we found that p33(ING1) enhanced the expression of endogenous Bax and altered the mitochondrial membrane potential. Taken together, these observations strongly suggest that p33(ING1) cooperates with p53 in UVB-induced apoptosis via the mitochondrial cell death pathway in melanoma cells.
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PMID:p33(ING1) enhances UVB-induced apoptosis in melanoma cells. 1224 54

BAG-1 protein can be expressed as four isoforms of 50, 46, 33 and 29 kDa with different subcellular localizations, which may have different functions in anti-apoptosis, but the exact mechanism remains unclear. We constructed BAG-1 full length and deletion mutated plasmids in a pCR3.1 vector and established stable transfections of BAG-1 isoforms in low BAG-1 expressing C33A cells. Treatment of the transfected cells with cisplatin, staurosporine, paclitaxel and doxorubicine showed that BAG-1 p50, p46 and p33 isoforms enhanced the resistance to apoptosis. BAG-1 p50, p46 and p33 exhibited different degrees of apoptosis inhibition in the transfected cells and BAG-1 p46 isoform had the most pronounced effect on anti-apoptosis. BAG-1 p29 failed to protect the transfected cells from apoptosis. Resistance to apoptosis by BAG-1 isoforms was correlated with decreased caspase-3 activation. We also detected the expression of Bax, Bak, p53, Bcl-2, Bcl-X(L), AIF and MRP1 by Western blots. Bcl-2 protein expression was significantly increased in p50, p46 and p33 transfected cells, while the expression of Bax, Bak, p53, Bcl-X(L) and MRP1 was essentially unchanged. These in vitro results suggest that distinct isoforms of BAG-1 have different anti-apoptotic functions and their functions may be correlated to increased Bcl-2 expression.
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PMID:Distinct BAG-1 isoforms have different anti-apoptotic functions in BAG-1-transfected C33A human cervical carcinoma cell line. 1237 Aug 27

The aim of this study was to characterize molecular alterations of the recently reported candidate tumor suppressor gene, ING1, and to explore the relationship between ING1 and p53 in a well-defined series of adenocarcinomas of the esophagogastric junction (AdEGJ). Polymerase chain reaction (PCR)-based assays were used to characterize ING1 and p53 alterations, relative to histologically normal esophageal mucosa. Two tumors were found to have ING1 mutations: one novel missense mutation (AGC(Ser)-->ATC(Ile)) at codon 147, and one silent mutation (TCG(Ser)-->TCA(Ser)) at codon 173. Reduced expression of the two major alternatively spliced ING1 messenger RNA variants, p47(ING1a) and p33(ING1b) was variable, but was reduced (1.2-10-fold) in 12 of 19 AdEGJs compared to normal esophageal epithelium. No association between p53 and ING1 alterations was apparent. We conclude that reduced ING1 expression is frequently associated with AdEGJ tumorigenesis, further supporting its role as a tumor suppressor gene, and that ING1 expression is independent of p53 status.
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PMID:ING1 and p53 tumor suppressor gene alterations in adenocarcinomas of the esophagogastric junction. 1263 59

Apoptosis has received widespread attention for its essential roles in biology, medicine and cancer. We previously found that normal, human papillomavirus (HPV) 16-immortalized and their transformed endocervical cells were increasingly resistant to apoptosis induced by a cancer therapeutic drug. Here, analogously, another common anticancer drug, 5-fluorouracil, in an ectocervical cell carcinogenesis model induced apoptosis in primary human ectocervical cells (HEC), whereas HPV18-immortalized HEC (HEC-18) and transformed HEC-18 (HEC-18T) were more resistant. Growth in serum/low density lipoprotein (LDL)-containing medium reversed resistance to 5-fluorouracil-induced apoptosis, particularly in HEC-18T. Cell viability results confirmed these findings. Using Western blots to compare protein levels with those of HEC not treated with 5-fluorouracil, the fold changes in HEC-18 and HEC-18T in LDL-free medium were 1.6-6.1-fold lower for pro-apoptotic p53, Bak and Bax. Four anti-apoptotic proteins were altered -2.1 to+14.6-fold for Bcl-2 and BAG-1 isoform p33 and p29. For BAG-1 p50 and p46, HEC-18 were weakly expressed and HEC-18T were moderately higher. Grown in LDL-containing medium, the differences in pro-apoptotic protein levels were mostly reversed. Expression was 1.4-32-fold higher in HEC-18 and HEC-18T of p53, Bax, BAG-1 p29, BAG-1 p33 and total BAG-1. These results showed that HEC carcinogenesis results in resistance to 5-fluorouracil-induced apoptosis, associated with reduced expression during carcinogenesis of pro-apoptotic proteins and increased expression of specific anti-apoptotic proteins.
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PMID:Apoptosis, 5-fluorouracil sensitivity and expression of apoptotic proteins in a human ectocervical cell carcinogenesis model using different media. 1270 50

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

p33ING2 is a novel candidate tumor suppressor, which has been shown to be involved in the regulation of gene transcription, cell cycle arrest, and apoptosis in a p53-dependent manner for maintaining the genomic stability. Previously, we showed that p33ING2 promoted UV-induced apoptosis in human melanoma cells. To further reveal the role of p33ING2 in cellular stress response to UV irradiation, we hypothesized that p33ING2 may enhance the repair of UV-damaged DNA, similarly to its homologue p33(ING1b). Using the host-cell reactivation assay, we show that overexpression of p33ING2 significantly enhances nucleotide excision repair of UV-induced DNA damage in melanoma cells in a p53-dependent manner. Furthermore, DNA repair is completely abolished in cells treated with p33ING2 small interfering RNA, suggesting that a physiologic level of p33ING2 is required for nucleotide excision repair. In addition, we found that p33ING2 is an essential factor for UV-induced rapid histone H4 acetylation, chromatin relaxation, and the recruitment of damage recognition protein, xeroderma pigmentosum group A protein, to the photolesions. These observations suggest that p33ING2 is required for the initial DNA damage sensing and chromatin remodeling in the nucleotide excision repair process.
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PMID:The novel tumor suppressor p33ING2 enhances nucleotide excision repair via inducement of histone H4 acetylation and chromatin relaxation. 1648 87

Many molecules, including several regulators and various target genes, are involved in the biological functions of p53, thus making the p53 pathway rather complicated. However, recent clinical studies have demonstrated that most human cancers have an abnormality in some of the molecules associated with the p53 pathway. Most non-small cell lung cancers (NSCLCs) have either mutations of p53, a reduced p14 alternate reading frame expression, a reduced herpesvirus-associated ubiquitin-specific protease expression or a reduced p33 inhibitor of growth gene1b expression. As a result, the balance of expression of p53 target genes, such as p21, Bax and PUMA, regulates the biological behavior and determines the fate of tumor cells. To date, many studies on cancer gene therapy using these molecules associated with the p53 pathway have been performed to develop new strategies for treating NSCLC patients. Thus, the establishment of a comprehensive and simple evaluation protocol for the p53 pathway is required for clinical use.
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PMID:Clinical significance of the p53 pathway and associated gene therapy in non-small cell lung cancers. 1728 May 5

The tumour suppressor p33(ING1b) ((ING1b) for inhibitor of growth family, member 1b) is important in cellular stress responses, including cell-cycle arrest, apoptosis, chromatin remodelling and DNA repair; however, its degradation pathway is still unknown. Recently, we showed that genotoxic stress induces p33(ING1b) phosphorylation at Ser 126, and abolishment of Ser 126 phosphorylation markedly shortened its half-life. Therefore, we suggest that Ser 126 phosphorylation modulates the interaction of p33(ING1b) with its degradation machinery, stabilizing this protein. Combining the use of inhibitors of the main degradation pathways in the nucleus (proteasome and calpains), partial isolation of the proteasome complex, and in vitro interaction and degradation assays, we set out to determine the degradation mechanism of p33(ING1b). We found that p33(ING1b) is degraded in the 20S proteasome and that NAD(P)H quinone oxidoreductase 1 (NQO1), an oxidoreductase previously shown to modulate the degradation of p53 in the 20S proteasome, inhibits the degradation of p33(ING1b). Furthermore, ultraviolet irradiation induces p33(ING1b) phosphorylation at Ser 126, which, in turn, facilitates its interaction with NQO1.
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PMID:NAD(P)H quinone oxidoreductase 1 inhibits the proteasomal degradation of the tumour suppressor p33(ING1b). 1838 57

Prognosis for patients with glioblastoma multiforme (GBM) is poor. Inhibitors of histone deacetylases (HDACi) like trichostatin A (TSA) are promising alternatives to conventional treatment. Deficient tumor suppressor functions, such as TP53 mutations and p14(ARF)/p16(INK4a) deletions, are characteristic for GBM and can cause resistance to DNA damaging agents such as cisplatin and to HDACi like TSA. The type II tumor suppressor Inhibitor of growth 1 (ING1) is involved in DNA damage response and histone modification. We have previously shown that ING1 is downregulated in GBM and involved in glioma-induced angiogenesis and in cisplatin-induced apoptosis in malignant glioma cells. Hence, the goal of our present study was to investigate whether TSA affects ING1 protein expression and also whether modulating ING1 levels affects TSA-induced apoptosis in malignant glioma cells that contain deficient p53 function and inactive pl4(ARF)/p16(INK4a) signaling. If so, we asked, which apoptotic pathway might be the major mediator beyond this interaction. To test whether ING1 proteins function in TSA-induced apoptosis in GBM, we analyzed TSA effects in LN229 GBM cells, which harbor TP53 mutations and INK4a deletion, following ING1 knockdown by siRNA. Expression of ING1, acetylated core histones H3 and H4, and the proapoptotic proteins caspase 3 and Fas-associated death domain (FADD) was determined by Western blotting. Percentages of apoptotic cells were obtained by flow cytometry. TSA induced the major ING1 isoform p33(ING1b) and increased levels of both histone acetylation and apoptosis in LN229 cells. ING1 knockdown cells revealed marked resistance to TSA-induced apoptosis, impairment of caspase 3 activation, and suppression of FADD. The data suggest that ING1 contributes to TSA-induced apoptosis in GBM cells with deficient p53 and p14(ARF)/p16(INK4a) functions, possibly by regulating FADD/caspase 3 signaling.
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PMID:The inhibitor of growth 1 (ING1) is involved in trichostatin A-induced apoptosis and caspase 3 signaling in p53-deficient glioblastoma cells. 2068 6

Exposure of the telomere overhang acts as a DNA damage signal, and exogenous administration of an 11-base oligonucleotide homologous to the 3'-telomere overhang sequence (T-oligo) mimics the effects of overhang exposure by inducing senescence and cell death in non-small cell lung cancer (NSCLC) cells, but not in normal bronchial epithelial cells. T-oligo-induced decrease in cellular proliferation in NSCLC is likely directed through both p53 and its homolog, p73, with subsequent induction of senescence and expression of senescence-associated proteins, p21, p33(ING), and p27(Kip1) both in vivo and in vitro. Additionally, T-oligo decreases tumor size and inhibits angiogenesis through decreased VEGF signaling and increased TSP-1 expression.
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PMID:Non-small cell lung cancer is susceptible to induction of DNA damage responses and inhibition of angiogenesis by telomere overhang oligonucleotides. 2404 68


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