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)

Acute promyelocytic leukemia (APL) represents a biologic and clinically well-defined subtype of acute nonlymphocytic leukemia with specific morphologic and karyotypic characteristics. Although secondary leukemia and myelodysplastic syndromes (MDS) are the most frequent secondary neoplasms following chemotherapy for acute leukemia, their development after complete remission in patients with APL is uncommon. We describe the clinical and genetic features of two APL patients who achieved CR after chemotherapy and all-trans retinoid acid treatment and subsequently developed a MDS. Therapy-related MDS karyotype changes such as abnormalities of chromosomes 5 and 7 were found in the cytogenetic analysis. Since TP53 alteration was detected in one case, possible implications of these findings in the onset of MDS are discussed.
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PMID:Secondary myelodysplastic syndrome after treatment for promyelocytic leukemia: clinical and genetic features of two cases. 1278 55

The response to exposure of all-trans-retinoic acid (RA) during development varies from physiologic to severe teratogenic outcomes and is dependent upon the dose and the stage of development in all species. Effects of RA-mediated teratogenesis may be due to its ability to cause apoptosis. We have recently reported the modulation of p53 in murine stem cells by RA. The aim of this study was to characterize the temporal and spatial pattern of p53 expression in Swiss Webster mouse fetuses following maternal treatment with a single oral dose of 100 mg/kg body weight of RA during organogenesis. RA treatment resulted in a decreased p53 mRNA level in fetuses 24, 48, and 72 h after maternal treatment as detected by semiquantitative reverse transcriptase polymerase chain reaction. Western blot analysis showed a decrease in p53 protein at 24 and 48 h. Immunohistochemistry revealed decreased localization of p53 in the neuroepithelium of fetuses exposed to RA in utero. RA treatment also resulted in decreased nuclear p21 and decreased expression of cytosolic as well as nuclear p27 at 72 h in the fetuses. These results demonstrated that RA-mediated teratogenesis is accompanied by a reduction in the temporal and spatial pattern of p53 gene and protein expression in addition to the disruption of the cell cycle by modulation of p21 and p27.
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PMID:Modulation of p53 after maternal exposure to all-trans-retinoic acid in Swiss Webster mouse fetuses. 1278 18

A cell line, AMOS-III has been established from the surgically resected specimen of an untreated primary human oral squamous cell carcinoma of the floor of mouth from a chronic smokeless tobacco consumer. Immunocytochemical analysis showed epithelial specific antigen, cytokeratins 5, 10, 13 and 16 and integrin alpha(6) markers in AMOS-III cells, confirming the epithelial lineage of the cell line. Analyses of morphology, ultrastructure, karyotype, anchorage independent growth and immunocytochemical properties of the cell line demonstrated the transformed phenotype of epithelial cells. AMOS-III cells have doubling time of 42-44 h. Giemsa-banding patterns of chromosomes confirmed the human origin of the AMOS-III cells. Molecular analysis of cancer-related gene products, p53 and p21(cip1/waf1) showed the presence of wild type p21(cip1/waf1) and truncated p53 proteins. The molecular mechanism underlying the action of retinoids in preventing the occurrence of second primary tumors in oral cancer patients remain to be clearly defined. Treatment of AMOS-III cells with all-trans retinoic acid (ATRA) at 10(-4) microM resulted in 81% cell death. ATRA treatment resulted in enhanced expression of p21(cip1/waf1), nuclear translocation of retinoic acid receptors and apoptotic cell death. Thus, this cell line provides an in vitro model for elucidating the mechanism involving p53 inactivation and p21(cip1/waf1) overexpression in smokeless tobacco-induced oral cancer. Furthermore, the ATRA responsiveness of the cell line underscores its potential utility in identifying the retinoid responsive molecular targets in oral cancer cells.
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PMID:Establishment and characterization of a cell line from smokeless tobacco associated oral squamous cell carcinoma. 1367 4

In this study, we evaluated by reverse transcription-polymerase chain reaction (RT-PCR) the expression pattern of retinoic acid receptors (RAR) alpha, beta, and gamma and cellular retinoic acid binding protein-I (CRBP-I) genes in 12 primary cultures of fibroblasts (F) from orbital tissue of Graves' ophthalmopathy (GO) patients. We also studied the in vitro effects of all-trans retinoic acid (RA) and N-(4-hydroxyphenil)-retinamide (4HPR), a less toxic and better tolerated synthetic derivative of RA, on cell morphology, growth, apoptosis, and cyclic adenosine monophosphate (cAMP) accumulation. All primary cultures expressed RAR alpha, beta, gamma, and CRBP-I. FGO treated with RA and 4HPR (10(-7) mol/L) presented morphologic changes and significantly inhibited cell growth after 72 hours. At 96 hours of drug exposure, apoptosis was detected in 15% and 50% of RA- and 4HPR (10(-7) mol/L)-treated cells, and p53 protein increased in cell lysates. 4HPR induced a 70% decrease of Bcl-2 protein. After 30 minutes of RA and 4HPR (10(-7) mol/L) exposure, a 20% decrease of basal cAMP accumulation was seen, and forskolin cAMP-induced increase was abolished. The expression of RAR alpha, beta, gamma, and CRBP-I in primary cultures of FGO indicates that they are targets for retinoids. Moreover, we show that RA and 4HPR are able to induce morphologic changes, inhibition of cell growth, and apoptosis in FGO exerting their effects through RAR-modulated pathways. The rapid inhibition of cAMP accumulation indicates that a novel nonclassic retinoid pathway may also be involved. Finally, the potent in vitro effects of 4HPR, a retinoid derivative with fewer adverse reactions in vivo, could justify further investigations on a clinical application of retinoids in GO.
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PMID:All-trans retinoic acid- and N-(4-hydroxyphenil)-retinamide-induced growth arrest and apoptosis in orbital fibroblasts in Graves' disease. 1462 95

To study the mechanism of action of BAG-1 in drug-induced apoptosis, we constructed an antisense BAG-1 vector and established a stably transfected cell line from BAG-1-over-expressing HeLa cells. Reduced BAG-1 protein was confirmed by Western blot. Treatment of the antisense BAG-1-transfected cells with the anti-cancer drugs staurosporine, paclitaxel, all-trans retinoic acid (ATRA), and N-(4-hydroxyphenyl) retinamide (4-HPR) resulted in significantly enhanced apoptosis and reduced cell viability relative to vector-transfected cells. While the expression of p53 was increased, the level of Bcl-2 and Bax was decreased. Cells underexpressing BAG-1 had reduced cytosolic cytochrome c level. Treatment with staurosporine and paclitaxel resulted in increased cytochrome c release from mitochondria, whereas there was no change induced by treatment with ATRA and 4-HPR. Our experiments suggest that BAG-1 inhibits anti-cancer drug-induced apoptosis through apoptosis regulation pathways that may involve the mitochondrial Bcl-2/Bax ratio, p53, and differential anti-cancer drug-mediated cytochrome c release.
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PMID:Antisense BAG-1 sensitizes HeLa cells to apoptosis by multiple pathways. 1468 Aug 5

The tumor suppressor gene p53 is a transcription factor that mediates both cell cycle arrest and apoptosis. Interestingly, p53 also induces differentiation of a number of tissues, including leukemic cells. However, although p53-mediated differentiation of leukemic U-937 cells depends on the transcriptional activity of p53, a p53 target gene mediating differentiation has hitherto not been identified. To screen for novel p53 target genes in leukemic cells, a cDNA microarray analysis was performed with U-937-4/ptsp53 cells, expressing a temperature-sensitive p53 mutant. We report that transcription of the Staf50 (stimulated transacting factor of 50 kDa) gene is upregulated in response to wild-type p53 in U-937-4, K562 and MCF-7 cells. Staf50 was directly activated by p53, as determined by the independence of de novo protein synthesis. Moreover, while the proximal promoter of Staf50 was found not to be p53 responsive, a functional enhancer-like p53-response element in intron 1 of the Staf50 gene was identified that was also transactivated by the p53-family member p73. Direct binding of p53 to the response element was shown by electrophoretic mobility shift analysis. Ectopic expression of Staf50 in U-937 cells resulted in reduced clonogenic growth. Moreover, levels of endogenous Staf50 mRNA correlated to all-trans retinoic acid-induced differentiation of promyelocytic NB-4 and HL60 cells, suggesting that Staf50 could be involved in proliferation and/or differentiation of leukemic cells.
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PMID:Staf50 is a novel p53 target gene conferring reduced clonogenic growth of leukemic U-937 cells. 1506 39

Apoptosis is also known as programmed cell death. Apoptosis plays an essential role in maintaining normal tissue and cell physiology in multicellular organisms. Clearance of aberrant or pre-cancerous cells occurs through the induction of apoptosis. It has been reported that many tumors and tumor cell lines have dysfunctional apoptosis signaling, causing these tumors to escape immune monitoring and internal cellular control mechanisms. One potential cause of this dysfunctional apoptosis is the tumor suppressor p53, an important regulator of growth arrest and apoptosis that is mutated in over 50% of all cancers. Retinoids have great potential in the areas of cancer therapy and chemoprevention. While some tumor cells are sensitive to the growth inhibitory effects of natural retinoids such as all-trans-retinoic acid (ATRA), many ovarian tumor cells are not. 6-[3-(1-Admantyl)]-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) and fenretinide N-[4-hydroxyphenyl] retinamide (4-HPR) are conformationally restricted synthetic retinoids that induce growth arrest and apoptosis in both ATRA-sensitive and ATRA-resistant ovarian tumor cell lines. Recently, we have identified the molecular pathways of apoptosis induced by treatment of ovarian carcinoma cells with mutated p53 by CD437 and 4-HPR.
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PMID:Synthetic retinoids as inducers of apoptosis in ovarian carcinoma cell lines. 1509 80

We have previously shown that all-trans-retinoic acid (atRA) induces apoptosis in melanoma cells and primary melanoma cells are more sensitive to the exposure of atRA than the matched metastases. However, mechanisms behind the atRA-induced apoptosis have not been studied. In this study, we used a similar cell culture model system of matched primary and metastatic melanoma cells from the same patient to investigate whether p53 and bcl-2 family proteins were involved in atRA-induced apoptosis. The primary and metastatic melanoma cells were exposed to 0.1 and 10 micro M atRA in serum-free RPMI 1640 cell culture medium in the dark for up to 96 h. The protein expression of p53, p21, bax and bcl-2 were examined by Western blotting and immunocytochemistry. Expression of p53, p21 and bax was increased, and bcl-2 was decreased in melanoma cells after exposure to atRA at different concentrations for various periods of time. The changes of p53, p21, bax, and bcl-2 protein levels were dose- and time-dependent. The primary melanoma cells were more sensitive to the atRA treatments than cells from matched metastatic melanoma. These data indicate that p53, p21, bax and bcl-2 proteins were involved in atRA-induced apoptosis in melanoma cells. Modification of these protein levels in the tumour cells might be beneficial for early treatment of melanoma.
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PMID:Expression profiles of p53, p21, bax and bcl-2 proteins in all-trans-retinoic acid treated primary and metastatic melanoma cells. 1525 26

Retinoids influence growth and differentiation of keratinocytes (KCs) and are widely used for the management of skin diseases and for prevention of nonmelanoma skin cancer (NMSC) in predisposed patients. Here we investigated the effect of all-trans-retinoic acid (ATRA) on KC apoptosis. When KCs were cultured in confluent monolayers for several days, they acquired resistance against UVB-induced apoptosis. In contrast, when the cells were treated with 1 micromol/L ATRA for 6 days and subsequently irradiated with different doses of UVB, they underwent massive apoptosis as assessed by morphology, expression of activated caspase-3, and DNA fragmentation. The same effect was observed when doxorubicin was used instead of UVB. Analysis by real-time PCR and Western blot revealed that ATRA treatment strongly increased the mRNA and protein expression of p53 and caspase-3, -6, -7, and -9, which are key regulators of apoptosis. UVB irradiation of ATRA-treated cells but not of control cells led to the accumulation of p53 protein and of its target gene Noxa. Inhibition of p53 and caspases with alpha-pifithrin and z-Val-Ala-Asp-fluoromethyl ketone, respectively, blocked UVB- and doxorubicin-induced apoptosis in ATRA-treated KCs. Analogous to the observed ATRA effects in monolayer cultures, in vitro-generated organotypic skin cultures reacted with up-regulation of p53 and proapoptotic caspases and displayed increased sensitivity to UVB-induced apoptosis. The ability of retinoic acid to regulate the expression of proapoptotic genes and to sensitize KCs to apoptosis may play a role in their prevention of NMSC in transplant patients and patients with DNA-repair deficiencies.
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PMID:Retinoic acid increases the expression of p53 and proapoptotic caspases and sensitizes keratinocytes to apoptosis: a possible explanation for tumor preventive action of retinoids. 1537 66

Testicular germ cell tumors (TGCTs) arise despite possessing high levels of wild-type p53, suggesting p53 latency. We have previously shown that p53 repression in TGCT-derived human embryonal carcinoma (EC) is relieved upon treatment with all-trans retinoic acid (RA), resulting in enhanced p53 transactivation activity. To further investigate p53 repression in EC, a series of gal4-p53 truncation constructs were generated. Deletion of the core DNA-binding region, residues 117-274, had no effect on basal or RA-induced p53 activity. Progressively, larger truncations were made in the C- or N-terminal direction. Deletion of residues toward the C-terminus of p53 as far as residue 354 did not affect either the basal or RA-inducible activity of gal4-p53. When a small region in the N-terminus was deleted (residues 105-116), relief of the basal repression of p53 activity characteristic of EC was observed. Fusion of this region to the VP16 activation domain (VPAD) resulted in a 10-20-fold repression of VPAD activity in NT2/D1 human EC cells, indicating that this region acts as a heterologous repressor. Owing to its location in the N-terminal half of p53, we have named this region the p53 N-terminal Repression Domain (p53-NRD). The p53-NRD mediated repression in a variety of cell lines, with the most prominent repression observed in human EC cells. While RA alone had no effect on p53-NRD activity, cotreatment with RA and the histone deacetylase inhibitor trichostatin-A (TSA) completely relieved p53-NRD-mediated repression. In contrast, NRD-mediated repression was not sensitive to RA and TSA in a derived RA-resistant cell line with a retinoic acid receptor gamma (RARgamma) defect, but sensitivity could be restored with transfection of RARgamma. These data indicate that a unique repressor domain resides in p53 at residues 90-116 whose activity can be modulated in the presence of 'differentiation therapy' and 'transcription therapy' agents.
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PMID:p53 in human embryonal carcinoma: identification of a transferable, transcriptional repression domain in the N-terminal region of p53. 1567 51


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