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)

We constructed stable Chinese hamster ovary (CHO) cell lines which conditionally and coordinately express the model product gene secreted alkaline phosphatase (SEAP) and one of the cytostatic genes p21, p27, and p53175P, a p53 mutant deficient in apoptotic but not cell-cycle arrest function. The use of dicistronic expression technology allowed the conditional expression of the model product gene and the cytostatic gene in a coordinated fashion from a single expression unit under the control of the tetracycline-responsive promoter PhCMV-1. Due to the presence of a cytostatic gene in the multicistronic expression unit, the growth behavior of the engineered CHO cell lines could be controlled by the addition or withdrawal of the exogenous agent tetracycline to or from the cell culture medium. Withdrawal of tetracycline resulted in sustained growth arrest of the stable cell lines for a prolonged period. The growth arrest of such cell lines was found to be accompanied by a 10-15-fold increase in their production of SEAP per cell. This controlled proliferation technology allows the design of a novel two-stage production process which consists of a proliferation phase leading to the desired cell density, followed by an extended production phase during which the cells remain growth-arrested and increase cell-specific production of a heterologous protein.
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PMID:Higher productivity of growth-arrested Chinese hamster ovary cells expressing the cyclin-dependent kinase inhibitor p27. 975 59

The effect of phenylbutyrate (PB), a nontoxic differentiation inducer, in human colon carcinoma cell lines treated with 5-fluorodeoxyuridine (FUdR) was evaluated. Two HT-29 human colon carcinoma subclones (U4 well differentiated and U9 poorly differentiated) were equally growth inhibited by 16 h of FUdR (0.2 microM) treatment but recovered cell growth in 3-6 days after the removal of FUdR. PB as a single agent had minimal effect on cell growth, but after FUdR treatment, PB inhibited cell growth for 12 days. The inhibition of cell growth in FUdR-treated cells by PB was more sustained in U4 than U9 cells and was associated with an increased and sustained expression of p21waf1 protein, secretion of transforming growth factor beta1, mediators of p53-dependent or -independent G1 cell cycle arrest, and an increase in the alkaline phosphatase activity as well, considered a marker of differentiation in colon carcinoma cells. These effects of PB were seen only in FUdR-pretreated cells because PB alone had minimal effect on the expression of these genes. The sequential use of FUdR followed by PB in patients with colon carcinoma should be explored because two subclones of HT29, irrespective of their state of differentiation, respond to this clinically achievable regimen.
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PMID:Enhanced growth inhibition and differentiation of fluorodeoxyuridine-treated human colon carcinoma cells by phenylbutyrate. 979 84

The diagnosis of malignancy in peritoneal and pleural effusions can be difficult, because activated mesothelial cells may resemble malignant cells. P53 mutations are the most frequent genetic changes in human cancer and translate into an overexpression of the p53 protein detectable by immunocytochemistry. In this study, we investigated the sensitivity and specificity of 4 different monoclonal antibodies (moAB) against p53 for the diagnosis of malignancy in effusions. We also compared p53 staining with CEA immunocytochemistry which previous work had established as a specific marker of malignancy in body cavity effusions. Normal and malignant cells from 28 benign and 52 malignant effusions (pleura and ascites) were examined by indirect immuno-alkaline phosphatase method. Four different moAB against p53 (PAB 1801, PAB 240, DO-1 and DO-7) and one moAB against CEA (CEA-84) were used. Antibodies p1801, p240 and DO-1 react with 52-75% of cases of effusions with malignant cells, but also with 38-80% of benign effusions. Only the antibody DO-7 and the CEA moAB show specificity for malignant cells reacting respectively with 20 (55%) of cases. A combination of these 2 markers does not enhance the sensitivity for the detection of tumor cells. No direct correlation between CEA and p53 immunostaining could be established. The sensitivity and specificity of staining p53 in malignant cells by immunocytochemistry depend strongly on the antibody used. Some p53 moAB are positive with reactive cells in ascites and pleural effusions. Currently, p53 staining of expressing cells does not improve the identification of malignant cells in comparison with CEA immunocytochemistry, but may help to screen for patients with p53 mutations.
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PMID:P53-immunoreactive cells in benign and malignant effusions: diagnostic value using a panel of monoclonal antibodies and comparison with CEA-staining. 1002 21

Background: Cytomegalovirus (CMV) infection has been shown to be associated with p53 overexpression in coronary artery restenosis. We investigated the occurance of this association in other forms of CMV infection using an automated in situ hybridization (ISH) technique. Methods and Results: We performed ISH for CMV using digoxigenin-labeled or biotinylated probes followed by avidin-alkaline phosphatase and nitroblue tetrazolium color substrate. Immunohistochemistry (IHC) was then performed using an anti-p53 antibody utilizing streptavidin-immunoperoxidase and 3,3;-diaminobenzidine tetrahydrochloride as a chromogen. Sixteen cases with characteristic cytomegalic inclusions from a variety of body sites were examined. All 16 cases were positive for CMV by ISH. Nine of sixteen expressed nuclear p53. Six of these nine cases showed viral cytopathic effect in the cells with p53 expression. In an illustrative case, double colocalized staining for CMV and p53 protein was demonstrated in individual cytopathic cells. When microwave antigen retrieval was necessary, ISH was performed before IHC, and our standard microwaving time was reduced by two-thirds. Conclusions: The colocalization of p53 protein overexpression with CMV within single cells adds further evidence that this overexpression is a viral-induced phenomenon. The combined ISH and IHC assay can be carried out in a rapid automated mode, increasing the ease of investigating relationships between message and protein expression within single cells in a wide variety of settings.
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PMID:Combined In Situ Hybridization and Immunohistochemistry for Automated Detection of Cytomegalovirus and p53. 1046 75

The purpose of this study was to determine whether point mutations and loss of the p53 gene take place in ulcerative colitis which is histologically negative for dysplasia. DNA was extracted from 13 frozen rectal or colon biopsies and blood samples. Ulcerative colitis was classified histologically as active (10 cases) and inactive (3 cases). Exons 5-8 were amplified by PCR, treated with exonuclease and shrimp alkaline phosphatase and sequenced by the dideoxy chain termination method with the Sequenase Version 2.0 DNA sequencing kit. PCR products of intron 6 and exon 4 were digested with MspI and AccII, respectively, for RFLP analysis. No p53 gene mutation was detected in these cases. The number of informative patients for loss of heterozygosity (LOH) at the p53 intron 6 was high, 11 out of 12 (92%), whereas no LOH was observed. LOH affecting p53 exon 4 was not detected in lesions from 5 of 12 patients (42%). In ulcerative colitis, tumor progression is similar to that in sporadic colon cancer, and other oncogenes and tumor suppressor genes are likely to be mutated before the p53 gene.
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PMID:Infrequent p53 gene alterations in ulcerative colitis. 1046 83

The p53-inducible gene product p21(WAF1/CIP1) plays a critical role in regulating the rate of tumor incidence, and identifying mechanisms of its post-translational regulation will define key pathways that link growth control to p21-dependent tumor suppression. A eukaryotic cell model system has been developed to determine whether protein kinase signaling pathways that phosphorylate human p21 exist in vivo and whether such pathways regulate the binding of p21 to one of its key target proteins, proliferating cell nuclear antigen (PCNA). Although human p21 expressed in Sf9 cells is able to form a complex with human PCNA, the inclusion of cell-permeable phosphatase inhibitors renders p21 protein inactive for PCNA binding. The treatment of this inactive isoform of p21 with alkaline phosphatase restores its binding to PCNA, suggesting that p21 expressed in Sf9 cells is subject to reversible phosphorylation at a key regulatory site(s). A biochemical approach was subsequently used to map the phosphorylation sites within p21, whose modification in vitro can inhibit p21-PCNA complex formation, to the C-terminal domain at residues Thr(145) or Ser(146). A phospho-specific antibody was developed that only bound to full-length p21 protein after phosphorylation in vitro at Ser(146), and this reagent was further used to demonstrate that the inactive isoform of p21 recovered from Sf9 cells treated with phosphatase inhibitors had been phosphorylated in vivo at Ser(146). These data identify the first phosphorylation site within the C-terminal regulatory domain of p21 whose modification in vivo modulates p21-PCNA interactions and define a eukaryotic cell model that can be used to study post-translational signaling pathways that regulate p21.
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PMID:Reversible phosphorylation at the C-terminal regulatory domain of p21(Waf1/Cip1) modulates proliferating cell nuclear antigen binding. 1075 73

Vitamin D3 is believed to reduce the risk of colon cancer, and serum levels inversely correlate with colorectal cancer incidence. The active metabolite, 1alpha,25-dihydroxyvitamin D3, has previously been shown to inhibit growth and promote differentiation of colon cancer cells. The vitamin D analogue, EB1089, is currently under clinical trial in a variety of cancers because of its growth-inhibitory effects in vitro and reduced hypercalcemic effects in vivo. The mechanism of growth inhibition by EB1089, however, remained to be determined. In this study we examined the effects of alpha,25-dihydroxyvitamin D3 and EB1089 on five colorectal tumor cell lines (two adenoma and three carcinoma) to determine the mechanism of growth inhibition and to ascertain whether premalignant adenoma cells were responsive to these agents. 1alpha,25-Dihydroxyvitamin D3 and EB1089 induced p53-independent apoptosis in adenoma and carcinoma cell lines in a dose-dependent manner between 10(-10) and 10(-6) M. EB1089, as well as inducing apoptosis, increased the proportion of cells in the G1 phase, particularly in the adenoma cell lines. In two of the three carcinoma cell lines (SW620 and PC/JW), levels of apoptosis induced by EB1089 were similar or greater than those induced by 1alpha,25-dihydroxyvitamin D3. Although the carcinoma cell line HT29 was relatively resistant to apoptosis induced by EB1089 compared with 1alpha,25-dihydroxyvitamin D3, EB1089 markedly inhibited cell yields. These observations offer promise for the clinical use of EB1089. To determine whether the induction of apoptosis by 1alpha,25-dihydroxyvitamin D3 and EB1089 was potentially via a differentiation pathway, alkaline phosphatase activity was measured as a marker of differentiation. Induction of alkaline phosphatase was observed in the floating apoptotic cells as well as in the adherent population. A link between the induction of differentiation and apoptosis by 1alpha,25-dihydroxyvitamin D3 and EB1089 is suggested by the occurrence of apoptosis subsequent to the induction of differentiation. To investigate the molecular pathway to apoptosis induction, members of the Bcl-2 family of proteins were examined (Bcl-2, Bcl-x, Bax, and Bak). Decreased Bcl-2 was observed in some cell lines, particularly in response to EB1089, but was not essential for apoptosis. Levels of the proapoptotic protein Bak, however, were consistently increased in all of the five cell lines in association with apoptosis induced by either agent. The results implicate Bak protein in the induction of apoptosis by 1alpha,25-dihydroxyvitamin D3 or its analogue EB1089. The ability of EB1089 to induce apoptosis in colorectal carcinoma cells suggests that this or other vitamin D analogues may prove clinically effective for the treatment of colorectal cancer. Furthermore, the fact that it induces cell cycle arrest and apoptosis in the premalignant adenoma cells may suggest an application in colorectal cancer chemoprevention.
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PMID:Apoptosis is induced by the active metabolite of vitamin D3 and its analogue EB1089 in colorectal adenoma and carcinoma cells: possible implications for prevention and therapy. 1078 99

The purpose of this study was to analyse the proliferative fraction with the monoclonal antibody M1-R-R to M1-subunit ribonucleotide reductase and with MIB-1 to Ki-67 antigen in relation to p53 protein expression in fine needle aspirates from B-cell non-Hodgkin's lymphomas. One hundred and thirty-seven cases, previously diagnosed and sub-typed according to the Kiel classification and characterized by immunophenotyping, were included in the study. The M-1 subunit ribonucleotide reductase (M1-R-R), Ki-67 and p53 antigens were detected using monoclonal antibodies on stored cytospin preparations. There was a good correlation (r = 0.72) between Ki-67 and M1-R-R positive cell fraction in both high and low grade lymphomas. High-grade lymphomas had a median percentage of M1-R-R/MIB-1 positive cells of 53.0/73.0 for lymphoblastic, 61.0/52.0 for immunoblastic and 33.5/41.0 for centroblastic lymphomas, respectively. In low grade lymphomas figures of median percentage of M1-R-R/MIB-1 were 9.0/15.0 for centroblastic/centrocytic, 11.0/9.5 for chronic lymphocytic leukaemia, 16.0/27.0 for centrocytic and 12.0/9.0 for immunocytomas, respectively. The median percentages of M1-R-R/MIB-1 for high and low grade lymphomas were 37.0/50.5 and 11.0/12.0, respectively. In the p53 positive cases the proliferation rate as measured by staining for M1-R-R and MIB-1 was higher than in p53 negative cases, but the difference was not statistically significant. The results show that cytospin material obtained by fine needle aspiration and stored at -70 degrees C for years can be used reliably for both peroxidase-avidin-biotin and three-step alkaline phosphatase immunocytochemical staining. In addition, proliferation fraction determined by M1-R-R monoclonal antibody staining correlates well with that measured by an established marker for cell proliferation, the Ki-67 antibody. However, the proliferation fraction as measured by the two antibodies differs in the various subtypes of non-Hodgkin's lymphoma which indicates that they may contribute different prognostic information.
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PMID:Analysis of proliferating cell fraction determined by monoclonal antibody to M1-subunit ribonucleotide reductase and Ki-67 in relation to p53 protein expression in fine-needle aspirates from non-Hodgkin's lymphomas. 1101 56

CD44, belongs to the cell adhesion molecule family and is expressed on cell surfaces in several isoforms which are generated by alternative splicing of messenger RNA. These splice variants have been shown in several cancer cell types and are thought to be involved in tumor progression. The aim of the current study was to evaluate the expression of selected CD44 variants on lung cancer cells of various histology and to compare these with other markers of tumor spread. Surgical samples of primary lung carcinoma of various histology were subjected to alkaline phosphatase-anti-alkaline phosphatase complex immunohistochemistry using a panel of monoclonal antibodies: anti-CD44 v5, v6, v7/8, v10, anti-Ki-67, anti-Bcl-2 and anti-p53. Positive cells were scored in a semiquantitative way. The patients were subdivided into groups with and without metastases, as found during surgery. All CD44 variants tested could be demonstrated on lung cancer cells, but the incidence of particular isoforms varied, depending on lung cancer histology. In general, CD44 expression was highest in squamous cell tumors and lowest in anaplastic small cell carcinomas. Squamous cell cancers had high expression of v5 and v6 variants, while in anaplastic large cell and small cell carcinomas v10 was abundant. When Ki-67, Bcl-2 and p53 protein expression was compared to the incidence of CD44 variants, coincidence was found for v10 only. Most of the cases positive for v10 were also Ki-67 positive (p = 0.0146). In 12 cases with metastases, tumor cells had high v6 and Ki-67 expression, but these data were not significant compared to cases without metastases. Overall, these data suggest that v5 and v6 variants are of significance in squamous cell lung carcinoma, presumably in the promotion of metastasis, while in anaplastic small cell or large cell cancers only v10 expression seems to correlate with proteins associated with tumor growth and progression.
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PMID:Isoform expression of CD44 adhesion molecules, Bcl-2, p53 and Ki-67 proteins in lung cancer. 1105 26

It has been shown that the expression of DAN as well as Drm/Gremlin, a member of DAN/Cerberus family, is significantly down-regulated in rodent fibroblasts transformed with various oncogenes and overexpression of DAN results in the phenotypic reversion of the transformed phenotypes. In the present study, we examined the expression levels of DAN, BMP-2, BMP-4, and BMPRs (BMP receptors) in five human cell lines derived from bone and soft tissue tumors. Northern blot analysis revealed that DAN mRNA was detected in OS-KH and RMS-NK cells, but was not detectable in SAOS-2, NOS-1, and ASPS-KY cells. Transient overexpression of DAN in SAOS-2 cells, which lack functional p53 and pRB, resulted in a remarkable growth suppression without the induction of p21(Waf1). Interestingly, overexpression of DAN was associated with a reduction of alkaline phosphatase activity in SAOS-2 cells. Stable transfection of DAN in SAOS-2 cells caused a significant reduction of numbers of drug-resistant colonies, whereas the truncated form of DAN which lacked a possible signal peptide, completely lost this capability. Our results suggest that the secreted form of DAN exerts its growth-suppressive function in SAOS-2 cells in a p53-independent manner.
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PMID:Overexpression of DAN causes a growth suppression in p53-deficient SAOS-2 cells. 1107 49


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