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 level of expression of thymidine kinase (TK), heat shock protein 70 (HSP70), beta-tubulin and p53 was assessed in human embryo kidney cells (HEKs) infected with adenovirus type 12 (Ad 12) and Ad 12 early region 1 (E1) mutants. HSP70, beta-tubulin and p53 levels were unchanged but TK activity was dramatically increased following wild-type infection. The initial activation of TK required the expression of the product of the E1A 13S mRNA but sustained expression only occurred with those viruses expressing the E1B proteins as well. A number of human cell lines transformed with either Ad 12 or Ad 5 E1 DNA were also assessed for the level of expression of HSP70, beta-tubulin and p53. Both HSP70 and beta-tubulin levels were greatly increased compared with primary human cells although there was considerable variation between lines. p53 was only expressed at high levels in Ad 12-transformed lines expressing E1A and E1B proteins.
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PMID:Modulation of the level of expression of cellular genes in adenovirus 12-infected and transformed human cells. 352 49

Genetic changes found in human osteogenic sarcoma cells, including loss of the p53 and Rb tumor suppressor elements and overexpression of the cyclin G1 (CYCG1) proto-oncogene, suggest the potential of gene transfer as a treatment for metastatic disease. In this study, we examined the effects of antisense cyclin G1, in comparison with antisense cyclin D1 (CYCD1) and enforced expression of the universal cyclin-dependent kinase inhibitor p21WAF1/CIP1 on the proliferation of human MG-63 osteosarcoma cells. Retroviral vectors bearing antisense CYCG1 as well as antisense CYCD1 and WAF1/CIP1 (in sense orientation) driven by the Moloney murine leukemia virus long terminal repeat promoter inhibited the growth and/or survival of transduced MG-63 cells in 2-7 day cultures. This represents the first demonstration that cyclin G1 is essential for the survival and/or growth of human osteosarcoma cells. Cytostatic and cytopathic effects were accompanied by a significant increase in the incidence of apoptosis, as determined by immunocytochemical analysis of DNA fragmentation. Furthermore, transduction of MG-63 cells with a retroviral vector bearing the suicide gene, herpes simplex thymidine kinase (HStk), induced cell death on treatment with ganciclovir, exhibiting pronounced bystander effects. Taken together, the data affirm the feasibility of modulating inducible cell cycle control enzymes as a potential gene therapy approach in the clinical management of osteogenic sarcoma.
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PMID:Retroviral vector-mediated gene transfer of antisense cyclin G1 (CYCG1) inhibits proliferation of human osteogenic sarcoma cells. 758 20

The expression of 6 different oncoproteins and 2 tumour suppressor gene products in the plasma cells of 63 bone marrow samples was used to determine a profile of the oncogenic phenotype of patients with multiple myeloma. Dual label flow cytometry after periodatelysine paraformaldehyde fixation was used to detect cell surface phenotype and intracellular protein expression simultaneously. The normal range for both the incidence and intensity of expression was determined for each protein by analysing plasma cells (high CD38 intensity) in 22 normal bone marrow samples. The percentage of myeloma patients with a greater than normal incidence of plasma cells expressing these proteins was 53% for c-myc, 28% for Rb, 28% for bcl-2, 27% for c-fos, 24% for p53 wild, 22% for p53 mutant, 13% for c-neu and 13% for pan-ras. When a panel of 8 antibodies was used, 82% of the samples (n = 28) had an increased incidence of expression by at least one oncoprotein or tumour suppressor gene product. The 5 patients with a normal incidence of expression of all 8 proteins were in plateau stage and 4 had not received chemotherapy for more than 12 months. The number of patients with an increased incidence of expression by 2 or more oncoproteins was significantly greater (X2 = 9.0; p < 0.005) in progressive disease (55%) than in stable disease (14%) but there was no specific phenotype pattern associated with progressive disease. All 6 oncoproteins and both tumour suppressor gene products had a greater incidence and intensity of expression in progressive than in stable disease. The expression of c-myc oncoprotein correlated with c-myc mRNA expression in the same samples (n = 10) but c-myc did not correlate with either the plasma cell labelling index (r = -0.15) nor serum thymidine kinase (r = 0.10). Our results suggest that there is a heterogeneous, non-systematic but almost universal presence of activated oncogenes and tumour suppressor genes in the plasma cells of patients with multiple myeloma and that disease progression is associated with the accumulation of a variety of secondary genetic changes which confer increased malignant behaviour.
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PMID:The oncoprotein phenotype of plasma cells from patients with multiple myeloma. 769 21

Proliferating cells characteristically undergo programmed (i.e. apoptotic) death if their progression through the cell cycle is sufficiently perturbed. To determine whether androgen ablation-induced programmed death of prostatic glandular cells involves apoptosis triggered by recruitment of nonproliferating cells into a perturbed cell cycle, rat ventral prostates were assessed temporally after castration for several stereotypical molecular stigmata of entry into the proliferative cell cycle. Northern blot analysis was used to assess levels of transcripts from genes characteristically activated 1) during the transition from quiescence (G(0)) into G1 of the proliferative cell cycle (cyclin-D1 and cyclin-C), 2) during the transition from G1 to S (cyclin-E, cdk2, thymidine kinase, and H4-histone), and 3) during progression through S (cyclin-A). Although levels of each of these transcripts increased as expected in prostatic glandular epithelial cells stimulated to proliferate by the administration of exogenous androgen to previously castrated rats, levels of the same transcripts decreased in prostatic glandular cells induced to undergo apoptosis after androgen withdrawal. Northern and Western blot analyses also demonstrated that there was no increase in prostatic p53 messenger RNA or protein content per cell after androgen ablation. Likewise, after castration, there was no enhanced prostatic expression of the WAF1/CIP1 gene, a gene whose expression is known to be induced in both a p53-dependent and -independent manner during recruitment from G0 into G1. In addition, androgen ablation-induced apoptosis of prostatic glandular cells was not accompanied by retinoblastoma protein phosphorylation, which is characteristic of progression into late G1. Nuclear run-on assays demonstrated that there was no increase in the prostatic rate of transcription of the c-myc and c-fos genes after castration. These results demonstrate that prostatic glandular cells undergo programmed death in G(0) without recruitment into the G1 phase of a defective cell cycle, and that an increase in p53 protein or its function is not involved in this death process.
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PMID:Androgen ablation-induced programmed death of prostatic glandular cells does not involve recruitment into a defective cell cycle or p53 induction. 772 Jun 36

The effect of alpha 2b-interferon administration on liver regeneration after partial hepatectomy in male Wistar rats was examined 24 hours after the operation. Tritium thymidine incorporation into liver DNA, liver mass restitution, mitotic index, and nuclear expression of proliferating cell nuclear antigen were determined as indexes of hepatic proliferation. Both early and late alpha 2b-interferon administration, 2 and 12 hours, respectively, after partial hepatectomy, at a dose of 3.3 x 10(4) IU per kg body weight, suppressed tritium thymidine incorporation and liver mass restitution (p < 0.001) when compared with that in untreated partially hepatectomized rats. The enzyme thymidine kinase (EC 2.7.1.21), a rate-determining enzyme of DNA biosynthesis, has been implicated in the suppression of proliferation in interferon-treated cell cultures. However, in the above-mentioned in vivo model of controlled cellular proliferation, thymidine kinase activity was not affected by alpha 2b-interferon administration, whereas DNA biosynthesis was inhibited. These findings, in contrast to previous observations in in vitro models, show that the inhibition of the in vivo liver regeneration by alpha 2b-interferon is not due to the inhibition of thymidine kinase activity. The expression of the cell cycle-related genes' products c-myc, p53, and c-erbB-2 proteins--which increase during the prereplicative phase that precedes DNA synthesis--was affected by interferon administration, being in accordance with liver proliferative status.
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PMID:Alpha 2b-interferon inhibits rat liver regeneration after partial hepatectomy without affecting thymidine kinase activity. 773 25

Allelic expression was examined by single-strand conformation polymorphism analysis in murine fibrosarcomas from inter-subspecific F1 mice between C57BL/6 and MSM. Ten genes encoding p53, mdm2, E-cadherin, 72 kD metalloproteinase and its inhibitor (Timp2), thymidine kinase and four glucose transporters (Gluts) were examined. These genes were chosen because of their probable association with tumor development and progression. In some of the tumors and cell lines, p53, E-cadherin and Glut3 genes showed remarkable differences in allelic expression, one allele being poorly expressed. The allele-specificity persisted in nine cell lines obtained by repeated transplantations from one tumor. These results suggest that expression of some genes is allele-specific in tumor cells and the pattern of specificity is stable. Such a decrease or a loss of expression in one of the alleles may be functionally equivalent to the loss of heterozygosity of the gene, and therefore this may confer malignant properties on tumor cells. It is also suggested that differential expression of two alleles is a common event in tumor cells.
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PMID:Difference in allelic expression of genes probably associated with tumor progression in murine fibrosarcomas and cell lines. 796 Nov 3

Two steps of gene targeting were used to replace the p53 gene with the E. coli beta-galactosidase (lacZ) gene in mouse embryonic stem (ES) cells. The first targeting vector consisted of neo and herpes simplex virus thymidine kinase (HSV-tk) genes as a neo-tk cassette in the middle of the targeting vector. At the first targeting, the homologous recombinants became G418 resistant and ganciclovir (GANC) sensitive and were selected by G418 alone. At the second targeting, homologous recombination reciprocally exchanged the neo-tk casette in the ES cell chromosome with the lacZ fragment in the second targeting vector and thus made the ES cells GANC resistant. We obtained two ES cell clones, in which the p53 gene for both had been replaced with a totally non-homologous sequence of the lacZ gene. The germ-line transmission of the manipulated ES cells also demonstrated that the entire procedure had no detrimental effects on ES cells at all.
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PMID:Gene replacement of the p53 gene with the lacZ gene in mouse embryonic stem cells and mice by using two steps of homologous recombination. 804 55

We analysed diagnostic phase plasma levels of thymidine kinase (TK) and mutated p53 in 81 patients with malignant lymphoma. Forty-three (53%) patients had increased (> 10 U/l) TK activity whereas 30 (37%) were positive for the mutated p53 gene product. In general, patients with p53 mutation positive tumors tended to have higher TK activity than those without. Furthermore, patients with high-grade non-Hodgkin's lymphoma (NHL) showed almost a linear correlation (rs = 0.79) between plasma levels of mutated p53 and TK. We conclude that the monoclonal antibody assisted detection of mutated p53 gene product may prove a useful adjunct to the diagnostic procedures of malignant lymphomas.
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PMID:Evaluation of plasma levels of thymidine kinase and mutated p53 in 81 patients with newly diagnosed malignant lymphoma. 830 26

p53 is known to bind specifically to the 44-bp human DNA sequence in an immunoprecipitation assay. We show here that the transcription of the reporter CAT gene linked with the herpesvirus thymidine kinase (tk) promoter containing the 44-base sequence is enhanced by mouse wild-type but not mutant-type p53 in F9 and p53-null Saos-2 cells. The p53-mediated transactivation was dramatically abrogated by introduction of SV40 large T antigen (SVLT) in Saos-2 cells in which p53 was clearly associated with SVLT. Furthermore, the p53-SVLT complex did not bind to the 44-base sequence at all. Thus, SVLT sequesters the transactivation function of the wild-type p53 by inhibiting the binding of p53 to the 44-base sequence. This is good evidence to show 'loss of functions' in the product of a tumor-suppressor oncogene by a dominant oncogene product at a molecular level.
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PMID:Abrogation of p53-mediated transactivation by SV40 large T antigen. 838 54

Herpes simplex thymidine kinase (TK) promoter was shown to be repressed by the wild-type p53. Using a model system that the p53-binding site was linked to the thymidine kinase promoter, we demonstrated that single p53-specific binding site was sufficient to abolish the repression. On the contrary, the mutant p53 had the opposite effects on the HSV-TK promoter in BHK cells. The results suggest that the p53-binding site may act as an enhancer to regulate the gene expression in a novel way in vivo.
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PMID:Release of the p53-induced repression on thymidine kinase promoter by single p53-binding sequence. 838 49


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