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 myeloid interleukin-3 (IL-3) dependent cell line, FDC-P1, enters the G0 stage of the cell cycle after IL-3 deprivation for 24 hr. The expression of 13 protooncogenes and immediate-early genes was compared with 4 "control" genes after the addition of either IL-3 or phorbol myristate acetate (PMA) to IL-3-deprived cells. mRNA transcripts encoding c-myc and the T-cell receptor c-gamma gene were induced to high levels only after IL-3 addition, whereas c-fos, fos-B, c-jun, jun-B, Krox-20, and Krox-24 were induced transiently only after PMA addition. The remaining genes (fra-1, p53, jun-D, c-Ha-ras, c-Ki-ras, c-raf, beta-actin, ornithine decarboxylase, and histone 2B) were detected after culture with either IL-3 or PMA. When cells were serum- and IL-3-deprived, c-fos, fos-B, c-jun, jun-B, Krox-20, and Krox-24 were detected after exposure to either serum or PMA. Moreover, culture with cycloheximide and PMA resulted in superinduction of these genes, whereas cycloheximide and IL-3 addition did not. mRNAs encoding these genes had half-lives of 10-20 min after PMA treatment, whereas that of beta-actin was longer (greater than 2 hr), suggesting that short mRNA half-lives contributed to the transient nature of these genes. Although c-fos, fos-B, c-jun, jun-B, Krox-20, and Krox-24 expression can be detected in IL-3-dependent cells after exposure to either PMA or serum, these genes were not detected after IL-3 addition, which allows cell-cycle progression. These results document the existence of IL-3 and PMA-responsive genes and demonstrate that IL-3 and protein kinase C agonists can induce distinct patterns of gene expression.
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PMID:Interleukin-3 and phorbol esters induce different patterns of immediate-early gene expression in an interleukin-3 dependent cell line. 170 18

Ultrastructural, flow cytometric, and molecular studies were performed on leukemia cells from bone marrow and pleural effusion of a 6-year-old boy diagnosed with undifferentiated (MO) leukemia, using routine histology and immunostains at diagnosis and relapse. Ultrastructurally, surface and/or intracellular ferritin particles were present on or in some blasts and the majority of blasts contained identifiable acid ferrocyanide reactive inorganic iron comparable to that seen in normal early erythroblasts. The cells lacked other evidence of differentiation, including diaminobenzidine-reactive or immunoreactive hemoglobin. Flow cytometric analysis of malignant cells showed a lack of lymphoid or myeloid markers. Anti-transferrin receptor antibody was positive on 93% of cells and antibody to glycophorin A reacted with 23% of cells. RNA blot analysis of leukemia cells with myeloperoxidase (MPO) showed an absence of appreciable levels of MPO mRNA. Chromosome analysis showed 51,XY, t(1;16)(p31;q24), +6, +10, +15, +19, +21. The oncogene c-myb, which is specifically expressed and regulated in hematopoietic cells and produces a DNA-binding protein responsible for myeloid differentiation, was found to be duplicated in the patient's tumor cells. Expression of c-jun, N-ras, c-myc, and p53 was normal. The data indicate that the malignant cells in this patient are of early erythroid lineage at diagnosis and relapse and that classification of cell lineage can be enhanced by ultrastructural Prussian blue staining. The failure of this otherwise undifferentiated leukemia to express or evolve into a myeloid phenotype is biologically and clinically distinct from previously described cases of erythroid and myeloid leukemia and may represent a previously unidentified phenotype which should be included in the spectrum of 'undifferentiated' childhood leukemia.
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PMID:Childhood undifferentiated leukemia with early erythroid markers and c-myb duplication. 170 34

An invariant genetic lesion in mouse plasmacytomas is deregulated expression of c-myc as a consequence of chromosomal translocation. However, retroviral and transgenic studies suggest that additional genetic lesions may contribute to the genesis of plasmacytomas. The p53 tumor suppressor gene is a likely contributor to this genetic lesion, since there is a high incidence of p53 mutation in Burkitt's lymphomas and B-ALL (L3), both of which contain translocations involving c-myc analogous to those in plasmacytomas. In addition, p53 has been shown to be a transcriptional modulator of c-myc expression. In a survey of 27 mouse plasmacytomas by single-strand conformation polymorphism, we identified a single mutation (3.7% incidence), suggesting that p53 lesions are not frequent contributors to plasmacytomagenesis. A similar study of macrophage-monocyte tumors generated by a c-myc-containing retrovirus also indicates a lack of p53 involvement in deregulated c-myc expression. These results suggest that the specific maturation stage of transformed B-lymphocytes, independent of c-myc deregulation, may be the critical factor which determines the involvement of mutant p53.
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PMID:Infrequent p53 mutation in mouse tumors with deregulated myc. 173 33

We examined structure and expression of the p53 and Rb genes in a C3HOS transplantable mouse model of osteosarcoma. The results were compared to analogous studies conducted with five human osteosarcoma cell lines. The p53 gene was found rearranged in the mouse tumour. The rearrangement mapped to the first intron region of the p53 gene and as a result, no p53 expression could be detected in C3HOS tumours. Using p53 genomic probes, we have detected the same rearrangement in the original radiation-induced tumour and the various clones that were isolated from it. Deletion and rearrangement of the p53 gene were also found in three out of five of the human osteosarcoma cell lines (MG-63, G-292, Saos-2). No p53 expression could be detected in these three cell lines. In the affected human osteosarcoma cell lines, the rearrangement involved the first intron region. In addition, the mouse tumor was analysed for structural and expression changes in the Rb and the c-myc genes. Normal expression of both genes were detected in the murine tumour. Only one (Saos-2) human osteosarcoma cell line exhibited gross structural alteration in the retinoblastoma gene. The results suggest that the inactivation of p53 may be an important step in the development of osteosarcomas, and that a rearrangement affecting the first intron is common in osteosarcomas.
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PMID:Inactivation of p53 gene in human and murine osteosarcoma cells. 173 19

Evaluation of molecular events in human colon polyps and tumors has revealed constitutive elevated expression of c-myc, activation of both ras and src proto-oncogenes, and allelic deletion events involving inactivation of putative regulatory genes, including p53. To evaluate the contribution of each of these events to colon carcinogenesis, it is desirable to establish epithelial cell lines representing different stages of neoplastic progression. Such in vitro models can be used to establish a primary role for different genes implicated in neoplastic transformation, identifying events involved in multistep carcinogenesis and delineating the factors modulating cellular transformation. We present herein a summary of such an in vitro model for colon carcinogenesis using the introduction of relevant genetic elements into normal mucosa to identify the molecular steps and accompanying cellular events underlying neoplastic progression in the colon.
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PMID:Oncogene-mediated transformation. An in vitro model for colon carcinogenesis. 174 51

Transforming growth factor beta 1 (TGF beta 1) is the prototype of a large family of polypeptides involved in growth control, extracellular matrix production, and development. The TGF beta s have marked stimulatory effects on connective tissue formation. They are chemotactic for fibroblasts, indirect mitogens for certain mesenchymal cells and stimulators of extracellular matrix deposition. The TGF beta s are also potent inhibitors of proliferation of most cell types in culture, and in vivo studies have indicated that the predominant effect of TGF beta 1 on cell proliferation is inhibition. We have investigated the mechanism of TGF beta 1 inhibition of skin keratinocyte growth. Earlier studies demonstrated that TGF beta 1 inhibition of keratinocyte proliferation involves suppression of c-myc transcription, and indirect evidence suggested that the product of the retinoblastoma tumor susceptibility gene, pRB, may be involved in this process. More recently, we have shown that transient expression of pRB in skin keratinocytes can repress human c-myc promoter/CAT transcription as effectively as TGF beta 1. The same c-myc promoter region, termed the TGF beta control element (TCE), was required for regulation by both TGF beta 1 and pRB. Oligonucleotides containing the TCE bound to several nuclear factors in mobility shift assays and a cellular protein of approximately 106 kD in Southwestern assays. Binding of these factors could be demonstrated in cells with or without normal pRB, and the binding of some factors was rapidly inhibited by TGF beta 1 treatment of TGF beta-sensitive but not TGF beta-insensitive cells. These data indicate that pRB can function to inhibit c-myc transcription and suggest the involvement of cellular factor(s) in addition to pRB in the TGF beta 1 pathway for suppression of c-myc transcription. Studies with other cell types have shown that another tumor suppressor gene, p53, can also regulate transcription of c-myc in transient assays. Whereas wild type p53 markedly suppressed transcription, four different mutant p53 clones caused transactivation. The data support the hypothesis that pRB and p53 can both cause growth inhibition by blocking the expression of the protooncogene, c-myc, and indicate that tumor suppressor genes may function in the response pathway for diffusible negative growth regulators such as TGF beta.
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PMID:TGF beta regulation of epithelial cell proliferation: role of tumor suppressor genes. 184 40

Nuclear oncoproteins are among the most rapidly degraded intracellular proteins. Previous work has implicated the ubiquitin-mediated proteolytic system in the turnover of short-lived intracellular proteins. In the present study, we have evaluated the potential role of the ubiquitin system in the degradation of the specific nuclear oncoproteins encoded by the N-myc, c-myc, c-fos, p53 and E1A genes. Each of these nuclear oncoproteins was synthesized in vitro by transcription of the appropriate cDNA and translation of the resulting mRNA in the presence of [35S]methionine. Degradation of labeled proteins was monitored in the ubiquitin cell-free system. ATP stimulated the degradation of all the proteins between 3- and 10-fold. The degradation was completely inhibited by neutralizing antibody directed against the ubiquitin-activating enzyme, E1, the first enzyme in the ubiquitin-mediated proteolytic cascade. Moreover, degradation in E1-depleted lysates could be restored in each case by the addition of affinity-purified E1. These data suggest that the ubiquitin system mediates the degradation of these oncoproteins in vitro. Degradation of other proteins, such as superoxide dismutase, cytochrome c, enolase, RNase A, and ornithine decarboxylase, is not mediated by the ubiquitin cell-free system. This suggests that the nuclear oncoproteins studied here possess specific signals that target them for rapid turnover by this proteolytic pathway. Furthermore, the relative sensitivity to degradation of various E1A mutants in vivo is also maintained in the cell-free system, suggesting that the ubiquitin pathway may play a role in the cellular degradation of these proteins as well.
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PMID:Degradation of nuclear oncoproteins by the ubiquitin system in vitro. 184 34

The inherited cancer-inducing disease familial polyposis coli (FPC) provides an excellent model not only for studying tumor progression in colorectal cancer but also for elucidating molecular mechanisms in general oncogenesis. This paper reviewed recent remarkable progresses of molecular mechanisms in colorectal tumorigenesis. This is concerned with the various kinds of genetic alterations that accumulate in the development from normal mucosa to adenoma, and then to adenocarcinoma in comparison with FPC and sporadic cases. This review included also information on the localization of FPC major gene. These observations indicate that in cases of colorectal tumorigenesis several genetic alterations may be involved, including activation of K-ras gene, deregulated expression of c-myc gene or c-fos gene and inactivation of tumor suppressor genes such as p53 and DCC genes, as well as the loss of heterozygosity. The observation suggest that adenomas will have undergone several gene or chromosome mutations before reaching to the fully malignant state. Therefore, DNA diagnosis for colorectal tumors in the clinical level may contribute to more accurate prognosis and better results for further therapy.
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PMID:[Diagnosis of colorectal cancer from DNA level]. 184 82

Inherited susceptibility to a wide variety of neoplasias (Li-Fraumeni syndrome), has been shown in studies of one cancer-prone family, to have an intriguing association with an aberrant c-raf-1 gene and inheritance of a radioresistant phenotype in their non-cancerous skin fibroblasts. This association together with observations that DNA topoisomerases, when defective, can introduce errors into DNA and that these enzymes are perturbed in vitro by serine/threonine kinases similar to raf encoded proteins, prompted investigation of DNA topoisomerase activity of the family's fibroblasts. Since radioresistance was transferred to murine cells (NIH-3T3) when the aberrant c-raf-1 gene from this family was transfected, we also examined transformants containing this and other oncogenes. V-raf/c-myc and EJ-ras transformants were examined, the former because the family's skin fibroblasts also have 3-8-fold elevated myc expression (not apparently relevant to radioresistance) and the latter because ras, like raf, conveys radioresistance. The family members' fibroblasts and the three transfected murine lines, showed a similar perturbation of a spermidine and ATP-dependent DNA catenation activity (typical of DNA topoisomerase II). There was a significant positive correlation (r = 0.93; P = 0.0026) between the degree of activation of topoisomerase II and one measure of radioresistance (the Dq value). Relaxation of DNA supercoiling (topoisomerase I activity and other DNA nicking enzymes) was not abnormal. Cytotoxicity assays and evaluation of the influence of topoisomerase II inhibitors on DNA/protein complex formation, corroborated the existence of a qualitative topoisomerase II defect in the family's cells and transfectants. Although the contention that the qualitative topoisomerase II abnormalities observed here may be associated with malfunction is highly speculative, these findings may be relevant to the mechanism of oncogenesis, not only in this family, but with raf and ras type oncogenes.
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PMID:Aberrant DNA topoisomerase II activity, radioresistance and inherited susceptibility to cancer. 184 52

In vitro and in vivo metastatic variants derived from Lewis lung carcinoma (3LL) were examined for the level of the expression of several growth-regulated genes, oncogenes, and transforming growth factor (TGF) genes. To determine whether the proliferative advantage of metastatic cells is due to an increased growth fraction of the cell population or to a deregulated expression of some growth-regulated genes, the mRNA levels of the S-phase-specific H3 histone gene were compared with that of some cell cycle-related genes (vimentin, calcyclin, c-myc, and p53) and oncogenes (Ki-ras, Ha-ras, c-sis, c-src, c-fes, and c-erb). In addition, to evaluate whether an autocrine pattern of cell proliferation is responsible for the proliferative advantage of metastatic cells, the level of the expression of TGF genes (alpha and beta 1) was studied. Northern blot analysis demonstrated that in 3LL metastatic variants the expression of TGF-alpha as well as the expression of all growth-regulated genes and oncogenes studied are similar. Only the TGF-beta 1 gene is expressed at higher levels in highly metastatic 3LL variants maintained either in vitro or in vivo. Data suggest that the proliferative advantage of 3LL metastatic cells is not due to a deregulated expression of some growth-regulated genes and oncogenes, but more likely is acquired through the expression of genes which might interfere with the ability of the tumor cells to escape hostile microenvironmental conditions.
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PMID:Differential expression of transforming growth factor-beta 1 gene in 3LL metastatic variants. 191 69


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