Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To study the immune response against oncogene-transformed tumors, C3H/HcN mouse embryo fibroblasts (MEF) were transfected with an activated allele of the H-ras proto-oncogene VaII2 and a dominant-negative allele of the murine p53 tumor suppressor gene VaII35. Transformed cell lines were derived and found to be tumorigenic in syngeneic mice. Immunization with irradiated p53 + ras-transformed MEF, but not primary MEF or unrelated syngeneic cells, protected mice from subsequent challenge with live tumor cells. The role of different immune cell subsets in the effector phase of anti-tumor immunity induced by immunization with p53 + ras-transformed MEF was investigated by in vivo antibody depletion experiments. Immunized mice depleted of CD8+ T, NK or B cells were resistant, but depletion of CD4+ T cells rendered mice susceptible to tumorigenic challenge. In contrast to the tumor-specific immune responses mounted against most chemically or UV-induced tumors, a series of independently derived p53 + ras-transformed MEF were cross-reactive in tumor rejection assays. In addition, immunization with C3H-derived L-929 cell lines expressing single gene products H-ras or p53 did not protect mice against tumorigenic challenge with p53 + ras-transformed tumors. However, MEF transformed by expression of either H-ras or p53 were cross-protective in vivo. Our data suggest that the p53 + ras-transformed MEF share tumor rejection antigens which are also induced by single gene transformation of the parental primary cell but are not the products of oncogenic ras or p53 protein.
 ...
PMID:Mouse embryo fibroblasts transformed by activated ras or dominant-negative p53 express cross-reactive tumor rejection antigens. 754 May 99

Diffuse large B cell lymphomas (DLBLs) represent a heterogeneous collection of aggressive non-Hodgkin's lymphomas that can arise either de novo or as a result of transformation from chronic lymphocytic leukemia, small lymphocytic lymphoma, follicular lymphomas, or lymphomas of mucosa-associated lymphoid tissue. A small percentage of DLBLs express the CD5 antigen. The majority of these cases have evolved from a pre-existing low grade non-Hodgkin's lymphoma (Richter's syndrome). However, we identified and characterized nine CD5-positive DLBLs in which the patients did not have a previous history or concomitant evidence of chronic lymphocytic leukemia, small lymphocytic lymphoma, follicular lymphoma, or mucosa-associated lymphoid tissue-associated non-Hodgkin's lymphoma, suggesting that they arose de novo. All nine cases expressed CD20 and monotypic immunoglobulin, all eight cases examined expressed CD19, CD22 and CD43, eight of the nine cases expressed HLA-DR, and two of eight cases expressed CD11c. None of the cases expressed CD3, CD10, CD11b, CD21, CD23 or CD30. CD5 expression by these cells was found to be identical to that of CD5-positive B cell chronic lymphocytic leukemia by quantitative polymerase chain reaction analysis of CD5 mRNA. These nine de novo CD5-positive DLBLs exhibited clonal immunoglobulin heavy and light chain gene rearrangements but lacked integration of the Epstein-Barr virus genome and structural alterations of the bcl-1, bcl-2, c-myc, H-ras, K-ras, and N-ras proto-oncogenes and the p53 tumor suppressor gene. However, bcl-6 proto-oncogene rearrangement, which is involved in chromosome band 3q27 aberrations, was found in four cases (44.4%). This is comparable with the frequency of bcl-6 gene rearrangement in CD5-negative DLBL. In contrast, bcl-6 gene rearrangement was absent in six cases of DLBL associated with Richter's syndrome. These findings suggest that de novo CD5-positive DLBLs are genotypically similar to CD5-negative DLBLs and may be pathogenetically distinct from the DLBLs associated with Richter's syndrome.
 ...
PMID:De novo CD5-positive and Richter's syndrome-associated diffuse large B cell lymphomas are genotypically distinct. 754 11

Hypothetical Products from Noncoding Frames (i.e., HyPNoFs) are hypothetical, not-coded proteins, translated from alternate reading frames (i.e., coding + 1 and coding + 2) of cDNAs. HyPNoFs of CD4, PKC, oncostatin, bcl-2 proto-oncogene, tumor suppressor p53, cystic fibrosis transmembrane regulator (CFTR), and tumor necrosis factors alpha and beta were searched as query sequences vs the SWISS-PROT data bank. Homology searchers carried out revealed that hypothetical products (i.e., HyPNoFs) may share high similarity with real protein products actually coded. Sequence similarity of hypothetical products to real proteins is sometimes very high, suggesting common conformational features, according to the Sander and Schneider cutoff value. This finding supports the hypothesis that eukaryotic DNA, currently considered to be monocistronic, might occasionally have polycistronic regions, carrying different protein messages on overlapping frames. As yet, polycistronic genes have been observed in viral genomes only. The presence of polycistronic regions in eukaryotic genes is likely reminiscent of an ancient strategy, rather than a present feature of the genome in eukaryotes. These data suggest that thorough investigation of HyPNoFs is likely to improve our ability to trace genes' evolution and to investigate structure-function relationships of protein and DNA sequences.
 ...
PMID:Investigating hypothetical products from noncoding frames (HyPNoFs). 754 50

To study the effects of acute ethanol on regenerating rat liver, the mRNA transcript levels of growth suppressor genes (prohibitin, TGF beta-1 and p53) were measured by Northern blot analysis during the G0, G1, and early S phases of compensatory growth after 70% partial hepatectomy (PH) in adult male rats. Selected animals were gavaged with either ethanol (3 g/kg) or glucose and underwent PH 1 h later. Other animals were either sham operated or underwent PH without gavage. Prohibitin and p53 transcripts were increased in relative abundance (as measured by an increase in band intensity) near the G1/S boundary (8-12 h post-PH) following both glucose and ethanol gavage. A transient increase in prohibitin transcripts at 0.5-1 h post-PH was found to be characteristic of glucose and nongavaged rats. Ethanol gavage significantly increased the relative abundance of prohibitin transcripts at 0.5-2 h post-PH. An increase in the TGF beta-1 transcripts at 4 h post-PH was found in the glucose and nongavaged rats. Ethanol gavage resulted in variable TGF beta-1 transcript expression near hepatectomy (0 h); however, mean differences were not statistically significant. Sham operation had no effect on the mRNA transcripts of the selected genes during the time periods sampled. These results and previous work suggest that the mitoinhibitory effects of acute ethanol exposure may occur via modulation of growth suppressor and proto-oncogene expression.
 ...
PMID:Acute ethanol and selected growth suppressor transcripts in regenerating rat liver. 754 33

The purpose of this study was to characterize the clinical and histological features of intraoral squamous cell carcinoma in men who were seropositive for the human immunodeficiency virus and to evaluate viral cofactors (human papillomavirus, herpes simplex virus, Epstein-Barr virus), proliferative index (proliferating cell nuclear antigen), a factor associated with invasion (cathepsin D), and mutated tumor suppressor gene and proto-oncogene products (mutated p53, c-erbB-2). Four men who were seropositive for the human immunodeficiency virus and had acquired immunodeficiency syndrome presented with painful oral lesions of variable duration. Oral cancer risk factors included heavy tobacco use (four of four), heavy alcohol use (three of four), and previous radiotherapy (one of four). The lesions consisted of ulcers (two of four), a fungating mass (one of four), and papillary erythroplakia (one of four). Incisional biopsy specimens were obtained. High-stringency in situ hybridization was performed with DNA probes to the human papillomavirus (types 6/11; 16/18; 31/33/35) and Epstein-Barr virus: Immunocytochemical studies for the herpes simplex virus, proliferating cell nuclear antigen, cathepsin D, mutated p53, and c-erbB-2 were performed. Two lesions were moderately differentiated squamous cell carcinoma, one lesion was a basaloid squamous cell carcinoma, and one was carcinoma in situ. Stage of disease at diagnosis was II (one of four), III (two of four), and IV (one of four). Three cases were positive for the human papillomavirus, one case was positive for Epstein-Barr virus, and three cases were positive for the herpes simplex virus. C-erbB-2 was focally positive in one case, and mutated p53 was positive in a separate case.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Intraoral squamous cell carcinoma in human immunodeficiency virus infection. A clinicopathologic study. 755 63

Mutant p53 tumour suppressor gene and c-erbB-2 proto-oncogene are involved in human carcinogenesis, and their protein product detection in human malignancies might influence the evolution of many neoplasms. Our aim was to estimate their association with histopathological and clinical parameters of prognostic value in colorectal cancer. An immunohistochemical assay was undertaken in formalin-fixed sections from tissue specimens of 60 colorectal carcinomas. Nuclear p53 expression was detected in 46.6%, while membranic c-erbB-2 positivity was noticed in 35% of the examined cases. P53 positivity rate significantly correlated with poor differentiation (p < 0.001), high mitotic activity (p < 0.0001), tumour stage (p < 0.001) and 5-year overall survival period (p < 0.01). C-erbB-2 positivity incidence significantly correlated with advanced Dukes' stage (p < 0.001) and high mitotic activity (p < 0.05). Significant association between p53 and c-erbB-2 immunostaining was observed (p < 0.05) and p53/c-erbB-2 co-expression was related to poor differentiation (p < 0.001), high mitotic activity (p < 0.001), advanced Dukes' stage (p < 0.001), tumour aneuploidy (p < 0.05) and worse overall survival (p < 0.05). P53 and c-erbB-2 immunohistochemical detection in combination with known prognostic indicators may be a useful future tool in determining colorectal cancer prognosis and subsequently in deciding on optimal postoperative treatments.
 ...
PMID:Prognostic significance of p53 and c-erbB-2 immunohistochemical evaluation in colorectal adenocarcinoma. 757 15

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.
 ...
PMID:Retroviral vector-mediated gene transfer of antisense cyclin G1 (CYCG1) inhibits proliferation of human osteogenic sarcoma cells. 758 20

The National Toxicology Program recently completed long-term ozone inhalation studies in B6C3F1 mice and F344/N rats. Mice and rats were exposed to 0, 0.5 or 1.0 p.p.m. ozone by inhalation for 24 or 30 months. There was an increased incidence of lung neoplasms in B6C3F1 mice. However, there was no evidence of carcinogenicity in F344/N rats. The objectives of this study were to (i) evaluate benign and malignant lung neoplasms from B6C3F1 mice for mutations in the K-ras gene at codons 12, 13 and 61, (ii) determine if the frequency and spectra of K-ras mutations were unique for ozone-induced lung neoplasms, (iii) determine if specific K-ras mutations were associated with the size and morphological patterns of lung neoplasms or ozone exposure concentrations and (iv) screen lung neoplasms by immunohistochemical methods for the p53 protein. K-ras mutations were detected by single-strand conformation analysis and identified by direct sequencing of polymerase chain reaction-amplified DNA isolated from formalin-fixed, paraffin-embedded neoplasms. K-ras mutations were detected in 73% of ozone-induced neoplasms, as compared with 33% of lung neoplasms from controls. The predominant mutations consisted of A-->T transversions at codon 61 (8/19) and G-->T transversions at codon 12 (7/19). Specific K-ras mutations in lung neoplasms were not associated with various morphological patterns. Our data suggests that ozone may cause direct and/or indirect DNA damage in the K-ras proto-oncogene of B6C3F1 mice.
 ...
PMID:Increased frequency of K-ras mutations in lung neoplasms from female B6C3F1 mice exposed to ozone for 24 or 30 months. 761 98

Mutated p53 proteins interfere in the function of wild type p53 and may also serve as a dominant oncogene. The vast majority of p53 mutations result in a protein of altered conformation and prolonged half-life. We sought to examine whether geldanamycin, a drug capable of destabilizing several oncogene and proto-oncogene products, could alter the stability and DNA binding characteristics of several mutated p53 proteins. Brief exposure to GA destabilized the p53 protein of several breast, prostate and leukemic cell lines harboring mutated p53 alleles, resulting in a significant reduction in p53 steady state level and half-life. In contrast to its effects on mutated p53, GA altered neither steady state level nor inducibility of the wild type protein. In addition to its effects on protein stability, GA also altered the conformation of mutated p53, so that it was no longer detectable with a mutant conformation-specific antibody. Finally, mutated p53 protein isolated from GA-treated cells regained partial ability to bind a wild type-specific p53 DNA consensus sequence. These data indicate the feasibility of pharmacologic intervention for altering the mutated p53 phenotype.
 ...
PMID:Geldanamycin selectively destabilizes and conformationally alters mutated p53. 767 52

By crossing mice that carry a null allele of p53 with transgenic mice that develop mammary adenocarcinomas under the influence of a Wnt-1 transgene, we have studied the consequences of p53 deficiency in mammary gland neoplasia. In Wnt-1 transgenic mice homozygous for the p53 null allele, tumors appear at an earlier age than in animals heterozygous or wild-type at the p53 locus. About half of the tumors arising in p53 heterozygotes exhibit loss of the normal p53 allele, implying selection for p53-deficient cells. Mammary tumors lacking p53 display less fibrotic histopathology and increased genomic instability with aneuploidy, amplifications, and deletions, as detected by karyotype analysis and comparative genomic hybridization. In one tumor, the amplified region of chromosome 7 had an ectopically expressed int-2/FGF3 proto-oncogene, a gene known to cooperate with Wnt-1 in the production of mammary tumors. These findings favor a model in which p53 deficiency relaxes normal restraints on chromosomal number and organization during tumorigenesis.
 ...
PMID:Deficiency of p53 accelerates mammary tumorigenesis in Wnt-1 transgenic mice and promotes chromosomal instability. 770 63


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>