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)

In most instances, the transfer of ubiquitin to target proteins is catalyzed by the action of ubiquitin protein ligases (E3s). Full-length cDNAs encoding murine E6-associated protein (mE6-AP) as well as Nedd-4, a protein that is homologous to E6-AP in its C terminus, were cloned. Nedd-4 and mouse E6-AP are both enzymatically active E3s and function with members of the UbcH5 family of E2s. Mouse E6-AP, like its human counterpart, ubiquitinates p53 in the presence of human papilloma virus E6 protein, while Nedd-4 does not. Consistent with its role in p53 ubiquitination, mE6-AP was found both in the nucleus and cytosol, while Nedd-4 was found only in the cytosol. Binding studies implicate a 150-amino acid region that is 40% identical between mE6-AP and Nedd-4 as a binding site for the C-terminal portion of an E2 enzyme (UbcH5B). Nedd-4 was determined to have a second nonoverlapping E2 binding site that recognizes the first 67 amino acids of UbcH5B but not the more C-terminal portion of this E2. These findings provide the first demonstration of physical interactions between mammalian E2s and E3s and establish that these interactions occur independently of ubiquitin and an intact E3 catalytic domain. Furthermore, the presence of two E2 binding sites within Nedd-4 suggests models for ubiquitination involving multiple E2 enzymes associated with E3s.
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PMID:Subcellular localization and ubiquitin-conjugating enzyme (E2) interactions of mammalian HECT family ubiquitin protein ligases. 918 27

There is no scientific study that has investigated the association between human papilloma virus (HPV) and p53 mutation in Hong Kong Chinese patients with esophageal cancers. The aim of this survey is to evaluate in details the prevalence and relationship of HPV and p53 mutation in these patients with esophageal squamous cell carcinomas. Fresh tissues from the resected specimens of 70 Chinese patients (59 men, 11 women) with primary esophageal squamous cell carcinomas (20 well-differentiated, 36 moderately differentiated, and 14 poorly differentiated squamous cell carcinomas) were tested for the presence of HPV and p53 mutation using the polymerase chain reaction (PCR), single-strand conformational polymorphism (SSCP) analysis, and DNA sequencing. No HPV type 18 was detected, whereas HPV type 16 was identified in 8.6% (6 of 75) of the cases. p53 mutation was found in 44% (31 of 70) of the tumors. The mean ages of HPV-positive and HPV-negative groups of patients were 55 and 64 years, respectively (P = .046, t-test). There was no correlation between the prevalence of HPV and p53 mutation in these tumors. The presence of HPV and p53 also had no relation to the sex of the patients or to the grade of the carcinomas. It is concluded that the overall low prevalence of HPV in esophageal carcinomas may suggest that the virus may not play an important role in the pathogenesis of these tumors in Hong Kong Chinese patients. Also, p53 mutation and integrated HPV DNA are not mutually exclusive in esophageal cancer.
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PMID:Presence of human papillomavirus in esophageal squamous cell carcinomas of Hong Kong Chinese and its relationship with p53 gene mutation. 919 Sep 99

Chemical influences, mainly heavy tobacco smoking, chewing snuff, excessive alcohol consumption, and some occupational hazards, are known to be important etiologic factors in laryngeal carcinogenesis. The synergistic or cooperative interaction of human papilloma virus (HPV) infection with these chemical factors are serious considerations in the development of laryngeal carcinoma. With the development during the last decade of Southern blot hybridization and polymerase chain reaction (PCR), extensive and comprehensive studies have been conducted to determine the presence and biological (etiologic) significance of HPV. Developed cancer, as well as juvenile and adult multiple and single papilloma of the larynx, have been the subject of clinical and molecular-pathological investigation. Our previous study showed that cancer may develop on the basis of leukoplakia and adult-onset papilloma. Extensive kilocytes, an indication of HPV infection, can be seen by histological examination in papillomas and carcinoma. Literary data suggest that in laryngeal squamous cell carcinoma, including varicoses carcinoma, HPV 16, HPV 18, and HPV 33 DNA have been detected. Both in juvenile and adult-onset respiratory papillomatosis, patients could have either HPV type 6 or 11 DNA sequences. Molecular biological and PCR studies indicate that HPV may play an etiologic role in the development of human malignancies of the upper aerodigestive tract and uterine (cervical) origin. However, evidence that unequivocally links HPV infection with laryngeal squamous cell carcinoma is still lacking. In laryngeal cancer, p53 abnormalities are related to smoking-induced mutagenesis rather than HPV. Studies have postulated an interaction between HPV infection and chemical carcinogens and have concluded that HPV possibly are co-adjuvants during the multistage process of neoplastic transformation.
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PMID:Some etio-pathogenetic factors in laryngeal carcinogenesis. 921 6

We have analyzed 30 cases of advanced-stage cervical squamous cell carcinoma (stages IIb-IV) by comparative genomic hybridization (CGH). The most consistent chromosomal gain in the aneuploid tumors was mapped to chromosome arm 3q in 77% of the cases. Acquisition of genetic material also occurred frequently on Iq (47%), 5p (30%), 6p (27%), and 20 (23%). Recurrent losses were mapped on 2q (33%), 3p (50%), 4 (33%), 8p (23%), and 13q (27%). High-level copy number increases were mapped to chromosome 8, chromosome arms 3q, 5p, 8q, 12p, 14q, 17q, 19q, 20p, and 20q, and chromosomal bands 3q26-27, 9p23-24, 11q22-23, and 12p13. In the majority of the cases, the presence of high-risk human papilloma virus genomes was detected. High proliferative activity was accompanied by crude aneuploidy. Increased p21/WAF-I activity, but low or undetectable expression of TP53 were representative for the immunophenotype. This study confirms the importance of a gain of chromosome arm 3q in cervical carcinogenesis and identifies additional, recurrent chromosomal aberrations that are required for progression from stage I tumors to advanced-stage carcinomas.
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PMID:Advanced-stage cervical carcinomas are defined by a recurrent pattern of chromosomal aberrations revealing high genetic instability and a consistent gain of chromosome arm 3q. 925 58

During the past decades, the expansion of molecular biology has had a pivotal role in understanding the basis of cancer development and progression. In addition, real advances have been made in the application of DNA recombinant technology to cancer therapy and patient management. In gynecologic oncologic fields, there are also many investigations to explore the basic pathogenesis of gynecologic cancer, such as cervical cancer, ovarian cancer, and endometrial cancer. It is now known that specific types of human papilloma virus (HPV) are the principal etiologic agents for both cervical cancer and its precursors. However, the various kinds of alterations in oncogenes and tumor suppressor genes may play additional roles in carcinogenesis of cervical cancer. Although ovarian carcinoma is the most frequent cause of death from gynecologic malignancies, the histogenesis and biological characteristics of these tumors are not well understood. During the last several years, many key observations have been made concerning the genetic alterations associated with ovarian cancer. Recent researches including some dominant oncogenes and tumor suppressor gene mutations common to these malignancies are providing bases to elucidate the mechanisms underlying this cancer. The most important basis of endometrial cancer is that K-ras and p53 mutations are also frequently observed.
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PMID:Molecular genetics of gynecologic cancer. 936 94

The clinical application of synthetic tumor peptide-based vaccines is currently limited to patients with specified major histocompatibility complex (MHC) class I alleles. Such logistic limitations may be overcome using tumor gene-based approaches. Here we describe the effective generation of dendritic cells (DC) expressing tumor peptide-MHC complexes as a result of particle-mediated transfer of genes encoding tumor-associated antigens (TAA). Bone marrow-derived DC were transfected with plasmid DNA encoding the tumor-associated viral antigen E7 derived from human papilloma virus (HPV) 16. When applied as a vaccine, these genetically modified DC induced antigen-specific CD8+ cytotoxic T lymphocytes (CTL) in vivo and promoted the rejection of a subsequent, normally lethal challenge with an HPV 16-transformed tumor cell line. Of greatest interest, immunization of mice with syngeneic DC genetically modified to enhance their presentation of a constitutive "self" epitope derived from the tumor-suppressor gene product p53 caused a significant reduction in the in vivo growth of a chemically induced p53-positive sarcoma. These results suggest that cancer vaccines consisting of DC genetically modified to express TAA of viral or "self" origin effectively induce antitumor immunity in vivo.
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PMID:Genetically modified bone marrow-derived dendritic cells expressing tumor-associated viral or "self" antigens induce antitumor immunity in vivo. 936 29

Tumor necrosis factor alpha (TNFalpha) is a cytotoxic/cytostatic compound for a variety of human cancer cells. The p21WAF1 protein is a cyclin-dependent kinase inhibitor (CDKI) that binds to cyclin/cyclin-dependent kinase (CDK) complexes and inhibits their kinase activities, thereby leading to cell cycle arrest. We found that the cytostatic effect of TNFalpha on the cervical cancer cell line, ME180, was concomitant with an arrest of these cells in the G0/G1 phase of the cell-cycle. This corresponded with an increase in both p21WAF1 mRNA and protein levels which likely occurred via a p53-independent pathway since ME180 is infected with the human papilloma virus. To elucidate the role of p21WAF1 in the TNFalpha-mediated growth and cell cycle arrest, we stably transformed ME180 cells with an antisense p21WAF1 expression vector. Two clones with reduced levels of p21WAF1 both in their basal state as well as after their exposure to TNFalpha were selected. The growth of these cells was still inhibited by TNFalpha and they arrested in G0/G1 similar to wildtype or empty vector transfected cells. These results indicate that although p21WAF1 expression increases dramatically with TNFalpha treatment, it may not play a critical role in the cytostatic effect of TNFalpha on ME180 cervical cancer cells.
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PMID:Cytostatic effect of TNFalpha on cancer cells is independent of p21WAF1. 938 Apr 13

B-Myb belongs to a family of related transcription factors which share a unique DNA binding domain. B-Myb plays an important role in regulation of the cell cycle. Its expression is upregulated by the human papilloma virus HPV16 E7 oncoprotein. Overexpression of B-Myb can bypass p53-mediated cell cycle arrest. The founding member of the myb gene family, c-Myb, and A-Myb are involved in hematopoiesis and neurogenesis, respectively, and are both activators of gene transcription. Whether B-Myb is a transactivator or a repressor, however, has remained a matter of discussion. We reviewed the transactivation potential of B-Myb in yeast, taking advantage of the fact that inducible gene activation is an evolutionarily conserved process. By mutational analysis we localized a conserved activation domain in B-Myb. In vertebrate cells the transactivation potential of B-Myb is concealed by the C-terminal part of the protein. We show that the cell cycle regulators cyclin A and cyclin E activate B-Myb by eradicating the inhibition mediated by its carboxy-terminus. Our data suggest that in vertebrates the trans-activating function of B-Myb is regulated during the cell cycle and link Myb functions to cell cycle progression.
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PMID:B-Myb, a repressed trans-activating protein. 942 11

A role for human papilloma virus (HPV) infection in the pathogenesis of head and neck neoplasms has gained support in recent years. Expression of two early-region HPV genes, E6 and E7, is widely accepted as essential for viral-induced carcinomas of the genital tract. These oncoproteins interact with the products of the cellular tumor suppressor genes, p53 and retinoblastoma, and inactivate them. Examining E6/E7 transforming gene expression is an important step toward elucidating the pathogenesis of HPV in head and neck neoplasms. We introduce nasal inverted papilloma (IP) as a novel system for evaluating viral genomic expression and transforming gene regulation of tumorigenesis by virtue of its association to HPV infection and potential for malignant progression. We describe here a reverse transcriptase-polymerase chain reaction approach for the detection of HPV E6/E7-specific transcripts in RNA extracted from IR. A primer pair flanking previously mapped HPV 6 E6/E7 splice donor/acceptor sites was used to direct amplification of cDNA. Reverse transcriptase-polymerase chain reaction experiments generated products representing the 1.2 Kb E1E4 splice transcript and a smaller unclassified fragment in IP from two patients. These results provide evidence for HPV 6 E6/E7 expression in IP with the potential to encode transforming proteins.
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PMID:The HPV 6 E6/E7 transforming genes are expressed in inverted papilloma. 952 9

Recent studies show that 1) the p53 tumor suppressor protein is overexpressed by rheumatoid arthritis (RA) synovium and fibroblast-like synoviocytes (FLS) and 2) somatic mutations previously identified in human tumors are present in RA synovium and FLS. We have hypothesized that abnormalities in p53 can contribute to chronic destructive RA synovitis. To understand the functional consequences of p53 abnormalities in FLS, RA and normal FLS expressing wild-type p53 were transduced with a retroviral vector encoding the human papilloma virus 18 E6 gene, which inactivates endogenous p53 protein. Three RA and one normal FLS lines were infected with recombinant retrovirus encoding the neomycin resistance gene (neo) or E6+neo. FLS proliferation, apoptosis, and invasion was studied in E6, neo, and uninfected parental strains (PS). The growth rate for E6 was significantly increased with a sixfold increase in cell number after 7 days compared with a twofold to threefold increase in neo and PS. When FLS were treated with cytokines, proliferative response of E6, neo, and PS to interleukin-1 and transforming growth factor-beta were similar. However, response to platelet-derived growth factor was significantly greater in E6 FLS compared with neo or PS. Apoptosis was studied by incubating FLS with sodium nitroprusside as a source of nitric oxide or hydrogen peroxide for 8 hours and examining DNA fragmentation and E6 cells were significantly less susceptible to cell death. In addition, E6 FLS were more invasive into cartilage extracts than neo or PS using an in vitro cell invasion assay. These data suggest that p53 is a critical regulator of FLS proliferation, apoptosis, and invasiveness. Abnormalities of p53 function might contribute to synovial lining expansion and joint destruction in RA.
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PMID:Regulation of synoviocyte proliferation, apoptosis, and invasion by the p53 tumor suppressor gene. 954 70


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