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)

To understand the role of the Src homology 2 (SH2) domain protein Shb in the signal transduction of tyrosine kinase receptor, NIH3T3 cells were transfected with a DNA construct expressing the Shb cDNA (NIHSHB cells). The NIHSHB cells expressed elevated levels of proteins with the estimated molecular weights of 77, 66 and 55 kDa as determined by immunoblotting. In contrast to the control cells, the NIHSHB cells failed to increase in cell number in the presence of 1% serum. This effect was largely due to apoptosis, since staining of pyknotic nuclei was observed using the terminal transferase labeling method. The NIHSHB cells displayed similar levels of c-myc mRNA and decreased contents of the p53 protein after culture in 1% serum compared with control cells. The addition of platelet-derived growth factor (PDGF-BB) restored the growth of the NIHSHB cells, whereas insulin-like growth factor-1 (IGF-1) failed to affect the proliferation of Shb overexpressing cells in 1% serum. We conclude that Shb overexpression is associated with cell degeneration under certain conditions, and that Shb could transduce apoptotic signals from tyrosine kinase receptors.
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PMID:Apoptosis of NIH3T3 cells overexpressing the Src homology 2 domain protein Shb. 880 85

A new cell line (LR10.6) with pre-B cell phenotype has been established from bone marrow cells obtained from a child with B lineage acute lymphoblastic leukemia in complete clinical remission. The line expresses nuclear TdT enzyme, cytoplasmic Ig lambda-chain and membrane mu-chain and other B but no T or myeloid markers. The cells also show activation antigens CD69 and CD71, adhesion molecules CD54, CD50 and CD56 and the tyrosine kinase receptor CD117. No expression of multidrug resistance phenotype MDR-1 is observed on these cells which nevertheless express the transcriptional factor p53 protein in a mutant form. Cytogenetic study shows a translocation t(5;12)(q31;p13) involving breakpoints which contain the growth factor interleukin 3 gene (5q31) and the recently identified TEL/ETV6 gene (12p13). Activation of the cells with phorbol-12 myristate 13-acetate (PMA) up-regulates the expression of the CD69 activation antigen and down-regulates the CD117 molecule. In addition, PMA fails to induce the CD20 B cell antigen.
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PMID:A new human cell line with pre-B cell phenotype and t(5;12). 920 88

Spi-1/PU.1 is a myeloid- and B-cell specific transcription factor which is also involved in Friend virus-induced murine erythroleukemia. The pre-leukemic phase of Friend erythroleukemia results from activation of the erythropoietin receptor (EpoR) by the spleen focus forming virus (SFFV) envelope glycoprotein, followed by the emergence of leukemic clones characterized by overexpression of Spi-1 and mutation of the p53 tumor suppressor gene. We developed a heterologous system to analyze the contribution of these alterations to the induction of primary erythroblast transformation. Avian erythroblasts expressing the activated mouse EpoR(R129C) differentiated into erythrocytes in response to hEpo. Expression of Spi-1 in these cells inhibited this ability to differentiate and rescued the cells from the apoptotic cell death program normally induced upon hEpo withdrawal. Although devoid of any effect by itself, a mutant p53 cooperated with Spi-1 and EpoR(R129C) to reinforce both phenotypes. Analysis of erythroblasts co-expressing Spi-1 and the wild-type mouse EpoR showed that differentiation arrest and inhibition of apoptosis depended on specific cooperation between Spi-1 and EpoR(R129C). This cooperation was also required to induce the sustained proliferation of differentiation-blocked erythroblasts in response to ligand activation of the endogenous tyrosine kinase receptor c-Kit. These results show that Spi-1/PU.1 requires signals emanating from specific cytokine and growth factor receptors to affect the survival, proliferation and differentiation control of primary erythroblasts. They also suggest that the function of Spi-1/PU.1 in the late phase of Friend leukemia requires specific signaling from the gp55-modified EpoR generated during the early phase of the disease.
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PMID:Cooperation of Spi-1/PU.1 with an activated erythropoietin receptor inhibits apoptosis and Epo-dependent differentiation in primary erythroblasts and induces their Kit ligand-dependent proliferation. 931 23

Overexpression of the erbB-2 tyrosine kinase receptor, p185erbB-2, is a common alteration in non-small cell lung cancer (NSCLC) and has been associated with poor prognosis and a tumor drug resistance phenotype. In this study, we have examined the consequences of erbB-2 depletion on DNA repair, cell cycle, and apoptosis using a panel of NSCLC cell lines constitutively overexpressing erbB-2 receptor. Depletion of the erbB-2 was achieved using the tyrosine kinase inhibitor CP127,374 which promotes erbB-2 degradation. Treatment with CP127,374 concentrations which deplete erbB-2 and inhibit tyrosine phosphorylation resulted in downregulation of DNA repair mechanisms and cell accumulation at G1 phase of the cell cycle. GI arrest was observed in cells with mutated p53 as well as cells lacking p53 protein, suggesting a p53-independent mechanisms. NSCLC cells which overexpress erbB-2 were more resistant to cisplatin-induced cytotoxicity in comparison to cells expressing low levels of erbB-2. Treatment with CP127,374 alone did not result in any induction of apoptosis. A combination of CP127,374 and cisplatin, however, was more potent in cell growth inhibition and induction of apoptosis compared to treatment with cisplatin alone. Together, our results further support a pivotal role of erbB-2 signaling in the regulatory balance between DNA repair, cell cycle checkpoints and apoptosis; all these mechanisms are essential determinants for tumor cell destiny following chemotherapy stress.
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PMID:Dual effect of erbB-2 depletion on the regulation of DNA repair and cell cycle mechanisms in non-small cell lung cancer cells. 987 33

Prognosis of infants born with sacrococcygeal teratomas (SCTs) correlates with gestational age (GA). The survival rate after 30 weeks of gestation is 75%, compared to 7% before 30 weeks of gestation. Studies correlating GA with size, morphologic composition of teratomas, ploidy or expression of cell cycle control proteins such as p53, and ret [a tyrosine kinase receptor of the GDNF (glial cell line-derived neurotrophic factors)] receptor family may provide information explaining differences in survival. Seven SCTs (GA 21 to 41 weeks), ranging in size from 5 to 15 cm, were evaluated for morphologic composition. DNA ploidy was assessed in mature and immature neural elements. Immunohistochemical reactivity with monoclonal antibodies recognizing p53, and ret was quantitated and correlated with morphological pattern and GA. Relative size of teratomas to infants' weight and content of immature neural tissues correlated inversely with advancement of GA. Yolk sac tumor (YST) and immature tissues showed aneuploid cell populations. Nuclear p53 reactivity was apparent in the teratoma with YST in the microcystic patterns, the neuroectodermal rosettes, and the glandular patterns. Ret reactivity was seen in osteoclasts adjacent to bone formation surrounding developing teeth in an immature teratoma, and in rare mature neural cells of one SCT of 35 weeks GA. The rapid growth of SCT (GA <30 weeks) correlates with increase in immature neural tissues. Our study confirms aneuploidy in YST and suggests aneuploid populations within immature tissues. p53 accumulates in a variety of patterns of YST and may be seen in immature components of SCTs. To understand the possible role of ret, further studies comparing ret expression in immature human tissues are needed.
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PMID:Congenital sacrococcygeal teratomas: effect of gestational age on size, morphologic pattern, ploidy, p53, and ret expression. 1074 11

The insulin-like growth factors (IGFs) are a ubiquitous family of growth factors, binding proteins and receptors that are involved in normal growth and development. They are also implicated in numerous pathological states, including malignancy. IGF-II is a commonly expressed growth factor in many tumors and may enhance tumor growth, acting via the overexpressed IGF-I receptor, a cell-surface tyrosine kinase receptor. The IGF-I receptor may be overexpressed due to mutations in tumor suppression gene products such as p53 and WT-1 or growth factors such as bFGF and PDGF. Thus, this family of growth factors, especially the IGF-I receptor, may present an excellent target for new therapeutic agents in the treatment of cancer and other disorders of excessive cellular proliferation.
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PMID:New concepts in regulation and function of the insulin-like growth factors: implications for understanding normal growth and neoplasia. 1095 Mar 8

Thyroid nodule genesis may be considered as an amplification of thyroid heterogeneity due to genetic and/or epigenetic mechanisms. We classified the thyroid nodules in five types with distinct histological features: hyperplastic, neoplastic, colloid, cystic and thyroiditic nodules. Hyperplastic: Thyrocyte proliferation is under the control of TSH but several other paracrine and autocrine factors are secreted by follicular cells, the stromal apparatus and the lymphocytes, which are implicated in initiation and perpetuation of thyroid hyperplasia. Growth occurs mainly through TSHR, cAMP and PKA. Constitutive cAMP overproduction has been shown to be due to point mutation of the TSHR or Gs protein, producing overgrowth and hyperfunction. Neoplastic: Several activated oncogenes have been identified in thyroid malignancies. Oncogenes relevant to the thyroid carcinogenesis are: mutated TSHR and gsp (constitutive activation of cAMP); TRK (receptor for NGF); RET/PTC (phosphorylation of tyrosine kinase receptor)--an isoform of this oncogene is induced by radiation: ras (it encodes Gs proteins transducing mitogenic signals); and c-MET (receptor for hepatocyte growth factor). The evolution of a differentiated thyroid cancer towards an undifferentiated cancer is due to a mutation of a family of proteins (i.e., p53), which acts as a brake, preventing the genomic instability of cancer. It is suggested that a tumor initiates by RET or ras and possibly progresses--as a result of additional mutations and by p53 mutation--to anaplastic carcinoma. Colloid: Flattening of the epithelium and dilatation of follicles containing viscous material--made up by a concentrated solution of thyroglobulin (hTg)--is the characteristic of the colloid nodule. A defect of intraluminal reabsorption of hTg has been suggested but not proven. Experimentally, a load of iodine is able to change thyroid hyperplasia to a colloid feature; however, a load of iodine is rarely found in the clinical history of patients. A new clue to the pathogenesis comes from the finding that a relevant part of the colloid (10-20%) is made up of insoluble globules, where hTg is compacted in a polymeric form. It is suggested that stocking hTg into globules is defective in colloid nodules, leading to enormous enlargement of the follicle. Cystic: It is estimated that between 15 and 40% of thyroid nodules are partly or entirely cystic. The 'true cyst' is rare; most of the so-called cystic nodules are 'pseudocysts', which follow necrosis and colliquation. Necrosis issues as an imbalance between growth and the precisely regulated process of angiogenesis. More recently, the VEGF/VPF has been found to be at the origin of recent and recurrent cysts. Immunotoxic and apoptotic mechanisms have also been suggested. Chemical analysis of cystic fluid showed a 'denatured' and 'serum-like' pattern suggesting different mechanisms in the pathogenesis of the pseudocystic thyroid nodules. Thyroiditic: Nodular lymphocytic thyroiditis (NLT) includes two different entities: 1) lymphocyte thyroiditis growing as a nodule in a hyperplastic or normal gland, and 2) lymphocyte thyroiditis associated in the same nodule with other nodular diseases of the thyroid: papillary thyroid carcinoma and lymphoma have been found to be associated to chronic lymphocytic thyroiditis.
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PMID:Pathogenesis of thyroid nodules: histological classification? 1123 84

The prognosis of pancreatic carcinoma is dismal. Its main reason can be attributed to the difficult early diagnosis. In fact, at diagnosis most patients show advanced disease. In recent years, studies on the biomolecular characteristics of this disease have been conducted. The obtained results have favored the understanding of the basic mechanisms of the biologic aggressiveness and the resistance to chemoradiation of pancreatic carcinoma. They include the frequent oncogene activation as well as the similarly frequent suppressor gene inhibition. Based on this new knowledge, novel therapeutic strategies have been identified and treatments of targeting the ras oncoprotein or mutated p53, metalloproteinase inhibitors and tyrosine kinase receptor inhibitors (trastuzumab and cetuximab) together with antiangiogenic therapies are under experimentation.
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PMID:Biological factors and therapeutic modulation in pancreatic carcinoma radiotherapy. 1269 52

Metastasis is usually responsible for mortality in patients suffering from muscle invasive bladder cancer. Whilst expression of a great number of genes and their protein products have been associated with metastasis and/or poor prognosis in bladder cancer, evidence that they actively drive the metastatic process, and hence make potentially good therapeutic targets, is often lacking. This is due to the limited number and application of effective animal models which reflect the pathogenesis of the human disease. In this review I will discuss the processes involved in metastasis, consider the established animal models of bladder cancer progression and metastasis, and review the evidence for a role of various gene products in this process. Consideration of clinical studies in conjunction with evidence from experimental animal models reveals that the tyrosine kinase receptor erbB1/EGFR, the calcium binding protein S100A4 and the the cell cycle arrest/apoptosis-inducing p53 protein are amongst the most promising targets for therapy against metastatic disease in patients with bladder cancer.
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PMID:Gene products involved in metastasis of bladder cancer. 1279 7

The EphA2 tyrosine kinase receptor is frequently overexpressed in ovarian cancer and this feature is predictive of poor clinical outcome. Preclinical investigation has also linked EphA2 with p53. In our present study, we examined EphA2 and p53 status (both expression and full-length mutation status) in 6 ovarian cell lines and 79 human ovarian cancers to determine potential associations. EphA2 was overexpressed in 80% of ovarian cancer cell lines and in 75% of clinical specimens. In particular, high levels of EphA2 occurred in 91% of tumors with p53 null mutations compared to 68% in tumors with wild-type or missense mutations (p=0.027). EphA2 expression did not relate to critical versus non-critical site missense p53 mutations or the location of mutations on specific p53 exons. We also demonstrated that while EphA2 and p53 can provide independent information regarding clinical status, the combination of EphA2 and p53 status can predict poor clinical outcome. In particular, the combination of EphA2 overexpression and p53 null status was associated with decreased overall patient survival and related to increased incidence of ascites and distant metastasis. Taken together, these data indicate a complex relationship between EphA2 and p53 that appears to regulate EphA2 expression and clinical outcome.
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PMID:Analysis of EphA2 expression and mutant p53 in ovarian carcinoma. 1742 37


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