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)

Oncogenes enhance the expression of cyclooxygenase (Cox)-2, but interactions between tumor suppressor genes and Cox-2 have not been studied. In the present work, we have compared the levels of Cox-2 and the production of prostaglandin E2 in mouse embryo fibroblasts that do not express any p53 ((10)1) versus the same cell line ((10. 1)Val5) engineered to overexpress wild-type (wt) p53 at 32 degrees C or mutant p53 at 39 degrees C. Cells expressing wt p53 showed about a 10-fold decrease in synthesis of prostaglandin E2 compared with those expressing mutant p53. Levels of Cox-2 protein and mRNA were markedly suppressed by wt p53 but not by mutant p53. Nuclear run-offs revealed decreased rates of Cox-2 transcription in cells expressing wt p53. The activity of the Cox-2 promoter was reduced by 85% in cells expressing wt p53 but was reduced only by 30% in cells expressing mutant p53 compared with cells null for p53. The effect of p53 on the suppression of Cox-2 promoter activity was localized to the first 40 base pairs 5' from the transcription start site. Electrophoretic mobility shift assay revealed that p53 competed with TATA-binding protein for binding to mouse Cox-2 or human Cox-2 promoter extending from -50 to +52 base pairs. The results of this study suggest that interactions between p53 and Cox-2 could be important for understanding why levels of Cox-2 are undetectable in normal cells and increased in many tumors.
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PMID:Inhibition of cyclooxygenase-2 gene expression by p53. 1019 69

We have previously shown that bladder urothelium of people living in the cesium-137 ((137)Cs)-contaminated areas of Ukraine demonstrates accumulation of stable p53 and p53 mutational inactivation, preferentially through G:C to A:T transition mutations at CpG dinucleotides, with a codon 245 hot spot. In the present study, we analyzed immuno-histochemically the relationship between oxidative stress markers and over-expression of p53 and H-ras in urinary bladder urothelium from 42 men with benign prostatic hyperplasia. Bladder mapping biopsies were obtained from 15 patients from a highly radiocontaminated area (group I), 14 patients from the less contaminated city of Kiev (group II) and 13 patients as a control group from "clean" (without radiocontamination) areas of Ukraine (group III). Irradiation cystitis with multiple foci of severe dysplasia and carcinoma in situ were observed in 15 of 15 (100%, group I) and 9 of 14 (64%, group II) cases, with 4 small transitional-cell carcinomas incidentally detected in groups I and II. Markedly elevated levels of inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2) and 8-hydroxy-2;-deoxyguanosine (8-OHdG) were noted in these bladder urothelial lesions from groups I and II, accompanied by strong over-expression of p53 and less H-ras expression. These findings support the hypothesis that iNOS, COX-2 and 8-OHdG in bladder urothelium are induced by long-term exposure to low-dose radiation with a close relationship to p53 over-expression that could predispose to bladder carcinogenesis.
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PMID:Increased oxidative stress with gene alteration in urinary bladder urothelium after the Chernobyl accident. 1084 92

Resveratrol, a trihydroxystilbene found in grapes and other plants, has been shown to be active in inhibiting multistage carcinogenesis. Using resveratrol as a prototype, we have synthesized a number of polyhydroxy- and polymethoxy-stilbenes and tested their anti-proliferative effect in normal and transformed human cells. Here we show that one of the resveratrol analogs, 3,4,5,4'-tetrahydroxystilbene (R-4), specifically inhibited the growth of SV40 virally transformed WI38 cells (WI38VA) at 10 microM, but had no effect on normal WI38 cells at even higher concentrations. R-4 also prominently induced apoptosis in WI38VA cells, but not in WI38 cells. RNase protection assay showed that R-4 significantly induced the expression of p53, GADD45 and Bax genes and concomitantly suppressed the expression of bcl-2 gene in WI38VA, but not in WI38 cells. A large increase in p53 DNA binding activity and the presence of p53 in the Bax promoter binding complex suggested that p53 was responsible for the Bax gene expression induced by R-4 in transformed cells. Within 4 h of treatment with R-4, the Bax to bcl-2 protein ratio in WI38 and WI38VA cells was, respectively, 0.1 and 105, a difference of three orders of magnitude. While R-4 prominently induced the p53/Bax pro-apoptotic genes, it also concomitantly suppressed the expression of Cox-2 in WI38VA cells. Taken together, our study suggests that the induction of p53 gene by R-4 in transformed cells may play a key role in the differential growth inhibition and apoptosis of transformed cells.
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PMID:Resveratrol analog, 3,4,5,4'-tetrahydroxystilbene, differentially induces pro-apoptotic p53/Bax gene expression and inhibits the growth of transformed cells but not their normal counterparts. 1118 55

Barrett esophagus is a premalignant condition that may progress to adenocarcinoma. The risk of developing cancer has been estimated to be approximately 1 in 250 patient-years of observation; however, there appear to be subsets of patients at much higher risk. Risk stratification has previously been determined by histological identification of dysplasia. Several new biomarkers are being tested to help clinicians better determine the risk of cancer development. Although none of these biomarkers has been proven in a prospective study to predict the onset of cancer, they have been correlated with cancer development. Most of these are factors that have been associated with cancer development in other organs. These include assessment of cell proliferation, expression of cyclooxygenase 2, growth factors and oncogenes, secretory factors, cell cycle proteins, adhesion molecules, and aneuploidy and other genetic abnormalities. In addition to their role as potential cancer biomarkers, these factors have increasingly been reported as surrogate markers to monitor the effectiveness of conservative treatments for Barrett esophagus. In this article, biological markers are reviewed for their relevance in Barrett esophagus. Although most biological markers need to be evaluated further and, for most, prospective follow-up studies are lacking, at present abnormal ploidy status, P16 and P53 gene abnormalities, or allelic losses are the most extensively documented.
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PMID:Biomarkers in Barrett esophagus. 1132 62

Laminin-5 is an extracellular matrix protein that plays a key role in cell migration and tumor invasion. Cox-2 is an induced isoform of cyclooxygenases that plays an important role in carcinogenesis, suppression of apoptosis, angiogenesis, and metastasis of colon cancer. We report frequent co-expression of cox-2 and laminin-5 at the invasive front of early-stage lung adenocarcinomas. We investigated the expression of cox-2 and laminin-5 immunohistochemically in 102 cases of small-sized lung adenocarcinoma (maximum dimension, 2 cm or less). Cox-2 and laminin-5 were expressed in 97 (95.1%) and 82 (80.4%) cases, respectively. Both were preferentially localized in cancer cells at the cancer-stroma interface, although cox-2 tended to show a diffuse staining pattern in some cases. A comparison of their staining patterns revealed a striking similarity in their distribution in 24 cases, and a partial overlap between their localization in another 20 cases. Moreover, an overall correlation was found between the expression levels of cox-2 and laminin-5 (P = 0.018). To gain insight into the mechanisms that regulate the expression of these proteins, we additionally studied their expression in 58 cases of stage I lung adenocarcinoma, in which p53 status was determined by immunohistochemistry, polymerase chain reaction-single strand conformation polymorphism analysis, and direct sequencing. The results showed that tumors with mutant p53 tended to express more cox-2 than those with wild-type p53 (P = 0.080). Also, tumors that overexpressed p53 had higher levels of cox-2 and laminin-5 than those without p53 overexpression (P = 0.032 and 0.047, respectively). Further immunohistochemical analysis showed that tumors that overexpressed both epidermal growth factor receptor (EGFR) and erbB-2 had higher levels of cox-2 and laminin-5 than those without concomitant overexpression of these proteins (P = 0.014 and P = 0.018, respectively). To see whether EGFR signaling is involved in cox-2 and laminin-5 expression, we further conducted in vitro analyses using six lung adenocarcinoma cell lines (A549, HLC-1, ABC-1, LC-2/ad, VMRC-LCD, and L27). Western blot analyses showed that cox-2 mRNA levels, and to a lesser extent laminin-5 gamma2 mRNA levels, correlated with the expression levels of erbB-2 and the phosphorylated form of MAPK/ERK-1/2 protein. The addition of transforming growth factor-alpha increased both cox-2 and laminin-5 gamma2 mRNA levels in A549, ABC-1, and L27 with different kinetics; the induction of cox-2 occurred earlier than that of laminin-5 gamma2. Finally, the migration of ABC-1 cells was inhibited by MAP kinase kinase inhibitor PD98059 and a selective cox-2 inhibitor NS-398. In contrast, the migration of A549 cells was inhibited by PD98059, but much less effectively by NS-398. These results suggest that co-stimulatory mechanisms may exist that increase the expression of cox-2 and laminin-5 at the invasive front of lung adenocarcinomas and that EGFR signaling could be one of the mechanisms. Further investigations are warranted concerning the role of cox-2 and laminin-5 in cancer cell invasion and the significance of p53 and EGFR signaling in the regulation of cox-2 and laminin-5 expression.
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PMID:Frequent co-localization of Cox-2 and laminin-5 gamma2 chain at the invasive front of early-stage lung adenocarcinomas. 1189 Dec 9

Current tumor, node, and metastasis (TNM) staging and grading systems are insufficient to accurately predict the evolution of most invasive bladder cancers irrespective of treatment. Predicting which invasive tumors will or will not recur or metastasize early is crucial in order to dictate initial therapy and to better counsel the patient. A need for tumor markers that could be incorporated into clinical practice to add prognostic information to the conventional TNM and grading systems in terms of treatment response and prognosis is crucial. This review provides an update on the most promising reported single markers and pathways, including the cell cycle markers p53, p21 and p27, and potential targets for novel therapies, such as cyclooxygenase 2 (COX 2) and factors of angiogenesis. The critical steps remain the availability of large and well-characterized data sets to validate the combination of markers, as well as high throughput methods to study tumor molecular fingerprints, such as DNA microarrays.
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PMID:Prognostic markers in muscle invasive bladder cancer. 1219 3

The identification of transcriptional targets of the tumor suppressor p53 is crucial in understanding mechanisms by which it affects cellular outcomes. Through expression array analysis, we identified cyclooxygenase 2 (Cox-2), whose expression was inducible by wild-type p53 and DNA damage. We also found that p53-induced Cox-2 expression results from p53-mediated activation of the Ras/Raf/MAPK cascade, as demonstrated by suppression of Cox-2 induction in response to p53 by dominant-negative Ras or Raf1 mutants. Furthermore, heparin-binding epidermal growth factor-like growth factor (HB- EGF), a p53 downstream target gene, induced Cox-2 expression, implying that Cox-2 is an ultimate effector in the p53-->HB-EGF-->Ras/Raf/MAPK-->Cox-2 pathway. p53-induced apoptosis was enhanced greatly in Cox-2 knock-out cells as compared with wild-type cells, suggesting that Cox-2 has an abrogating effect on p53-induced apoptosis. Also, a selective Cox-2 inhibitor, NS-398, significantly enhanced genotoxic stress-induced apoptosis in several types of p53+/+ normal human cells, through a caspase-dependent pathway. Together, these results demonstrate that Cox-2 is induced by p53-mediated activation of the Ras/Raf/ERK cascade, counteracting p53-mediated apoptosis. This anti-apoptosis effect may be a mechanism to abate cellular stresses associated with p53 induction.
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PMID:P53-mediated induction of Cox-2 counteracts p53- or genotoxic stress-induced apoptosis. 1241 81

Interferon-gamma (IFN-gamma) induces cell-cycle arrest and p53-independent apoptosis in primary cultured hepatocytes. However, the detailed mechanism, including regulating molecules, is still unclear. In this study, we found that IFN-gamma induced generation of reactive oxygen species (ROS) in primary hepatocytes and that pyrrolidinedithiocarbamate (PDTC), an anti-oxidant reagent, completely suppressed IFN-gamma-induced hepatic apoptosis. PDTC blocked apoptosis downstream from IRF-1 and upstream from caspase activation, suggesting that the generation of ROS occurred between these stages. However, IFN-gamma also induced the generation of ROS in IRF-1-deficient hepatocytes, cells insensitive to IFN-gamma-induced apoptosis. Moreover, a general cyclooxygenase (COX) inhibitor, indomethacin (but not the cyclooxygenase 2-specific inhibitor, NS-398) also inhibited the apoptosis without blocking the generation of ROS. Both PDTC and indomethacin also blocked IFN-gamma-induced release of cytochrome c from mitochondria. These results suggest that ROS are not the only or sufficient mediators of IFN-gamma-induced hepatic apoptosis. In contrast, we also found that IFN-gamma induced endoplasmic reticulum (ER) stress proteins, CHOP/GADD153 and caspase 12, in wild-type primary hepatocytes, but induced only caspase 12 and not CHOP/GADD153 protein in IRF-1-deficient hepatocytes. These results suggest that IFN-gamma induces ER stress in primary hepatocytes. Both the ROS and ER stress induced by IFN-gamma may be complementary mediators that induce apoptosis in primary hepatocytes.
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PMID:Interferon-gamma induces reactive oxygen species and endoplasmic reticulum stress at the hepatic apoptosis. 1270 88

Cyclooxygenase-2 (cox-2) overexpression has been observed in several types of human cancers and has been implicated in carcinogenesis. To elucidate the role of cox-2 in esophageal carcinogenesis, we evaluated the expression of cox-2 in normal squamous epithelium squamous epithelial dysplasia (n=47), and squamous cell carcinoma of the esophagus (n=86) by immunohistochemistry, reverse transcription-PCR assay, and western blotting. A significant overexpression of cox-2 was observed in esophageal squamous dysplasia and squamous cell carcinoma compared with normal squamous epithelium. The immunoreactive score of cox-2 expression, an index determined by intensity and positivity of cox-2 staining, was 0.71 +/- 0.46 (mean +/- SD) in normal squamous esophagus, 2.19 +/- 1.79 in squamous epithelial dysplasia, and 2.67 +/- 1.77 in squamous cell carcinoma. The results of immunohistochemistry were confirmed by a reverse transcription-PCR assay and western blotting analysis. Cox-2 expression level was correlated with proliferation activity assessed by proliferating cell nuclear antigen (PCNA) index and MIB-1 index in dysplastic lesion (r=0.55, P<0.01 with PCNA and r=0.72, P<0.01 with MIB-1) and carcinoma (r=0.56, P<0.01 with PCNA and r=0.72, P<0.01 with MIB-1). Elevated cox-2 expression was associated with high p53 expression (p<0.001) but not with clinicopathological features including age, sex, tumor size, histological grade, lymph node metastasis, and TNM stage. The results indicated that cox-2 may be involved in an early stage of squamous carcinogenesis of the esophagus, and that cox-2 overexpression was related to cell proliferation in esophageal squamous dysplasia and squamous cell carcinoma.
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PMID:Cyclooxygenase-2 expression in squamous dysplasia and squamous cell carcinoma of the esophagus. 1295 58

Clinical and pathological heterogeneity of breast cancer hinders selection of appropriate treatment for individual cases. Molecular profiling at gene or protein levels may elucidate the biological variance of tumors and provide a new classification system that correlates better with biological, clinical and prognostic parameters. We studied the immunohistochemical profile of a panel of seven important biomarkers using tumor tissue arrays. The tumor samples were then classified with a monothetic (binary variables) clustering algorithm. Two distinct groups of tumors are characterized by the estrogen receptor (ER) status and tumor grade (p = 0.0026). Four biomarkers, c-erbB2, Cox-2, p53 and VEGF, were significantly overexpressed in tumors with the ER-negative (ER-) phenotype. Eight subsets of tumors were further identified according to the expression status of VEGF, c-erbB2 and p53. The malignant potential of the ER-/VEGF+ subgroup was associated with the strong correlations of Cox-2 and c-erbB2 with VEGF. Our results indicate that this molecular classification system, based on the statistical analysis of immunohistochemical profiling, is a useful approach for tumor grouping. Some of these subgroups have a relative genetic homogeneity that may allow further study of specific genetically-controlled metabolic pathways. This approach may hold great promise in rationalizing the application of different therapeutic strategies for different subgroups of breast tumors.
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PMID:Tissue microarray study for classification of breast tumors. 1456 24


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