Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.1 (ERK)
 95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mouse-transformed keratinocytes cultured in the presence of transforming growth factor beta1 (TGF-beta1) acquire an array of morphologic and functional properties that give rise to a migratory phenotype that expresses mesenchymal molecular markers. This cellular conversion involves activation of the Ras-ERK pathway, enhancement of urokinase (uPA) and matrix metalloproteinase-9 (MMP-9) expression and induction of invasiveness. In our present work, we demonstrate that cAMP and forskolin are able to prevent the expression of these mesenchymal properties, probably due to blockade of the Ras-ERK pathway. Our results also show that cAMP and forskolin are able to abolish the TGF-beta1-induced reorganization of the actin cytoskeleton that is characteristic of the mesenchymal phenotype and also inhibits the disruption of the E-cadherin cell to cell interactions. The latter responses seem to depend on the activity of protein kinase A, as demonstrated by the activation of the Ras-ERK pathway by specific protein kinase A inhibitors.
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PMID:Cyclic AMP inhibits TGFbeta1-induced cell-scattering and invasiveness in murine-transformed keratinocytes. 1456 20

Tight junctions (TJs) are the most apical cell-cell junctions, and claudins, the recently identified TJ proteins, are critical for maintaining cell-cell adhesion in epithelial cell sheets. Based on their in vivo distribution and the results of overexpression studies, certain claudins, including claudin-1 and -4, are postulated to increase, whereas other claudins, especially claudin-2, are postulated to decrease the overall transcellular resistance. The overall ratio among claudins expressed in a cell/tissue has been hypothesized to define the complexity of TJs. Disruption of the TJs contributes to various human diseases, and a correlation between reduction of TJ function and tumor dedifferentiation has been postulated. The epidermal growth factor (EGF) receptor (EGFR) is overexpressed in a wide spectrum of epithelial cancers, and its expression correlates with a more metastatic cancer phenotype. However, normal functioning of EGFR is essential for normal epithelial cell proliferation and differentiation. The role of EGFR-dependent signaling in the development and maintenance of epithelial TJ integrity has not been studied in detail. This study demonstrates that, in polarized Madin-Darby canine kidney II cells, EGF-induced EGFR activation significantly inhibited claudin-2 expression while simultaneously inducing cellular redistribution and increased expression of claudin-1, -3, and -4. Accompanying these EGF-induced changes in claudin expression was a 3-fold increase in transepithelial resistance, a functional measure of TJs. In contrast, there were no alterations in protein expression and/or intracellular localization of other TJ-related proteins (ZO-1 and occludin) or adherens junction-associated proteins (E-cadherin and beta-catenin), suggesting that EGF regulates TJ function through selective and differential regulation of claudins.
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PMID:Epidermal growth factor receptor activation differentially regulates claudin expression and enhances transepithelial resistance in Madin-Darby canine kidney cells. 1459 19

We recently generated transgenic mice expressing the RET proto-oncogene with a multiple endocrine neoplasia type 2A mutation (RET-MEN2A). Mammary tumors with frequent lung metastasis were developed in 22% of female transgenic mice in a stochastic fashion. In the current study, we established two cell lines (named MKK-f and MKK-s) from mammary tumors developed in RET-MEN2A transgenic mice. MKK-f and MKK-s were derived from well-differentiated ductal carcinoma and sarcomatous spindle cell carcinoma, respectively. MKK-f cells show epithelial-like morphology with a doubling time of 19 h, and MKK-s cells show spindle-shaped morphology with a doubling time of 15 h. When inoculated in immunodeficient mice, both cell lines were tumorigenic, metastasized to the lung and displayed histological features similar to those of the primary tumors. They maintained a high level of RET expression and activation of signaling molecules downstream of RET. Consistent with the histological phenotype, expression of E-cadherin was almost undetectable in MKK-s cells, whereas its expression was very high in MKK-f cells. When the difference of gene expression between the two cell lines was analyzed using cDNA microarrays including approximately 900 genes/ESTs, a total of 21 up- or down-regulated (> 2.0-fold) genes were identified. Differentially regulated genes included thymosin beta-10, fibroblast growth factor receptor 4, aldo-keto reductase and caspase 6 genes, which are known to be associated with tumor development and progression. These results may reflect the profiles of the transcriptional changes associated with dedifferentiation or progression of mammary carcinomas developed in genetically engineered mice.
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PMID:Establishment and characterization of mouse mammary carcinoma cell lines expressing RET with a multiple endocrine neoplasia 2A mutation. 1461 77

Transcriptional repression of E-cadherin, characteristic of epithelial to mesenchymal transition, is often found also during tumor cell invasion. At metastases, migratory fibroblasts sometimes revert to an epithelial phenotype, by a process involving regulation of the E-cadherin-beta-catenin complex. We investigated the molecular basis of this regulation, using human colon cancer cells with aberrantly activated beta-catenin signaling. Sparse cultures mimicked invasive tumor cells, displaying low levels of E-cadherin due to transcriptional repression of E-cadherin by Slug. Slug was induced by beta-catenin signaling and, independently, by ERK. Dense cultures resembled a differentiated epithelium with high levels of E-cadherin and beta-catenin in adherens junctions. In such cells, beta-catenin signaling, ErbB-1/2 levels, and ERK activation were reduced and Slug was undetectable. Disruption of E-cadherin-mediated contacts resulted in nuclear localization and signaling by beta-catenin, induction of Slug and inhibition of E-cadherin transcription, without changes in ErbB-1/2 and ERK activation. This autoregulation of E-cadherin by cell-cell adhesion involving Slug, beta-catenin and ERK could be important in tumorigenesis.
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PMID:Autoregulation of E-cadherin expression by cadherin-cadherin interactions: the roles of beta-catenin signaling, Slug, and MAPK. 1462 71

Resveratrol (3,4',5-trihydroxystilbene) is a phytoalexin found in grapes and other food products that can prevent cancer. We studied the in vitro biological activity of this compound by examining its effect on proliferation and inducing apoptosis in three lung cancer cell lines (A549, EBC-1, Lu65). Resveratrol inhibited the growth of A549, EBC-1 and Lu65 lung cancer cells by 50% (ED50) at concentrations between 5-10 microM. We also examined the combined effects in these cells of resveratrol and paclitaxel, an essential chemotherapeutic agent against lung cancer. Although simultaneous exposure to resveratrol plus paclitaxel did not result in significant synergy, resveratrol (10 microM, 3 days) significantly enhanced the subsequent antiproliferative effect of paclitaxel. In addition, resveratrol as well as paclitaxel induced apoptosis in EBC-1 and Lu65 cells, as measured by TUNEL and caspase assays, as well as flow cytometry. Resveratrol (10 microM, 3 days) similarly enhanced the subsequent apoptotic effects of paclitaxel. We examined the effects of resveratrol and paclitaxel on levels of p21waf1, p27kip1, E-cadherin, EGFR and Bcl-2 in EBC-1 cells. Resveratrol (10 microM, 3 days) prior to paclitaxel induced p21waf1 expression approximately 4-fold. These results suggest that resveratrol may be a promising alternative therapy for lung cancer and that lung cancer cells exposed to resveratrol have a lowered threshold for killing by paclitaxel.
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PMID:Combined effects of resveratrol and paclitaxel on lung cancer cells. 1466 16

We performed a retrospective analysis of potential prognostic markers in 260 patients with surgically resected stage I and II non small-cell lung cancer (NSCLC) with a minimum 5-year follow-up. Cox proportional hazard models and Wilcoxon tests were employed to analyze the effect of patient characteristics on survival and disease-free survival (DFS). In the univariate analysis, the following were significant predictors of shorter overall survival: N-stage (N1 vs N0) (p<0.001); T-stage (T2 vs T1) (p<0.001); antigen A (loss vs presence) (p<0.01); cough (present vs absent) (p=0.01); bcl-2 expression (positive vs negative) (p=0.03); age (>63.5 vs <63.5) (p=0.03); mucin (positive vs negative) (p<0.03). The following were significant predictors of shorter DFS: N-stage (p<0.001); T-stage (p=0.001); loss of antigen A (p=0.01); mucin expression (p<0.01); cough (p=0.02); Ki-67 expression (p=0.02) and negative bcl-2 expression (p=0.03). Analysis of survival difference for histologic subtype, degree of differentiation, aneuploidy, %S-phase, codon 12 K-ras mutation, and immunohistochemistry staining for Lewisy, p53, Rb, microvessel count, HER2, E-cadherin and neuroendocrine markers did not reach statistical significance. In multivariate analysis, the following predicted for shorter overall survival: N-stage (p<0.01), antigen A (p=0.01), age (p<0.01), and bcl-2 (p=0.05); and for DFS, N-stage (p<0.01), antigen A (p<0.01), Ki-67 (p=0.03), mucin (p=0.04) and T-stage (p=0.05). Of all the clinical-pathological, proliferative, and biological markers studied, only a few carried independent prognostic significance.
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PMID:Prognostic markers in resected stage I and II non small-cell lung cancer: an analysis of 260 patients with 5 year follow-up. 1472 52

The expression of activated mutants of M-Ras (G22V or Q71L), but not wild-type M-Ras, in a murine mammary epithelial cell line, scp2, resulted in epithelial-mesenchymal transition (EMT) and oncogenic transformation. Cells expressing constitutively active M-Ras continued to grow in the absence of serum and exhibited a loss of the epithelial markers cytokeratin, E-cadherin and beta-catenin, together with a gain of the mesenchymal marker vimentin, a loss of contact inhibition in monolayer growth and a gain of the capacity for anchorage-independent growth. Moreover, unlike the parental cells, they failed to form differentiated mammospheres on Matrigel and instead formed branched networks of cells that grew and invaded the Matrigel. The expression of activated p21 Ras (G12V H-Ras or Q61K N-Ras) also resulted in EMT and tumorigenesis, although there was evidence that expression of higher levels was toxic. Tumors derived from scp2 cells expressing activated M-Ras exhibited activation of Akt and of ERK. The levels of expression of Q71L M-Ras and G12V H-Ras required for tumorigenesis were comparable, although higher levels of the weaker G22V M-Ras mutant were selected for in vivo. These data indicate that the expression of activated mutants of M-Ras was sufficient for oncogenic transformation of a murine mammary epithelial cell line.
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PMID:Expression of activated M-Ras in a murine mammary epithelial cell line induces epithelial-mesenchymal transition and tumorigenesis. 1496 Oct 75

In vitro experiments have shown that the establishment of cell-cell contacts in intestinal epithelial cell cultures is a critical step in initiating ERK inhibition, cell cycle arrest, and induction of the differentiation process. Herein, we determined the mechanisms through which E-cadherin-mediated cell-cell contacts modulate the ERK pathway in intestinal epithelial cells. We report that: (1) removal of calcium from the culture medium of newly confluent Caco-2/15 cells (30 min, 4 mM EGTA) results in the disruption of both adherens and tight junctions and clearly decreases Akt phosphorylation while increasing MEK and ERK activities. Akt, MEK, and ERK activation levels return to control levels 60 min after calcium restoration; (2) the use of E-cadherin blocking antibodies efficiently prevents Akt phosphorylation and MEK-ERK inhibition after 70 min of calcium restoration; (3) using the PI3K inhibitor LY294002 (15 microM) in calcium switch experiments, we demonstrate that the assembly of adherens junctions activates Akt activity and triggers the inhibition of ERK1/2 activities in a PI3K-dependent manner; (4) adenoviral infection of confluent Caco-2/15 cells with a constitutively active mutant of Akt1 strongly represses ERK1/2 activities; (5) inhibition of PI3K abolishes Akt activity but leads to a rapid and sustained activation of the MEK-ERK1/2 in confluent differentiating Caco-2/15 cells, but not in undifferentiated growing Caco-2/15 cells. Our data suggest that E-cadherin engagement leads to MEK/ERK inhibition in a PI3K/Akt-dependent pathway. This mechanism may account for the role of E-cadherin in proliferation/differentiation transition along the crypt-villus axis of the human intestinal epithelium.
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PMID:Down-regulation of MEK/ERK signaling by E-cadherin-dependent PI3K/Akt pathway in differentiating intestinal epithelial cells. 1497 32

Inflammatory breast cancer (IBC) is a rare but very aggressive form of breast cancer. Its definition is based on clinical criteria, but a molecular definition could be useful when data are incomplete or features are missing. Recently, the identification of overexpression of E-cadherin in IBC has improved understanding of the molecular basis of this disease. Consequently, the aim of this study was to try to determine an immunophenotypic 'signature' of IBC. A series of 80 cases of IBC were compared with 552 non-IBC control cases and a model was elaborated to evaluate the probability of an inflammatory carcinoma being present in any clinical situation. Tissue microarrays (TMAs) were used to determine the immunohistochemical profile of eight proteins including E-cadherin, EGFR, oestrogen and progesterone receptor (ER and PR), MIB1, ERBB2, MUC1, and P53. All the parameters tested were differentially expressed between IBC and control cases in univariate analysis (p < 0.001). The five variables that were significantly associated with IBC in multivariate analysis were E-cadherin > or = 300 [HR = 5.64 (2.92-10.87)], ER negative [HR = 3.00 (1.67-5.51)], MIB1 > 20 [HR = 3.54 (1.87-6.71)], MUC1 cytoplasmic staining [HR = 2.72 (1.49-4.96)], and ERBB2 positive 2+ or 3+ [HR = 2.46 (1.26-4.78)]. The probability that a breast cancer with this full phenotype at diagnosis was an IBC was 90.5%. If any one of the five parameters was missing, this probability dropped to 75% and was less than 50% when one, two, or three parameters were present. The 5-year overall survival (OS) and 5-year disease-free survival (DFS) of patients with IBC were not significantly different from those of the non-IBC control group that expressed four or five parameters (nIBC-1), but this nIBC-1 control group had a significantly worse outcome than the non-IBC control group (nIBC-2) with only 0-3 parameters (p = 0.0049 for OS and p < 0.0001 for DFS). In conclusion, an immunophenotypic signature was suggested for IBC. This could help to determine the worst cases, independent of clinical criteria.
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PMID:Immunophenotypic analysis of inflammatory breast cancers: identification of an 'inflammatory signature'. 1499 91

Mammary small cell carcinoma (SmCC) is a very rare neoplasm with a poor prognosis compared with other invasive carcinomas. We studied the histological and immunohistochemical profiles of two cases of mammary SmCC, and compared them with those of five cases of carcinoma with endocrine features (CEF) and five cases of invasive ductal carcinoma (IDC), to elucidate the correct diagnosis of mammary SmCC. Immunohistochemical analysis was performed with antibodies against cytokeratins (CKAE1/AE3, CK34betaE12, CKCAM5.2, CK7, CK8, CK19, CK20), epithelial membrane antigen (EMA), vimentin, CD10, neural cell adhesion molecule (NCAM; CD56), neuron-specific enolase (NSE), chromogranin A, S-100 protein, carcino-embryonic antigen (CEA), E-cadherin, N-cadherin, thyroid transcription factor-1 (TTF-1), p53, estrogen (ER), progesterone (PR), HER2/neu, bcl-2, synaptophysin, calcitonin and Leu7. SmCCs were diffusely and strongly positive for NCAM in comparison with CEFs and IDCs. SmCCs were negative for vimentin, whereas CEFs and IDCs were positive. Neuro-endocrine carcinomas, including SmCCs and CEFs, were diffusely and strongly positive for NSE, compared with IDCs. Moreover, neuroendocrine carcinomas were negative for CK34betaE12, CK20 and CD10, whereas IDCs were positive. Our study suggests that NCAM and vimentin are useful markers for the diagnosis of mammary SmCC. CK34betaE12, NSE, CD10, CK20 and chromogranin A appear to be useful for differentiating neuroendocrine carcinoma from IDCs.
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PMID:Comparative study of primary mammary small cell carcinoma, carcinoma with endocrine features and invasive ductal carcinoma. 1501 Aug 80


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