Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Selenium has been associated with anticancer activity by affecting multiple cellular processes. We reasoned that the simultaneous modulation of multiple radioresponse regulators by selenium should increase radiosensitivity if selenium is combined with radiation in cancer therapy. Therefore, we explored the possibility of whether we could obtain an enhancement of radiosensitivity by the combination of selenium and ionizing radiation. We used two human lung cancer cell lines, NCI-H460 and H1299, as well as a human diploid lung fibroblast, WI-38, as the normal cell counterpart. The combined treatment of the cancer cell lines with Seleno-methionine and ionizing radiation resulted in increased cell killing as assessed by clonogenic survival assay whereas it had little effect on the normal diploid WI-38 cells. The increased radiosensitivity in the cancer cells was correlated with the attenuation of the key proteins involved in either cell survival signaling [Akt, EGFR (epidermal growth factor receptor), ErbB2 and Raf1] or DNA damage response (Mre11, Rad50, Nbs1, Ku80, 53BP1 and DNAPK). The attenuation of the proteins by the selenium compound was possibly caused by the effect on transcription and on protein stability since selenium treatment decreased both the RNA transcript and the protein stability of EGFR and DNAPK. By contrast, Seleno-L-methionine had no effect on the protein profile of a normal diploid fibroblast which is consistent with an intact radiosensitivity. These data provide possible clinical applications, as selenium selectively enhanced the radiosensitivity of the tumor cells whereas that of the normal cells was unaffected. Moreover, the selective decrease of cell proliferation signaling in tumor cells but not in normal cells should facilitate the repopulation of normal cells required for healing during radiation therapy. On the whole, the results suggest that the cancer preventive activity of selenium can be combined with ionizing radiation to improve the control of lung cancer.
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PMID:Enhanced lung cancer cell killing by the combination of selenium and ionizing radiation. 1714

High-selenium containing yeast is being evaluated in clinical trials against colon polyp recurrence. However, the molecular targets for the anticancer effects of selenium remain unclear. Previous studies by our group demonstrated that selenomethionine-induced growth arrest appears to be mediated by activation of ERK and subsequent phosphorylation of RSK and histone H3. These results suggest that selenomethionine can alter gene expression. In the present study, we have used cDNA microarrays to determine whether gene expression differences exist in HCT116 colon cancer cells treated with selenomethionine. These experiments reveal statistically significant expression changes for 50 genes. Genes we found to increase with selenomethionine treatment include KLK6, ATOX1, SGK, GJB2, DAP-1, PLAU, VIM, DPYSL2, STC2 and PXN. Conversely, genes downregulated by selenomethionine include PRKACB, LIM, DEPP, MYC, CDH5, ELF3, VSNL1, SAT and EGLN3. Further analysis of those genes using chromatin immunoprecipitation experiments showed that phosphorylated histone H3 on serine 10 bound to the GJB2 promoter (connexin 26) or the serum glucocorticoid kinase promoter is increased with selenomethionine treatment. Cells overexpressing CX26 or DAP-1 displayed a reduced number of colonies which suggests that these two genes could play a functional role in the growth inhibitory effects of selenomethionine. These data support the notion that selenomethionine-induced growth inhibition is associated with global changes in gene expression. They also demonstrate that selenomethionine can modify chromatin state to alter gene transcription. Finally, our studies provide a practical foundation for the further development of biomarkers to monitor the efficacy of selenomethionine in clinical trials.
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PMID:Profiling of selenomethionine responsive genes in colon cancer by microarray analysis. 1737 85

Type 2 deiodinase (D2) and type 3 deiodinase (D3) locally achieve the determination of the concentration of T3, which binds to the thyroid hormone receptor with high affinity. D2 converts T4 into T3, and D3 degrades T4 and T3. Neurons take up T3 released by astrocytes, the main cerebral site for the D2 expression. Because oxidative stress is believed to be involved in several neurological disorders, we explored the effects of oxidative stress on D3 and D2 in primary culture of rat astrocytes. H2O2 (250 microm) increased D3 activity with maximal effects around 8 h. Stimulation of D3 activity by H2O2 was synergistic with T4, phorbol ester, and also cAMP. H2O2 (250 microm) did not affect basal D2 activity but inhibited the stimulation of D2 activity by cAMP and factors implicating cAMP-independent pathways in astrocytes, TSH, and phorbol ester. N-Acetyl cysteine and selenium repletion, which respectively increase intracellular glutathione and glutathione peroxidase, inhibited D2 and D3 regulation by H2O2, whereas L-buthionine sulfoximine, which decreases intracellular glutathione, mimicked H2O2 effects. Oxidative stress up-regulated D3 and inhibited cAMP-stimulated D2 by transcriptional mechanisms. A decrease in cAMP by oxidative stress could contribute to the inhibition of cAMP-stimulated D2. Using specific inhibitors of signaling pathways, we show that the ERK pathway was required in D2 and D3 regulation by oxidative stress and that the p38 MAPK pathway was implicated in H2O2-induced D3. We suggest that the expected decrease in T3 might modulate the cellular injury of oxidative stress in some pathological brain conditions.
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PMID:Oxidative stress regulates type 3 deiodinase and type 2 deiodinase in cultured rat astrocytes. 1842 Jul 45

Previous studies have demonstrated that the ERK MAPK acts as a negative regulator of gamma-secretase. Here, we demonstrate that the activation of ERK MAPK pathway by sodium selenite can inhibit endogenous gamma-secretase activity. Consistently, the gamma-secretase-mediated production of amyloid-beta (Abeta) was dramatically attenuated by sodium selenite in a temporal manner. To substantiate the functional role of ERK MAPK in the regulation of gamma-secretase, we demonstrate that cells transfected with the wild-type MEK1 and a constitutively active mutant of MEK1 also displayed a significant attenuation of gamma-secretase activity. The active purified ERK1/2 can significantly reduce the gamma-secretase-mediated processing of C99, possibly through inducing alterations in the phosphorylation of both nicastrin and presenilin-1. Together, our data suggest that the selenite-elicited ERK activation could effectively reduce Abeta production, supporting that selenium compounds could represent a novel class of nutrient supplements to slow down the progression of Alzheimer's disease.
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PMID:Sodium selenite inhibits gamma-secretase activity through activation of ERK. 1854 22

Selenium at low concentrations has a chemopreventive role against cancer, while at high concentrations, selenite exerts a direct antitumor effect. However, the mechanisms behind these effects remain elusive. In this study, we found that different concentrations of selenite triggered different signal pathways in human leukemia NB4 cells. Low concentrations of selenite elicited mild endoplasmic reticulum (ER) stress and mediated cell survival by activating unfolded protein response signaling, whereas high concentrations of selenite induced severe ER stress and caused cell death by activation of the pro-apoptotic transcription factors GADD153. In addition, selenite at low concentrations activated other anti-apoptotic pathways, such as AKT and ERK, whereas high concentrations of selenite induced activation of p53 and oxidative stress, which mediated the antitumor activity of selenite by causing mitochondrial dysfunction and caspase activation. These findings uncover the molecular mechanisms of the chemopreventive and antitumor effects of different concentrations of selenite.
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PMID:Exposure of human leukemia NB4 cells to increasing concentrations of selenite switches the signaling from pro-survival to pro-apoptosis. 1915 35

Management of Type 1 diabetes is burdensome, both to the individual and society, costing over 100 billion dollars annually. Despite the widespread use of glucose monitoring and new insulin formulations, many individuals still develop devastating secondary complications. Pancreatic islet transplantation can restore near normal glucose control in diabetic patients, without the risk of serious hypoglycemic episodes that are associated with intensive insulin therapy. Providing sufficient islet mass is important for successful islet transplantation. However, donor characteristics, organ procurement and preservation affect the isolation outcome. At University of Illinois at Chicago (UIC) we developed a successful isolation protocol with an improved purification gradient. The program started in January 2004 and more than 300 isolations were performed up to November 2008. The pancreata were sent in cold preservation solutions (UW, University of Wisconsin or HTK, Histidine-Tryptophan Ketoglutarate) to the Cell Isolation Laboratory at UIC for islet isolation. Pancreatic islets were isolated using the UIC method, which is a modified version of the method originally described by Ricordi et al. As described in Part I: Digestion and Collection of Pancreatic Tissue, human pancreas was trimmed, cannulated, perfused, and digested. After collection and at least 30 minutes of incubation in UW solution, the tissue was loaded in the cell separator (COBE 2991, Cobe, Lakewood, CO) for purification. Following purification, islet yield (expressed as islet equivalents, IEQ), tissue volume, and purity was determined according to standard methods. Isolated islets were cultured in CMRL-1066 media (Mediatech, Herndon, VA), supplemented with 1.5% human albumin, 0.1% insulin-transferrin-selenium (ITS), 1 ml of Ciprofloxacin, 5 ml o f 1M HEPES, and 14.5 ml of 7.5% Sodium Bicarbonate in T175 flasks at 37 degrees C overnight culture before islets were transplanted or used for research.
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PMID:Human pancreatic islet isolation: Part II: purification and culture of human islets. 1947 Dec 43

Selenium reportedly contribute to the modulation process of protein phosphorylation to regulate various cellular functions including growth, differentiation, proliferation and development. The aim of this study was to investigate whether selenium and Selenoprotein M (SelM) affects the mechanism of Alzheimer's disease. To achieve this, we determined the change of the MAPK pathway, secretase activity, and Tau phosphorylation in the transgenic rat overexpressing human selenoprotein M. Based on these results, we concluded that, i) CMV/GFP-hSelM Tg rats showed a high activity level of antioxidant enzyme in the brain tissues, ii) in response to selenium treatment, the ERK signaling pathway was significantly increased in Tg rats, but did not change in wild-type rats, iii) the activation of the ERK pathway by selenium treatment and SelM overexpression induced the inhibition of the alpha/gamma-secretase activity related to the protection of Abeta-42 production, iv) the activation of the ERK pathway by selenium treatment and SelM overexpression inhibited the phosphorylation in several sites of Tau protein. Therefore, these results provide strong evidence that selenium treatment and SelM activate the ERK pathway to attenuate alpha/gamma-secretase-mediated proteolysis and Tau phosphorylation to protect brain function.
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PMID:ERK activation induced by selenium treatment significantly downregulates beta/gamma-secretase activity and Tau phosphorylation in the transgenic rat overexpressing human selenoprotein M. 1951 40

The application of semiconducting thallium selenide for ir detection is described. A responsivity of 10(6) V/W and NEP of the order of 10(-15) W/ radicalHz with a response time of 3 msec can be obtained by operating the detector at 1.5 K.
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PMID:Thallium selenide infrared detector. 2017 71

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) of Rocky Mountain elk in North America. Recent studies suggest that tissue and blood mineral levels may be valuable in assessing TSE infection in sheep and cattle. The objectives of this study were to examine baseline levels of copper, manganese, magnesium, zinc, selenium, and molybdenum in the brains of Rocky Mountain elk with differing prion genotypes and to assess the association of mineral levels with CWD infection. Elk with leucine at prion position 132 had significantly lower magnesium levels than elk with 2 copies of methionine. Chronic wasting disease-positive elk had significantly lower magnesium than control elk. The incorporation of manganese levels in addition to magnesium significantly refined explanatory ability, even though manganese alone was not significantly associated with CWD. This study demonstrated that mineral analysis may provide an additional disease correlate for assessing CWD risk, particularly in conjunction with genotype.
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PMID:Increased risk of chronic wasting disease in Rocky Mountain elk associated with decreased magnesium and increased manganese in brain tissue. 2035 59

Cancer therapy has moved beyond conventional chemotherapeutics to more mechanism-based targeted approaches. Studies demonstrate that histone deacetylase (HDAC) is a promising target for anticancer agents. Numerous, structurally diverse, hydroxamic acid derivative, HDAC inhibitors have been reported and have been shown to induce growth arrest, differentiation, autophagy, and/or apoptotic cell death by inhibiting multiple signaling pathways in cancer cells. Suberoylanilide hydroxamic acid (SAHA) has emerged as an effective anticancer therapeutic agent and was recently approved by the FDA for the treatment of advanced cutaneous T-cell lymphoma. In our previous study, we reported the development of the novel, potent, selenium-containing HDAC inhibitors (SelSA-1 and SelSA-2). In this study, the effects of SelSA-1 and SelSA-2 on signaling pathways and cytotoxicity were compared with the known HDAC inhibitor, SAHA, in lung cancer cell lines. After 24 h of treatment, SelSA-1 and SelSA-2 inhibited lung cancer cell growth to a greater extent than SAHA in a dose-dependent manner with IC(50) values at low micromolar concentrations. SelSA-1 and SelSA-2 inhibited ERK and PI3K-AKT signaling pathways while simultaneously increasing in autophagy in A549 cells in a time dependent manner. This preliminary study demonstrates the effectiveness of the selenium-containing analogs of SAHA, SelSA-1, and SelSA-2, as HDAC inhibitors and provides insight into the improvement and/or development of these analogs as a therapeutic approach for the treatment of lung cancer.
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PMID:Selenium-containing analogs of SAHA induce cytotoxicity in lung cancer cells. 2085 8


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