Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.26 (GSK)
 6,788 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this age of molecularly targeted drug discovery, robust techniques are required to measure pharmacodynamic (PD) responses in tumors so that drug exposures can be associated with their effects on molecular biomarkers and efficacy. Our aim was to develop a rapid screen to monitor PD responses within xenografted human tumors as an important step towards a clinically applicable technology. Currently there are various methods available to measure PD end points, including immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), reverse transcription-polymerase chain reaction, gene expression profiling, and western blotting. These may require relatively large samples of tumor, surrogate tissue, or peripheral blood lymphocytes with subsequent analyses taking several days. The phosphoinositide 3-kinase (PI3-kinase) pathway is frequently deregulated in cancer and is also important in diabetes and autoimmune conditions. In this paper, optimization of the Meso Scale Discovery (MSD) (Gaithersburg, MD) platform to quantify changes in phospho-AKT and phospho-glycogen synthase kinase-3beta in response to a PI3-kinase inhibitor, LY294002, is described, initially in vitro and then within xenografted solid tumors. This method is highly practical with high throughput since large number of samples can be run simultaneously in 96-well format. The assays are robust (coefficient of variation for phospho-AKT 13.4%) and offer significant advantages (in terms of speed and quantitation) over western blots. This optimized procedure can be used for both in vitro and in vivo analysis, unlike an established fixed-cell ELISA with a time-resolved fluorescent end point.
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PMID:Application of meso scale technology for the measurement of phosphoproteins in human tumor xenografts. 1763 39

Inositol phospholipids phosphorylated on D3-position of their inositol rings (3-phosphoinositides) are known to play important roles in various cellular events. Activation of PI (phosphatidylinositol) 3-kinase is essential for aspects of insulin-induced glucose metabolism, including translocation of GLUT4 to the cell surface and glycogen synthesis. The enzyme exists as a heterodimer containing a regulatory subunit and one of two widely-distributed isoforms of the p110 catalytic subunit: p110alpha or p110beta. Activation of PI 3-kinase and its downstream AKT has been demonstrated to be essential for almost all of the insulin-induced glucose and lipid metabolism such as glucose uptake, glycogen synthesis, suppression of glucose output and triglyceride synthesis as well as insulin-induced mitogenesis. Accumulated PI(3,4,5)P(3) activates several serine/threonine kinases containing a PH (pleckstrin homology) domain, including Akt, atypical PKCs, p70S6 kinase and GSK. In the obesity-induced insulin resistant condition, JNK and p70S6K are activated and phosphorylate IRS-proteins, which diminishes the insulin-induced tyrosine phosphorylation of IRS-proteins and thereby impairs the PI 3-kinase/AKT activations. Thus, the drugs which restore the impaired insulin-induced PI 3-kinase/AKT activation, for example, by suppressing JNK or p70S6K, PTEN or SHIP2, could be novel agents to treat diabetes mellitus.
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PMID:Role of phosphatidylinositol 3-kinase activation on insulin action and its alteration in diabetic conditions. 1782 8

Axonal transport of mitochondria is critical for proper neuronal function. However, little is known about the extracellular signals that regulate this process. In the present study, we show that the neuromodulator serotonin (5-HT) greatly enhances mitochondrial movement in the axons of rat hippocampal neurons in vitro. Administration of a 5-HT1A receptor antagonist inhibited mitochondrial movement, whereas addition of fluoxetine, a selective serotonin reuptake inhibitor, promoted mitochondrial movement. 5-HT receptors are known to activate the Akt/Protein kinase B pathway. Consistent with this, directional mitochondrial movement was almost completely blocked by a specific Akt inhibitor. Moreover, an inhibitor of glycogen synthase kinase-3beta (GSK3beta), a kinase whose activity is blocked by Akt-mediated phosphorylation, promoted mitochondrial movement. These findings show that 5-HT1A receptor activation stimulates mitochondrial movement in hippocampal neurons by inhibiting GSK3beta activity via Akt. Our findings suggest that 5-HT may mediate the redistribution of energy sources within responsive neurons, a possibility that has significant implications for understanding the global biological effects of this important neuromodulator.
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PMID:Serotonin stimulates mitochondrial transport in hippocampal neurons. 1790 80

Recent studies indicate that secondary bile acids promote colon cancer cell proliferation but their role in maintaining cell survival has not been explored. We found that deoxycholyltaurine (DCT) markedly attenuated both unstimulated and TNF-alpha-stimulated programmed cell death in colon cancer cells by a phosphatidylinositol 3-kinase (PI3K)-dependent mechanism. To examine the role of bile acids and PI3K signaling in maintaining colon cancer cell survival, we explored the role of signaling downstream of bile acid-induced activation of the epidermal growth factor receptor (EGFR) in regulating both apoptosis and proliferation of HT-29 and H508 human colon cancer cells. DCT caused dose- and time-dependent Akt (Ser(473)) phosphorylation, a commonly used marker of activated PI3K/Akt signaling. Both EGFR kinase and PI3K inhibitors attenuated DCT-induced Akt phosphorylation and Akt activation, as demonstrated by reduced phosphorylation of a GSK-3-paramyosin substrate. Transfection of HT-29 cells with kinase-dead EGFR (K721M) reduced DCT-induced Akt phosphorylation. In HT-29 cells, EGFR and PI3K inhibitors as well as transfection with dominant negative AKT attenuated DCT-induced cell proliferation. DCT-induced PI3K/Akt activation resulted in downstream phosphorylation of GSK-3 (Ser(21/9)) and BAD (Ser(136)), and nuclear translocation (activation) of NF-kappaB, thereby confirming that DCT-induced activation of PI3K/Akt signaling regulates both proproliferative and prosurvival signals. Collectively, these results indicate that DCT-induced activation of post-EGFR PI3K/Akt signaling stimulates both colon cancer cell survival and proliferation.
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PMID:Deoxycholyltaurine rescues human colon cancer cells from apoptosis by activating EGFR-dependent PI3K/Akt signaling. 1806 5

Smad proteins are intracellular transducers for transforming growth factor-beta (TGF-beta) signaling and play a critical role in differentiation, tissue repair and apoptosis of the central nervous system. Both TGF-beta and its regulated gene, plasminogen activator inhibitor type-1 (PAI-1), have been implicated in the etiology and progression of neurodegenerative diseases and mood disorders. We previously reported that GSK-3beta protein depletion suppresses Smad3/4-dependent gene transcription and causes a reduction in PAI-1 expression. Here, we provide evidence that lithium, the drug for the treatment and prophylaxis of bipolar disorder, inhibits Smad-dependent signaling by regulating cAMP-protein kinase A (PKA), AKT-glycogen synthase kinase-3beta (GSK-3beta), and CRE-dependent signaling pathways in neuron-enriched cerebral cortical cultures of rats. We demonstrate that lithium-induced activation of these pathways inhibits Smad3/4-dependent gene transcription through an increase in pCREB(Ser133) protein levels, an enhanced interaction between pCREB(Ser133) and p300/CBP, which causes Smad3/4-p300/CBP complex disruption and transcriptional suppression of Smad3/4-dependent genes. Therapeutic implications of our findings are discussed.
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PMID:Lithium inhibits Smad3/4 transactivation via increased CREB activity induced by enhanced PKA and AKT signaling. 1807 82

The role of presenilin-1 (PS1) in neuronal phosphatidylinositol 3-kinase (PI3K)/Akt signaling was investigated in primary neuronal cultures from wild-type (WT) and PS1 null (PS1-/-) embryonic mouse brains. Here we show that in PS1-/- cultures, the onset of neuronal maturation coincides with a decrease in the PI3K-dependent phosphorylation-activation of Akt and phosphorylation-inactivation of glycogen synthase kinase-3 (GSK-3). Mature PS1-/- neurons show increased activation of apoptotic caspase-3 and progressive degeneration preceded by dendritic retraction. Expression of exogenous WT PS1 or constitutively active Akt in PS1-/- neurons stimulates PI3K signaling and suppresses both caspase-3 activity and dendrite retraction. The survival effects of PS1 are sensitive to inhibitors of PI3K kinase but insensitive to gamma-secretase inhibitors. Familial Alzheimer disease (FAD) mutations suppress the ability of PS1 to promote PI3K/AKT signaling, prevent phosphorylation/inactivation of GSK-3 and promote activation of caspase-3. These mutation effects are reversed upon coexpression of constitutively active Akt. Together, our data indicate that the neuroprotective role of PS1 depends on its ability to activate the PI3K/Akt signaling pathway and that PS1 FAD mutations increase GSK-3 activity and promote neuronal apoptosis by inhibiting the function of PS1 in this pathway. These observations suggest that stimulation of PI3K/Akt signaling may be beneficial to FAD patients.
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PMID:Wild-type but not FAD mutant presenilin-1 prevents neuronal degeneration by promoting phosphatidylinositol 3-kinase neuroprotective signaling. 1818 91

Human intestinal lamina propria T lymphocytes (LPT), when investigated ex vivo, exhibit functional properties profoundly different from those of peripheral blood T lymphocytes (PBT). One prominent feature represents their enhanced sensitivity to CD2 stimulation when compared to PBT. Given that LPT are hyporesponsive to T cell receptor (TCR)/CD3 stimulation, an alternative activation mode, as mimicked by CD2 triggering in vitro, may be functional in mucosal inflammation in vivo. This study provides insight into signalling events associated with the high CD2 responsiveness of LPT. When compared to PBT, LPT show an increased activation of the phosphoinositide 3/protein kinase B/glycogen synthase kinase 3beta (PI3-kinase/AKT/GSK-3beta) pathway in response to CD2 stimulation. Evidence is provided that up-regulation of this pathway contributes to the enhanced CD2-induced cytokine production in LPT. Given the importance of TCR-independent stimulation for the initiation of intestinal immune responses analysis of signalling pathways induced by 'co-stimulatory' receptors may provide valuable information for therapeutic drug design.
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PMID:Up-regulation of the phosphoinositide 3-kinase pathway in human lamina propria T lymphocytes. 1823 58

Since the generation of nitric oxide (NO) is an essential step in the trigger phase of ischemic preconditioning, short-term inhalation of NO before ischemia should ameliorate ischemia/reperfusion (I/R) injury of the lung. We tested this hypothesis in high oxygen (>99%) ventilated rats in order to additionally evaluate compatibility of NO and exposure to hyperoxia. Male adult Sprague-Dawley rats inhaled NO (15 ppm, 10 min) before the left lung hilum was clamped for 1 h, and the reperfusion phase was observed for 4 h (NO group). Animals in the I/R group underwent the same treatment, but without NO inhalation. A third group without I/R served as time-matched controls. Animals in the I/R group showed severe I/R injury in terms of arterial pO2 (apO2), which was reduced to 22% of surgical controls (SCs) at time point 30 min reperfusion, and increased endothelial permeability (Evans blue procedure). The pretreatment with NO attenuated these effects. The pO2 after 4 h reperfusion was still 3.0-fold higher in the NO group compared to I/R. In contrast, the I/R- and hyperoxia-induced invasion of leukocytes, as determined by measuring myeloperoxidase (MPO) activity, was not affected by NO. These data were correlated with the activity of major cellular signaling pathways by measuring the phosphorylation at activating and inhibitory sites of extracellular-signal regulated kinase (ERK), c-Jun N-terminal kinase (JNK), p38, protein kinase B (AKT), and glycogen synthase kinase 3beta (GSK-3beta), and by determination of cGMP in plasma and lung tissue. Inhalation of NO partly prevented the loss of activation by I/R and hyperoxic ventilation of ERK, JNK, and AKT, and it reduced the I/R-induced activation of GSK-3beta. The level of cGMP in plasma and lung tissue was increased in the NO group after 4 h reperfusion. In conclusion, application of inhaled NO in the preconditioning mode prevented I/R injury in the rat lung without interfering effects of hyperoxic ventilation. The effects of NO on cellular signaling pathways resemble mechanisms of ischemic preconditioning, but further studies have to evaluate the physiological relevance of these results.
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PMID:Preconditioning by inhaled nitric oxide prevents hyperoxic and ischemia/reperfusion injury in rat lungs. 1845 45

Constitutively activated AKT kinase is a common feature of T-cell acute lymphoblastic leukemia (T-ALL). Here, we report that the novel AKT inhibitor (2S)-1-(1H-indol-3-yl)-3-[5-(3-methyl-2H-indazol-5-yl)pyridin-3-yl]oxypropan2-amine (A443654) leads to rapid cell death of T-ALL lines and patient samples. Treatment of CEM, Jurkat, and MOLT-4 cells with nanomolar doses of the inhibitor led to AKT phosphorylation accompanied by dephosphorylation and activation of the downstream target, glycogen synthase kinase-3beta. Effects were time- and dose-dependent, resulting in apoptotic cell death. Treatment of Jurkat cells with A443654 resulted in activation of caspase-2, -3, -6, -8, and -9. Apoptotic cell death was mostly dependent on caspase-2 activation, as demonstrated by preincubation with a selective pharmacological inhibitor. It is remarkable that A443654 was highly effective against the drug-resistant cell line CEM-VBL100, which expresses 170-kDa P-glycoprotein. Moreover, A443654 synergized with the DNA-damaging agent etoposide in both drug-sensitive and drug-resistant cell lines when coadministered [combination index (CI) = 0.39] or when pretreated with etoposide followed by A443654 (CI = 0.689). The efficacy of A443654 was confirmed using blasts from six patients with T-ALL, all of whom displayed low levels of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and constitutive phosphorylation of Akt on Ser473. At 1 microM, the inhibitor was able to induce apoptotic cell death of T-ALL blast cells, as indicated by flow cytometric analysis of samples immunostained for active (cleaved) caspase-3. Because activated AKT is seen in a large percentage of patients with T-ALL, A443654, either alone or in combination with existing drugs, may be a useful therapy for primary and drug-resistant T-ALL.
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PMID:Proapoptotic activity and chemosensitizing effect of the novel Akt inhibitor (2S)-1-(1H-Indol-3-yl)-3-[5-(3-methyl-2H-indazol-5-yl)pyridin-3-yl]oxypropan2-amine (A443654) in T-cell acute lymphoblastic leukemia. 1857 85

Metastasis is responsible for 90% of cancer patient deaths. More information is needed about the molecular basis for its potential detection and treatment. The activated AKT kinase is necessary for many events of the metastatic pathway including escape of cells from the tumor's environment, into and then out of the circulation, activation of proliferation, blockage of apoptosis, and activation of angiogenesis. A series of steps leading to metastatic properties can be initiated upon activation of AKT by phosphorylation on Ser-473. These findings lead to the question of how this activation is connected to metastasis. Activated AKT phosphorylates GSK-3beta causing its proteolytic removal. This increases stability of the negative transcription factor SNAIL, thereby decreasing transcription of the transmembrane protein E-cadherin that forms adhesions between adjacent cells, thereby permitting their detachment. How is AKT hyperactivated in metastatic cells? Increased PI3K or TORC2 kinase activity- or decreased PHLPP phosphatase could be responsible. Furthermore, a positive feedback mechanism is that the decrease of E-cadherin lowers PTEN and thereby increases PIP3, further activating AKT and metastasis.
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PMID:Metastasis and AKT activation. 1881 26


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