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)

Recent studies suggest AMP-activated protein kinase (AMPK), an enzyme involved in energy homeostasis, might be a novel signaling pathway in regulating inflammatory response, but the precise intracellular mechanisms are not fully understood. In this study, we have demonstrated that 5-aminoimidazole-4-carboxamide riboside (AICAR), an activator of AMPK, inhibited lipopolysaccharide (LPS)-induced protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in macrophages and microglial cells at the gene transcription level. Data obtained from electrophoretic mobility shift assay (EMSA) and promoter activity assay have further confirmed the ability of AICAR to block LPS-mediated NF-kappaB, AP-1, CREB, and C/EBPbeta activation. However, AICAR did not affect LPS-mediated IKK, ERK, and p38 activation. Regardless of the ability of AICAR to activate AMPK, the inhibitory effects of AICAR on iNOS and COX-2 expression were not associated with AMPK. An adenosine kinase inhibitor 5'-iodotubercidin, which effectively abolished AMPK activation caused by AICAR, did not reverse the anti-inflammatory effect of AICAR. Moreover, another AMPK activator metformin was not able to mimic the effects of AICAR. Direct addition of AICAR in EMSA assay interrupted binding of NF-kappaB, CREB, and C/EBPbeta to specific DNA elements. Taken together, this study demonstrates that the anti-inflammatory effects of AICAR against LPS-induced iNOS and COX-2 gene transcription are not associated with AMPK activation, but might be resulting from the direct interference with DNA binding to transcription factors.
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PMID:Inhibition of lipopolysaccharide-induced inducible nitric oxide synthase and cyclooxygenase-2 gene expression by 5-aminoimidazole-4-carboxamide riboside is independent of AMP-activated protein kinase. 1761 55

LFM-A13 (alpha-cyano-beta-hydroxy-beta-methyl-N-(2,5-dibromophenyl)propenamide) has recently been identified as an inhibitor of Polo-like kinases (Plk). LFM-A13 does not inhibit other serine/threonine kinases including CDK, CHK, RAF, DAPK, IKK, IRAK, JNK, MAPK, PKC and SAPK. LFM-A13-treated human cancer cells develop abnormal mitotic spindles and G(2)/M-arrest during cell cycle progression. LFM-A13 was not toxic to rodents or dogs at daily dose levels as high as 100 mg/kg. Notably, at a low dose level of 10 mg/kg, which does not result in delayed tumor progression in the MMTV/neu transgenic mouse model of HER2 positive breast cancer, LFM-A13 markedly enhanced the anti-cancer activity of the mitotic spindle poison paclitaxel. These results indicate that LFM-A13 may be useful in the treatment of cancer patients.
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PMID:Chemosensitizing anti-cancer activity of LFM-A13, a leflunomide metabolite analog targeting polo-like kinases. 1807 37

The persistence of latent reservoirs of HIV-1 represents a major barrier to virus eradication in patients treated with antiretrovirals. Prostratin is a non-tumor promoting 12-deoxyphorbol monoester capable of up-regulating viral expression from latent provirus and therefore is potentially useful for HIV adjuvant therapy and similar properties might be elicited by related non-tumor promoting phorboids. We have therefore investigated a series of phorbol 13-monoesters for their capacity to reactivate HIV latency. Using a Jurkat T cell line containing latent HIV proviruses, we found that prostratin and phorbol-13-stearate effectively activate HIV-1 gene expression in these latently infected cells, with phorbol-13-stearate being at least 10-fold more potent than prostratin, and its activity rapidly decreasing with a shortening of the acyl side chain. We further demonstrated that phorbol-13-stearate and prostratin stimulate IKK-dependent phosphorylation and degradation of IkappaBalpha, leading to activation of NF-kappaB. Moreover, prostratin, phorbol-13-hexanoate and phorbol-13-stearate also activate the JNK and ERK pathways. Studies with isoform-specific PKC inhibitors suggest that the classical PKCs play a prominent role in the responses elicited by phorbol-13-stearate. Nevertheless, this compound induces a translocation pattern of the PKC isotypes alpha and delta to cellular compartments distinctly different from that elicited by prostratin and PMA.
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PMID:Differential effects of phorbol-13-monoesters on human immunodeficiency virus reactivation. 1824 38

Celecoxib is a specific inhibitor of cyclooxygenase 2 (COX2). While it has been used for the treatment of chronic inflammatory conditions, including rheumatoid arthritis, its detailed anti-inflammatory mechanism has not been clarified. Here, we found that Celecoxib potently inhibited TNFalpha-induced transcriptional activity and DNA binding activity of NF-kappaB; however, Celecoxib had no effect on TNFalpha-induced IKK activation and degradation of IkappaBalpha and IkappaBbeta, suggesting that it inhibited NF-kappaB activation via suppressing downstream of IKK activation and IkappaBs degradation. Interestingly, it was also found that Celecoxib abrogated TNFalpha-induced nuclear accumulation of the NF-kappaB p65 subunit. As a result, TNFalpha-induced expression of inflammatory cytokines, CXCL1/KC and CCL2/MCP-1, was clearly inhibited by Celecoxib. On the other hand, Celecoxib had no effect on the TNFalpha-induced nuclear translocation of c-jun and activation of ERK, JNK, p38 and Akt. Taken together, these data indicate that Celecoxib specifically inhibits TNFalpha-induced NF-kappaB activation at the level of its nuclear translocation. This negative regulation of NF-kappaB activation by Celecoxib might be an important mechanism leading to its anti-inflammatory activity.
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PMID:Celecoxib potently inhibits TNFalpha-induced nuclear translocation and activation of NF-kappaB. 1864 47

The nuclear receptor PPARgamma is a lipid sensor that regulates lipid metabolism through gene transcription. Inhibition of PPARgamma activity by TNF-alpha is involved in pathogenesis of insulin resistance, atherosclerosis, inflammation, and cancer cachexia. PPARgamma activity is regulated by TNF-alpha at pre-translational and post-translational levels. Activation of serine kinases including IKK, ERK, JNK, and p38 may be involved in the TNF-regulation of PPARgamma. Of the four kinases, IKK is a dominant signaling molecule in the TNF-regulation of PPARgamma. IKK acts through at least two mechanisms: inhibition of PPARgamma expression and activation of PPARgamma corepressor. In this review article, literature is reviewed with a focus on the mechanisms of PPARgamma inhibition by TNF-alpha.
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PMID:Regulation of PPARgamma function by TNF-alpha. 1865 73

Intestinal subepithelial myofibroblasts (SEMFs) is a specific population of cells involved in intestinal inflammation and carcinogenesis via an elaborate network of cytokines, chemokines and other inflammatory factors, including PGE(2). Sphingosine-1-phosphate (S1P) has been implicated as an important mediator of inflammation and cancer and in certain cell types increases cyclooxygenase-2 (COX-2) expression. In the present study, we aimed to assess involvement of S1P in COX-2 expression by SEMFs. Primary SEMFs were obtained from C57BL/6J mouse and their identity was verified by fluorescent staining of specific marker proteins. Expression of S1P receptors 1, 2, 3 and sphingosine kinases 1 and 2 in SEMFs were determined by RT-PCR analysis. COX-2 expression and PGE(2) production were assayed by Western blotting and ELISA, respectively. COX-2 mRNA stability was assayed by Northern blotting. S1P produced dose-dependent increase in COX-2 expression, resulting in increased PGE(2) release from SEMFs. Using specific inhibitors, we show that actions of p38, ERK, IKK, and PKC were involved in S1P-induced COX-2 expression. On the other hand, p38 and PKC had lesser roles in IL-1beta-induced COX-2 expression. Inhibition of sphingosine kinase to block S1P production did not affect IL-1beta-induced COX-2 expression, but S1P amplified IL-1beta-induced p38 activation and COX-2 expression. PKC inhibition blocked S1P amplified COX-2 expression. S1P addition increased COX-2 mRNA stability. In SEMFs, S1P amplifies IL-1beta-induced COX-2 expression through increased mRNA stability. These observations point to involvement of S1P in activation of SEMFs that may contribute to intestinal inflammation and carcinogenesis.
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PMID:Sphingosine-1-phosphate enhances IL-1{beta}-induced COX-2 expression in mouse intestinal subepithelial myofibroblasts. 1870 38

Neutrophils are key players of innate immunity and influence inflammatory and immune reactions through the production of numerous cytokines. Interleukin-18 (IL-18) is known to stimulate several neutrophil responses, and recent evidence suggests that neutrophils might represent a source of IL-18. Here, we show that neutrophils constitutively produce both IL-18 and its antagonist, IL-18BP. Cell activation does not affect IL-18BP release but leads to an increased gene expression and secretion of IL-18, a process that depends on NF-kappaB activation. Moreover, endogenous IL-18 feeds back on the neutrophils to augment cytokine generation in lipopolysaccharide-treated cells. Accordingly, exogenous IL-18 can induce the gene expression and release of several inflammatory cytokines in neutrophils, including its own expression. We finally report that IL-18 activates the p38 MAPK, MEK/ERK, and PI3K/Akt pathways in neutrophils. The IKK cascade is also activated by IL-18, resulting in IkappaB-alpha degradation, NF-kappaB activation, and RelA phosphorylation. Accordingly, these pathways contribute to the generation of inflammatory cytokines in IL-18-stimulated neutrophils. By contrast, the phosphorylation and DNA-binding activity of various STAT proteins were not induced by IL-18. Collectively, our results unveil new interactions between IL-18 and neutrophils and further support a role for these cells in influencing both innate and adaptive immunity.
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PMID:Autocrine role of endogenous interleukin-18 on inflammatory cytokine generation by human neutrophils. 1878 Jul 64

Hexamethylene Bisacetamide (HMBA) is a hybrid polar compound originally developed as a differentiation inducing agent. We show in this study that HMBA can inhibit activation of several NF kappaB target genes in both lung and breast cancer cell lines. Furthermore, consistent with its ability to inhibit NF kappaB function, HMBA can also sensitize cells to apoptosis. We show that HMBA mediates inhibition of the Akt and ERK/MAPK cascade, both of which are critical for cell survival and proliferation and are well known regulators of NF kappaB activation. We also show that PTEN negative breast cancer cells which have hyper activation of the PI3K/Akt pathway show increased sensitivity to growth inhibitory effects of combination of HMBA and TNFalpha. Furthermore, HMBA can decrease the kinase activity of the IKK complex leading to defective phosphorylation of I kappaB alpha and Ser536 of p65. This study gives mechanistic insight into the mechanism of action of HMBA, provides the rationale for the potential use of HMBA in combination with various existing kinase inhibitors in combination therapy and also suggests useful biomarkers for monitoring tumor response to HMBA.
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PMID:Hexamethylene bisacetamide (HMBA) simultaneously targets AKT and MAPK pathway and represses NF kappaB activity: implications for cancer therapy. 1902 24

There is increasing evidence that urokinase-type plasminogen activator (u-PA) and matrix metalloproteinases (MMPs) play an important role in cancer metastasis and angiogenesis. Inhibition of u-PA and MMPs could suppress migration and invasion of cancer cells. Berberine, one of the main constituents of the plant Rhizoma coptidis, is a type of isoquinoline alkaloid, reported to have anti-cancer effects in different human cancer cell lines. There is however, no available information on effects of berberine on migration and invasion of human tongue cancer cells. Here, we report that berberine inhibited migration and invasion of human SCC-4 tongue squamous carcinoma cells. This action was mediated by the p-JNK, p-ERK, p-p38, IkappaK and NF-kappaB signaling pathways resulting in inhibition of MMP-2 and -9 in human SCC-4 tongue squamous carcinoma cells. Our Western blowing analysis also showed that berberine inhibited the levels of urokinase-plasminogen activator (u-PA). These results suggest that berberine down-regulates u-PA, MMP-2 and -9 expressions in SCC-4 cells through the FAK, IKK and NF-kappaB mediated pathways and a novel function of berberine is to inhibit the invasive capacity of malignant cells.
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PMID:Berberine suppresses in vitro migration and invasion of human SCC-4 tongue squamous cancer cells through the inhibitions of FAK, IKK, NF-kappaB, u-PA and MMP-2 and -9. 1925 61

When modeling cell signaling networks, a balance must be struck between mechanistic detail and ease of interpretation. In this paper we apply a fuzzy logic framework to the analysis of a large, systematic dataset describing the dynamics of cell signaling downstream of TNF, EGF, and insulin receptors in human colon carcinoma cells. Simulations based on fuzzy logic recapitulate most features of the data and generate several predictions involving pathway crosstalk and regulation. We uncover a relationship between MK2 and ERK pathways that might account for the previously identified pro-survival influence of MK2. We also find unexpected inhibition of IKK following EGF treatment, possibly due to down-regulation of autocrine signaling. More generally, fuzzy logic models are flexible, able to incorporate qualitative and noisy data, and powerful enough to produce quantitative predictions and new biological insights about the operation of signaling networks.
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PMID:Fuzzy logic analysis of kinase pathway crosstalk in TNF/EGF/insulin-induced signaling. 1934 94


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