Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.24 (mitogen-activated protein kinase)
 95,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously established two lung cancer cell lines, OKa-C-1 and MI-4, which constitutively produce abundant granulocyte-colony stimulating factor (G-CSF) and granulocyte macrophage-colony stimulating factor (GM-CSF). Inflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1beta stimulated the expression of G-CSF, GM-CSF, and cyclooxygenase (COX)-2 in the two cell lines. It is known that increased COX-2 activity promotes tumor growth and induces G-CSF and GM-CSF expression in non-malignant cells, and that selective COX-2 inhibitors inhibit the growth of some types of malignant cells. Therefore, we hypothesized that inhibition of COX-2 activity might suppress constitutive production of G-CSF or GM-CSF in addition to reducing the growth of malignant cells. We confirmed that the selective COX-2 inhibitor, NS-398 suppressed the constitutive production of G-CSF and GM-CSF, and the cell growth in both OKa-C-1 and MI-4 cell lines. Prostaglandin E2 (PGE2) reversed the inhibitions of G-CSF and GM-CSF expression, as well as cell growth, by NS-398. This result confirms that the effects of NS-398 are based on the inhibition of COX activity. Some studies have indicated that nuclear factor kappa B (NF-kappaB) or MAPK (mitogen-activated protein kinase) activation is related to upregulation of G-CSF, GM-CSF or COX-2 expression in some types of cells. Therefore, we examined if the actions of NS-398 might be mediated by the MAP kinase pathway or NF-kappaB activity in OKa-C-1 and MI-4 cells. We found that NS-398 inhibits G-CSF and GM-CSF production and cell growth through an extracellular signal-regulated kinase kinase (MEK) signaling pathway in these cell lines. The prognosis of non-small cell lung cancer showing G-CSF gene expression is significantly worse. G-CSF overproduction by tumor cells is observed at an advanced clinical stage. Our findings imply that a COX-2 inhibitor might improve the prognosis of patients with lung cancer through the reduction of G-CSF or GM-CSF.
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PMID:Cyclooxygenase-2 inhibitor NS-398 suppresses cell growth and constitutive production of granulocyte-colony stimulating factor and granulocyte macrophage-colony stimulating factor in lung cancer cells. 1270 93

The regulation of neutrophil half-life by members of the coagulation cascade is critical for the resolution of the inflammatory response. We have demonstrated that soluble fibrinogen (sFbg) delays human neutrophil (PMN) apoptosis through a mechanism that involves CD11b interactions, and phosphorylation of focal adhesion kinase (FAK) and extracellular signal-regulated kinase 1/2 (ERK1/2). Since NF-kappa B is a key element in the regulation of apoptotic mechanisms in several immune cells, we investigated whether NF-kappa B is involved in the control of PMN survival by sFbg. We show that sFbg triggers inhibitor protein kappa B (I kappa B-alpha) degradation and NF-kappa B activation. Furthermore, pharmacological inhibition of NF-kappa B abrogates sFbg effects on apoptosis. In addition, specific inhibition of MAPK ERK1/2 significantly reduces NF-kappa B translocation by sFbg, suggesting a relationship between ERK1/2 and NF-kappa B activation. Similar results are obtained when granulocytic-differentiated HL-60 cells are treated with sFbg, making this model highly attractive for integrin-induced gene expression studies. It can be concluded that NF-kappa B participates in the prevention of apoptosis induced by sFbg with the participation of MAPK ERK1/2. These results shed light on the molecular mechanisms that control human granulocyte apoptosis, and suggest that NF-kappa B regulation may be of benefit for the resolution of the inflammatory response.
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PMID:Fibrinogen-CD11b/CD18 interaction activates the NF-kappa B pathway and delays apoptosis in human neutrophils. 1273 Oct 70

We report here for the first time the detection of the ribosomal p70S6 kinase (p70S6K) in a hematopoietic cell, the neutrophil, and the stimulation of its enzymatic activity by granulocyte macrophage colony-stimulating factor (GM-CSF). GM-CSF modified the Vmax of the enzyme (from 7.2 to 20.5 pmol/min/mg) and induced a time- and dose-dependent phosphorylation on p70S6K residues Thr389 and Thr421/Ser424. The immunosuppressant macrolide rapamycin caused either a decrease in intensity of phospho-Thr389 bands in Western blots, or as a downshift in the relative mobility of phospho-Thr421/Ser424 bands (consistent with the loss of phosphate), but not both simultaneously. The immunosuppressant FK506 failed to inhibit p70S6K activation, but was able to rescue the rapamycin-induced downshift, pointing to a role for the mammalian target of rapamycin (mTOR) kinase. Rapamycin also caused an inhibition (IC50 0.2 nm) of the in vitro enzymatic activity of p70S6K. However, the inhibition of activity was not complete, but only a 40-50%, indicating that neutrophil p70S6K activity has a rapamycin-resistant component. This component was totally inhibited by pre-incubating the cells with the mitogen-activated protein kinase (MAPK) kinase (MEK) inhibitor PD-98059 prior to treatment with rapamycin. This indicated that a kinase from the MEK/MAPK pathway also plays a role in p70S6K activation. Thus, GM-CSF causes the dual activation of a rapamycin-resistant, MAPK-related kinase, that targets Thr421/Ser424 S6K phosphorylation, and a rapamycin-sensitive, mTOR-related kinase, that targets Thr389, both of which are needed in cooperation to achieve full activation of neutrophil p70S6K.
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PMID:Mechanism of ribosomal p70S6 kinase activation by granulocyte macrophage colony-stimulating factor in neutrophils: cooperation of a MEK-related, THR421/SER424 kinase and a rapamycin-sensitive, m-TOR-related THR389 kinase. 1274 Mar 86

Prostaglandin E2 (PGE2), which is generated by the enzymatic activity of cyclooxygenase-1 and -2 (COX-1/2), plays a central role in the maturation process of dendritic cells (DC). Since regulation of COX-1/2 expression in human DC is only partially understood, we addressed the expression and activity of COX-1/2 in these cells. Here we show that lipopolysaccharide (lps) induces COX-2 mRNA and protein synthesis as well as the release of PGE2 in human interleukin-4 and granulocyte/macrophage colony-stimulating factor-differentiated monocyte-derived DC cultivated in the presence of 1% human plasma. Moreover, we found that lps induces p38 stress-activated protein kinase (p38) in these cells and inhibitors of p38 blocked lps-induced COX-2 expression and activity. Our data indicate that during lps-induced maturation p38 regulates COX-2 expression and PGE2 synthesis in DC.
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PMID:Prostaglandin E2 synthesis in human monocyte-derived dendritic cells. 1279 14

HEK-293T cells transiently transfected with ovine (o) GH receptor (GHR) and prolactin receptor (PRLR) constructs respectively tagged downstream with cyan or yellow fluorescent proteins were used to study ovine placental lactogen (oPL)-stimulated heterodimerization by fluorescence resonance energy transfer (FRET) microscopy. The oPL-stimulated transient heterodimerization of GHR and PRLR had a peak occurring 2.5-3 min after oPL application, whereas oGH or oPRL had no effect at all. The results indicate none or only little dimerization occurring before the hormonal stimulation. The effect of heterodimerization was studied by comparing activation of Janus kinase 2, signal transducer and activator of transcription (STAT)1, STAT3, STAT5, and MAPK in Chinese hamster ovary cells stably transfected with chimeric genes encoding receptors consisting of cytosolic and transmembrane parts of oGHR and oPRLR, extracellular domains of human granulocyte and macrophage colony-stimulating factor (hGM-CSF) receptor alpha or beta, and cells transfected with the two forms (alpha or beta) of PRLR and GHR. Functionality of those proteins was verified by hGM-CSF-induced phosphorylation of both intracellular PRLR and GHR domains and hGM-CSF-induced heterodimerization was documented by chimeric receptor coimmunoprecipitation. Homodimerization or heterodimerization of PRLRs and GHRs had no differential effect on activation of STAT5 and MAPK. However, heterodimerization resulted in a prolonged phosphorylation of STAT1 and in particular STAT3, suggesting that the heterodimerization of alpha-oGHR and beta-oPRLR is able to transduce a signal, which is distinct from that occurring on homodimeric associations.
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PMID:Ovine placental lactogen-induced heterodimerization of ovine growth hormone and prolactin receptors in living cells is demonstrated by fluorescence resonance energy transfer microscopy and leads to prolonged phosphorylation of signal transducer and activator of transcription (STAT)1 and STAT3. 1286 35

Acute myelogenous leukemia (AML) is a heterogeneous disease consisting of a variety of different leukemic subtypes. While acute promyelocytic leukemia displays marked sensitivity to the differentiating effects of trans-retinoic acid (tRA), other subtypes of AML display resistance. We now describe a novel compound (E)-4-[3-(1-adamantyl)-4-hydroxyphenyl]-3-chlorocinnamic acid (3-Cl-AHPC/MM002) that induces apoptosis in the tRA-resistant leukemia cell lines M07e, KG-1, and HL-60R, and in tRA-resistant patient leukemic blasts. The 3-Cl-AHPC totally inhibits leukemia colony formation at concentrations that inhibit committed human bone marrow stem cell proliferation, that is, granulocyte/macrophage colony-forming units (CFU-GMs) by only 30%. Exposure to 3-Cl-AHPC results in caspase activation and the cleavage of poly(adenosine diphosphate) (poly(ADP)) ribose polymerase. While activation of the extracellular signal-regulated kinase (ERK) and p38 pathways is not necessary for 3-Cl-AHPC-mediated apoptosis, maximal apoptosis requires c-Jun N-terminal kinase (JNK) activation. The 3-Cl-AHPC-mediated cleavage of the antiapoptotic B-cell leukemia XL (Bcl-XL) protein to a proapoptotic 18-kDa product is found in both the M07e cell line and patient leukemic blasts. The 3-Cl-AHPC treatment of mice bearing the AML 1498 cell line results in a 3.3-log kill in the leukemic blasts. While 3-Cl-AHPC does not activate retinoic nuclear receptors, it is a potent inducer of apoptosis in AML cells and may represent a novel therapy in the treatment of this disease.
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PMID:Induction of apoptosis in retinoid-refractory acute myelogenous leukemia by a novel AHPN analog. 1289 63

Stimulation of human neutrophils with tumor necrosis factor-alpha (TNF), granulocyte-macrophage colony-stimulating factor (GM-CSF), or granulocyte CSF (G-CSF) resulted in decreased fluorescence intensity of FITC-phalloidin (actin depolymerization) and morphological changes. Cytokine-induced actin depolymerization was dependent on the concentration of cytokines used as stimuli. The maximal changes were detected at 10 min after stimulation with TNF or GM-CSF and at 20 min after stimulation with G-CSF. Cytokine-induced actin depolymerization was sustained for at least 30 min after stimulation. In contrast, N-formyl-methionyl-leucyl-phenylalanine (FMLP) rapidly (within 45 s) induced an increase in the fluorescence intensity of FITC-phalloidin (actin polymerization) and morphological changes. TNF- and GM-CSF-induced actin depolymerization and morphological changes, but not FMLP-induced responses, were partially inhibited by either PD-98059, an inhibitor of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) kinase, or SB-203580, an inhibitor of p38 MAPK, and were almost completely abolished by these inhibitors in combination. G-CSF-induced responses were almost completely abolished by PD-98059 and were unaffected by SB-203580. These findings are consistent with the ability of these cytokines to activate the distinct MAPK subtype cascade in human neutrophils. Phosphorylated ERK and p38 MAPK were not colocalized with F-actin in neutrophils stimulated by cytokines or FMLP. Furthermore, FMLP-induced polarization and actin polymerization were prevented by cytokine pretreatment. These findings suggest that TNF, GM-CSF, and G-CSF induce actin depolymerization and morphological changes through activation of ERK and/or p38 MAPK and that cytokine-induced actin reorganization may be partly responsible for the inhibitory effect of these cytokines on neutrophil chemotaxis.
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PMID:Actin reorganization and morphological changes in human neutrophils stimulated by TNF, GM-CSF, and G-CSF: the role of MAP kinases. 1295 1

We previously reported that p38 MAPK signaling is required for osteoclast differentiation but not osteoclast function. Here we further investigated the role of p38 MAPK in the function and differentiation of mouse bone marrow macrophages (BMM phi), common precursors of osteoclasts and dendritic cells. Lipopolysaccharide (LPS) activated the p38 MAPK signaling pathway in BMM phi by sequential phosphorylation of MAPK kinase 3/6, p38 MAPK, and activating transcription factor-2. Treatment of BMM phi with SB203580, a p38 MAPK inhibitor, suppressed LPS-induced phosphorylation of activating transcription factor-2. LPS stimulated production of IL-1 beta, TNF alpha, and IL-6 in BMM phi, and SB203580 failed to inhibit the LPS-induced cytokine production. BMM phi incorporated latex beads via phagocytosis, and SB203580 had no effect on this phagocytosis. BMM phi differentiated into dendritic cells when treated with granulocyte macrophage colony-stimulating factor together with CD40 ligand, TNF alpha, or LPS, and SB203580 failed to inhibit this differentiation. Thus, p38 MAPK-mediated signals are not involved in either BMM phi function or BMM phi differentiation into dendritic cells. The differentiation of BMM phi into osteoclasts in response to receptor activator of nuclear factor-kappa B ligand or TNF alpha was strongly inhibited by SB203580. These findings emphasize the crucial roles of p38 MAPK-mediated signaling in osteoclast differentiation.
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PMID:p38 Mitogen-activated protein kinase is crucially involved in osteoclast differentiation but not in cytokine production, phagocytosis, or dendritic cell differentiation of bone marrow macrophages. 1296 69

Tumor necrosis factor-alpha (TNFalpha) and granulocyte macrophage colony-stimulating factor (GM-CSF) individually enhance monocyte matrix metalloproteinase-9 (MMP-9) but induce MMP-1 only when added in combination. Because interferon-gamma (IFNgamma) is also found at inflammatory sites, we determined its effect on monocyte MMPs in the presence or absence of TNFalpha and GM-CSF. IFNgamma alone did not stimulate monocyte MMP-9 or MMP-1; however, in the presence of GM-CSF it induced MMP-1 and enhanced MMP-1 stimulated by GM-CSF and TNFalpha. IFNgamma induced MMP-1 in the presence of GM-CSF through the stimulation of TNFalpha production through a mechanism involving both p38 and ERK1/2 MAPKs, in which GM-CSF stimulated ERK1/2 whereas IFNgamma activated p38. In support of this conclusion TNFalpha neutralizing antibody and antibodies against TNF receptor I and -II blocked the induction of MMP-1 by GM-CSF and IFNgamma. In contrast to its effects on MMP-1, IFNgamma inhibited TNFalpha-induced MMP-9 through a caspase 8-dependent pathway as demonstrated by the restoration of MMP-9 with caspase 8 inhibitors. Moreover, the phosphorylation of STAT1 by IFNgamma was blocked by an inhibitor of caspase 8, indicating that STAT1 had a suppressive effect on MMP-9. Caspase 8-mediated phosphorylation of STAT1 through p38 MAPK as shown by the inhibition of IFNgamma-induced phosphorylation of p38 by caspase 8 inhibitors. Activation of caspase 8 by IFNgamma did not result in increased apoptosis. Thus IFNgamma in the presence of GM-CSF and/or TNFalpha differentially regulates monocyte MMPs through induction of TNFalpha and a novel mechanism involving caspase 8 that is independent of apoptosis.
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PMID:Interferon-gamma differentially regulates monocyte matrix metalloproteinase-1 and -9 through tumor necrosis factor-alpha and caspase 8. 1296 Jan 56

It has been shown that glutathione S-transferase pi (GSTpi) interacts with and suppresses the activity of c-Jun NH(2)-terminal kinase (JNK). GST-deficient mice (GSTpi(-/-)) have higher levels of circulating white blood cells, with similar proportions of lymphocytes, monocytes, and granulocytes. Interestingly, a selective expansion of splenic B lymphocytes was observed in GSTpi(-/-) animals but no change in T lymphocytes or natural killer cells. A peptidomimetic inhibitor of GSTpi that disrupts the interaction between GSTpi and JNK mimics in wild type mice the increased myeloproliferation observed in GSTpi(-/-) animals. Until now, the molecular basis for this effect has not been defined. In an in vitro hematopoiesis assay, interleukin-3, granulocyte colony-stimulating factor, and granulocyte/macrophage colony-stimulating factor were more effective at stimulating proliferation of hematopoietic cells in GSTpi(-/-) mice than in wild type. The JNK inhibitor SP600125 which caused little inhibition of cytokine-induced myeloproliferation in wild type mice, decreased the number of colonies in GSTpi(-/-) animals. A more sustained phosphorylation of the STAT family of proteins was also observed in GSTpi(-/-) bone marrow-derived mast cells exposed to interleukin-3. This was associated with an increased proliferation and a down-regulation of expression of negative regulators of the Janus kinase-STAT pathway SHP, Src homology 2 domain-containing tyrosine phosphatase-1 and -2. The increased activation of JNK and STATs in GSTpi-deficient mice provides a viable mechanism for the increased myeloproliferation in these animals. These data also confirm the important role that GSTpi plays in the regulation of cell signaling pathways in a myeloproliferative setting.
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PMID:Increased myeloproliferation in glutathione S-transferase pi-deficient mice is associated with a deregulation of JNK and Janus kinase/STAT pathways. 1468 49


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