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

---

Query: EC:2.7.11.24 (mitogen-activated protein kinase)
95,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The p3 peptide [amyloid beta-peptide (Abeta) 17-40/42], derived by alpha- and gamma-secretase cleavage of the amyloid precursor protein (APP), is a major constituent of diffuse plaques in Alzheimer's disease and cerebellar pre-amyloid in Down's syndrome. However, the importance of p3 peptide accumulation in Alzheimer's disease and its toxic properties is not clear. Here, we demonstrate that treatment of cells with Abeta 17-42 leads to apoptosis in two human neuroblastoma cell lines, SH-SY5Y and IMR-32. Abeta 17-42 activated caspase-8 and caspase-3, induced poly(ADP-ribose) polymerase cleavage, but did not activate caspase-9. Selective caspase-8 and caspase-3 inhibitors completely blocked Abeta 17-42-induced neuronal death. Abeta 17-42 moderately activated c-Jun N-terminal kinase (JNK); however, overexpression of a dominant-negative mutant of SEK1, the upstream kinase of JNK, protected against Abeta 17-42 induced neuronal death. These results demonstrate that Abeta 17-42 induced neuronal apoptosis via a Fas-like/caspase-8 activation pathway. Our findings reveal the previously unrecognized toxic effect of Abeta 17-42. We propose that Abeta 17-42 constitutes an additional toxic peptide derived from APP proteolysis and may thus contribute to the neuronal cell loss characteristic of Alzheimer's disease.
...
PMID:Abeta 17-42 in Alzheimer's disease activates JNK and caspase-8 leading to neuronal apoptosis. 1218 49

Neurodegenerative disorders in humans may be triggered or exacerbated by exposure to occupational or environmental agents. Here, we show that a brief exposure to methylisothiazolinone, a widely used industrial and household biocide, is highly toxic to cultured neurons but not to glia. We also show that the toxic actions of this biocide are zinc dependent and require the activation of p44/42 extracellular signal-regulated kinase (ERK) via a 12-lipoxygenase-mediated pathway. The cell death process also involves activation of NADPH oxidase, generation of reactive oxygen species, DNA damage, and overactivation of poly(ADP-ribose) polymerase, all occurring downstream from ERK phosphorylation. The toxic effects of methylisothiazolinone and related biocides on neurons have not been reported previously. Because of their widespread use, the neurotoxic consequences of both acute and chronic human exposure to these toxins need to be evaluated.
...
PMID:In vitro neurotoxicity of methylisothiazolinone, a commonly used industrial and household biocide, proceeds via a zinc and extracellular signal-regulated kinase mitogen-activated protein kinase-dependent pathway. 1219 62

The effects of combined exposure to the checkpoint abrogator UCN-01 and pharmacologic MEK1/2 inhibitors were examined in human multiple myeloma (MM) cell lines. Treatment of RPMI8226, NCI-H929, and U266 MM cells with a minimally toxic concentration of UCN-01 (150 nM) for 24 hours resulted in mitogen-activated protein (MAP) kinase activation, an effect that was blocked by coadministration of the MEK1/2 inhibitor PD184352. These events were accompanied by enhanced activation of p34(cdc2) and a marked increase in mitochondrial damage (loss of DeltaPsim; cytochrome c and Smac/DIABLO (direct IAP binding protein with low pI) release), poly(ADP-ribose) polymerase (PARP) cleavage, and apoptosis. PD184352/UCN-01 also dramatically reduced clonogenic survival in each of the MM cell lines. In contrast to As(2)0(3), apoptosis induced by PD184352/UCN-01 was not blocked by the free-radical scavenger N-acetyl-L-cysteine. Whereas exogenous interleukin 6 substantially prevented dexamethasone-induced lethality in MM cells, it was unable to protect them from PD184352/UCN-01-induced apoptosis despite enhancing Akt activation. Insulinlike growth factor 1 (IGF-1) also failed to diminish apoptosis induced by this drug regimen. MM cell lines selected for a high degree of resistance to doxorubicin, melphalan, or dexamethasone, or displaying resistance secondary to fibronectin-mediated adherence, remained fully sensitive to PD184352/UCN-01-induced cell death. Finally, primary CD138(+) MM cells were also susceptible to UCN-01/MEK inhibitor-mediated apoptosis. Together, these findings suggest that simultaneous disruption of cell cycle and MEK/MAP kinase signaling pathways provides a potent stimulus for mitochondrial damage and apoptosis in MM cells, and also indicate that this strategy bypasses the block to cell death conferred by several other well-described resistance mechanisms.
...
PMID:Combined treatment with the checkpoint abrogator UCN-01 and MEK1/2 inhibitors potently induces apoptosis in drug-sensitive and -resistant myeloma cells through an IL-6-independent mechanism. 1238 35

Selenium has been implicated as a promising chemopreventive agent for prostate cancer. Whereas the anticancer mechanisms have not been clearly defined, one hypothesis relates to selenium metabolites, especially the monomethyl selenium pool, generated under supranutritional selenium supplementation. To explore potential molecular targets for mediating the chemopreventive activity, we contrasted the effects of methylseleninic acid (MSeA), a novel precursor of methylselenol, versus sodium selenite, a representative of the hydrogen selenide metabolite pool, on apoptosis execution, cell cycle distribution, and selected protein kinases in DU145 human prostate cancer cells. Exposure of DU145 cells to 3 microM MSeA led to a profound G1 arrest at 24 h, and exposure to greater concentrations led to not only G1 arrest, but also to DNA fragmentation and caspase-mediated cleavage of poly(ADP-ribose) polymerase (PARP), two biochemical hallmarks of apoptosis. Immunobiot analyses indicated that G1 arrest induced by the subapoptogenic doses of MSeA was associated with increased expression of p27kip1 and p21cip1, but apoptosis was accompanied by dose-dependent decreases of phosphorylation of protein kinase AKT and extracellular signal-regulated kinase (ERK1/2) in the absence of any phosphorylation change in p38 mitogen-activated protein kinase (p38MAPK) and c-Jun NH2-terminal kinase (JNK1/2). In contrast, selenite exposure caused S-phase arrest and caspase-independent apoptotic DNA fragmentation, which were associated with decreased expression of p27kip1 and p21cip1 and increased phosphorylation of AKT, JNK1/2, and p38MAPK. Although apoptosis induction by MSeA exposure was not sensitive to superoxide dismutase added into the cell culture medium, cell detachment and DNA nucleosomal fragmentation induced by selenite exposure were greatly attenuated by this enzyme, supporting a chemical mediator role of superoxide for these processes. Despite a temporal relationship of AKT and ERK1/2 de-phosphorylation changes before the onset of PARP cleavage in MSeA-exposed cells, experiments with phosphatidylinositol 3-kinase inhibitors wortmannin and LY294002 did not show an enhancing effect of specific blocking of AKT on MSeA-induction of PARP cleavage. Taken together, exposure of DU145 cells to MSeA versus selenite induced differential patterns of cell cycle arrest and apoptosis execution as well as distinct patterns of effects on AKT, ERK1/2, JNK1/2, and p38MAPK phosphorylation and p27kip1 and p21cip1 expression. Multiple molecular pathways are likely differentially targeted by selenium metabolite pools to mediate cancer chemoprevention.
...
PMID:Distinct effects of methylseleninic acid versus selenite on apoptosis, cell cycle, and protein kinase pathways in DU145 human prostate cancer cells. 1248 29

Leptin, the Ob gene product, has emerged recently as a key regulator of bone mass. However, the mechanism mediating leptin effect remains controversial. Because the action of leptin is dependent on its receptors, we analyzed their expression in osteoblast-lineage primary human bone marrow stromal cells (hBMSC). Both the short and long forms of leptin receptors were detected in hBMSC. Leptin significantly decreased the viability of hBMSC. This cytotoxic effect was prevented by Z-Val-Ala-Asp-fluoromethylketone, a pan-caspase inhibitor, implicating that leptin-induced hBMSC death was caspase-dependent. Further investigation demonstrated that leptin activated caspase-3 and caspase-9, but not caspase-8, and increased the cleavage of poly-(ADP-ribose) polymerase and cytochrome c release into cytosol. Leptin activated ERK, but not p38 and JNK, and up-regulated cPLA2 activity; the latter was abolished by pre-treatment of cells with the MEK inhibitor (PD98059 or U0126) or cPLA2 inhibitor (AACOCF3). PD98059, U0126, and AACOCF3 also diminished the leptin-induced cytochrome c release into cytosol, cell death, and caspase-3 activation. These data indicated that leptin induced hBMSC apoptosis via ERK/cPLA2/cytochrome c pathway with activation of caspase-9 and caspase-3, and cleavage of poly(ADP-ribose) polymerase. To our knowledge, this is the first study demonstrating the direct detrimental effect of leptin on bone cells.
...
PMID:Leptin induces apoptosis via ERK/cPLA2/cytochrome c pathway in human bone marrow stromal cells. 1266 5

Carbon monoxide is protective in ischemia-reperfusion organ injury, but the precise mechanisms remain elusive. We have recently shown that low levels of exogenous carbon monoxide (CO) utilize p38 MAPK and attenuate caspase 3 activity to exert an antiapoptotic effect during lung ischemia-reperfusion injury. Our current data demonstrate that CO activates the p38alpha MAPK isoform and the upstream MAPK kinase MKK3 to modulate Fas/Fas ligand expression; caspases 3, 8, and 9; mitochondrial cytochrome c release; Bcl-2 proteins; and poly(ADP-ribose) polymerase cleavage. We correlate our in vitro findings with in vivo studies using MKK3-deficient and Fas-deficient mice. Taken together, our data are the first to demonstrate that CO has an antiapoptotic effect by inhibiting Fas/Fas ligand, caspases, proapoptotic Bcl-2 proteins, and cytochrome c release via the MKK3/p38alpha MAPK pathway.
...
PMID:Carbon monoxide modulates Fas/Fas ligand, caspases, and Bcl-2 family proteins via the p38alpha mitogen-activated protein kinase pathway during ischemia-reperfusion lung injury. 1269 Jan

Whether deletion of tumor necrosis factor (TNF) receptor 1 or 2 affects lipopolysaccharide (LPS)-mediated signaling is not understood. In this report, we used macrophages derived from wild type (wt) mice and from mice null for the type 1 receptor (p60-/-), the type 2 receptor (p80-/-), or both (p60-/- p80-/-) to investigate the effect of these receptors on LPS-mediated activation of NF-kappaB, mitogen-activated protein kinases, and apoptosis. LPS activated NF-kappaB by 3-4-fold in wt cells but by 9-10-fold in p60-/-, p80-/-, and p60-/- p80-/- macrophages. These results correlated with the IkappaBalpha kinase activation, which is needed for NF-kappaB activation. LPS-induced cyclooxygenase-2 and inducible NO synthase proteins and NO production were maximum in p60-/- p80-/- macrophages and minimum in wt cells. LPS activated C-Jun N-terminal kinase, p38MAPK, and extracellular signal-regulated kinase in wt cells, but the levels were much higher in p60-/-, p80-/-, and p60-/- p80-/- cells. LPS-induced cytotoxicity, poly(ADP-ribose) polymerase cleavage, and annexin V staining were also highest in p60-/- p80-/- cells and lowest in wt cells. The difference in LPS signaling was unrelated to the expression of LPS receptors, CD14, or toll-like receptor 4. Overall, our studies indicate that deletion of either of the TNF receptors sensitizes the macrophages to LPS and provide evidence for cross-talk between TNF and LPS signaling.
...
PMID:Genetic deletion of the tumor necrosis factor receptor p60 or p80 sensitizes macrophages to lipopolysaccharide-induced nuclear factor-kappa B, mitogen-activated protein kinases, and apoptosis. 1269 14

Previous studies have identified RRR-alpha-tocopheryl succinate (vitamin E succinate, VES) as a potential chemotherapeutic agent. VES induces human breast cancer cells to undergo apoptosis in a concentration- and time-dependent manner by restoring transforming growth factor beta (TGF-beta) and Fas (CD95) apoptotic signaling pathways, that contribute to the activation of c-Jun NH(2)-terminal kinase (JNK)-mediated apoptosis. The objective of these studies was to clarify biochemical events involved in VES-induced apoptosis. Data show that VES-induced apoptosis involves: (a) translocation of Bax from the cytosol to the mitochondria and cytochrome c release from the mitochondria to the cytosol as determined by Western immunoblot analyses of mitochondrial- and cytosolic-enriched cellular fractions; (b) increased permeabilization of mitochondrial membranes as determined by confocal and fluorescence-activated cell sorting analyses of loss of a mitochondrial selective fluorescent dye; (c) processing of caspase-9 and -3 but not caspase-8 to active forms and cleavage of poly(ADP-ribose) polymerase (PARP) as determined by Western immunoblot analyses using antibodies capable of detecting both proenzyme and processed enzyme forms or the intact or cleaved forms of PARP. Transient transfection of cells with antisense oligonucleotides to Bax or transient overexpression of Bcl-2 prevented VES-induced mitochondrial permeability transition and apoptosis. The use of cell-permeable caspase inhibitors indicated that caspase-9 and -3 but not caspase-8 are involved in VES-induced apoptosis. JNK inhibitor II blocked VES-induced Bax conformational change, indicating a role for JNK in Bax translocation to the mitochondria. Taken together, these data suggest that the activation of JNK, translocation of Bax to the mitochondria, increased mitochondrial membrane permeability with release of cytochrome c, and activation of caspase-9 and -3 are critical events in VES-induced apoptosis of human MDA-MB-435 breast cancer cells.
...
PMID:RRR-alpha-tocopheryl succinate-induced apoptosis of human breast cancer cells involves Bax translocation to mitochondria. 1275 Feb 70

The epidermal growth factor receptor (EGFR) is an important novel target for anticancer therapy. In this study, we examined the molecular mechanisms that underlie the antitumor effects of the anti-EGFR monoclonal antibody C225 (Cetuximab) and the selective EGFR tyrosine kinase inhibitor ZD1839 (Iressa; AstraZeneca) in non-small cell lung cancer (NSCLC) cell lines. Cell growth, assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, was inhibited at low concentrations of ZD1839 and C225 in control A431 cells, whereas the NSCLC cell lines were comparatively more resistant. In A431 cells, but not in the NSCLC cells, ZD1839 treatment resulted in a modest increase in DNA fragmentation, the externalization of phosphatidyl serine, and the activation of caspase-3, known markers of apoptotic cell death. However, poly(ADP-ribose) polymerase cleavage was not detected, and caspase inhibition by carbobenzoxy-Val-Ala-Asp-fluoromethyl ketone partially reduced ZD1839-generated DNA fragmentation. Overexpression of the antiapoptotic protein Bcl-2 in A431 cells suppressed the cytotoxicity upon anti-EGFR treatment. These results thus demonstrate that the toxic effect of ZD1839 in A431 cells is caused by a form of cell death that involves a mitochondrial step and is, at least in part, dependent on caspase activation. EGFR expression levels showed no significant correlation with sensitivity to ZD1839 and C225. Evaluation of the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase and phosphatidylinositol 3'-kinase/Akt pathways showed considerable inhibition of these pathways by ZD1839 and C225 in A431 cells, whereas one or both of these pathways remained active upon anti-EGFR treatment in NSCLC cells. In addition, treatment with specific inhibitors of mitogen-activated protein kinase kinase or phosphatidylinositol 3'-kinase resulted in a smaller effect on proliferation than simultaneous treatment with both inhibitors, whereas induction of apoptosis was observed only when both pathways were blocked. Together, these data suggest that persistent activity of either of these signaling pathways is involved in the lack of sensitivity of NSCLC cell lines to EGFR inhibitors.
...
PMID:Response to epidermal growth factor receptor inhibitors in non-small cell lung cancer cells: limited antiproliferative effects and absence of apoptosis associated with persistent activity of extracellular signal-regulated kinase or Akt kinase pathways. 1279 1

Transient exposure of rat cortical cultures to nonlethal oxygen-glucose deprivation (OGD preconditioning) induces tolerance to otherwise lethal oxygen-glucose deprivation (OGD) or N-methyl-D-aspartate 24 h later. This study evaluates the role of cytosolic and mitochondrial Ca2+-dependent cellular signaling. Mechanistic findings are placed in context with other models of ischemic preconditioning or known neurotoxic pathways within cortical neurons. Tolerance to otherwise lethal OGD is suppressed by performing OGD preconditioning in the presence of the broad-scope catalytic antioxidants Mn(III)tetra(4-carboxyphenyl)porphyrin (MnTBAP) or Zn(II)tetra(4-carboxyphenyl)porphyrin [Zn(II)TBAP], but not by a less active analog, Mn(III)tetra(4-sulfonatophenyl)porphyrin, or a potent superoxide scavenger, Mn(III)tetra(N-ethyl-2-pyridyl)porphyrin chloride. Inhibitors of adenosine A1 receptors, nitric oxide synthase, mitogen-activated protein kinase, and poly(ADP-ribose) polymerase fail to suppress OGD preconditioning despite possible links with reactive oxygen species in other models of ischemic preconditioning. Preconditioning is suppressed by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), which has been ascribed elsewhere to inhibition of superoxide transport to the cytosol through mitochondrial anion channels. However, although it induces mitochondrial Ca2+ uptake, neuronal preconditioning is largely insensitive to mitochondrial uncoupling with carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone or 2,4-dinitrophenol. Un-couplers will prevent production of mitochondrial reactive oxygen species, implying nonmitochondrial targets by MnTBAP, Zn(II)TBAP, and DIDS. Emphasizing the importance of an increase in cytosolic Ca2+ during preconditioning, a Ca2+/calmodulin-dependent protein kinase II inhibitor, KN-62, suppresses development of subsequent tolerance. Summarizing, only those cellular transduction pathways that have the potential to be neurotoxic may be activated by preconditioning in cortical neurons. Finally, a marked decrease in extracellular glutamate is observed during otherwise lethal OGD in preconditioned cultures, suggesting that this end effector may represent a point of convergence across different preconditioning models.
...
PMID:Preconditioning of cortical neurons by oxygen-glucose deprivation: tolerance induction through abbreviated neurotoxic signaling. 1281 13


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---