Hepatitis B virus x gene product (HBx) is known to be a transactivator of transcriptional elements that regulate the expression of a variety of genes associated with the growth, differentiation, survival and the apoptosis of cells. However, the exact mechanism of the activation and inhibition of cellular events by HBx remains uncertain. The present study was designed to measure the effect of HBx, on the signal transduction pathways associated with intracellular Ca(2+)mobilization following HBx transfection in the stable Chang liver cells (CHL-X). Enhanced cell proliferation by HBx in CHL-X was confirmed by MTT assay and by the immunodetection of PCNA. The transactivation of AP-1 by HBx induced in CHL-X was inhibited by cyclosporin A (CsA), a mitochondrial Ca(2+)channel blocker and by BAPTA-AM, a cytosolic Ca(2+)blocker. Activation of the SAPK/JNK signaling pathway by HBx was evidenced by the increased phosphorylations of c-Jun (Ser63) and of JNK (Thr183/Tyr185). Increased phospho-Erk/Erk and phospho-Raf1/Raf in HBx-induced CHL-X indicated that HBx might stimulate the MAPK pathway. PI3K activity and cytosolic free Ca(2+)levels were elevated in HBx-induced CHL-X. These results imply that HBx transactivates both JNK and MAPK signal transduction pathways in association with the mobilization of cytosolic Ca(2+).
1-Phosphatidylinositol 3-Kinase/metabolism ; Calcium/*metabolism ; Calcium Signaling/*physiology ; Cell Division ; Hepatitis B Virus/*metabolism ; Human ; Liver/*metabolism ; Mitogen-Activated Protein Kinases/metabolism ; Trans-Activators/*metabolism ; Transcription Factor AP-1/metabolism

Endothelin can affect the contractile properties of cardiacmyocyte, stimulate myocyte growth and myofibrillogenesis, and increase resistance to apoptosis by intracellular signaling pathways. This article briefly reviews the regulative effects of these signaling pathways including protein kinase C, mitogen activated protein kinase, and phosphoinositide 3'-OH kinase/protein kinase B.
Animals ; Endothelin-1 ; physiology ; Endothelins ; physiology ; Humans ; Mitogen-Activated Protein Kinases ; metabolism ; Myocardial Contraction ; drug effects ; Myocytes, Cardiac ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Protein Kinase C ; metabolism ; Signal Transduction

At this time, brain tumor stem cells remain a controversial hypothesis while malignant brain tumors continue to present a dire prognosis of severe morbidity and mortality. Yet, brain tumor stem cells may represent an essential cellular target for glioma therapy as they are postulated to be the tumorigenic cells responsible for recurrence. Targeting oncogenic pathways that are essential to the survival and growth of brain tumor stem cells represents a promising area for developing therapeutics. However, due to the multiple oncogenic pathways involved in glioma, it is necessary to determine which pathways are the essential targets for therapy. Furthermore, research still needs to comprehend the morphogenic processes of cell populations involved in tumor formation. Here, we review research and discuss perspectives on models of glioma in order to delineate the current issues in defining brain tumor stem cells as therapeutic targets in models of glioma.
1-Phosphatidylinositol 3-Kinase/genetics/metabolism ; Animals ; Brain Neoplasms/genetics/*metabolism/*pathology/therapy ; Glioma/genetics/*metabolism/*pathology/therapy ; Humans ; Neoplastic Stem Cells/*metabolism/*pathology ; Receptors, Notch/genetics/metabolism ; Signal Transduction/genetics/physiology

His-Phe-Tyr-Leu-Pro-Met (HFYLPM) is a synthetic peptide that stimulates Jurkat T cells resulting in intracellular calcium ([Ca2+]i) increase in a pertussis toxin (PTX)-sensitive manner. We have examined the physiological role of the peptide in T cell activity by comparative investigation of intracellular signaling pathways accompanied with HFYLPM-induced T cell chemotaxis with a well-known chemokine, stromal cell-derived factor-1 (SDF-1)-induced signalings. Wortmannin and genistein inhibited both of HFYLPM- and SDF-1-induced Jurkat T cell chemotaxis indicating that phosphoinositide-3-kinase and tyrosine kinase activity were required for the processes. However, U-73122 and BAPTA/AM preferentially blocked HFYLPM- but not SDF-1-induced T cell chemotaxis. It indicates that phospholipase C/calcium signaling is necessary for only chemotaxis by HFYLPM. One of the well-known cellular molecules involving chemotaxis, extracellular signal-regulated protein kinase (ERK), was activated by SDF-1 but not by HFYLPM ruling out a possible role of ERK on the peptide-mediated chemotaxis. These results indicate that the synthetic peptide, HFYLPM, stimulates T cell chemotaxis showing unique signaling and provide a useful tool for the study of T cell activation mechanism.
1-Phosphatidylinositol 3-Kinase/metabolism ; Androstadienes/pharmacology ; Calcium/metabolism ; Cell Line ; Chemokines, CXC/*pharmacology ; Chemotaxis, Leukocyte/drug effects/*physiology ; Dose-Response Relationship, Drug ; Genistein/pharmacology ; Human ; Jurkat Cells ; Oligopeptides ; Peptide Fragments/chemical synthesis/metabolism/*physiology ; Pertussis Toxin ; Phospholipase C/metabolism ; Protein-Tyrosine Kinase/metabolism ; Signal Transduction/drug effects ; T-Lymphocytes/*drug effects ; Virulence Factors, Bordetella/pharmacology

His-Phe-Tyr-Leu-Pro-Met (HFYLPM) is a synthetic peptide that stimulates Jurkat T cells resulting in intracellular calcium ([Ca2+]i) increase in a pertussis toxin (PTX)-sensitive manner. We have examined the physiological role of the peptide in T cell activity by comparative investigation of intracellular signaling pathways accompanied with HFYLPM-induced T cell chemotaxis with a well-known chemokine, stromal cell-derived factor-1 (SDF-1)-induced signalings. Wortmannin and genistein inhibited both of HFYLPM- and SDF-1-induced Jurkat T cell chemotaxis indicating that phosphoinositide-3-kinase and tyrosine kinase activity were required for the processes. However, U-73122 and BAPTA/AM preferentially blocked HFYLPM- but not SDF-1-induced T cell chemotaxis. It indicates that phospholipase C/calcium signaling is necessary for only chemotaxis by HFYLPM. One of the well-known cellular molecules involving chemotaxis, extracellular signal-regulated protein kinase (ERK), was activated by SDF-1 but not by HFYLPM ruling out a possible role of ERK on the peptide-mediated chemotaxis. These results indicate that the synthetic peptide, HFYLPM, stimulates T cell chemotaxis showing unique signaling and provide a useful tool for the study of T cell activation mechanism.
1-Phosphatidylinositol 3-Kinase/metabolism ; Androstadienes/pharmacology ; Calcium/metabolism ; Cell Line ; Chemokines, CXC/*pharmacology ; Chemotaxis, Leukocyte/drug effects/*physiology ; Dose-Response Relationship, Drug ; Genistein/pharmacology ; Human ; Jurkat Cells ; Oligopeptides ; Peptide Fragments/chemical synthesis/metabolism/*physiology ; Pertussis Toxin ; Phospholipase C/metabolism ; Protein-Tyrosine Kinase/metabolism ; Signal Transduction/drug effects ; T-Lymphocytes/*drug effects ; Virulence Factors, Bordetella/pharmacology

Interleukin 1 beta (IL-1 beta), a proinflammatory cytokine, is related with inflammatory diseases and it up-regulates MUC2 gene expression and mucin secretion. This study was designed to investigate the signal transduction pathway of the IL-1 beta-mediated MUC2 gene expression and mucin secretion in human airway epithelial cells. In cultured human airway NCI-H292 epithelial cells, the steady state of the mRNA level of MUC2 gene expression and mucin secretion induced by IL-1 were determined by reverse transcriptase-polymerase chain reaction (RT-PCR), enzyme immunoassay, and immunoblot analysis. To observe the signal pathway of the IL-1 beta-mediated MUC2 gene expression and mucin secretion, we used several specific inhibitors. PD98059 (MEK/ERK inhibitor) suppressed IL-1 beta-mediated MUC2 gene expression and mucin secretion, while SB203580 (p38 inhibitor) did not. Ro31-8220 (PKC inhibitor) inhibited IL-1 beta-mediated MUC2 gene expression and mucin secretion. It inhibited ERK phosphorylation, but did not inhibit p38 phosphorylation. LY294002 (PI3K inhibitor) also suppressed MUC2 expression, but did not inhibit any MAPKs phosphorylation. These results suggest that the IL-1 -mediated MUC2 gene expression and mucin secretion in NCI-H292 cells are regulated through activation of the PKC-MEK/ERK pathway, and that PI3K is also involved in the IL-1 beta-mediated MUC2 gene expression and mucin secretion.
1-Phosphatidylinositol 3-Kinase/*metabolism ; Cell Line ; Chromones/pharmacology ; Dose-Response Relationship, Drug ; Enzyme Activation ; Enzyme Inhibitors/pharmacology ; Epithelium/*enzymology ; Flavonoids/pharmacology ; Humans ; Imidazoles/pharmacology ; Immunoassay ; Immunoblotting ; Indoles/pharmacology ; Interleukin-1/metabolism/*physiology ; Lung/cytology/*metabolism ; MAP Kinase Signaling System ; Mitogen-Activated Protein Kinase Kinases/*metabolism ; Morpholines/pharmacology ; Mucin-2 ; Mucins/*biosynthesis/metabolism ; Phosphorylation ; Protein Kinase C/*metabolism ; Protein Structure, Tertiary ; Pyridines/pharmacology ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; Time Factors

BACKGROUNDAlthough the insulinotropic role of glucagon-like peptide-1 (GLP-1) in type 2 diabetes mellitus has been substantiated, its role in cardioprotection remains largely unknown. This study aimed to determine the effects of GLP-1 on injury of rats cardiac myocytes induced by hypoxia-reoxygenation (H/R) and the possible mechanisms.

METHODSThe cultured neonatal rats cardiac myocytes were randomly divided into seven groups: the normal control group, the H/R group, the GLP-1 + H/R group, the GLP-1 + H/R + UO126 (the p42/44 mitogen-activated protein kinase (MAPK) inhibitor) group, the GLP-1 + H/R + LY294002 (phosphatidylinositol 3-kinase (PI3K) inhibitor) group, the H/R + UO126 group, and the H/R + LY294002 group. The lactate dehydrogenase (LDH) activity, apoptosis rate of cardiac myocytes, and caspase-3 activity were detected after the injury of H/R.

RESULTSCompared with the normal control group, the activity of LDH, cardiac myocyte apoptosis rate, and caspase-3 activity all increased significantly in the H/R group (P < 0.01). Compared with the H/R group, these three indices all decreased in the H/R + GLP-1 group (P < 0.01). However, the changes of LDH activity, apoptosis rate, and caspase-3 activity were inhibited by LY294002 and UO126 respectively.

CONCLUSIONSGLP-1 can directly act on cardiac myocytes and protect them from H/R injury mainly by inhibiting their apoptosis. Its mechanism may be through the PI3K-Akt pathway and the MAPK signaling pathway.

Actins ; analysis ; Animals ; Butadienes ; pharmacology ; Cell Hypoxia ; Cells, Cultured ; Chromones ; pharmacology ; Extracellular Signal-Regulated MAP Kinases ; physiology ; Glucagon-Like Peptide 1 ; pharmacology ; MAP Kinase Signaling System ; Morpholines ; pharmacology ; Myocytes, Cardiac ; drug effects ; Nitriles ; pharmacology ; Phosphatidylinositol 3-Kinases ; physiology ; Rats ; Rats, Wistar

Matrix metalloproteinase-9 (MMP-9) may play an important role in emphysematous change in chronic obstructive pulmonary disease (COPD), one of the leading causes of mortality and morbidity worldwide. We previously reported that simvastatin, an inhibitor of HMG-CoA reductase, attenuates emphysematous change and MMP-9 induction in the lungs of rats exposed to cigarette smoke. However, it remained uncertain how cigarette smoke induced MMP-9 and how simvastatin inhibited cigarette smoke-induced MMP-9 expression in alveolar macrophages (AMs), a major source of MMP-9 in the lungs of COPD patients. Presently, we examined the related signaling for MMP-9 induction and the inhibitory mechanism of simvastatin on MMP-9 induction in AMs exposed to cigarette smoke extract (CSE). In isolated rat AMs, CSE induced MMP-9 expression and phosphorylation of ERK and Akt. A chemical inhibitor of MEK1/2 or PI3K reduced phosphorylation of ERK or Akt, respectively, and also inhibited CSE-mediated MMP-9 induction. Simvastatin reduced CSE-mediated MMP-9 induction, and simvastatin-mediated inhibition was reversed by farnesyl pyrophosphate (FPP) or geranylgeranyl pyrophosphate (GGPP). Similar to simvastatin, inhibition of FPP transferase or GGPP transferase suppressed CSE-mediated MMP-9 induction. Simvastatin attenuated CSE-mediated activation of RAS and phosphorylation of ERK, Akt, p65, IkappaB, and nuclear AP-1 or NF-kappaB activity. Taken together, these results suggest that simvastatin may inhibit CSE-mediated MMP-9 induction, primarily by blocking prenylation of RAS in the signaling pathways, in which Raf-MEK-ERK, PI3K/Akt, AP-1, and IkappaB-NF-kappaB are involved.
1-Phosphatidylinositol 3-Kinase/metabolism ; Alkyl and Aryl Transferases/metabolism ; Animals ; Anticholesteremic Agents/pharmacology ; Cells, Cultured ; Enzyme Inhibitors/metabolism/pharmacology ; Extracellular Signal-Regulated MAP Kinases/metabolism ; Gene Expression Regulation, Enzymologic/*drug effects ; I-kappa B Kinase/antagonists & inhibitors/metabolism ; Macrophages, Alveolar/cytology/*drug effects/*enzymology ; Matrix Metalloproteinase 9/genetics/*metabolism ; Mitogen-Activated Protein Kinase Kinases/metabolism ; Polyisoprenyl Phosphates/metabolism ; Proto-Oncogene Proteins c-akt/metabolism ; Rats ; Sesquiterpenes/metabolism ; Signal Transduction/physiology ; Simvastatin/*pharmacology ; Smoke/*adverse effects ; *Tobacco/adverse effects/chemistry

Akt plays pivotal roles in many physiological responses including growth, proliferation, survival, metabolism, and migration. In the current studies, we have evaluated the isoform-specific role of akt in lysophosphatidic acid (LPA)-induced cell migration. Ascites from ovarian cancer patients (AOCP) induced mouse embryo fibroblast (MEF) cell migration in a dose-dependent manner. On the other hand, ascites from liver cirrhosis patients (ALCP) did not induce MEF cell migration. AOCP-induced MEF cell migration was completely blocked by pre-treatment of cells with LPA receptor antagonist, Ki16425. Both LPA- and AOCP-induced MEF cell migration was completely attenuated by PI3K inhibitor, LY294002. Furthermore, cells lacking Akt1 displayed defect in LPA-induced cell migration. Re-expression of Akt1 in DKO (Akt1(-/-)Akt2(-/-)) cells restored LPA-induced cell migration, whereas re-expression of Akt2 in DKO cells could not restore the LPA-induced cell migration. Finally, Akt1 was selectively phosphorylated by LPA and AOCP stimulation. These results suggest that LPA is a major factor responsible for AOCP-induced cell migration and signaling specificity of Akt1 may dictate LPA-induced cell migration.
1-Phosphatidylinositol 3-Kinase/physiology ; Adult ; Aged ; Animals ; Ascites/pathology ; Cell Movement/*drug effects ; Cells, Cultured ; Embryo, Mammalian ; Enzyme Activation/drug effects ; Female ; Humans ; Liver Cirrhosis/pathology ; Lysophospholipids/isolation & purification/*pharmacology ; Mice ; Middle Aged ; Ovarian Neoplasms/pathology ; Pregnancy ; Proto-Oncogene Proteins c-akt/*agonists/*metabolism ; Substrate Specificity

Angiotensin II (AngII) is a crucial hormone that affects vasoconstriction and exerts hypertrophic effects on vascular smooth muscle cells. Here, we showed that phosphatidylinositol 3-kinase-dependent calcium mobilization plays pivotal roles in AngII-induced vascular constriction. Stimulation of rat aortic vascular smooth muscle cell (RASMC)-embedded collagen gel with AngII rapidly induced contraction. AngII-induced collagen gel contraction was blocked by pretreatment with a phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002) whereas ERK inhibitor (PD98059) was not effective. AngII-induced collagen gel contraction was significantly blocked by extracellular calcium depletion by EGTA or by nifedipine which is an L-type calcium channel blocker. In addition, AngII-induced calcium mobilization was also blocked by nifedipine and EGTA, whereas intracellular calcium store-depletion by thapsigargin was not effective. Finally, pretreatment of rat aortic ring with LY294002 and nifedipine significantly reduced AngII-induced constriction. Given these results, we suggest that PI3K-dependent activation of L-type calcium channels might be involved in AngII-induced vascular constriction.
1-Phosphatidylinositol 3-Kinase/*metabolism/pharmacology ; Angiotensin II/metabolism/*pharmacology ; Animals ; Aorta, Thoracic/*drug effects/physiology ; Calcium Channels, L-Type/drug effects/*metabolism ; Muscle Contraction/drug effects ; Muscle, Smooth, Vascular/drug effects/enzymology ; Rats ; Rats, Sprague-Dawley ; Signal Transduction/*drug effects ; Specific Pathogen-Free Organisms ; Vasoconstriction/*drug effects