BACKGROUNDPreviously, we reported that dual-specificity phosphatase 1 (DUSP1) was differentially expressed in endometrioid adenocarcinoma (EEA). However, the role of DUSP1 in EEA progression and the relationship between DUSP1 and medroxyprogesterone (MPA) are still unclear.

METHODSThe expression of DUSP1 in EEA specimens was detected by immunohistochemical analysis. The effect of DUSP1 on cell proliferation was analyzed by Cell Counting Kit 8 and colony formation assay, and cell migration was analyzed by transwell assay. MPA-induced DUSP1 expression in EEA cells was measured by Western blot.

RESULTSDUSP1 expression was deficient in advanced International Federation of Gynecology and Obstetrics stage, high-grade and myometrial invasive EEA. In EEA cell lines (Hec1A, Hec1B, RL952, and Ishikawa), the DUSP1 expression was substantially higher in Ishikawa cells than in other cell lines (P < 0.05). Knockdown of DUSP1 promoted Ishikawa cells proliferation, migration, and activation of mitogen-activated protein kinases/extracellular signal-regulated kinase (MAPK/Erk) pathway. MPA-induced DUSP1 expression and inhibited MAPK/Erk pathway in Ishikawa cells.

CONCLUSIONSOur data suggest that DUSP1 deficiency promotes EEA progression via MAPK/Erk pathway, which may be reversed by MPA, suggesting that DUSP1 may serve as a potential therapeutic target for the treatment of EEA.

Carcinoma, Endometrioid ; metabolism ; Cell Culture Techniques ; Cell Proliferation ; genetics ; physiology ; Dual-Specificity Phosphatases ; genetics ; metabolism ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Female ; Humans ; Mitogen-Activated Protein Kinases ; metabolism

OBJECTIVETo analyze the expression and functions of ERK (extracellular regulated kinase) in Fas-mediated apoptosis in gastric carcinoma cell line SGC-7901 and to elucidate the potential significance of this signaling pathway in tumor progression.

METHODSRadioisotope labeling and Western blotting with special anti-ERK antibody were used to check ERK activity in SGC-7901 cell line after anti-Fas antibody treatment. Apoptosis induced by several treatment factors was evaluated by FACS can flow cytometer.

RESULTSERK activity increased and reached the peak at 30 min after treatment with anti-Fas antibody and decreased in PD98059 pretreated group. The number of sub-G(1) cell was 30.5% +/- 2.6% in PD98059 pretreated group, which was higher than anti-Fas treatment group and control group, respectively.

CONCLUSIONIn gastric cancer cell line SGC-7901, Fas-induced ERK activation may suppress Fas-mediated apoptosis. Inhibition of ERK may enhance the sensitivity of SGC-7901 cells to Fas-mediated apoptosis. Fas-induced ERK activation may confer gastric cancer cells ability to escape the immune surveillance.

Apoptosis ; physiology ; Cell Line, Tumor ; Extracellular Signal-Regulated MAP Kinases ; antagonists & inhibitors ; metabolism ; Fas Ligand Protein ; metabolism ; Humans ; Signal Transduction ; Stomach Neoplasms ; pathology

Animals ; Dementia, Vascular ; metabolism ; physiopathology ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Hippocampus ; cytology ; metabolism ; physiopathology ; Male ; Mice ; Neurons ; metabolism ; physiology ; Random Allocation

OBJECTIVE: To investigate the role of focal adhesion kinase (FAK) in extracellular signal-regulated kinase (ERK) signaling pathway mediated invadsion of trophoblasts. METHODS: We established a human extravillous cytotrophoblasts in vitro invasion model. Different concentrations of herbimycin A(FAK inhibitor)and PD98059 (ERK inhibitor) were given to observe the influence on the growth of trophoblast cells, FAK, ERK phosphorylation, and trophoblast invasion abilities. RESULTS: The expression of phosphorylated FAK in the extravillous cytotrophoblasts (EVCT) was inhibited by herbimycin A in a concentration-dependent manner and expression of phosphorylated ERK1/2 was also partially reduced. PD98059 had no effect on the expression of phosphorylated FAK. Herbimycin A and PD98059 suppressed the in vitro invasion of EVCT to various degrees. CONCLUSION ERK signaling pathway may be the common pathway for many invasive signals,and play a key role in the regulation of trophoblast invasion.
Benzoquinones ; pharmacology ; Cell Division ; physiology ; Cell Movement ; physiology ; Extracellular Signal-Regulated MAP Kinases ; antagonists & inhibitors ; metabolism ; Flavonoids ; pharmacology ; Focal Adhesion Protein-Tyrosine Kinases ; antagonists & inhibitors ; metabolism ; Humans ; Lactams, Macrocyclic ; pharmacology ; Phosphorylation ; Rifabutin ; analogs & derivatives ; Signal Transduction ; physiology ; Trophoblasts ; cytology ; physiology

AIMTo investigate the relationship between the spatial learning and memory and hippocampal ERK1/2 pathway activity in ovariectomized rats.

METHODSFemale SD rats were randomly divided into sham operated group (Sham group) and ovariectomized group (OVX group), and fed 4 months. Then spatial learning and memory of rats were evaluated by the Morris water maze task. Rats in each group were randomly divided into training group and untraining group before the test. Induced activity of ERK 1/2 stimulated by learning and memory was detected in the training group, and basic activity of ERK 1/2 was detected in the untraining group. The protein expression of p-ERK 1/2 and Raf kinase inhibitor protein (RKIP) were assayed by Western blotting respectively.

RESULTS(1) During the training session the OVX rats held longer escape latenci than the sham rats did (P < 0.05). (2) The relative level of pERK1/2 protein in training rats of the both groups was higher than that in untraining rats (P < 0.05). (3) The relative level of p-ERK1/2 protein both training and untraining rats in OVX group was lower than that in sham group correspondingly (P < 0.05). (4) Compared with sham group, the relative expression of RKIP in OVX group was significantly higher (P < 0.05).

CONCLUSIONSpatial learning and memory deficits in ovariectomized rats might be correlated with the decreased basic and induced activity of ERK1/2 pathway and increased expression of RKIP in the CA1/CA2 region of hippocampus.

Animals ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Female ; Hippocampus ; physiology ; Learning ; physiology ; MAP Kinase Signaling System ; physiology ; Memory ; physiology ; Ovariectomy ; Phosphatidylethanolamine Binding Protein ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley

Animals ; Cell Nucleus ; enzymology ; Drosophila Proteins ; genetics ; metabolism ; Drosophila melanogaster ; Extracellular Signal-Regulated MAP Kinases ; genetics ; metabolism ; Long-Term Potentiation ; physiology ; MAP Kinase Signaling System ; physiology ; Memory Consolidation ; physiology ; Neurons ; cytology ; enzymology

OBJECTIVETo investigate the effect of mitogen-activated protein kinase (MEK) kinase cascade, extracellular signal-regulated kinase (ERK1/2) signal pathway on Schwann cells proliferation promoted by Pyrroloquinoline Quinine (PQQ) and its molecular mechanisms.

METHODSSchwann cells were cultured and purified in vitro. The purity was identified by S-100. Different time and concentration of PQQ was added into culture medium. The expression of ERK1/2 and phosphorylated-ERK1/2 was detected by western blot. The expression of p-ERK1/2 after blocking of MEK signal pathway by specific inhibitor PD98059 was detected by western blot.

RESULTSMorphological change was observed in PQQ treated Schwann cells. 1-500 nmol/L PQQ could up-regulate the expression of p-ERK1/2, and 1000 nmol/L had no effects, while 10 000 nmol/L exhibited inhibitory effect (P < 0.05). p-ERK1/2 increased to peak 1 h after PQQ added, and this up-regulation of p-ERK1/2 was inhibited by PD98059 (P < 0.05).

CONCLUSIONSPQQ could affect morphology of Schwann cells and activation of ERK1/2. MEK inhibitor PD98059 could, block this activation. It suggests that MEK/ERK signal pathway should be involved in Schwann cells proliferation promoted by PQQ.

Animals ; Cell Proliferation ; drug effects ; Cells, Cultured ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; physiology ; Mitogen-Activated Protein Kinases ; metabolism ; physiology ; Pyrroles ; pharmacology ; Quinolines ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Schwann Cells ; cytology ; drug effects ; Signal Transduction

BACKGROUNDThrombin is a multifunctional serine protease that plays a crucial role in hemostasis following tissue injury. In addition to its procoagulation effect, thrombin is also a potent mesenchymal cell mitogen, therefore it plays important roles in the local proliferation of mesenchymal cells in the tissue repair process. Reactive oxygen species (ROS) can induce some human cells to proliferate at lower rates while at higher concentrations they promote cells to undergo apoptosis or necrosis. Accumulative evidence suggests that thrombin can induce some cells to produce ROS. Based on these observations, we provide a hypothesis that thrombin can stimulate human lung fibroblasts to produce ROS, which play an important role in human lung fibroblast proliferation.

METHODSROS were detected in fibroblasts at 30 minutes and 60 minutes following thrombin (20 U/ml) exposure using flow cytometry. The ratio of reduced glutathione/oxidized glutathione (GSH/GSSG) was assayed in lung fibroblasts using a commercial kit following treatment with thrombin at different concentrations. NADPH oxidase and the extracellular regulated kinase1/2 (ERK1/2) signaling pathway were detected by Western blotting after thrombin stimulation to lung fibroblasts.

RESULTSThrombin, at 20 U/ml, stimulated human lung fibroblasts (HLF) to generate ROS in a time dependent manner. The ratio of GSH/GSSG in fibroblasts treated with thrombin showed a significant decrease. NADPH oxidase was activated and the ERK1/2 signal pathway was involved in the proliferation process of fibroblasts treated with thrombin.

CONCLUSIONThe activation of NADPH oxidase by thrombin leads to the production of ROS, which promotes fibroblasts proliferation via activation of the ERK1/2 signaling pathway.

Cell Proliferation ; drug effects ; Cells, Cultured ; Extracellular Signal-Regulated MAP Kinases ; analysis ; physiology ; Fibroblasts ; drug effects ; physiology ; Flow Cytometry ; Glutathione ; metabolism ; Humans ; Lung ; cytology ; NADPH Oxidases ; analysis ; physiology ; Reactive Oxygen Species ; metabolism ; Signal Transduction ; physiology ; Thrombin ; pharmacology

This study was aimed to investigate the regulative effect of ERK and p38 signal transduction pathway on cell cycle of CML. The mRNA and protein expression of ERK, p38, cyclin D(2), cyclin E and p27 (ERK and p38 were Phosph-ERK and Phosph-P38) in CML cells and K562 cell lines were detected by RT-PCR and Western blot, respectively; cell cycle was determined by FCM, and their relationship was analyzed. The results showed that the mRNA and protein expressions of ERK, p38, cyclin D(2) and cyclin E in CML cells and K562 cells increased (P<0.01) and the expression of p27 decreased (P<0.01). There was positive correlation between the protein expressions of cyclin D(2) and the protein expression of ERK, p38 and cyclin E, but there was negative correlation between the protein expressions of cyclin D(2) and the protein expression of p27. The percentage of cells in G(0)/G(1) phase was decreased and the percentage of cells in S phase was increased, there was significant difference as compared with control (P<0.05). It is concluded that increase of the mRNA expression and protein activity of ERK and p38 activate the cell cycle-regulating proteins such as cyclin D(2), cyclin E, p27 which results in shortening of G(0)/G(1) phase, switching cell to S phase through G(1)/S check point quickly and accelerating cell cycle progression and cell proliferation, and eventually leads to occurrence of CML.
Adult ; Cell Cycle ; physiology ; Cells, Cultured ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Female ; Humans ; K562 Cells ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; metabolism ; pathology ; Male ; Middle Aged ; Signal Transduction ; p38 Mitogen-Activated Protein Kinases ; metabolism

OBJECTIVEAirway remodeling in asthma makes treatment of asthma very difficult, and study of its pathogenesis becomes very important. The present study aimed to explore the role of external signal regulated kinase (ERK) signal transduction pathway in airway remodeling in rats asthma model and regulatory effects of glucocorticoids on ERK signal transduction pathway and airway remodeling.

METHODSTotally 80 male Sprague-Dawlay rats (6-8 weeks old, weighing about 120 g) were randomly divided into control groups (30 rats), asthma groups (30 rats) and treated groups [including a group intervened with dexamethasone (DM group) and budesonide (BUD group), each had 10 rats]. The rats were sensitized for inducing asthma by intraperitoneal injection of ovalbumin and Al (OH)(3) and were repeatedly exposed to aerosolized ovalbumin for 4, 8, or 12 weeks [respectively called 4, 8 or 12 wk asthma group (A4, A8 or A12 group), each had 10 rats]; and correspondingly control rats were intraperitoneally injected with 0.9% NaCl, then were repeatedly exposed to 0.9% NaCl for 4, 8, or 12 weeks [respectively called 4, 8 or 12 wk control group (C4, C8 or C12 group), each had 10 rats]; DM group rats were repeatedly exposed to aerosolized ovalbumin for 8 wk, and BUD group rats for 12 wk. Total bronchial wall thickness (Wat) and smooth muscle thickness (Wam) were measured by an image analysis system. Concentrations of PDGF-AB in serum were measured by sandwich ELISA. Phospho-ERK (P-ERK) and c-Fos were detected by immunohistochemical technique; lung tissue extracts were analyzed for phosphorylation of ERK by Western blotting.

RESULTSWat and Wam in all asthma groups were significantly higher than those in corresponding control groups (P < 0.01, respectively), those of the treated groups were significantly lower than asthma groups (P < 0.01). The concentrations of PDGF-AB in serum of asthma groups [(228 +/- 18) pg/ml, (293 +/- 77) pg/ml, (225 +/- 66) pg/ml for A4, A8, A12 groups, respectively] were all significantly higher than those of the control groups [(160 +/- 14) pg/ml, (165 +/- 29) pg/ml and (164 +/- 27) pg/ml for C4, C8, C12 group, respectively] (P < 0.01 or P < 0.05); the value of DM group [(157 +/- 46) pg/ml] was significantly lower than that of the group A8 (P < 0.01), no significant difference was found when the values of BUD group [(208 +/- 40) pg/ml] was compared with that of A12 group (P > 0.05). Mean absorbance values (by immunohistochemistry) of P-ERK and c-Fos in asthma groups were significantly higher than those in corresponding control groups (P < 0.01, respectively), DM group had a significantly lower value than group A8 (P < 0.01), BUD group had a significantly lower value than group A12 (P < 0.01); absorbance (by Western blot) of P-ERK in A4, A8, A12 group was significantly higher than that in C4 and C8 group, the value of DM group was significantly lower than that of group A8 (P < 0.01), and that of BUD group (1.8 +/- 0.2) was significantly lower than that of group A12 (P < 0.01).

CONCLUSIONAsthmatic rats have higher concentrations of PDGF-AB in serum and phosphorylation of ERK and c-Fos; glucocorticoids inhibit phosphorylation of ERK and c-Fos in asthmatic rats, and to some extent also inhibit Wat and Wam.

Animals ; Asthma ; drug therapy ; metabolism ; Bronchi ; drug effects ; physiology ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Glucocorticoids ; pharmacology ; Male ; Phosphorylation ; Platelet-Derived Growth Factor ; metabolism ; Proto-Oncogene Proteins c-fos ; metabolism ; Rats ; Rats, Sprague-Dawley ; Signal Transduction