AIMTo explore the effects of intrathecal injection of selective cyclooxygenase-1 (COX-1) inhibitor, SC-560, on mechanical allo dynia and spinal ERK protein expression in rats with postoperative pain.

METHODSRats were divided into 4 groups: control group, postoperative pain group, SC-560 group and DMSO group. Mechanical withdrawal threshold (MWT), immunohistochemical and Western blotting technique were used to evaluate mechanical hypersensitivity and the expression of phospho-ERK in the spinal cord, respectively.

RESULTS(1) Behavior test rats developed allodynia 1 h after operation and SC-560 100 microg administrated intrathecally demonstrated a significant reduction in postoperative hypersensitivity. (2) Immunohistochemical staining Phospho-ERK positive neurons in the rat superficial spinal dorsal horn increased significantly 1 h after incision compared with that of non-incision group. Intrathecal administration of SC-560 preoperatively could significantly reduce the number of phospho-ERK positive neurons. (3) Western blot expression of phospho-ERK1/2 protein in the lumbar spinal cord increased significantly 1 h after incision and decreased by intrathecal injection of SC-560.

CONCLUSIONSC-560 administrated intrathecally can inhibit mechanical hypersensitivity induced by postoperative pain in rats and this anti-allodynic process may mediated by spinal ERK.

Animals ; Cyclooxygenase Inhibitors ; pharmacology ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Male ; Pain Measurement ; drug effects ; Pain, Postoperative ; metabolism ; Pyrazoles ; pharmacology ; Rats ; Rats, Wistar ; Spinal Cord ; drug effects ; metabolism

The study was purposed to investigate the effect of extract of Agkistrodon Halys venom on proliferation and apoptosis of K562 cells. The inhibition of K562 cell proliferation was measured by MTT assay; The morphologic changes of K562 cells was observed by microscopy; the apoptosis of K562 cells was measured by flow cytometry; the activity of extracellular signal-regulated kinase (ERK) in K562 cells was detected by Western blot. The results showed that when K562 cells were treated with 0, 1, 10, 20 microg/ml of the extraction for 48 hours, the apoptosis rates were 2.1%, 21.3%, 49.7%, 70.1%, respectively. The proliferation of K562 cells was obviously inhibited in dose-dependent manner. Typical morphologic changes significantly appeared in the extract-treated K562 cells. The extract obviously inhibited the activity of ERK in K562 cells. It is concluded that the extract of Agkistrodon Halys' venom can inhibit the proliferation of K562 cells and induce apoptosis of K562 cells.
Agkistrodon ; Animals ; Apoptosis ; drug effects ; Cell Proliferation ; drug effects ; Complex Mixtures ; pharmacology ; Crotalid Venoms ; chemistry ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Humans ; K562 Cells

The purpose of this study was to investigate the effect and molecular mechanism of metformin (Met) on biological characteristics of acute promyelocytic leukemia (APL) cell line NB4. NB4 cells were treated with various concentrations of Met for different time, MTT method was used to detect cell proliferation, the alteration of cell apoptosis was analyzed by flow cytometry, and the change of cell adhesion ability was examined by cell adhesion assay. NB4 cells were pretreated with U0126, a specific inhibitor for extracellular signal-regulated kinase (ERK) phosphorylation, ERK phosphorylation was assessed by Western blot analysis, apoptosis and cell adhesion ability were evaluated by flow cytometry and cell adhesion test respectively. The results showed that Met could inhibit the cell proliferation, induce the cell apoptosis and increase the ability of cell adhesion. The pretreatment of NB4 cells with 5 µmol/L U0126 could effectively inhibit the phosphorylation of ERK, and reduce cell apoptosis and adhesion induced by 5 mmol/L Met. It is concluded that Met can inhibit the proliferation and promote the apoptosis and adhesion of NB4 cells. MEK/ERK signaling pathway may be one of the molecular mechanisms of metformin on NB4 cells.
Apoptosis ; drug effects ; Cell Adhesion ; drug effects ; Cell Line, Tumor ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Humans ; Leukemia, Promyelocytic, Acute ; metabolism ; pathology ; MAP Kinase Signaling System ; drug effects ; Metformin ; pharmacology ; Mitogen-Activated Protein Kinase Kinases ; metabolism ; Phosphorylation

OBJECTIVETo investigate the alteration of activator protein-1 (AP-1) luciferase activity in human embryo lung fibroblasts (HELF) after exposed to silica, and the role of mitogen activated protein kinase (MAPK)/AP-1 pathway on silica-induced cell cycle changes.

METHODSAfter HELF cells were treated with 200 microg/ml silica, immunofluorescence assays were employed to detect the translocation and the phosphorylation level of extracellular signal-regulated protein kinase (ERK) and c-Jun N-terminal kinase (JNK), flow cytometry was used to detect the distributions of cell cycle, the dominant negative mutant of ERK, JNK and p38 were applied to detect the upstream or downstream relationship of signaling pathways.

RESULTSAfter HELF-AP-1 cells were exposed to 200 microg/ml silica 6, 12, 24 h respectively, silica exposure lead to AP-1 activation in a time-dependent manner, inducing significant AP-1 activation at 6 h, reaching a maximum activation at 12 h, and having a little decrease at 24 h. After silica exposure 1 h, phosphorylation level of ERK and JNK increased mainly in cytoplasm, however, after exposure 2 h, they translocated to nucleus. The proportion of cells in G1 phases was decreased from (63.80 +/- 9.57)% to (32.23 +/- 7.22)%, and the proportion of cells in S phases was increased from (35.17 +/- 10.33)% to (66.00 +/- 8.07)% after exposed to silica 24 h. Curcumin, a chemical inhibitor of AP-1, impaired the decrease of cells in G1 phases. Furthermore we found expression of dominant-negative mutant of ERK and JNK impaired silica-induced AP-1 activation, whereas, dominant-negative mutant of p38 did not show the effect.

CONCLUSIONThese result suggested that 200 microg/ml silica exposure can induce AP-1 activation, induce cell cycle changes through ERK, JNK/AP-1-dependent pathway.

Cell Cycle ; drug effects ; Cells, Cultured ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Fibroblasts ; cytology ; drug effects ; metabolism ; Humans ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Lung ; cytology ; Quartz ; pharmacology ; Signal Transduction ; drug effects ; Transcription Factor AP-1 ; metabolism

The study was purposed to investigate the role of extracellular signal-regulated kinase (ERK) pathway in the differentiation of human MDS cell lines SKM-1 induced by sodium butyrate (NaB), and to elucidate the molecular mechanism of differentiation in SKM-1 cells induced by NaB. The expression levels of total ERK and phosphorylated-ERK were determined by Western blot. The effect of NaB in combination with the ERK inhibitor PD98059 on the proliferation/differentiation of SKM-1 cells was studied, and then the expression levels of the P21 and HDAC protein were detected by Western blot. The results showed that the expression level of phosphorylated ERK was down-regulated by the 1 mmol/L NaB, and the level of total ERK had not changed. NaB or combination of the MEK inhibitor PD98059 with NaB could increase the differentiation of the SKM-1 cells and up-regulated the levels of the P21 and HDAC protein, but the effect of combination of NaB with PD98059 was higher than that of NaB alone. It is concluded that the inhibition of ERK may be involved in sodium butyrate inducing differentiation in SKM-1 cells.
Butyrates ; pharmacology ; Cell Transformation, Neoplastic ; drug effects ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Humans ; Myelodysplastic Syndromes ; enzymology ; pathology ; Tumor Cells, Cultured

OBJECTIVETo observe the effect of Jianpi Bushen Qingchang Huashi Recipe (JBQHR) on proliferation and migration of bone marrow mesenchymal stem cells (BMSCs).

METHODSBMSCs were isolated and cultured in vitro with adherence screening method to prepare cell suspension. No drug intervention was given to BMSCs in the vehicle control group. JBQHR at 0.39, 0.78, 1.56 µg/mL was added in BMSCs of low, mid, and high dose JBQHR groups for co-incubation. Its effect on the proliferation of BMSCs was detected by CCK-8. BMSCs migration and chemotactic ability was detected using Transwell method. Each dose JBQHR combined ERK kinase inhibitor U0126 was set up as control. The phosphorylation of extracellular regulated protein kinase (ERK) and CAMP responsive element-binding protein (CREB) were detected by Western blot.

RESULTSCompared with the vehicle control group, the proliferation of BMSCs and BMSCs migration number could be promoted in the 3 JBQHR groups (P < 0.05). Besides, the proliferation of BMSCs was better in mid and high dose JBQHR groups than in the low dose JBQHR group (P < 0.05). Compared with the vehicle control group, the phosphorylation of ERK and CREB could be elevated in the 3 JBQHR groups (P < 0.05), and could be inhibited by U0126 (P < 0.01). Compared with the low dose JBQHR group, the phosphorylation of ERK increased in mid and high dose JBQHR groups with statistical difference (P < 0.05).

CONCLUSIONJBQHR could promote the proliferation and migration of BMSCs, and its mechanism might be related to ERK/CREB signaling pathway

Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Cyclic AMP Response Element-Binding Protein ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Humans ; MAP Kinase Signaling System ; Mesenchymal Stromal Cells ; cytology ; drug effects

OBJECTIVETo study the effect of genistein (Gen) on MAPK signal pathway in the CIA rat fibroblast-like synoviocytes (FLS).

METHODSThe rat model of collagen-induced arthritis (CIA) was established. The cultured FLS of CIA rats were divided using randomized method. The effects of Gen (at the concentration of 50, 100, and 200 micromol/L, respectively) on the proliferation of FLS in CIA rats using methyl thiazolyl tetrazolium (MTT) assay. Effects of Gen (at the concentration of 50, 100, and 200 pmol/L, respectively) on the expressions of extracellular signal-regulated kinase (ERK) and phosphorylated extracellular signal-regulated kinase (p-ERK) in the FLS of CIA rats were detected.

RESULTSGen could inhibit the proliferation of FLS in CIA rats. The FLS proliferation in the high dose Gen group at 72 h was only 1.10+/-0.04, significantly lower than that in the model group (2.12+/-0.03, P<0.01). Besides, after Gen's action on FLS, the expression of p-ERK was down-regulated. It was only 0.34+/-0.02 in the high dose Gen group, significantly lower than that in the model group (2.68+/-0.14, P<0.01). There was no change in the expression of ERK (P>0.05).

CONCLUSIONSGen could inhibit the proliferation of FLS in CIA rats. Its mechanism of action was mainly correlated to down-regulating the tyrosine kinase of MAPK signal transduction pathway and inhibiting phosphorylation of ERK.

Animals ; Arthritis, Experimental ; metabolism ; Cells, Cultured ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Female ; Genistein ; pharmacology ; MAP Kinase Signaling System ; drug effects ; Rats ; Rats, Sprague-Dawley ; Synovial Membrane ; cytology ; drug effects ; metabolism

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

OBJECTIVETo investigate the inhibiting effect of salianic-acid B (SA-B) on mitogen-activated protein kinase (MAPK) Signaling in activated rat hepatic stellate cells (HSCs).

METHODSHSCs were isolated from normal rat by in situ perfusion and Nycodenz density-gradient centrifugation method. HSCs were primarily cultured on uncoated plastic for 7 days. Then cells were stimulated with 10ng/ml transforming growth factor-beta1 (TGF-beta1) after incubated with 10-6 M/L SA-B. The effects of SA-B on Extracellular-regulated kinase (ERK) expression and its phosphorylation. Transforming growth factor beta1 receptor I (TbetaR I) and transforming growth factor beta1 receptor II (TbetaR II) on HSCs, type I collagen expression in HSC Induced by TGF-beta1 were detected with western blot assay. Quantity of Type I collagen in the medium of HSCs was detected by ELISA. Matrix metalloproteinase 2, 9, 13 (MMP-2, MMP-9 and MMP-13) in the medium of HSCs was tested by Zymography.

RESULTSThe phosphorylation of ERK1/2 in HSCs with or without TGF-beta1 was inhibited by SA-B. The expression of TbetaR I and TbetaR II on HSCs can not be affected by SA-B. The synthesization of Type I collagen in HSCs was decreased by SA-B; The synthesization and secretion of type I collagen in HSCs with TGF-beta1 were reduced by SA-B too. SA-B had no effect on the activity of MMP-2 and MMP-13, but induced the activity of MMP-13.

CONCLUSIONSA-B inhibits ERK signaling induced by TGF-b1 in HSC. This inhibition has no association with the expression of TbetaR I and TbetaR II on HSCs. SA-B reduces the synthesization and secretion of Type I collagen in HSC by means of inhibiting TGF-beta1 signaling, which might be not related to the degrading activities of MMPs.

Animals ; Benzofurans ; pharmacology ; Cells, Cultured ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Liver ; cytology ; drug effects ; enzymology ; Male ; Mitogen-Activated Protein Kinase Kinases ; metabolism ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; drug effects ; Transforming Growth Factor beta ; pharmacology

OBJECTIVETo investigate the role of extracellular signal-regulated kinase (ERK) in apoptosis of human colon cancer (HCT116) cells.

METHODSAfter the HCT116 cells were pretreated with specific ERK inhibitor (U0126) or specific siRNA and exposed to 10 mmol/L sodium butyrate (NaBT) for 24 h, their apoptosis was detected by flow cytometry, levels of SphK2 and ERK protein were measured by Western blot, and translocation of SphK2 was assayed by immunofluorescence microscopy.

RESULTSThe U0126 and siRNAs specific for SphK2 blocked the export of SphK2 from nuclei to cytoplasm and increased the apoptosis of HCT116 cells following NaBT exposure. Over-expression of PKD decreased NaBT-induced apoptosis of HCT116 cells, which was reversed by U0126. Furthermore, transfection of HCT116 cells with constitutively activated PKD plasmids recovered the U0126-blocked export of SphK2.

CONCLUSIONERK regulates the export of SphK2 and apoptosis of HCT116 cells by modulating PKD. Modulation of these molecules may help increase the sensitivity of colon cancer cells to the physiologic anti-colon cancer agent, NaBT.

Apoptosis ; drug effects ; physiology ; Butyric Acid ; pharmacology ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; HCT116 Cells ; drug effects ; Humans ; Phosphotransferases (Alcohol Group Acceptor) ; genetics ; metabolism ; Protein Kinase C ; genetics ; metabolism ; RNA, Small Interfering ; Signal Transduction ; drug effects