OBJECTIVETo study the role of MEKK2 on the production of IL-2 in Jurkat cells stimulated by PHA/anti-CD28 antibody.

METHODSThe MEKK2 and JNK kinase activities were measured in both dominant negative MEKK2 Jurkat (dnMEKK2 Jurkat) cells and parental Jurkat cells. The AP(1) and IL-2 promotor activities were measured by luciferase activity assay. The IL-2 mRNA and protein were detected by RT-PCR and Western blot.

RESULTSAfter stimulation by PHA/anti-CD28, JNK was activated in parental Jurkat cells but not in dnMEKK2 Jurkat cells. The luciferase report gene activities of AP1 and IL-2 promotors were increased by 4- and 5-folds in parental cells whereas only by 1 fold in dnMEKK2 Jurkat cells. The level of IL-2 mRNA and IL-2 protein were increased in parental Jurkat cells but not in dnMEKK2 Jurkat cells.

CONCLUSIONMEKK2 plays an important role on the production of IL-2 in Jurkat cell stimulated with PHA/anti-CD28 antibody. It is a potential drug target for the treatment of GVHD and autoimmune disease.

Humans ; Interleukin-2 ; biosynthesis ; genetics ; Jurkat Cells ; MAP Kinase Kinase 4 ; metabolism ; MAP Kinase Kinase Kinase 2 ; metabolism ; physiology

OBJECTIVETo investigate the role of mitogen activated protein kinase kinase 1 (MAPKK, MEK1) and regulated kinase1/2 (ERK1/2) on cardiac hypertrophy induced by rat parathyroid hormone1-34 (rPTH1-34).

METHODNeonatal rat cardiomyocytes was treated with or without 10(-7) mol/L rPTH1-34 in the absence or presence 2 x 10(-5) mol/L PD98059, a MEK1 inhibitor. Cellular diameter was measured by Motic Images Advanced 3.0 software and the synthetic rate of protein in cardiac myocytes was detected by 3H-leucine incorporation, mRNA expression of atrial natriuretic peptide (ANP) was measured by RT-PCR and protein expression of ERK1/2 and p-ERK1/2 was measured by Western blot.

RESULTSrPTH1-34 (10(-7) mol/L) significantly increase cellular diameter (+13.6 microm), 3H-leucine incorporation (+898 cpm/well), ANP mRNA expression (+73.9%), and p-ERK1/2 protein expression (+15%) compared to control cells (all P < 0.05) and these effects could be significantly attenuated by PD98059: cellular diameter (-7.1 microm), 3H-leucin e incorporation (-644 cpm/well), ANP mRNA expression (-52.2%), and protein expression of p-ERK1/2 (-18%) (all P < 0.05 vs. PTH group). PD98059 did not affect control cells without PTH treatment (all P > 0.05).

CONCLUSIONSPD98059 attenuates PTH induced cardiac hypertrophy in vitro via inhibiting the expression of ERK1/2 and p-ERK1/2.

Animals ; Atrial Natriuretic Factor ; metabolism ; Cardiomegaly ; chemically induced ; metabolism ; Cells, Cultured ; Flavonoids ; pharmacology ; Gene Expression Regulation ; MAP Kinase Kinase 1 ; metabolism ; MAP Kinase Kinase 2 ; metabolism ; MAP Kinase Signaling System ; Myocytes, Cardiac ; metabolism ; Parathyroid Hormone ; adverse effects ; Rats ; Rats, Wistar

OBJECTIVETo investigate the MEK and ERK expression and their relationship with clinicopathological parameters in human breast carcinoma, and the effect of preoperative chemotherapy on MEK and ERK protein expression.

METHODSSamples were obtained from 56 patients with breast carcinoma and 8 patients with benign tumors. Sixteen of the 56 patients received preoperative chemotherapy. Western blot and immunohistochemistry were used to measure the expression of MEK1, MEK2 and ERK1, ERK2 protein.

RESULTSMEK2 and ERK1, ERK2 protein levels were increased in breast carcinoma tissue compared with those in adjacent normal tissues (t = 7.244, 5.959, 3.735, P < 0.01) and benign tumors (t = 2.206, P < 0.05). The levels of MEK1 were decreased. The expression of MEK2 protein in ER negative patients was higher than that in ER positive ones. MEK2 protein levels were lower in patients who received preoperative chemotherapy than in those who did not.

CONCLUSIONOverexpression of MEK-ERK may play an important role in the development of human breast carcinoma. MEK and ERK protein expressions are inhibited by preoperative chemotherapy.

Adult ; Aged ; Blotting, Western ; Breast Neoplasms ; diagnosis ; enzymology ; metabolism ; Female ; Humans ; Immunohistochemistry ; MAP Kinase Kinase 1 ; MAP Kinase Kinase 2 ; MAP Kinase Signaling System ; physiology ; Middle Aged ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; Mitogen-Activated Protein Kinase Kinases ; metabolism ; Mitogen-Activated Protein Kinases ; metabolism ; Prognosis ; Protein Kinases ; metabolism ; Protein-Serine-Threonine Kinases ; metabolism ; Protein-Tyrosine Kinases ; metabolism

OBJECTIVETo explore the effect of reinforcing qi for resolving masses method (RQRMM) on expressions of extracellular signal regulated kinase 2 (MEK2) and phosphorylation extracellular signal regulated kinase (p-ERK) protein in estrogen induced uterine leiomyoma model Guinea pigs' uterine tissue.

METHODSGuinea pigs were randomly divided into five groups, i.e., the model group, the high dose group, the middle dose group, the low dose group, and the Western medicine group (mifepristone). The normal control group was set up. The uterine leiomyoma model in guinea pigs was established by castrating and subcutaneous injecting estradiol (E2). The protein expression levels of MEK2 and p-ERK of guinea pigs' uterine tissues were detected by immunohistochemical assay.

RESULTSThe protein expressions of MEK2 and p-ERK in the uterine muscular tissue of Guinea pigs' uterine tissue were higher in the model group than in the normal group (P < 0.01). They decreased to some degree in the high dose group, the middle dose group, and the low dose group. Of them, the protein expressions of MEK2 and p-ERK were significantly lower in the high dose group than in the model group and the Western medicine group (P < 0.01).

CONCLUSIONRQRMM could treat uterine leiomyoma possibly through intervening the MAPK/ERK cell signal pathway to inhibit the proliferation of myoma cells.

Animals ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Estrogens ; adverse effects ; Female ; Guinea Pigs ; MAP Kinase Kinase 2 ; metabolism ; MAP Kinase Signaling System ; drug effects ; Phytotherapy ; methods ; Signal Transduction ; Uterine Neoplasms ; chemically induced ; drug therapy ; metabolism ; Uterus ; metabolism

BACKGROUNDIncreased risk of bladder cancer has been reported in diabetic patients. This study was to investigate the roles of mitogen-activated protein kinase kinase (MEK) 1 and 2 in the regulation of human insulin- and insulin glargine-induced proliferation of human bladder cancer T24 cells.

METHODSIn the absence or presence of a selective inhibitor for MEK1 (PD98059) or a specific siRNA for MEK2 (siMEK2), with or without addition of insulin or glargine, T24 cell proliferation was evaluated by cell counting kit (CCK)-8 assay. Protein expression of MEK2, phosphorylation of ERK1/2 and Akt was analyzed by Western blotting.

RESULTST24 cell proliferation was promoted by PD98059 at 5 - 20 µmol/L, inhibited by siMEK2 at 25 - 100 nmol/L. PD98059 and siMEK2 remarkably reduced phosphorylated ERK1/2. Insulin- and glargine-induced T24 cell proliferation was enhanced by PD98059, suppressed while not blocked by siMEK2. Insulin- and glargine-induced ERK1/2 activation was blocked by PD98059 or siMEK2 treatment, whereas activation of Akt was not affected.

CONCLUSIONMEK1 inhibits while MEK2 contributes to normal and human insulin- and insulin glargine-induced human bladder cancer T24 cell proliferation.

Blotting, Western ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Flavonoids ; pharmacology ; Humans ; Insulin ; pharmacology ; Insulin Glargine ; Insulin, Long-Acting ; pharmacology ; MAP Kinase Kinase 1 ; antagonists & inhibitors ; metabolism ; MAP Kinase Kinase 2 ; genetics ; metabolism ; MAP Kinase Signaling System ; drug effects ; genetics ; Phosphorylation ; drug effects ; RNA, Small Interfering ; genetics ; physiology ; Urinary Bladder Neoplasms ; metabolism

To investigate the mechanism of inhibitory effect of a novel bFGF antagonist peptide isolated from the phage display random heptapeptide library on cell proliferation induced by basic fibroblast growth factor. The effect of P7 on cell morphology was observed under an inverted microscope. Flow cytometry was applied to analyze the effect of P7 on cell cycle progress of bFGF-stimulated cells. The effect of P7 on bFGF-induced activation of MEK and Erk1/2 in MAPK pathway was detected by Western blotting. The results showed that no significant cell morphology change was observed in the range of detected concentrations of P7. Cell cycle analysis showed that P7 decreased S-phase cell population and arrested cell cycle at the G0/G1 phase of bFGF-stimulated cells. The results of MAP kinase activation assay indicated that P7 decreased bFGF-induced MEK and Erk1/2 phosphorylation in a dose-dependent manner. P7 inhibited proliferation of bFGF-stimulated Balb/c 3T3 cells possibly via cell cycle arrest at the G0/G1 phase and down-regulation of signal molecular activation in MAPK pathway.
Animals ; BALB 3T3 Cells ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Fibroblast Growth Factor 2 ; antagonists & inhibitors ; pharmacology ; MAP Kinase Kinase Kinases ; metabolism ; MAP Kinase Signaling System ; drug effects ; Mice ; Mice, Inbred BALB C ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Peptides ; pharmacology ; Phosphorylation ; Protein Binding

Bibenzyl is a type of active compounds abundant in Dendrobium. In the present study, we investigated the inhibitory effects of six bibenzyls isolated from Dendrobium species on vascular endothelial growth factor (VEGF)-induced tube formation in human umbilical vascular endothelial cells (HUVECs). All those bibenzyls inhibited VEGF-induced tube formation at 10 micromol x L(-1) except tristin, and of which moscatilin was found to have the strongest activity at the same concentration. The lowest effective concentration of moscatilin was 1 micromol x L(-1). Further results showed that moscatilin inhibited VEGF-induced capillary-like tube formation on HUVECs in a concentration-dependent manner. Western blotting results showed that moscatilin also inhibited VEGF-induced phosphorylation of VEGFR2 (Flk-1/KDR) and extracellular signal-regulated kinase 1/2 (ERK1/2). Further results showed that moscatilin inhibited VEGF-induced activation of c-Raf and MEK1/2, which are both upstream signals of ERK1/2. Taken together, results presented here demonstrated that moscatilin inhibited angiogenesis via blocking the activation of VEGFR2 (Flk-1/KDR) and c-Raf-MEK1/2-ERK1/2 signals.
Angiogenesis Inhibitors ; administration & dosage ; isolation & purification ; pharmacology ; Animals ; Benzyl Compounds ; administration & dosage ; isolation & purification ; pharmacology ; Bibenzyls ; isolation & purification ; pharmacology ; Cell Count ; Cells, Cultured ; Dendrobium ; chemistry ; Dose-Response Relationship, Drug ; Human Umbilical Vein Endothelial Cells ; Humans ; MAP Kinase Kinase 1 ; metabolism ; MAP Kinase Kinase 2 ; metabolism ; MAP Kinase Signaling System ; drug effects ; Mice ; Mice, Inbred C57BL ; Neovascularization, Physiologic ; drug effects ; Phosphorylation ; drug effects ; Plants, Medicinal ; chemistry ; Proto-Oncogene Proteins c-raf ; metabolism ; Signal Transduction ; drug effects ; Vascular Endothelial Growth Factor Receptor-2 ; metabolism

Angiotensin II (Ang II), which is an important mediator of both vascular responsiveness and growth, has been shown to induce vascular smooth muscle cell (VSMC) hypertrophy via the activation of a complex series of intracellular signaling events. Heat shock protein 70 (Hsp70) has recently been shown to protect against Ang II-induced hypertension. In this study, we tested the hypothesis that Hsp70 can protect VSMC from Ang II-induced hypertrophy. We treated VSMCs with Ang II to induce hypertrophy and to activate MAPK signaling pathway. We observed that the augmentation of Hsp70 expression inhibited Ang II-stimulated VSMC hypertrophy. This inhibitory effect of Hsp70 appears to be partly due to extracellular signal-regulated kinase (ERK1/2) inactivation, which in turn, may possibly result from the accumulation of MAP kinase phosphatase-1 (MKP-1).
Rats, Sprague-Dawley ; Rats ; RNA, Small Interfering/pharmacology ; Protein-Tyrosine-Phosphatase/metabolism/physiology ; Phosphoprotein Phosphatase/metabolism/physiology ; Muscle, Smooth, Vascular/*cytology/*drug effects ; Mitogen-Activated Protein Kinase 3/antagonists & inhibitors ; Mitogen-Activated Protein Kinase 1/antagonists & inhibitors ; Male ; MAP Kinase Kinase 2/metabolism ; MAP Kinase Kinase 1/metabolism ; Immediate-Early Proteins/metabolism/physiology ; Hypertrophy ; HSP70 Heat-Shock Proteins/antagonists & inhibitors/*pharmacology ; Flavonoids/pharmacology ; Enzyme Stability/drug effects ; Cells, Cultured ; Cell Cycle Proteins/metabolism/physiology ; Aorta/drug effects/pathology ; Animals ; Angiotensin II/*pharmacology

BACKGROUNDObstructive sleep apnea is a frequent medical condition consisting of repetitive sleep-related episodes of upper air ways obstruction and can lead to hypertension. Ang II type 1 receptor (AT1R) played important roles in hypertension since it binds with Ang II, controlling salt-water and blood pressure homeostasis. This study explores rat aorta AT1R expression during intermittent hypoxia (IH) and the signaling pathways involved.

METHODSA rat model and a cell model used a BioSpherix-OxyCycler A84 system and a ProOx C21 system respectively. The arterial blood pressure was recorded by a Nihon Kohden Polygraph System. Immunohistochemic was used to focus and analyze the expression of AT1R in rat aorta. Real-time PCR and Western blotting were used to explore the signaling pathways that participated in AT1R expression.

RESULTSIn this study, we found that chronic intermittent hypoxia (CIH) induced AT1R transcription which increased the blood pressure in rat aorta compared to normoxia and to sustained hypoxia. The AT1R protein expression in the aorta was similar to the real-time PCR results. We explored the signaling mechanisms involved in the AT1R induction in both rat aorta and the aortic endothelial cells by real-time PCR and Western blotting. Compared to normoxia, CIH increased ERK1 mRNA transcription but not ERK2 or p38MAPK in the aorta; whereas sustained hypoxia (SH) upregulated ERK2 but not ERK1 or p38MAPK mRNA. In cells, IH induced AT1R expression with ERK1/2 phosphorylation but reduced p38MAPKs phosphorylation, whereas SH induced only ERK1/2 phosphorylation. The ERK1/2 inhibitor PD98059 attenuated the IHinduced AT1R increase but the p38MAPK inhibitor SB203580 did not.

CONCLUSIONSOur results indicate that CIH induced the elevation of rat blood pressure and aorta AT1R expression. Moreover, AT1R expression in IH and sustained hypoxia might be regulated by different signal transduction pathways, highlighting a novel regulatory function through ERK1/2 signaling in IH.

Animals ; Aorta ; metabolism ; Blood Pressure ; physiology ; Hypoxia ; genetics ; physiopathology ; MAP Kinase Signaling System ; genetics ; physiology ; Male ; Rats ; Rats, Wistar ; Receptor, Angiotensin, Type 2 ; genetics ; metabolism

Both bone morphogenetic protein 2 (BMP2) and the wingless-type MMTV integration site (WNT)/β-catenin signalling pathway play important roles in odontoblast differentiation and dentinogenesis. Cross-talk between BMP2 and WNT/β-catenin in osteoblast differentiation and bone formation has been identified. However, the roles and mechanisms of the canonical WNT pathway in the regulation of BMP2 in dental pulp injury and repair remain largely unknown. Here, we demonstrate that BMP2 promotes the differentiation of human dental pulp cells (HDPCs) by activating WNT/β-catenin signalling, which is further mediated by p38 mitogen-activated protein kinase (MAPK) in vitro. BMP2 stimulation upregulated the expression of β-catenin in HDPCs, which was abolished by SB203580 but not by Noggin or LDN193189. Furthermore, BMP2 enhanced cell differentiation, which was not fully inhibited by Noggin or LDN193189. Instead, SB203580 partially blocked BMP2-induced β-catenin expression and cell differentiation. Taken together, these data suggest a possible mechanism by which the elevation of β-catenin resulting from BMP2 stimulation is mediated by the p38 MAPK pathway, which sheds light on the molecular mechanisms of BMP2-mediated pulp reparative dentin formation.
Bone Morphogenetic Protein 2 ; physiology ; Cell Differentiation ; physiology ; Dental Pulp ; cytology ; Humans ; MAP Kinase Signaling System ; Wnt Proteins ; metabolism ; beta Catenin ; metabolism