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

AIMTo study the development of changes for signaling molecules related to Raf/MEK/ERK pathway in hippocampus of rats after electromagnetic radiation, and investigate the mechanisms of radiation injury.

METHODSRats were exposed to X-HPM, S-HPM and EMP radiation source respectively, and animal model of electromagnetic radiation was established. Western blot was used to detect the expression of Raf-1, phosphorylated Raf-1 and phospholylated ERK.

RESULTSThe expression of Raf-1 down-regulated during 6 h-14 d after radiation, most significantly at 7 d, and recovered at 28 d. There was no significant difference between the radiation groups. The expression of phosphorylated Raf-1 and phosphorylated ERK both up-regulated at 6 h and 7 d after radiation, more significantly at 6 h, and the two microwave groups were more serious for phosphorylated ERK. During 6 h-14 d after S-HPM radiation, the expression of phosphorylated Raf-1 increased continuously, but phosphorylated ERK changed wavily, 6 h and 7 d were expression peak.

CONCLUSIONRaf/MEK/ERK signaling pathway participates in the hippocampus injury induced by electromagnetic radiation. The excessive activation of ERK pathway may result in the apoptosis and death of neurons, which is the important mechanism of recognition disfunction caused by electromagnetic radiation.

Animals ; Apoptosis ; Electromagnetic Radiation ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Hippocampus ; metabolism ; physiopathology ; radiation effects ; MAP Kinase Kinase Kinases ; metabolism ; MAP Kinase Signaling System ; radiation effects ; Male ; Phosphorylation ; Proto-Oncogene Proteins c-raf ; metabolism ; Random Allocation ; Rats ; Rats, Wistar

OBJECTIVETo study the effects of 50 Hz power-frequency magnetic fields on signal transduction pathway of P38 mitogen-activated protein kinase (P38 MAPK), and explore the cellular signal transduction mechanism of the biological effects induced by power-frequency magnetic fields.

METHODSChinese hamster lung (CHL) cell line was exposed to power-frequency magnetic fields with two intensities(0.1 and 0.4 mT) for different exposure durations. The cytoplasmic protein was extracted. The phosphorylated(activated) and non-phosphorylated P38 MAPK and MKK3/MKK6 were measured by Western blotting analysis with their specific corresponding antibodies.

RESULTSPower-frequency magnetic fields at 0.4 mT for 10 min could transitorily induce the activation of P38 MAPK and after 15 min the phosphorylation of P38 MAPK restored to control level, while 0.1 mT power-frequency magnetic fields could not induce the activation of P38 MAPK within 24 h. However, both 0.1 mT and 0.4 mT power-frequency magnetic fields could not phosphorylate(activate) the MKK3/MKK6, which is a general upstream kinase of P38 MAPK.

CONCLUSIONPower-frequency magnetic fields could transitorily activate the P38 MAPK, but not MKK3/MKK6. The activation mechanism of P38 MAPK needs to be further identified.

Animals ; Cell Line ; Cricetinae ; Cricetulus ; Enzyme Activation ; radiation effects ; Lung ; enzymology ; radiation effects ; MAP Kinase Kinase 3 ; metabolism ; MAP Kinase Kinase 6 ; metabolism ; Magnetics ; p38 Mitogen-Activated Protein Kinases ; metabolism ; radiation effects

Neuronal atrophy is a common pathological feature occurred in aging and neurodegenerative diseases. A variety of abnormalities including motor protein malfunction and mitochondrial dysfunction contribute to the loss of neuronal architecture; however, less is known about the intracellular signaling pathways that can protect against or delay this pathogenic process. Here, we show that the DYNC1I1 deficiency, a neuron-specific dynein intermediate chain, causes neuronal atrophy in primary hippocampal neurons. With this cellular model, we are able to find that activation of RAS-RAF-MEK signaling protects against neuronal atrophy induced by DYNC1I1 deficiency, which relies on MEK-dependent autophagy in neuron. Moreover, we further reveal that BRAF also protects against neuronal atrophy induced by mitochondrial impairment. These findings demonstrate protective roles of the RAS-RAF-MEK axis against neuronal atrophy, and imply a new therapeutic target for clinical intervention.
Animals ; Cell Line ; Cytoplasmic Dyneins ; genetics ; metabolism ; Hippocampus ; metabolism ; pathology ; MAP Kinase Kinase Kinases ; genetics ; metabolism ; MAP Kinase Signaling System ; Mice ; Mice, Knockout ; Neurodegenerative Diseases ; genetics ; metabolism ; pathology ; Proto-Oncogene Proteins B-raf ; genetics ; metabolism ; ras Proteins ; genetics ; metabolism

This study was purposed to investigate the effect of blocking Ras/Erk signaling pathway on expression of important transcription factor c-fos, c-jun and TAK1 gene in primary acute lymphocytic leukemia (ALL) cells. The best effective concentration and effect time of PD98059 were screened; the expression levels of c-fos, c-jun and TAK1 in primary cultured cells of normal persons, primary cultured ALL cells and primary cultured ALL cells treated by PD98059 were detected by SYBR GreenI real-time quantitative-PCR. The results showed that before treatment by PD98059 the expression levels of c-fos and TAK1 mRNA were significantly up-regulated in primary cultured ALL cells as compared with primary cultured cells of normal persons (P = 0.014 and P = 0.017 respectively). After treatment by PD98059, the expression levels of c-fos, c-jun mRNA decreased in all 7 serum samples, while expression of TAK1 was down-regulated in 5 samples, and up-regulated in 2 samples. After treatment with PD98059, there was no statistical difference of c-fos, c-jun and TAK1 expression levels in primary cultured ALL cells and primary cultured normal cells. It is concluded that the c-fos and TAK1 activity of primary cultured ALL cells increases, and blocking the Ras/Erk signaling pathway of ALL cells can lead to obvious decrease of important transcription factors c-fos, c-jun, TAK1 genes expression.
Flavonoids ; pharmacology ; Humans ; MAP Kinase Kinase Kinases ; metabolism ; MAP Kinase Signaling System ; drug effects ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; metabolism ; Proto-Oncogene Proteins c-fos ; metabolism ; Proto-Oncogene Proteins c-jun ; metabolism ; Tumor Cells, Cultured

OBJECTIVETo detect protein expression of ERK(1), ERK(2), JNK(1), p38 and MEK(1), MEK(2) in human hepatocellular carcinoma and adjacent non-neoplastic liver.

METHODSIn 16 surgically resected hepatocellular carcinoma and para-carcinoma tissues, Western blotting was used to detect expression of ERK(1), ERK(2), JNK(1), p38 and MEK(1), MEK(2).

RESULTSIn all cases, ERK(1), ERK(2), p38 expression in hepatocellular carcinoma was significantly higher than that in para-carcinoma: integral optic density (IOD) of ERK(1) was 300 +/- 98 in carcinoma and 98 +/- 48 in para-carcinoma tissues (t = 2.519, P < 0.01); IOD of ERK(2) was 587 +/- 83 in carcinoma and 232 +/- 96 in para-carcinoma tissues (t = 2.745, P < 0.01); IOD of p38 was 270 +/- 85 in carcinoma and 107 +/- 88 in para-carcinoma tissues (t = 2.491, P < 0.01). JNK(1) expression in hepatocellular carcinoma was significantly lower than that in para-carcinoma; IOD of JNK(1) was 111 +/- 93 in carcinoma and 292 +/- 109 in para-carcinoma tissues (t = 2.473, P < 0.01). Protein levels of MEK(1) and MEK(2) in carcinoma were significantly higher than in para-carcinoma. IOD of MEK(1) was 1 418 +/- 244 in carcinoma and 806 +/- 90 in para-carcinoma tissues (t = 2.546, P < 0.01). IOD of MEK(2) was 1 041 +/- 122 in carcinoma and 468 +/- 40 in para-carcinoma tissues (t = 2.861, P < 0.01).

CONCLUSIONSERK(1), ERK(2), MEK(1) and MEK(2) in the signal transduction pathway for cell proliferation are significantly overexpressed and the expression of JNK(1) is lower in hepatocellular carcinoma. Their unbalance is one of the important reasons for the over growth and infinite proliferation of the hepatocellular carcinoma cell. The p38 and JNK(1) may be activated by different pathway.

Adult ; Aged ; Carcinoma, Hepatocellular ; enzymology ; Enzyme Activation ; Female ; Humans ; JNK Mitogen-Activated Protein Kinases ; Liver Neoplasms ; enzymology ; MAP Kinase Kinase 1 ; Male ; Middle Aged ; Mitogen-Activated Protein Kinase Kinases ; analysis ; Mitogen-Activated Protein Kinases ; metabolism ; Protein-Serine-Threonine Kinases ; analysis

AIMTo assess the spatiotemporal changes in the expression of extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Jun N-terminal kinases (JNK) and p38 mitogen-activated protein kinases (MAPK) in response to heat stress in the cryptorchid testis, and to investigate a possible relation to Sertoli cell dedifferentiation.

METHODSImmunohistochemistry and western blot were used to examine the expression and activation of ERK1/2, p38 and JNK in the cryptorchid testis at various stages after experimental cryptorchidism.

RESULTSThe abdominal temperature did not obviously change the total ERK1/2 expression but significantly activated phospho-ERK1/2 in the Sertoli cells of the cryptorchid testis. Heat stress increased total JNK expression in the Sertoli cells of the cryptorchid testis but did not activate phospho-JNK. Neither total p38 nor phospho-p38 was induced by heat stress in the Sertoli cells of the cryptorchid testis. Changes in the spatiotemporal expression of cytokeratin 18 (CK18), a marker of immature or undifferentiated Sertoli cells, were induced in the cryptorchid testis in a pattern similar to the activation of ERK1/2.

CONCLUSIONThe activation of ERK1/2 in the testis may be related to dedifferentiation of Sertoli cells under heat stress induced by experimental cryptorchidism.

Animals ; Cryptorchidism ; enzymology ; pathology ; Disease Models, Animal ; Enzyme Activation ; Immunohistochemistry ; MAP Kinase Kinase 4 ; metabolism ; Macaca mulatta ; Male ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Scrotum ; enzymology ; p38 Mitogen-Activated Protein Kinases ; metabolism

Allergic rhinitis is a kind of nasal mucosal chronic noninfectious inflammatory disease, which is caused by an imbalance in the body cytokine network,a number of intracellular signaling pathways being actived. Many studies have shown that mitogen-activated protein kinase (MAPK) involved in the activation process of allergic rhinitis. p38 mitogen-activated protein kinase (MAPK), as one kind of that, plays a key role in the process of inflammatory cells proliferation and differentiation, as well as production of inflammatory cytokines, and involved in airway inflammatory mechanisms of chronic airway disease. In vitro experiments have confirmed that p38 MAPK inhibitors have anti-inflammatory effect by blocking the downstream related response.
Cell Differentiation ; Cell Proliferation ; Cytokines ; Humans ; Inflammation ; MAP Kinase Signaling System ; Rhinitis, Allergic ; metabolism ; p38 Mitogen-Activated Protein Kinases ; metabolism

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 study the effects of benzo(a)pyrene (BaP) on the cell cycle distribution and activities of mitogen-activated protein kinase (MAPK) signal molecules (ERK1/2, JNK1/2 and p38) in human embryo lung cells (HELF), and to investigate the relationship between alterations of MAPK protein phosphorylation and the cell cycle distributions.

METHODSThe phosphorylation of MAPK were induced by exposing HELF cells to BaP at 0.1, 0.5, 2.5 and 12.5 micromol/L. The phosphorylation and protein expression levels of ERK1/2, JNK1/2 and p38 were determined through western-blotting assay. And the flow cytometry assay was used to measure the cell cycle effects in HELF cells after treatment with 2.5 micromol/L BaP for 24 h.

RESULTSThe phosphorylation levels of ERK1/2, JNK1/2 and p38 were significantly increased through BaP exposure. In addition, the phosphorylation of these three MAPKs has similar alteration pattern. We found that exposure of cells to 2.5 microM of BaP for 24 h resulted in a decrease of G(0) and G(1) population by 11.9% (F = 41.38, P < 0.01) and an increase of S population by 17.2% (F = 68.13, P < 0.01). Three chemical inhibitors of MAPK (AG126, SP600125 and SB203580) could significantly inhibit the cell cycle alteration because of BaP treatment.

CONCLUSIONERK1/2, JNK1/2 and p38 could positively regulate the BaP independently induced cell cycle alterations.

Benzo(a)pyrene ; toxicity ; Cell Cycle ; drug effects ; Cells, Cultured ; Fibroblasts ; drug effects ; metabolism ; Humans ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Lung ; cytology ; embryology ; MAP Kinase Kinase 4 ; metabolism ; MAP Kinase Signaling System ; drug effects ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Mitogen-Activated Protein Kinase 8 ; metabolism ; Mitogen-Activated Protein Kinase 9 ; metabolism ; Signal Transduction ; drug effects ; p38 Mitogen-Activated Protein Kinases ; metabolism