<b>OBJECTIVEb>To 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.

<b>METHODSb>Samples 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.

<b>RESULTSb>MEK2 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.

<b>CONCLUSIONb>Overexpression 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

<b>AIMb>To 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.

<b>METHODSb>Immunohistochemistry 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.

<b>RESULTSb>The 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.

<b>CONCLUSIONb>The 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

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

<b>OBJECTIVEb>To 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.

<b>METHODSb>The 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.

<b>RESULTSb>The 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.

<b>CONCLUSIONb>ERK1/2, 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

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

Endothelins (ETs), which were originally found to be potent vasoactive transmitters, were known to be implicated in nervous system, but the mode of mechanism remains unclear. ETs (ET-1, ET-2, and ET-3) were added to HN33 (mouse hippocampal neuron chi neuroblastoma) cells. Among the three types of ET, only ET-1 increased the intracellular calcium levels in a PLC dependent manner with the induction of ERK 1/2 activation. As the result of ET-1 exposure, the survival rate of HN33 cells and the PKCalpha translocation into the plasma membrane were increased. We suggest that ET-1 participated in the neuroprotective effect involving the calcium-PKCalpha-ERK1/2 pathway.
Animals ; Apoptosis/*drug effects ; Calcium/*metabolism ; Cell Line ; Cell Survival/drug effects ; Cytosol/drug effects/metabolism ; Endothelin-1/*pharmacology ; Endothelin-2/pharmacology ; Endothelin-3/pharmacology ; Estrenes/pharmacology ; Extracellular Signal-Regulated MAP Kinases/*metabolism ; Immunoblotting ; Mice ; Mitogen-Activated Protein Kinase 1/metabolism ; Mitogen-Activated Protein Kinase 3/metabolism ; Neurons/*cytology/drug effects/*enzymology ; Neuroprotective Agents/pharmacology ; Phosphoproteins/metabolism ; Protein Kinase C-alpha/*metabolism ; Protein Transport/drug effects ; Pyrrolidinones/pharmacology ; Serum

BACKGROUND/OBJECTIVES: Resveratrol, a natural polyphenol, has multiple functions in cellular responses including apoptosis, survival, and differentiation. It also participates in the regulation of inflammatory response and oxidative stress. MicroRNA-Let-7A (miR-Let7A), known as a tumor suppressor miRNA, was recently reported to play a crucial role in both inflammation and apoptosis. Therefore, we examined involvement of miR-Let7A in the modulation of inflammation and cell survival/apoptosis regulated by resveratrol. MATERIALS/METHODS: mRNA expression of pro-/anti-inflammatory cytokines and sirtuin 1 (SIRT1), and protein expression of apoptosis signal-regulating kinase 1 (ASK1), p-ASK1, and caspase-3 and cleaved caspase-3 were measured, and cell viability and Hoechst/PI staining for apoptosis were observed in Lipopolysaccharide (LPS)-stimulated human THP-1 macrophages with the treatment of resveratrol and/or miR-Let7A overexpression. RESULTS: Pre-treatment with resveratrol (25-200 µM) resulted in significant recovery of the reduced cell viabilities under LPS-induced inflammatory condition and in markedly increased expression of miR-Let7A in non-stimulated or LPS-stimulated cells. Increased mRNA levels of tumor necrosis factor-α and interleukin (IL)-6 induced by LPS were significantly attenuated, and decreased levels of IL-10 and brain-derived neurotrophic factor were significantly restored by resveratrol and miR-Let7A overexpression, respectively, or in combination. Decreased expression of IL-4 mRNA by LPS stimulation was also significantly increased by miR-Let7A overexpression co-treated with resveratrol. In addition, decreased SIRT1 mRNA levels, and increased p-ASK1 levels and PI-positive cells by LPS stimulation were significantly restored by resveratrol and miR-Let7A overexpression, respectively, or in combination. CONCLUSIONS: miR-Let7A may be involved in the inflammatory response and cell survival/apoptosis modulated by resveratrol in human THP-1 macrophages.
Apoptosis ; Brain-Derived Neurotrophic Factor ; Caspase 3 ; Cell Survival ; Cytokines ; Humans ; Inflammation ; Interleukin-10 ; Interleukin-4 ; Interleukins ; Macrophages* ; MAP Kinase Kinase Kinase 5 ; MicroRNAs ; Necrosis ; Oxidative Stress ; RNA, Messenger ; Sirtuin 1

Overexpression of HER2 correlates with more aggressive tumors and increased resistance to cancer chemotherapy. However, a functional comparison between the HER2high/HER3 and the HER2low/HER3 dimers on tumor metastasis has not been conducted. Herein we examined the regulation mechanism of heregulin-beta1 (HRG)-induced MMP-1 and -9 expression in breast cancer cell lines. Our results showed that the basal levels of MMP-1 and -9 mRNA and protein expression were increased by HRG treatment. In addition, HRG-induced MMP-1 and -9 expression was significantly decreased by MEK1/2 inhibitor, U0126 but not by phosphatidylinositol 3-kinase (PI-3K) inhibitor, LY294002. To confirm the role of MEK/ERK pathway on HRG-induced MMP-1 and -9 expression, MCF7 cells were transfected with constitutively active adenoviral-MEK (CA-MEK). The level of MMP-1 and -9 expressions was increased by CA-MEK. MMP-1 and -9 mRNA and protein expressions in response to HRG were higher in HER2 overexpressed cells than in vector alone. The phosphorylation of HER2, HER3, ERK, Akt, and JNK were also significantly increased in HER2 overexpressed MCF7 cells compared with vector alone. HRG-induced MMP-1 and -9 expressions were significantly decreased by lapatinib, which inhibits HER1 and HER2 activity, in both vector alone and HER2 overexpressed MCF7 cells. Finally, HRG-induced MMP-1 and MMP-9 expression was decreased by HER3 siRNA overexpression. Taken together, we suggested that HRG-induced MMP-1 and MMP-9 expression is mediated through HER3 dependent pathway and highly expressed HER2 may be associated with more aggressive metastasis than the low expressed HER2 in breast cancer cells.
Breast Neoplasms/enzymology/*genetics/*metabolism ; Butadienes/pharmacology ; Cell Line, Tumor ; Dose-Response Relationship, Drug ; Enzyme Inhibitors/pharmacology ; Female ; Gene Expression ; Gene Expression Regulation, Neoplastic/drug effects ; Humans ; MAP Kinase Signaling System ; MCF-7 Cells ; Matrix Metalloproteinase 1/*genetics/metabolism ; Matrix Metalloproteinase 9/*genetics/metabolism ; Neuregulin-1/*pharmacology ; Nitriles/pharmacology ; Phosphatidylinositol 3-Kinases/metabolism ; Protein Kinase Inhibitors/pharmacology ; Protein Multimerization ; Proto-Oncogene Proteins c-akt/metabolism ; Quinazolines/pharmacology ; Receptor, erbB-2/genetics/*metabolism ; Receptor, erbB-3/*metabolism

<b>OBJECTIVEb>To explore the prognostic values of Raf-1 kinase (Raf-1), phosphorylated mitogen extracellular kinase 1 (pMEK1), and phosphorylated extracellular signal-regulated protein kinase 1/2(pERK1/2) in hepatocellular carcinoma (HCC) patients.

<b>METHODSb>We assessed the expressions of Raf-1, pMEK1, and pERK1/2 in HCC using immunohistochemical techniques. The relationships between the expressions of Raf-1, pMEK1, and pERK1/2 and the prognosis were explored.

<b>RESULTSb>The over-expression rates of Raf-1, pMEK1, and pERK1/2 in HCC were 38.3%, 46.7%, and 38.3%, respectively. The over-expressions of Raf-1, pMEK1, and pERK1/2 were positively correlated with each other (P>0.05), but had no significant correlation with sex, age, α-fetoprotein, hepatitis B surface antigen status, the TNM stage, size,differentiation and vascular invasion of tumor, and liver cirrhosis (P>0.05). Univariate survival analysis and COX proportional hazard regression model showed that Raf-1 over-expression was an independent prognostic factor of poor survival (P<0.05).

<b>CONCLUSIONb>Raf-1 over-expression is an independent marker for the patients of HCC, which may provide new clue in the future targeted therapy.

Adult ; Aged ; Carcinoma, Hepatocellular ; diagnosis ; enzymology ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Female ; Humans ; Liver Neoplasms ; diagnosis ; enzymology ; MAP Kinase Kinase 1 ; metabolism ; Male ; Middle Aged ; Phosphorylation ; Prognosis ; Proto-Oncogene Proteins c-raf ; metabolism

The aim of this study is to investigate the neurotoxic effect and mechanism of 1-methyl-4-phenylpyridinium (MPP+) on PC12 cells. MTT assay was used to investigate cell viability, Western blotting assay was performed to observe the protein level and phosphorylation, and dual-luciferase assay was used to study the transactivation. The experiment showed that MPP+ could decrease cell viability significantly in a dose-dependent manner and could decrease BDNF protein level, depress the phosphorylation of ERK, and attenuate the phosphorylation and transactivation of CREB, which is one of transcription factors of BDNF, but did not affect the activity of CaMK II in PC12 cells. So MPP+ might decrease BDNF protein level through MAPK/ERK signal pathway.
1-Methyl-4-phenylpyridinium ; administration & dosage ; pharmacology ; Animals ; Brain-Derived Neurotrophic Factor ; metabolism ; Calcium-Calmodulin-Dependent Protein Kinase Type 2 ; metabolism ; Cell Survival ; drug effects ; Cyclic AMP Response Element-Binding Protein ; drug effects ; Dose-Response Relationship, Drug ; Extracellular Signal-Regulated MAP Kinases ; drug effects ; PC12 Cells ; Phosphorylation ; Rats ; Signal Transduction