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

OBJECTIVETo construct antisense c-Jun N-terminal kinase 1 (JNK1) eukaryotic fluorescent expressing vector and JNK1-/- human embryo lung fibroblasts cell line.

METHODSTrizol reagent was used to extract total RNA in HELF. The proper primers of JNK1 were chosen and synthesized. RT-PCR and gene recombinant techniques were used to construct the fragment of JNK1. After purification, the PCR products were cut, and JNK1 were inserted reversely into eukaryotic fluorescent expressing vector pEGFP-C1. Enzyme-cutting and DNA auto-sequencing were used to prove the successful construction of JNK1 eukaryotic expressing vector. Then plasmids were extracted and transfected into HELF cells and screen by G418 24 h later. Monoclone was chosen and cultured. Fluorescent imaging and Western blot were used to identify the JNK1-/- HELF cell line.

RESULTSSequence analysis of pEGFP-C1-as JNK1 plasmids was same as expected. The expression level of JNK1 was inhibited markedly.

CONCLUSIONConstruction of antisense JNK1 eukaryotic fluorescent expressing vectors and JNK1-/- HELF cell line is successful.

Cell Line ; DNA, Antisense ; genetics ; Fibroblasts ; metabolism ; Genetic Vectors ; Humans ; Mitogen-Activated Protein Kinase 8 ; genetics ; metabolism ; Transfection

OBJECTIVETo detect the mRNA expression of ERK1, ERK2, JNK1 and P38 gene in mitogen-activated protein kinase(MAPK) path way in the arseniasis patients caused by burning coal.

METHODS70 arseniasis patients caused by burning coal at Jiaole village XingRen county in December 2006 were selected as case group, and another 30 villagers with similar living habits, matched gender and age, healthy physical condition without history of burning high arsenic coal were selected as control group from 12 km nearby the same village.Silver diethyl dithiocarbamate method (Ag-DDC) was taken to detect the arsenic contents in the environmental media, food, and arsenic level in the urine and hair of arseniasis patients.On the principle of informed consent, the peripheral blood was collected from the patients. The total RNA was extracted with Trizol method and cDNA was reversed from it. The mRNA expression of ERK1, ERK2, JNK1 and P38 gene in MAPK path way were tested by real-time fluorescent quantitative PCR (QT-PCR).

RESULTSA total of 70 cases of arseniasis patients (31 cases of mild, 25 cases of moderate and 14 cases of severe) and 30 cases of control were chosen. The median (quartile) of arsenic contents in the indoor air, outdoor air, coal, chili and corn were 0.079 (0.053-0.117) mg/m(3) ,0.007 (0.002-0.015) mg/m(3) , 93.010 (39.460-211.740) mg/kg, 3.460(0.550-16.760) mg/kg and 1.500(0.300-4.140) mg/kg respectively. They were above the national health standards. The median (quartile) of arsenic contents in the soil, rice and drinking water were separately 12.130(4.230-24.820) mg/kg, 0.650(0.300-0.980) mg/kg and 0.043(0.012-0.089)mg/kg, which were within the national health standards. Compared with the control group ((26.97 ± 9.71)µg/g Cr), arsenic level in the patients' urine ((71.48 ± 22.74)µg/g Cr) increased significantly, the differences were significant (F = 90.38, P < 0.01). Compared with the control group ((1.58 ± 1.07)µg/g), arsenic level in the patients' hair ((4.45 ± 2.78) µg/g) increased significantly, the differences were significant (F = 48.22, P < 0.01). The relative expression amount of the median(quartile) for ERK2, JNK1 mRNA were 0.0667 (0.0378-0.1371) and 0.0013 (0.0009-0.0025), respectively. Compared with the control group 0.1744 (0.1009-0.1985) and 0.0022 (0.0017-0.0030) , only the decreases of ERK2, JNK1 mRNA expression was significant (χ(2) = 15.10, 14.25, P < 0.01), and no significance in the other index. ERK2 mRNA relative expression for mild, medium and severe groups were separately 0.0818 (0.0408-0.1509) ,0.0582 (0.0154-0.1699) and 0.0588 (0.0399-0.1034) . Compared with the control group (0.1744 (0.1099-0.1985) ), there was significant difference (Z = -2.89, -3.19, -2.67, P < 0.01). JNK1 mRNA relative expression were 0.0012 (0.0007-0.001 57), 0.0019 (0.0011-0.0035), 0.0013 (0.0010-0.0026), respectively. Compared with the control group (0.0022 (0.0017-0.0030) ), significances were found in the mild groups (Z = -3.72, P < 0.01).

CONCLUSIONSArsenic could induce the changes of ERK2 and JNK1mRNA expression in the MAPK path way in arseniasis patients.It suggests that the MAPK signaling pathway take part in the occurrence and development process of arseniasis caused by burning coal.

Adult ; Air Pollution, Indoor ; Arsenic Poisoning ; blood ; etiology ; Case-Control Studies ; Coal ; Female ; Humans ; MAP Kinase Signaling System ; Male ; Middle Aged ; Mitogen-Activated Protein Kinase 1 ; blood ; genetics ; Mitogen-Activated Protein Kinase 8 ; blood ; genetics ; RNA, Messenger ; genetics ; Transcription, Genetic

OBJECTIVETo explore the effects of hydrogen sulfide (H(2)S) on myocardial fibrosis and expressions of MAPK1/3 and MMP-8 in diabetic rats.

METHODSForty adult male SD rats were randomized into 4 groups, namely the control group, diabetes mellitus group (STZ group), diabetes mellitus with H(2)S treatment group (STZ+H(2)S group), and normal rats with H(2)S treatment group (H(2)S group). Diabetes was induced by intraperitoneal injections of 40 mg/kg streptozotocin (STZ). The rats in the control group received daily intraperitoneal injections of saline, and those in STZ+H(2)S group and H(2)S group were given NaHS (100 µmol/kg) injections. After 8 weeks, the pathologies of cardiac fibrosis were examined with HE staining, and the expressions of collagen I, MAPK1/3 and MMP-8 were analyzed with Western blotting.

RESULTSCompared with the control group, the diabetic rats showed increased collagen content and obvious interstitial fibrosis in the myocardial tissue with significantly increased expression levels of collagen I, MAPK1/3 and MMP-8 (P<0.05); all these changes were obviously reversed by treatment with H(2)S (P<0.05). Collagen I, MAPK1/3 and MMP-8 expression levels and the degree of myocardial fibrosis were comparable between H(2)S group and control group (P>0.05).

CONCLUSIONHydrogen sulfide can attenuate cardiac fibrosis in diabetic rats, and the mechanism may involve the inhibition of MAPK1/3/MMP-8 signal pathway.

Animals ; Collagen Type I ; metabolism ; Diabetes Mellitus, Experimental ; metabolism ; pathology ; Fibrosis ; Hydrogen Sulfide ; pharmacology ; Injections, Intraperitoneal ; Male ; Matrix Metalloproteinase 8 ; metabolism ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Myocardium ; pathology ; Rats ; Rats, Sprague-Dawley

Fluid shear stress plays an important role in many physiological and pathophysiological processes of the cardiovascular system. It modulates vascular function and structure via stimulating mechanosensitive endothelial cell signal events. Previous studies have identified that the exposure of vascular endothelial cells to fluid mechanical forces can modulate the expressions of many genes, including IL-8 gene. In order to gain an insight into the role of extracellular signal regulated kinase (ERK1/2) signal pathway in the expression of IL-8 mRNA in human umbilical vein endothelial cells (HUVECs) under the stimulation by low shear stress (4.20 dyne/cm2), we employed Western blot to measure phosphorylation of ERK1/2 and used quantitative reversal transcription-polymerase chain reaction (qRT-PCR) to assay the expression of IL-8 mRNA. The results showed: (1) Shear stress could activate ERK1/2 with a rapid, biphasic time course (maximum by 10 min and basal by 2 h); the treatment of HUVECs with Genistein (a highly specific inhibitor of tyrosine protein kinase, TPK) or PD98059 (the inhibitor of mitogen-activated protein/extracellular signal regulated kinase kinase, MEK) culd prevent shear-dependent activation of ERK1/2; (2) When treated with Genistein or PD98059, significant inhibition of IL-8 mRNA expression induced by low shear stress was observed in HUVECs. This in vitro study demonstrates that ERK1/2 plays an important role in IL-8 mRNA expression induced by low shear stress.
Cells, Cultured ; Endothelium, Vascular ; cytology ; metabolism ; Humans ; Interleukin-8 ; biosynthesis ; genetics ; Mitogen-Activated Protein Kinase 1 ; physiology ; Mitogen-Activated Protein Kinase 3 ; physiology ; RNA, Messenger ; biosynthesis ; genetics ; Signal Transduction ; Stress, Mechanical ; Umbilical Veins ; cytology

OBJECTIVETo investigate the effect of SP600125, a specific c-jun N-terminal protein kinase (JNK) inhibitor, on Staphylococcus aureus (S. aureus)-induced U937 cell death and the underlying mechanism.

METHODSThe human monocytic U937 cells were treated with S. aureus at different time with or without SP600125. Cell apoptosis was analyzed by flow cytometry. JNK, Bax, and caspase-3 activities were detected by Western blotting.

RESULTSS. aureus induced apoptosis in cultured U937 cells in a time-dependent manner. Expression of Bax and phospho-JNK significantly increased in S. aureus-treated U937 cells, and the level of activated caspase-3 also increased in a time-dependent manner. Inhibition of JNK with SP600125 significantly inhibited S. aureus-induced apoptosis in U937 cells.

CONCLUSIONSS. aureus can induce apoptosis in U937 cells by phosphorylation of JNK and activation of Bax and caspase-3. SP600125 protects U937 cells from apoptosis induced by S. aureus via inhibiting the activity of JNK.

Anthracenes ; pharmacology ; Apoptosis ; physiology ; Caspase 3 ; metabolism ; Humans ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Macrophages ; cytology ; metabolism ; microbiology ; Mitogen-Activated Protein Kinase 8 ; antagonists & inhibitors ; metabolism ; Mitogen-Activated Protein Kinase 9 ; antagonists & inhibitors ; metabolism ; Phosphorylation ; drug effects ; Protein Kinase Inhibitors ; pharmacology ; Signal Transduction ; physiology ; Staphylococcus aureus ; physiology ; U937 Cells ; bcl-2-Associated X Protein ; metabolism

Both in vivo and cultured cardiomyocyte experiments were performed to investigate the alteration of expression of calreticulin (CRT) during the delayed cardioprotection induced by hypoxic preconditioning (HPC) and the intracellular signal transduction mechanisms of the alteration. (1) Wistar rats were randomly divided into three groups: sham operation group (Sham), myocardial infarction (MI) group induced by left coronary artery ligation and HPC+MI group (4-hour HPC 24 h before MI). Twenty-four hours, 14 d and 28 d after left coronary artery ligation, myocardial function, infarction size and the area at risk were measured. Western blot was used to detect the expression of CRT, the activity of p38 mitogen-activated protein kinase (MAPK) and stress-activated protein kinase (SAPK). (2) Cultured cardiomyocytes from neonatal Sprague-Dawley (SD) rat were divided into six groups: hypoxia/reoxygenation (H/R), HPC, HPC+H/R, p38 MAPK inhibitor SB203580+HPC+H/R (SB+HPC+H/R), SAPK inhibitor SP600125+HPC+H/R (SP+HPC+H/R) and control. Survival rate and apoptosis rate of cardiomyocytes 6 h after H/R and activities of lactate dehydrogenase (LDH) in culture medium in each group were measured. Western blot was used to detect the expression of CRT and activities of p38 MAPK and SAPK. The results are as follows: (1) During in vivo experiment, compared with MI group, HPC significantly improved +dp/dt(max) and -dp/dt(max), reduced infarction size and the area at risk. HPC dramatically changed the expression of CRT. CRT expression in HPC+MI group was 206% of that in MI group (P<0.05) 24 h after infarction, especially in the area at risk. However, 28 d after operation, the expression of CRT decreased by 57%. Correlation analysis indicated a positive correlation between CRT expression and myocardial function (r=0.9867, P<0.05), and negative correlation between CRT expression and infarction size (r=-0.9709, P<0.05). (2) In cultured cardiomyocytes, HPC attenuated cell injury induced by H/R. CRT expression increased moderately to 222% of control (P<0.05) during HPC, but increased dramatically to 503% of control (P<0.05) after H/R. HPC reduced H/R-induced CRT up-regulation to 56% of that in H/R group (P<0.05). Correlation analysis indicated that CRT expression induced by HPC had a positive correlation with p38 MAPK activity (r=0.9021, P<0.05), but a negative correlation with SAPK activity (r=-0.8211, P<0.05). Both in vivo and in vitro results indicate that HPC protects myocardium from ischemia or H/R injury. p38 MAPK is possibly involved in the up-regulation of CRT induced by HPC, while SAPK has a negative influence.
Animals ; Calreticulin ; metabolism ; Cells, Cultured ; Ischemic Preconditioning, Myocardial ; Mitogen-Activated Protein Kinase 8 ; metabolism ; Myocardium ; pathology ; Myocytes, Cardiac ; metabolism ; Rats, Sprague-Dawley ; Rats, Wistar ; Signal Transduction ; p38 Mitogen-Activated Protein Kinases ; metabolism

Nerve growth factor (NGF) is known to regulate both cancer cell survival and death signaling, depending on the cellular circumstances, in various cell types. In this study, we showed that NGF strongly upregulated the protein level of tropomyosin-related kinase A (TrkA) in TrkA-inducible SK-N-MC cancer cells, resulting in increases in various TrkA-dependent cellular processes, including the phosphorylation of c-Jun N-terminal kinase (JNK) and caspase-8 cleavage. In addition, NGF enhanced TrkA-induced morphological changes and cell death, and this effect was significantly suppressed by the JNK inhibitor SP600125, but not by the phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin. To investigate novel targets associated with the enhancement of TrkA-induced SK-N-MC cell death caused by NGF, we performed Coomassie Brilliant Blue staining and two-dimensional (2D) proteomic analysis in TrkA-inducible SK-N-MC cells. We identified 31 protein spots that were either greatly upregulated or downregulated by TrkA during NGF treatment using matrix-associated laser desorption/ionization time of flight/time of flight mass spectrometry, and we analyzed the effects of SP600125 and wortmannin on the spots. Interestingly, 11 protein spots, including heterogeneous nuclear ribonucleoprotein K (hnRNP K), lamin B1 and TAR DNA-binding protein (TDP43), were significantly influenced by SP600125, but not by wortmannin. Moreover, the NGF/TrkA-dependent inhibition of cell viability was significantly enhanced by knockdown of hnRNP K using small interfering RNA, demonstrating that hnRNP K is a novel target associated with the regulation of TrkA-dependent SK-N-MC cancer cell death enhanced by NGF.
Caspase 8 ; Cell Death* ; Cell Survival ; Heterogeneous-Nuclear Ribonucleoprotein K ; JNK Mitogen-Activated Protein Kinases ; Mass Spectrometry ; Nerve Growth Factor* ; Phosphatidylinositol 3-Kinase ; Phosphorylation ; Phosphotransferases ; RNA, Small Interfering

OBJECTIVETo study the role of mitogen activated protein kinase (MAPK)/activator protein-1 (AP-1) pathway in benzo(a)pyrene (B(a)P)-induced changes of cell cycle in human embryo lung fibroblasts (HELF).

METHODSAP-1 luciferase activity was determined by the Luciferase reporter gene assay using a luminometer. The expression levels and activity of extracellular signal-regulated protein kinase (ERK), c-Jun NH2-terminal kinase (JNK) and p38 were determined by Western blot. Flow cytometric analysis was employed to detect the distributions of cell cycle. The dominant negative mutant of ERK2, JNK1 and p38 were applied to detect the upstream or downstream relationship of signaling pathways.

RESULTSB(a)P treatment resulted in a marked activation of AP-1 and its upstream MAPK, including ERK, JNK and p38 in human embryo lung fibroblasts (HELF). B(a)P exposure also led to increase the population of cells at S phase compared to control (P < 0.01) with a concomitant decline of cells at G(1) phase. B(a)P-induced cell cycle alternation was markedly impaired by stable expression of a dominant negative mutant of ERK2 or JNK1, but not p38. B(a)P-induced AP-1 transactivation was inhibited by the overexpression of dominant-negative mutant of ERK2 or JNK1, but not p38. Inhibition of the activation of AP-1 by curcumin, a chemical inhibitor of AP-1, significantly inhibited the cell cycle changes in response to B(a)P treatment.

CONCLUSIONERK and JNK, but not p38, mediated benzo(a)pyrene-induced cell cycle changes by AP-1 transactivation in HELF.

Benzo(a)pyrene ; pharmacology ; Blotting, Western ; Cell Cycle ; drug effects ; Cells, Cultured ; Fibroblasts ; cytology ; drug effects ; metabolism ; Flow Cytometry ; Humans ; Lung ; cytology ; embryology ; Mitogen-Activated Protein Kinase 1 ; metabolism ; physiology ; Mitogen-Activated Protein Kinase 8 ; metabolism ; physiology ; Phosphorylation ; Transcription Factor AP-1 ; metabolism ; p38 Mitogen-Activated Protein Kinases ; metabolism

OBJECTIVETo investigate the expression of Smad4 in non-small cell lung cancer (NSCLC), its correlation with MAPK (mitogen activated protein kinase) and their clinical significance in NSCLC.

METHODSWestern blotting and RT-PCR were employed to test 42 resected lung cancers and normal lung tissues for the expression of Smad4. Imunohistochemistry was used to detect Smad4 and subtribes of MAPK in 71 paraffin samples.

RESULTSThe level of protein and mRNA expression of Smad4 in lung cancer tissues were 0.2092 +/- 0.1308 and 0.3986 +/- 0. 1982, respectively, lower than those in normal tissues (0.7852 +/- 0.4386 and 1.1206 +/- 0.6772, P < 0.05). The expression of p38, ERK1 and Smad4 was associated with TNM staging (P = 0.000, 0.000 and 0.005, respectively) and JNK1 with tumor location (P = 0.028) and staging (P = 0.000). There was a correlation between p38 and Smad4 (P = 0.000). The expression of Smad4 (P = 0.0001), p38 (P = 0.0000) and JNK1 (P = 0.0208), tumor differentiation (P = 0.0059) and staging (P = 0.0000) were significantly correlated with prognosis of NSCLC by univariate analysis. Smad4 (P = 0.019), p38 (P = 0.044), tumor differentiation (P = 0.003), and staging (P = 0.020) were correlated with prognosis tested by multivariable analysis. Taking p38 and Smad4 together, we found that the negative expression of p38 and positive expression of Smad4 were associated with a better prognosis of NSCLC (P = 0.000).

CONCLUSIONSmad4 could be of importance for the initiation and development of NSCLC. There is a significant correlation between main proteins of TGF-beta/smad4 and those of ras-MAPK signal transduction pathways. The expression of Smad4 is inhibited by p38. Smad4, as well as p38, tumor differentiation and staging can be used as prognostic factors of NSCLC.

Adult ; Aged ; Blotting, Western ; Carcinoma, Non-Small-Cell Lung ; metabolism ; pathology ; Cell Differentiation ; Female ; Humans ; Lung Neoplasms ; genetics ; metabolism ; pathology ; Male ; Middle Aged ; Mitogen-Activated Protein Kinase 3 ; genetics ; metabolism ; Mitogen-Activated Protein Kinase 8 ; genetics ; metabolism ; Mitogen-Activated Protein Kinases ; genetics ; metabolism ; Neoplasm Staging ; Prognosis ; RNA, Messenger ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; Smad4 Protein ; genetics ; metabolism ; physiology ; p38 Mitogen-Activated Protein Kinases ; genetics ; metabolism