Phospho-p38 Expression Research Articles

β-Funaltrexamine inhibits chemokine (CXCL10) expression in normal human astrocytes

Neuroinflammation is an integral component of neurodegenerative disorders, CNS infection and trauma. Astroglial chemokines, such as CXCL10, are instrumental in neuroinflammatory signaling as well as neurotoxicity. We have utilized proinflammatory-induced CXCL10 expression in normal human astrocytes (NHA) as a model in which to assess the anti-inflammatory actions of the selective, mu-opioid receptor (MOR) antagonist, β-funaltrexamine (β-FNA). Interferon (IFN)γ+HIV-1 Tat-induced CXCL10 expression (secreted protein and mRNA) was inhibited by co-treatment with β-FNA. Neither the MOR-selective antagonist, D-Phe-Cys-Tyr-D-Trp-Arg-Pen-Thr-NH2 (CTAP) nor the nonselective opioid receptor antagonist, naltrexone inhibited IFNγ+HIV-1 Tat-induced CXCL10 expression. Furthermore, co-treatment with excess CTAP or naltrexone did not prevent β-FNA mediated inhibition of IFNγ+HIV-1 Tat-induced CXCL10 expression. Additionally, we utilized an inhibitor of NF-κB activation (SN50) to demonstrate that IFNγ+HIV-1 Tat-induced CXCL10 expression is NF-κB-dependent in NHA. Subsequent experiments revealed that β-FNA did not significantly affect NF-κB activation. Interestingly, we discovered that β-FNA inhibited p38 activation as indicated by decreased expression of phospho-p38. Together, these findings suggest that the inhibitory actions of β-FNA are MOR-independent and mediated, in part, via a transcriptional mechanism. These findings add to our understanding of the mechanism by which chemokine expression is inhibited by β-FNA. In conjunction with future investigations, these novel findings are expected to provide insights into the development of safe and effective treatments for neuroinflammation.

Palmitic acid increases apoptosis of neural stem cells via activating c-Jun N-terminal kinase

Elevated plasma free fatty acid (FFA) level is common in many pathological conditions, including neurological disorders, and their deleterious effects on various cells have been well documented. However, it remains to be investigated whether elevated FFAs would have a direct effect on neural stem cells (NSCs). Here, we reported that palmitic acid (PA) impaired cell viability and increased apoptosis of NSCs significantly in a dose- and time-dependent manner. Increased protein levels of Bax and cleaved caspase 3 coupled with decreased expression of Bcl-2 were also observed in NSCs with increasing dose or time of PA treatment, whereas caspase 3 expression remained relatively unaltered. In parallel to this, the expression of phospho-c-Jun N-terminal kinase (p-JNK) in NSCs challenged with PA was increased significantly; however, JNK expression appeared stable. Remarkably, JNK inhibitor effectively reduced the apoptosis of NSCs induced by PA. The expression of phospho-p38 (p-p38), p38, phospho-extracellular regulated protein kinases 1/2 (p-EKR1/2) and EKR1/2 in NSCs was not affected by PA treatment. In consideration of the above, it is suggested that elevated plasma FFA level may induce apoptosis of NSCs in vivo, and that this might be one of possible underlying mechanisms for the cognitive disturbance in neurological disorders.

Analysis of the osteogenetic effects exerted on mesenchymal stem cell strain C3H10T1/2 by icariin via MAPK signaling pathway in vitro

To investigate the effects of icariin, an effective extract from traditional Chinese medicine Epimedium pubescens with the function of tonifying kidney, in promoting osteogenesis of mesenchymal stem cell line C3H10T1/2, and to explore the underlying mechanism. After culture with icariin (0, 10(-7), 10(-6), 10(-5), and 10(-4) mol/L) and osteogenic supplement for 26 d in vitro, osteogenic differentiation of C3H10T1/2 cells was detected by alkaline phosphatase (ALP) assay. The RNA was extracted from cells cultured with 10(-5) mol/L icariin for 2, 8, 24 and 48 hours, and mRNA expressions of p38, p42 and p44 were measured using real-time reverse transcription-polymerase chain reaction (PCR) method. Three main proteins of MAPK signaling pathway (p38, and extracellular signal-regulated protein kinase (ERK), also named p42/44) and c-Jun N-terminal kinase (JNK) and their phospho-products were examined using Western blotting after icariin treatments of 10, 30, 60 and 120 min. Icariin at a dose of 10(-5) mol/L, when combined with the osteogenic supplement, had the best ability to promote osteogenic differentiation on C3H10T1/2 cells. Based on real-time PCR, the authors found that after two-hour ICA treatment, the gene expression of p38 revealed a significant decline compared with the control group (P<0.01). The levels of p42 and p44 mRNAs were decreased greatly after two-hour ICA treatment, while increased after 48-hour ICA treatment (P<0.05, P<0.01). There was no significant difference at other time points (P>0.05). Phospho-p42 was decreased after 10-minute icariin treatment, while phospho-p38 expression displayed an increase after 10- and 30-minute of treatment with icariin. There was no notable difference in phospho-JNK expression at these four time points. Icariin promotes differentiation of the mesenchymal stem cells C3H10T1/2 into osteoblasts, and its effect is related to the restraining of ERK expression and activation of p38 expression in the MAPK signaling pathway.

Activation of Src Family Kinases in Spinal Microglia Contributes to Formalin-Induced Persistent Pain State Through p38 Pathway

Protein tyrosine phosphorylation has been implicated in normal and pathological functions such as cell proliferation, migration and differentiation. Recently, some studies have shown that Src family kinases (SFKs) were involved in neurological disorders and neuropathic pain states in which microglial activation plays a role. In the formalin test, we have reported that microglia undergo at least 2 distinct stages of activation on the basis of signaling events regarding p38 mitogen-activated protein kinases (MAPK). Here, we investigated the involvement of SFKs signaling in a formalin pain animal model and the association with p38 MAPK. Our results showed that SFKs were activated in the spinal microglia beginning 1 day after peripheral formalin injection lasting for 7 days. Pretreatment with SFK specific inhibitor PP2 could not inhibit formalin-induced spontaneous pain behaviors. However, PP2 inhibited formalin injury, induced persistent mechanical hyperalgesia, and reversed microglial phospho-p38 expression as well using immunohistostaining and Western blot at day 3 and 7 after injection. Our results suggested that the activation of the Src/p38MAPK signaling cascade in spinal microglia contributed to late stage persistent mechanical hyperalgesia evoked by formalin injection into the paw. PerspectiveThis study presents unique properties of spinal microglial activation in a pain animal model. This finding could potentially help clinicians to further understand the contributions of spinal microglia to acute and persistent pain state.

Abstract 374: Genetic Disruption of Guanylyl Cyclase/Natriuretic Peptide Receptor-AUpregulates Renal (Pro)Renin Receptor Gene Expression in Npr1 Mutant Mice

Mice carrying targeted-disruption of guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) gene ( Npr1 ) exhibits hypertension, cardiac, and kidney hypertrophy, and congestive heart failure. The objective of the present study was to determine the role of (pro)renin receptor (P)RR in the kidneys of Npr1 gene-disrupted (-/-; 0-copy), and wild-type (+/+; 2-copy) mice. Disruption of Npr1 gene leads to increased systolic blood pressure by 36mmHg in 0-copy mice (138.4 ± 3.6) as compared with wild-type mice (102.2 ± 3.2 mm Hg). The renal (P)RR protein and mRNA levels were increased by 3-fold (4.8 ± 0.7 vs.1.3±0.4) and 3.5-fold (5.0 ± 0.5 vs.1.9 ± 0.3), respectively, in 0-copy mice compared with 2-copy control mice. To identify the Angiotensin II-independent mechanism of (P)RR, angiotensin converting enzyme (ACE) inhibitor, captopril and angiotensin II receptor-1 (AT1R) antagonist, losartan were administered to all Npr1 mice genotypes. The protein expression of ACE (3.9 ± 0.6 vs.1.9 ± 0.4; 2-fold) and AT1R (4.5 ± 0.4 vs.1.7; 2.5-fold) were decreased in 0-copy treated mice compared with 0-copy control mice, whereas the (P)RR expression was not altered by both inhibitors. Further, expression of phospho-extracellular regulated kinases (p-Erk1/2, 5.3 ± 0.7 vs 1.6 ± 0.5; 3-fold) and phospho-p38 (p-p38, 8.0 ± 0.8 vs. 2.1 ± 0.7; 4-fold) were increased in 0-copy mice as compared with 2-copy control mice. Treatment with Erk1/2 inhibitor U0126 and p38 inhibitor SB203580 attenuated the levels of p-Erk1/2 (6.8 ± 0.5 ± vs.1.1 ± 0.3; 6-fold) and p-p38 (4.7 ± 0.4 vs. 1.6 ± 0.5; 3-fold) in 0-copy treated mice as compared with 0-copy control mice. Captopril and losartan did not alter the expression levels of p-Erk1/2 and p-p38 in 0-copy mice as compared with 0-copy treated mice. The present results suggests that absence of NPRA/cGMP signaling causes increased expression of (P)RR and leads to MAPKs activation in the Npr1 null mutant mice.

HIV-induced kidney cell injury: role of ROS-induced downregulated vitamin D receptor.

Reactive oxygen species (ROS) have been demonstrated to contribute to HIV-induced tubular cell injury. We hypothesized that HIV-induced ROS generation may be causing tubular cell injury through downregulation of vitamin D receptor (VDR) and associated downstream effects. In the present study, HIV not only downregulated tubular cell VDR expression but also inflicted DNA injury. On the other hand, EB-1089, a VDR agonist (VD), inhibited both downregulation of VDR and tubular cell DNA injury in the HIV milieu. H(2)O(2) (an O(-) donor) directly downregulated tubular cell VDR, whereas catalase, a free radical scavenger, inhibited HIV-induced downregulation of tubular cell VDR expression. HIV also stimulated the tubular cell renin-angiotensin system (RAS) through downregulation of VDR. Because losartan (an ANG II blolcker) partially inhibited HIV-induced tubular cell ROS generation while ANG II directly stimulated tubular cell ROS generation, it appears that HIV-induced ROS production was partly contributed by the RAS activation. VD not only inhibited HIV-induced RAS activation but also attenuated tubular cell ROS generation. Tubular cells displayed double jeopardy in the HIV milieu induction of double-strand breaks and attenuated DNA repair; additionally, in the HIV milieu, tubular cells exhibited enhanced expression of phospho-p53 and associated downstream signaling. A VDR agonist and an ANG II blocker not only preserved expression of tubular cell DNA repair proteins but also inhibited induction of double-strand breaks. In in vivo studies, renal cortical sections of Tg26 mice displayed attenuated expression of VDR both in podocytes and tubular cells. In addition, renal cortical sections of Tg26 mice displayed enhanced oxidative stress-induced kidney cell DNA damage. These findings indicated that HIV-induced tubular cell downregulation of VDR contributed to the RAS activation and associated tubular cell DNA damage. However, both VD and RAS blockade provided protection against these effects of HIV.

BCAR1 Protein Plays Important Roles in Carcinogenesis and Predicts Poor Prognosis in Non-Small-Cell Lung Cancer

ObjectiveOur previous study suggested the potential clinical implications of BCAR1 in non-small-cell lung cancer (NSCLC) (Mol Diagn Ther. 2011. 15(1): 31–40). Herein, we aim to evaluate the predictive power of BCAR1 as a marker for poor prognosis in NSCLC cases, verify the carcinogenic roles of BCAR1 in the A549 lung adenocarcinoma cell line, and testify to the BCAR1/phospho-p38 axis.MethodsBetween January 2006 and June 2010, there were a total of 182 patients with NSCLC (151 cases with available follow up data, and 31 cases lost to follow-up due to the invalid contact information). We inspected BCAR1, phospho-BCAR1(Tyr410), phospho-p38(Thr180/Tyr182) and p38 expression in NSCLC tissues and matched adjacent normal tissues by immunoblotting and IHC. After BCAR1 -RNA interference in A549 cells, we inspected the protein expression (BCAR1, phospho-BCAR1, phospho-p38 and p38) and performed cell biology experiments (cell growth, migration and cycle).ResultsBCAR1 was overexpressed in NSCLC tissues (177/182) and cell lines (A549 and Calu-3). However, it was not detected in the normal adjacent tissue in 161 of the 182 cases. Higher BCAR1 levels were strongly associated with more poorly differentiated NSCLC and predicted poorer prognosis. BCAR1 knockdown caused cell growth arrest, cell migration inhibition and cell cycle arrest of A549 cells. Overexpression of BCAR1 was associated with activation of p38 in NSCLC cases, and BCAR1 knockdown caused reduction of phospho-p38 levels in A549 cells.ConclusionOverexpression of BCAR1 is a predictor of poor prognosis in NSCLC and plays important carcinogenic roles in carcinogenesis, probably via activation of p38 MAPK. However, further investigations are required immediately.

113 DECREASE OF UROTHELIAL CELL APOPTOSIS SIGNAL MOLECULES IS ASSOCIATED WITH IMPROVEMENT OF CLINICAL SYMPTOMS AFTER SINGLE INTRAVESICAL BOTULINUM TOXIN A INJECTION FOR PATIENTS WITH INTERSTITIAL CYSTITIS

INTRODUCTION AND OBJECTIVES: Interstitial cystitis/painful bladder syndrome (IC/PBS) is considered to result from long-standing inflammation of bladder. Currently, no one treatment provides longterm efficacy. Intravesical botulinum toxin A (BoNT-A) injection seems to have promising therapeutic effect on IC/PBS. Several studies indicated that p38 MAPK activation is implicated in inflammation, fibrosis and mediating apoptosis in different cell types in various species. We have found that apoptosis of urothelial cells in IC/PBS could be due to up-regulation of inflammatory signals, including p38 MAPK and TNF . This study aimed to investigate whether the changes of bladder inflammation and apoptotic signal transduction could be modulated by intravesical BoNT-A injection in IC/PBS. METHODS: Twenty three patients with IC/PBS were enrolled. All patients received intravesical 100U BoNT-A injection. The bladder specimens were obtained at baseline and 6 months after the first injection. The double stain, protein array analysis and western blotting were performed to analyze the alterations of tryptase (mast cell activity), Bax, and phospho-p38 . The intensities of proteins in the arrays and Western blots were quantified using Image J processing. Inflammatory molecule treated urothelial cells were analyzed by TUNEL staining and western blotting for level of molecules involved in apoptosis. RESULTS: Clinical results after BoNT-A injection revealed improvement of visual analog score, O’Leary-Sant symptom score, and global response assessment but not glomerulation and maximal bladder capacity in overall patients (Table). Phospho-p38 and TUNEL double staining indicated that inflammatory and apoptotic events were co-existed in IC/PBS bladders. Analysis of the western blot results revealed significant decrease of phospho-p38 and Bax expression after the first time BoNT-A injection. However, the change of tryptase did not reach statistical significance. CONCLUSIONS: Single BoNT-A injection provides clinical improvement and reduce apoptotic signal protein production but mast cell activity did not significantly reduce, suggesting repeat BoNT-A injection is necessary to achieve long-term effect. Table. The changes of clinical measures and western blot measures parameters Baseline 6 months after BoNT-A P values VAS 5.30 2.46 3.78 2.61 0.048

The Effect of PPAR Agonists on the Migration of Mature and Immature Eosinophils

PPARγ agonists can either enhance or inhibit eosinophil migration, which is a sum of directional migration (chemotaxis) and random cell movement (chemokinesis). To date, the effects of PPAR agonists on chemokinesis have not been examined. This study investigates the effects of PPARα, δ, and γ agonists on eosinophil migration and chemokinesis. Eosinophils purified from blood of atopic donors were preincubated with rosiglitazone (PPARγ agonist), GW9578 (PPARα agonist), GW501516 (PPARδ agonist), or diluent. The effects of PPAR agonists were examined on eosinophil chemokinesis, eotaxin-induced migration of eosinophils, and migration of IL-5Rα+ CD34+ cells. Expressions of CCR3, phospho-p38, phospho-ERK, and calcium release were also measured in eosinophils after rosiglitazone treatment. Low concentrations of rosiglitazone, but not GW9578 or GW501516, increased chemokinesis of eosinophils (P = 0.0038), and SDF-1α-induced migration of immature eosinophils (P = 0.0538). Rosiglitazone had an effect on eosinophil calcium flux but had no effect on expression of CCR3 or phosphorylation of p38 or ERK. In contrast, high concentrations of rosiglitazone inhibited eosinophil migration (P = 0.0042). The effect of rosiglitazone on eosinophil migration and chemokinesis appears to be through modification of calcium signaling, which alludes to a novel PPAR-mediated mechanism to modulate eosinophil function.

P53 is correlated with low BMI negative progesterone receptor status and recurring disease in patients with endometrial cancer

ObjectiveP53 tumor suppressor gene plays a role in endometrial carcinogenesis. Former studies described correlations between p53 protein overexpression in endometrial cancer and prognostic factors, measured by immunohistochemistry. But data is still controversial. The aim of this study was to measure p53 and phospho-p53 overexpression by Western blot and evaluate correlations between overexpression and prognostic and clinical factors. Phospho-p53 seems to be the functional p53 protein and was examined for the first time in endometrial cancer. Methods40 patients with endometrial cancer were included in the study. A control group of 20 patients with normal endometrial tissue samples was used. Western blot was performed for detection of p53 and phospho-p53. Clinical and pathological parameters were obtained from medical records. Statistical analysis was performed using the log-rank test, the Mann–Whitney test for two independent groups and the Fisher’s exact test for dichotomous groupings. ResultsIn 17.5% of the patients with endometrial cancer a p53 overexpression could be evaluated. There was a correlation between a p53 overexpression and recurring disease (p: 0.014), a negative progesterone receptor status (p: 0.021) and a low BMI (p: 0.022). Only one of 40 patients had a phospho-p53 expression. ConclusionWestern blot is a valid method for the detection of p53 overexpression. As other authors described before, p53 overexpression seems to correlate with negative prognostic factors. The correlation between p53 overexpression and a low BMI may underline the relationship between p53 alterations and biological aggressive endometrial carcinomas.

Cytoprotective effects of CSTMP, a novel stilbene derivative, against H2O2-induced oxidative stress in human endothelial cells

AbstractA novel stilbene derivative, (E)-2-(2-chlorostyryl)-3,5,6-trimethylpyrazine (CSTMP), was designed and synthesized based on the pharmacophores of tetramethylpyrazine (TMP) and resveratrol (RES). In the present study, we investigated the protective effects of CSTMP on vascular endothelial cells under oxidative stress and elucidated its molecular mechanisms. The radical scavenging activity of CSTMP was assessed by the DPPH test. Human Umbilical Vein Endothelial Cells (HUVECs) were exposed to 150µM hydrogen peroxide (H2O2) for 12 h, resulting in a decrease of cell viability assessed by the MTT assay and an increase of apoptotic cells assessed by the nuclear staining assay and flow cytometry. The activities of lactate dehydrogenase (LDH), superoxide dismutase (SOD) and nitric oxide synthase (NOS) and the contents of malondialdehyde (MDA), reduced glutathione (GSH) and nitric oxide (NO) in cells were determined by commercial kits. The expression levels of pro-apoptotic factor caspase-3 and anti-apoptotic signal ERK1/2 were detected by western blot. The results showed that CSTMP had a moderate anti-oxidative effect against the DPPH test, which was less than RES. Co-incubation with CSTMP increased the cell viability, markedly reduced the LDH leakage from the cells and decreased the lipid peroxidation. These effects of CSTMP were accompanied by increasing activity of the endogenous antioxidant enzyme SOD, the level of GSH, the production of NO and cNOS activity. Moreover, CSTMP showed stronger effects on the inhibition of apoptosis, caspase-3 expression, and the activation of phosphorylated ERK1/2 compared to RES. Furthermore, CSTMP could inhibit the expression of phospho-JNK and phospho-p38 induced by H2O2. These results suggest that CSTMP prevents H2O2-induced cell injury through anti-oxidation and anti-apoptosis via the MAPK and caspase-3 pathways.

Reactive Oxygen Species and p38 Mitogen-activated Protein Kinase Mediate Tumor Necrosis Factor α-Converting Enzyme (TACE/ADAM-17) Activation in Primary Human Monocytes

Tumor necrosis factor α-converting enzyme (TACE) is responsible for the shedding of cell surface TNF. Studies suggest that reactive oxygen species (ROS) mediate up-regulation of TACE activity by direct oxidization or modification of the protein. However, these investigations have been largely based upon nonphysiological stimulation of promonocytic cell lines which may respond and process TACE differently from primary cells. Furthermore, investigators have relied upon TACE substrate shedding as a surrogate for activity quantification. We addressed these concerns, employing a direct, cell-based fluorometric assay to investigate the regulation of TACE catalytic activity on freshly isolated primary human monocytes during LPS stimulation. We hypothesized that ROS mediate up-regulation of TACE activity indirectly, by activation of intracellular signaling pathways. LPS up-regulated TACE activity rapidly (within 30 min) without changing cell surface TACE expression. Scavenging of ROS or inhibiting their production by flavoprotein oxidoreductases significantly attenuated LPS-induced TACE activity up-regulation. Exogenous ROS (H(2)O(2)) also up-regulated TACE activity with similar kinetics and magnitude as LPS. H(2)O(2)- and LPS-induced TACE activity up-regulation were effectively abolished by a variety of selective p38 MAPK inhibitors. Activation of p38 was redox-sensitive as H(2)O(2) caused p38 phosphorylation, and ROS scavenging significantly reduced LPS-induced phospho-p38 expression. Inhibition of the p38 substrate, MAPK-activated protein kinase 2, completely attenuated TACE activity up-regulation, whereas inhibition of ERK had little effect. Lastly, inhibition of cell surface oxidoreductases prevented TACE activity up-regulation distal to p38 activation. In conclusion, our data indicate that in primary human monocytes, ROS mediate LPS-induced up-regulation of TACE activity indirectly through activation of the p38 signaling pathway.

Effects of andrographolide on the activation of mitogen activated protein kinases and nuclear factor-κB in mouse peritoneal macrophage-derived foam cells

To observe the effect of andrographolide on the activation of mitogen-activated protein kinases (MAPKs) and expression of nuclear factor-κB (NF-κB) in macrophage foam cells. The mouse peritoneal macrophages were cultured in the media in the presence of oxidized low-density lipoprotein (ox-LDL), ox-LDL+andrographolide, or neither (control). The phosphorylation of MAPK molecules (p38MAPK, JNK, ERK1/2) and the expressions of NK-κB p65 were examined by Western blot. As compared with cells in the control group, the expressions of phospho-p38 and NF-κB p65 were increased in the cells cultured with either ox-LDL or ox-LDL+andrographolide (P<0.01), but attenuated significantly in the presence of ox-LDL+ andrographolide when compared with ox-LDL (P<0.05). The phospho-JNK increased in the presence of either ox-LDL or ox-LDL+andrographolide when compared with control cells (P<0.01), but no significant difference existed between ox-LDL and ox-LDL+andrographolide (P>0.05). The expression of phospho-ERK1/2 was increased in the presence of ox-LDL compared with the control cells (P<0.01), but no significant differences existed between the cells cultured in the presence of ox-LDL+andrographolide and the control medium (P>0.05). Andrographolide could inhibit the activation of ERK1/2, p38MAPK and NK-κB induced by ox-LDL in macrophage foam cells, which might be one of its mechanisms in preventing atherosclerosis.

Effect of N-nitrosodimethylamine on inducible nitric oxide synthase expression and production of nitric oxide by neutrophils and mononuclear cells: the role of JNK signalling pathway

In neutrophils (PMN) and mononuclear cells (PBMC), one of the enzymes responsible for nitric oxide (NO) synthesis is inducible nitric oxide synthase (iNOS). Changes in iNOS expression result from various signalling pathways including the mitogen-activated protein kinase (MAPK) pathway activated by endogenic and exogenic factors. N-nitrosodimethylamine (NDMA) is a xenobiotic with widespread occurrence in human environment and has an effect on cells of the immune system. The aim of this study was to determine the effect of NDMA on iNOS expression and NO production by human PMN and PBMC cells in the light of superoxide anion production by PMN cells. Moreover, the role of JNK and p38 pathways in NO production with involvement of iNOS was studied. Additionally, the function of JNK pathway in generation of superoxide anion was determined. Moreover, nitrotyrosine expression was studied in PMN and PBMC cells in the presence of NDMA. This work shows that NDMA increases iNOS expression and NO production by PMN and PBMC cells. In addition, elevated expression of phospho-JNK and phospho-p38, which are markers of JNK and p38 MAPK pathways activation, were observed. Lower iNOS expression and NO production by neutrophils exposed to extended action of NDMA were observed after application of inhibitor of JNK and p38 pathways. Lower phospho-p38 expression in PMN stimulated by NDMA was found as a result of arresting JNK pathway, whereas, application of inhibitor of p38 pathway resulted in enhanced phospho-JNK expression in PMN and PBMC cells. Increased ability to release superoxide anion by NDMA-stimulated PMN cells was observed. This ability was reduced after the application of inhibitor of JNK pathway. In PMN and PBMC cells exposed to NDMA, an increased expression of nitrotyrosine, which is dependant on JNK and p38 pathways that are activated by this particular xenobiotic, was observed. Generally, increased induction of iNOS related to elevated production of NO by PMN and PBMC cells exposed to NDMA may result in dysfunction of regulation of immunity responses controlled by this molecule in various conditions. Increased expression of nitrotyrosine in PMN and PBMC cells exposed to NDMA may affect their functions in an auto- and/or a paracrine way. Mutual interactions of JNK and p38 MAPK during the induction of iNOS expression in cells exposed to NDMA indicate complex mechanism of induction of iNOS synthase.

Abstract 4291: Functional p38 mitoge-activated protein kinase activity restrains pancreatic cancer growth in vitro and correlates with improved eurvival of pancreatic cancer patients

Abstract Introduction: Mammalian p38 mitogen-activated protein kinases (MAPKs) are activated by a wide range of cellular stresses as well as in response to inflammatory cytokines. However, depending on the cell type, p38 MAPK family members and their isoforms may either suppress or promote growth. Because we recently identified p38 as a differentially expressed protein in pancreatic duct adenocarcinoma (PDAC), our goal was to clarify its role in this tumor type. Methods: Immunolabeling for phospho-p38 was performed using a rabbit PAb (Cell Signaling). Kaplan Meier survival plots were determined based on p38 labeling intensity. Total protein was extracted from PDAC cell lines and used for Western blot analysis of p38 expression. Functional kinase activity was also determined by the p38 kinase assay. Growth of PDAC cell lines in vitro was determined in the presence or absence of the p38 inhibitors SB202190, SB203580 and SB239063 by MTT assay. Results: Immunolabeling for phospho-p38 in PDAC tissues indicated strong positive expression in 65.06% (54/83) of analyzed cases. p38 overexpression was significantly correlated with prolonged overall survival of these same patients by Kaplan Meier analysis (p=0.0155). By Western blot, phospho-p38 expression was confirmed in a subset of PDAC cell lines, and correlated with functional p38 kinase activity in these same cell lines. Inhibition of p38 MAPK activity using the selective p38 inhibitors SB202190 and SB203580 inhibited starvation and gemcitabine-induced cell death in PDAC cells with high p38 activity compared with vehicle control. By contrast, there was no significant difference in cell growth in PDAC cells without p38 activity when treated with these same p38 inhibitors compared with untreated control cells. Conclusions: Functional p38 MAPK expression restrains cell growth in vitro, and phospho-p38 overexpression in vivo correlates with improved survival of PDAC patients. These studies support the notion that p38 has anti-proliferative or tumor suppressive functions, and that loss of p38 expression prevents cell stress induced sensitization to cell death. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4291. doi:10.1158/1538-7445.AM2011-4291

Fucoidan from Undaria pinnatifida induces apoptosis in A549 human lung carcinoma cells.

Fucoidan, a sulfated polysaccharide, has various biological activities, such as anticancer, antiangiogenic and antiinflammatory effects; however, the mechanisms of action of fucoidan on anticancer activity have not been fully elucidated. The anticancer effects of fucoidan from Undaria pinnatifida on A549 human lung carcinoma cells were examined. Treatment of A549 cells with fucoidan resulted in potent antiproliferative activity. Also, some typical apoptotic characteristics, such as chromatin condensation and an increase in the population of sub-G1 hypodiploid cells, were observed. With respect to the mechanism underlying the induction of apoptosis, fucoidan reduced Bcl-2 expression, but the expression of Bax was increased in a dose-dependent manner compared with the controls. Furthermore, fucoidan induced caspase-9 activation, but decreased the level of procaspase-3. Cleavage of poly-ADP-ribose polymerase (PARP), a vital substrate of effector caspase, was found. The study further investigated the role of the MAPK and PI3K/Akt pathways with respect to the apoptotic effect of fucoidan, and showed that fucoidan activates ERK1/2 in A549 cells. Unlike ERK1/2, however, treatment with fucoidan resulted in the down-regulation of phospho-p38 expression. In addition, fucoidan resulted in the down-regulation of phospho-PI3K/Akt. Together, these results indicate that fucoidan induces apoptosis of A549 human lung cancer cells through down-regulation of p38, PI3K/Akt, and the activation of the ERK1/2 MAPK pathway.

Prostaglandin I2 analogues suppress TNF-α expression in human monocytes via mitogen-activated protein kinase pathway

Although treatment for asthma control has improved a lot recently, refractory asthma is still a challenge for clinicians. Evidence revealed that anti-tumor necrosis factor (TNF)-α therapy may have potential in treating refractory asthma. Recently in an animal model, prostaglandin I(2) (PGI(2)) analogues can suppress the cardinal feature of asthma. However, whether PGI(2) analogues can regulate TNF-α expression in monocytes and the mechanism is not well-known. The human monocytes were pretreated with beraprost, iloprost and treprostinil, three PGI(2) analogues, before stimulation with lipopolysaccharide (LPS). TNF-α concentration of the cell supernatants was measured by ELISA. Intracellular signaling was investigated by Western blot. PGI(2) analogues suppressed LPS-induced TNF-α expression in THP-1 cells. CAY10449, an I prostanoid receptor antagonist, could reverse these effects. Beraprost increased intracellular cAMP level in THP1 cells. Forskolin, an adenylyl cyclase activator, could confer similar effect. LPS-induced TNF-α expression in THP-1 cells could be reversed by mitogen-activator protein kinase (MAPK)-p38, extracellular signal-related kinase (ERK) and c-Jun N-terminal kinase (JNK) inhibitors. Western blot revealed that beraprost suppressed MAPK phospho-p38, phosphor-JNK and phosphor-ERK expression. PGI(2) analogues suppressed LPS-induced TNF-α expression in THP-1 cells via the IP receptor-cAMP and the MAPK pathways. PGI(2) analogues may have potentiality to treat asthma.

Effect of Diode Laser on Proliferation and Differentiation of PC12 Cells

This study investigated the effects of diode (GaAlAs) laser irradiation at an effective energy density of 5 or 20 J/cm(2) on cell growth factor-induced differentiation and proliferation in pheochromocytoma cells (PC12 cells), and whether those effects were related to activation of the p38 pathway. Laser irradiation at 20 J/cm(2) significantly decreased the number of PC12 cells, while no difference was seen between the 5 J/cm(2) group and the control group (p<0.05). Western blotting revealed marked expression of neurofilament and β-tubulin, indicating greater neurite differentiation in the irradiation groups than in the control group at 48 hr. Irradiation also enhanced expression of phospho-p38. The decrease in number of cells after laser irradiation was accelerated by p38 inhibitor, while neurite differentiation was up-regulated by laser irradiation, even when the p38 pathway was blocked. This suggests that laser irradiation up-regulated neurite differentiation in PC12 cells involving p38 and another pathway.

Resveratrol Arrests Cell Cycle and Induces Apoptosis in Human Hepatocellular Carcinoma Huh-7 Cells

Resveratrol has been shown to possess anticancer, anti-aging, anti-inflammatory, antimicrobial, and neuroprotective activities. In this study, we examined the antiproliferative properties of resveratrol and its molecular mechanism(s) of action in Huh-7 cells, a new human hepatoma cell line system for hepatitis C virus. Results showed that resveratrol significantly inhibited Huh-7 cell proliferation (50% inhibitory concentration = 22.4 μg/mL) and effectively induced cell cycle arrest and apoptosis. It up-regulated p21/WAF1 expression in a p53-independent manner, but the expressions of cyclin E, cyclin A, and cyclin-dependent kinase 2 were down-regulated. It also caused an increase in the ratio of pro-apoptotic/anti-apoptotic protein, which was associated with the mitochondrial membrane depolarization and the increase in caspase activity. Resveratrol showed no effect on Fas, Fas ligand, extracellular signal regulated kinase (ERK) 1/2, and p38 expression but down-regulated phospho-ERK and phospho-p38 expression. In addition, resveratrol was noted to trigger autophagic cell death through the increased expression of autophagy-related Atg5, Atg7, Atg9, and Atg12 proteins. These results suggest that resveratrol could be an important chemoprevention agent for hepatoma of hepatitis C virus infection.

Effect of Thrombin Fragment (TP508) on Myocardial Ischemia Reperfusion Injury in a Model of Type 1 Diabetes Mellitus

We investigated the efficacy of novel thrombin fragment TP508 on ischemia-reperfusion injury using a porcine model of type 1 diabetes mellitus. Alloxan-induced diabetic male Yucatan swine underwent 60 minutes of mid-left anterior descending coronary artery occlusion, followed by 120 minutes of reperfusion. Fifty minutes into ischemia, animals received either placebo (DM; n=8) or TP508 as a bolus of 1 mg/kg followed by infusion at 2.5 mg/kg per hour (DMT; n=8). Hemodynamic parameters and myocardial function were monitored. Monastryl blue/triphenyl tetrazolium chloride staining was used to assess sizes of the areas at risk and infarction. Coronary microvascular reactivity was measured and expression of cell survival and proapoptotic proteins quantified. Preoperative serum glucose values were similar between groups (309±57 mg/dL in DM versus 318±67 mg/dL in DMT; P=0.92). Infarct size was smaller in the TP508-treated group (5.3±1.9% in DMT versus 19.4±5.6% in DM; P=0.03). There was no statistically significant difference in global or regional left ventricular function between groups. Endothelium-dependent microvessel relaxation was moderately improved in the DMT group (P=0.09), whereas endothelium-independent relaxation was similar between groups. The expression of cell survival proteins Akt, phospho-p38, and mammalian target of rapamycin was higher in the areas at risk of DMT animals compared with DM animals (P<0.05), and expressions of proapoptotic glycogen synthase kinase 3β and caspase 3 were lower in the DMT group (P<0.05). This study demonstrates that, in type 1 diabetic swine, TP508 reduces infarct size after ischemia-reperfusion. Thus, TP508 may offer a novel approach in cardioprotection from ischemia-reperfusion injury in diabetic patients.