Pharmacokinetic drug interaction and safety after coadministration of clarithromycin, amoxicillin, and ilaprazole: a randomised, open-label, one-way crossover, two parallel sequences study.

PURPOSE: Ilaprazole, the latest proton pump inhibitor, can be used with clarithromycin and amoxicillin as a triple therapy regimen for eradicating Helicobacter pylori. The aim of this study was to evaluate pharmacokinetic drug interactions and safety profiles after coadministration of clarithromycin, amoxicillin, and ilaprazole. METHODS: A randomised, open-label, one-way crossover, two parallel sequences study was conducted in 32 healthy subjects. In part 1, the subjects received a single dose of ilaprazole 10 mg in period 1 and clarithromycin 500 mg and amoxicillin 1000 mg twice daily for 6 days in period 2. In part 2, the subjects received clarithromycin 500 mg and amoxicillin 1000 mg once in period 1 and ilaprazole 10 mg twice daily for 6 days in period 2. In both sequences, the three drugs were coadministrated once on day 5 in period 2. Pharmacokinetic evaluations of ilaprazole (part 1), and clarithromycin and amoxicillin (part 2) were conducted. RESULTS: Twenty-eight subjects completed the study. For ilaprazole, the peak concentration (Cmax) slightly decreased from 479 (ilaprazole alone) to 446 ng/mL (triple therapy) [Geometric least square mean ratio (90% confidence interval), 0.93 (0.70-1.22)]. The area under the concentration-time curve from 0 h to the last measurable concentration (AUClast) slightly increased from 3301 to 3538 µg·h/mL [1.07 (0.85-1.35)]. For clarithromycin, the Cmax slightly decreased from 1.87 to 1.72 µg/mL [0.90 (0.70-1.15)], and AUClast slightly increased from 14.6 to 16.5 µg·h/mL [1.09 (0.87-1.37)]. For amoxicillin, the Cmax slightly decreased from 9.37 to 8.14 µg/mL [0.86 (0.74-1.01)], and AUClast slightly decreased from 27.9 to 26.7 µg·h/mL [0.98 (0.83-1.16)]. These changes in the PK parameters of each drug were not statistically significant. CONCLUSIONS: The coadministration of ilaprazole, clarithromycin, and amoxicillin was tolerable and did not cause a significant PK drug interaction. Thus, a triple therapy regimen comprising ilaprazole, clarithromycin, and amoxicillin may be an option for the eradication of H. pylori. Clinicaltrials.gov number: NCT02998437.

Inhibition of hepatitis C virus (HCV) replication by specific RNA aptamers against HCV NS5B RNA replicase.

This study identified specific and avid RNA aptamers consisting of 2'-hydroxyl- or 2'-fluoropyrimidines against hepatitis C virus (HCV) NS5B replicase, an enzyme that is essential for HCV replication. These aptamers acted as potent decoys to competitively impede replicase-catalyzed RNA synthesis activity. Cytoplasmic expression of the 2'-hydroxyl aptamer efficiently inhibited HCV replicon replication in human liver cells through specific interaction with, and sequestration of, the target protein without either off-target effects or escape mutant generation. A selected 2'-fluoro aptamer could be truncated to a chemically manufacturable length of 29 nucleotides (nt), with increase in the affinity to HCV NS5B. Noticeably, transfection of the truncated aptamer efficiently suppressed HCV replication in cells without escape mutant appearance. The aptamer was further modified through conjugation of a cholesterol or galactose-polyethylene glycol ligand for in vivo availability and liver-specific delivery. The conjugated aptamer efficiently entered cells and inhibited genotype 1b subgenomic and genotype 2a full-length HCV JFH-1 RNA replication without toxicity and innate immunity induction. Importantly, a therapeutically feasible amount of the conjugated aptamer was delivered in vivo to liver tissue in mice. Therefore, cytoplasmic expression of 2'-hydroxyl aptamer or direct administration of chemically synthesized and ligand-conjugated 2'-fluoro aptamer against HCV NS5B could be a potent anti-HCV approach.

Effects of addition of Ta and Y ions to InZnO thin film transistors by sol-gel process.

We have investigated the effects of the addition of tantalum (Ta) and yttrium (Y) ions to InZnO thin film transistors (TFTs) using the sol-gel process. TaInZnO and YInZnO TFTs had significantly lower off current and higher on-to-off current ratio than InZnO TFTs. Ta and Y ions have strong affinity to oxygen and so suppress the formation of free electron carriers in thin films; they play an important role in enhancing the electrical characteristic due to their high oxygen bonding ability. The optimized TaInZnO and YInZnO TFTs showed high on/off ratio and low subthreshold swing.

The Effects of C. lacerata on Insulin Resistance in Type 2 Diabetes Patients.

BACKGROUND: Several experimental studies have suggested beneficial effects of Ceriporia lacerata on glucose metabolism. However, there has been no human study assessing the effects of C. lacerata on glucose metabolism. Therefore, we investigated whether C. lacerata improves glucose control and insulin resistance in type 2 diabetes patients. METHODS: Ninety patients diagnosed with type 2 diabetes (T2DM) for more than 6 months were enrolled. Subjects were randomly divided into placebo (n = 45) or C. lacerata (n = 45) groups and then assigned to take placebo or C. lacerata capsules (500 mg/capsule) for a 12-week intervention period. Biochemical markers, including fasting glucose, 2-hour postprandial plasma glucose, and lipid profile levels, as well as insulin, c-peptide, and Hba1c, were measured. Furthermore, insulin sensitivity indices, such as HOMA-IR, HOMA-beta, and QUICKI, were assessed before and after the 12-week administration. RESULTS: Eighty-four patients completed the study. There were no significant differences in fasting, postprandial glucose, HbA1c, or lipid parameters. HOMA-IR and QUICKI indices were improved at week 12 in the C. lacerata group, especially in subjects with HOMA-IR of 1.8 or more (p < 0.05). Fasting, postprandial c-peptide, and insulin levels decreased at week 12 in the C. lacerata group (p < 0.05). These significant differences were not observed in the placebo group. CONCLUSION: Twelve-week administration of C. lacerata in T2DM patients resulted in significant improvement in insulin resistance, especially in those with lower insulin sensitivity. A larger population study with a longer follow-up period and an effort to elucidate the mechanism is warranted to further assess the effects of C. lacerata on T2DM patients.

Antioxidant-Rich Dietary Intervention Improves Cardiometabolic Profiles and Arterial Stiffness in Elderly Koreans with Metabolic Syndrome.

PURPOSE: Oxidative stress plays an important role in the pathogenesis of chronic metabolic diseases. This study investigated the effect of the antioxidant-rich dietary intervention on oxidative stress, metabolic parameters, and arterial stiffness in elderly Koreans with metabolic syndrome (MetS). MATERIALS AND METHODS: Thirty-one subjects with MetS were enrolled and randomly divided into dietary intervention group and control group. Subjects in the intervention group received three meal boxes prepared with antioxidant-rich ingredients every day for 4 weeks, and subjects in the control group maintained their usual diets. Anthropometric and various biochemical parameters related to oxidative stress, inflammation, and MetS were assessed. Brachial-ankle pulse wave velocity (baPWV) and fat measurement using computed tomography were also conducted before and after 4 weeks. RESULTS: There were significant differences in waist circumference, visceral to subcutaneous fat ratio, lipid peroxidation, oxidized low density lipoprotein (oxLDL), systolic and diastolic blood pressure, lipid parameters, advanced glycation end products, and baPWV between before and after the study in the experimental group (all p<0.05). Significant inter-group differences were observed between the experimental and control group in terms of the differences in body mass index, waist circumference, oxygen radical absorbance capacity, protein carboxylation, lipid peroxidation, oxLDL, blood pressure, lipid parameters, and baPWV between before and after the study (all p<0.05). CONCLUSION: Antioxidant-rich dietary intervention for a 4-week period ameliorated the state of oxidative stress and improved the components of MetS including central obesity, dyslipidemia, hypertension, and arterial stiffness in elderly Koreans with MetS.

Cumulative exposure amount of PM2.5 in the ambient air is associated with coronary atherosclerosis - Serial coronary CT angiography study.

BACKGROUND: We investigated the change of coronary atherosclerosis with long-term exposure to fine particulate matter of aerodynamic diameter <2.5 â€‹µm (PM2.5) using coronary computed tomography angiography (CCTA). METHODS: Subjects undergoing serial CCTAs between January 2007 and December 2017 (n â€‹= â€‹3,127) were analyzed. Each individual's cumulative amount of PM2.5 exposure between the two CCTAs was evaluated by Kriging interpolation and zonal analysis, considering the time interval between the two CCTAs. The main outcome was progression of coronary artery calcium (CAC) with additional semiquantitative analysis on the changes in the severity and composition of atherosclerotic plaques. RESULTS: The CAC scores increased by 30.8 Agatston units per-year under a median PM2.5 concentration 24.9 â€‹µg/m3 and tended to increase with the cumulative amount of PM2.5 exposure (r â€‹= â€‹0.321, p â€‹<0.001). The CAC progressed in 1,361 (43.5%) subjects during a median 53 months follow-up. The cumulative amount of PM2.5 exposure was independently associated with CAC progression (adjusted OR 1.09, p â€‹<0.001). By random forest analysis, the relative impact of cumulative amount of PM2.5 exposure on CAC progression was higher than that of traditional cardiovascular risk factors and the average concentration of PM2.5. The extent of coronary atherosclerosis and newly developed calcified plaque on follow-up were also significantly associated with the cumulative amount of PM2.5 exposure. CONCLUSIONS: Cumulative exposure to air pollution is associated with the progression of diffuse coronary calcification, the importance of which may be more significant than other traditional cardiovascular risk factors. Further investigations into the causality between PM2.5 and coronary atherosclerosis are warranted to improve global cardiovascular health.

Induction of cellular senescence by insulin-like growth factor binding protein-5 through a p53-dependent mechanism.

The insulin-like growth factor (IGF) signaling pathway plays a crucial role in the regulation of cell growth, differentiation, apoptosis, and aging. IGF-binding proteins (IGFBPs) are important members of the IGF axis. IGFBP-5 is up-regulated during cellular senescence in human dermal fibroblasts and endothelial cells, but the function of IGFBP-5 in cellular senescence is unknown. Here we show that IGFBP-5 plays important roles in the regulation of cellular senescence. Knockdown of IGFBP-5 in old human umbilical endothelial cells (HUVECs) with IGFBP-5 micro-RNA lentivirus caused partial reduction of a variety of senescent phenotypes, such as changes in cell morphology, increases in cell proliferation, and decreases in senescence-associated beta-galactosidase (SA-beta-gal) staining. In addition, treatment with IGFBP-5 protein or up-regulation of IGFBP-5 in young cells accelerates cellular senescence, as confirmed by cell proliferation and SA-beta-gal staining. Premature senescence induced by IGFBP-5 up-regulation in young cells was rescued by knockdown of p53, but not by knockdown of p16. Furthermore, atherosclerotic arteries exhibited strong IGFBP-5-positive staining along intimal plaques. These results suggest that IGFBP-5 plays a role in the regulation of cellular senescence via a p53-dependent pathway and in aging-associated vascular diseases.

HGF and BMP-7 ameliorate high glucose-induced epithelial-to-mesenchymal transition of peritoneal mesothelium.

Over time, peritoneal dialysis results in functional and structural alterations of the peritoneal membrane, but the underlying mechanisms and whether these changes are reversible are not completely understood. Here, we studied the effects of high levels of glucose, which are found in the dialysate, on human peritoneal mesothelial cells (HPMCs). We found that high concentrations of glucose induced epithelial-to-mesenchymal transition (EMT) of HPMC, suggested by decreased expression of E-cadherin and increased expression of alpha-smooth muscle actin, fibronectin, and type I collagen and by increased cell migration. Normalization of glucose concentration on day 2 reversed the phenotypic transformation, but the changes were irreversible after 7 d of stimulation with high glucose. In addition, exposure of HPMC to high glucose resulted in a decreased expression of the antifibrotic cytokines, hepatocyte growth factor (HGF) and bone morphogenic protein 7 (BMP-7). Exogenous treatment with HGF resulted in a dosage-dependent prevention of high glucose-induced EMT. Both BMP-7 peptide and gene transfection with an adenoviral vector of BMP-7 also protected HPMCs from EMT. Furthermore, adenoviral BMP-7 transfection decreased peritoneal EMT and ameliorated peritoneal thickening in an animal model of peritoneal dialysis. In summary, high concentrations of glucose induce a reversible EMT of HPMCs, associated with decreased production of HGF and BMP-7. Treatment of HPMCs with HGF or BMP-7 blocks high glucose-induced EMT, and BMP-7 ameliorates peritoneal fibrosis in an animal model of peritoneal dialysis.

Toll-like receptor 9-stimulated monocyte chemoattractant protein-1 is mediated via JNK-cytosolic phospholipase A2-ROS signaling.

Monocyte chemoattractant protein-1 (MCP-1) influences monocyte migration into sites of inflammation. This study highlights the importance of cytosolic phospholipase A2 (cPLA2)-mediated reactive oxygen species (ROS) signaling processes in the regulation of MCP-1 release as a result of toll-like receptor (TLR) activation. In macrophages, activation of TLR9 induced MCP-1 and cPLA2-phosphorylated arachidonic acid (AA) release. Inhibition of cPLA2 blocked CpG-induced MCP-1 and AA release. Although CpG stimulates phosphorylation of ERK, p38 and JNK, only inhibition of the JNK signaling pathways attenuated MCP-1 release, suggesting that the TLR9-mediated MCP-1 release was dependent upon the JNK pathway. TLR9 activation also stimulated ROS generation, while inhibition of NADPH oxidases (Noxs) blocked CpG-induced MCP-1 release. The CpG treatment increased macrophage Nox1 mRNA level, however it had no effect on macrophage Nox2 mRNA level. Overall, these results suggest that CpG enhances ROS generation through cPLA2-dependent pathways, which results in MCP-1 release.

Relationship between natural killer cell activity and glucose control in patients with type 2 diabetes and prediabetes.

AIMS/INTRODUCTION: Natural killer (NK) cells are cytotoxic lymphocytes critical to human immunity. Previous studies showed correlations between NK cell function and blood glucose concentrations. The purpose of the present study was to assess the NK cell activity and various metabolic parameters in people with type 2 diabetes, prediabetes and normal glucose tolerance. MATERIALS AND METHODS: A total of 49 participants were enrolled in the study. Anthropometric and biochemical parameters including age, sex, body mass index, smoking status, blood pressure, fasting plasma glucose, C-peptide, insulin, glycated hemoglobin, total cholesterol, triglyceride, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol were assessed. The 75 g oral glucose tolerance test was carried out for 2-h postload glucose level. Homeostatic model assessment was calculated for insulin resistance and ß-cell function. NK cell activity was measured by detecting the circulating interferon-gamma level secreted from NK cells. RESULTS: NK cell activity was lower in patients with type 2 diabetes (768.01 ± 650.35) compared with those with prediabetes (2,396.08 ± 653.76, P < 0.001) and normal glucose tolerance (2,435.31 ± 633.22, P < 0.001). In patients with type 2 diabetes, there was a significant inverse linear relationship between NK cell activity and fasting plasma glucose, glycated hemoglobin, and 2-h postload glucose level (all P < 0.001). Multiple regression analysis showed glycated hemoglobin to be an independent predictor of NK cell activity in patients with type 2 diabetes. CONCLUSIONS: Compared with individuals with normal glucose tolerance or prediabetes, type 2 diabetes patients have a reduced NK cell activity, and it is significantly related to glucose control.

Use of RBC deformability index as an early marker of diabetic nephropathy.

BACKGROUND AND OBJECTIVE: Hemorheologic alterations have been suggested to play a role in the pathogenesis of diabetic microvascular complications. We measured various hemorheologic parameters and assessed their possible role as a diagnostic tool for diabetic nephropathy (DN). METHODS: 248 subjects with type 2 diabetes and 222 subjects with prediabetes were included in this study. Hemorheologic parameters, including erythrocyte sedimentation rate (ESR), elongation index at 3 Pa (EI) were measured using microfluidic hemorheometer. Various metabolic parameters were measured from fasting blood samples. The subjects were stratified into three groups according to classification of DN by urinary albumin to creatinine ratio (ACR) and four groups by estimated glomerular filtration rate (GFR), than analyzed. RESULTS: Significant differences were observed in metabolic and hemorheologic parameters according to progression of DN. Among them, (Fibrinogen×ESR)/ EI differed in all three groups of urinary ACR. In multiple regression analysis, (Fibrinogen×ESR)/ EI was an independent predictor of urine ACR after adjusted with confounding factors (ß â€Š= 0.010, p < 0.001). (Fibrinogen×ESR)/ EI also showed significant difference no or minimal CKD stage, moderate CKD and severe CKD classified by GFR. This parameter showed area under curve (AUC) of the receiver operating characteristic (ROC) curve of 0.762, and moderate sensitivity and specificity to predict prevalence of microalbuminuria. CONCLUSIONS: (Fibrinogen×ESR)/ EI is a sensitive parameter for screening diabetic nephropathy.

Elevated TyG Index Predicts Progression of Coronary Artery Calcification.

OBJECTIVE: To investigate the triglyceride-glucose (TyG) index association with coronary artery calcification (CAC) progression in adult Koreans. RESEARCH DESIGN AND METHODS: Various cardiovascular risk factors and anthropometric profiles were assessed in 1,175 subjects who previously had a CAC evaluation at least twice by multidetector computed tomography in a health care center. The TyG index was determined using ln(fasting triglycerides [mg/dL] × fasting glucose [mg/dL]/2). The CAC progression was defined as either incident CAC in a CAC-free population at baseline or an increase of ≥2.5 units between the square roots of the baseline and follow-up coronary artery calcium scores (CACSs) of subjects with detectable CAC at baseline. RESULTS: CAC progression was seen in 312 subjects (27%) during 4.2 years follow-up. On the basis of the TyG index, subjects were stratified into three groups. Follow-up CACS and incidence of CAC progression were markedly elevated with rising TyG index tertile. Logistic regression analysis adjusted for various risk factors revealed an odds ratio for CAC progression of 1.82 (95% CI 1.20-2.77; P ≤ 0.01) when the highest and lowest TyG index tertiles were compared. CONCLUSIONS: The TyG index is an independent predictor of CAC progression.

Triglyceride Glucose Index Is Superior to the Homeostasis Model Assessment of Insulin Resistance for Predicting Nonalcoholic Fatty Liver Disease in Korean Adults.

BACKGROUND: Recently, the triglyceride glucose (TyG) index has been considered a surrogate marker of insulin resistance which is a well-known pathogenic factor in nonalcoholic fatty liver disease (NAFLD). However, few studies have investigated the relationship between the TyG index and NAFLD. Thus, we investigated the relationship between the TyG index and NAFLD and the effectiveness of the TyG index compared with the homeostasis model assessment of insulin resistance (HOMA-IR) in identifying NAFLD in Korean adults. METHODS: Participants of 4,986 who underwent ultrasonography in a health promotion center were enrolled. The TyG index was calculated as ln [fasting triglycerides (mg/dL)×fasting glucose (mg/dL)/2], and HOMA-IR was estimated. NAFLD was diagnosed by ultrasonography. RESULTS: Significant differences were observed in metabolic parameters among the quartiles of the TyG index. The prevalence of NAFLD significantly increased with increment in the TyG index. After adjusting for multiple risk factors, a logistic regression analysis was performed. When the highest and lowest quartiles of the TyG index and HOMA-IR were compared, the odds ratios for the prevalence of NAFLD were 2.94 and 1.93 (95% confidence interval, 2.32 to 3.72 and 1.43 to 2.61; both P for trend <0.01), respectively. According to the receiver operating characteristic analysis, the TyG index was superior to HOMA-IR in predicting NAFLD. CONCLUSION: The TyG index and prevalence of NAFLD were significantly related and the TyG index was superior to HOMA-IR in predicting NAFLD in Korean adults.

Role of hepatocyte growth factor/c-Met signaling in regulating urokinase plasminogen activator on invasiveness in human hepatocellular carcinoma: a potential therapeutic target.

Hepatocyte growth factor (HGF), its transmembrane tyrosine kinase receptor (c-Met), and urokinase type plasminogen activator (uPA) is a key protein in the plasminogen activation system, which plays a proteolytically important role in the invasion and metastasis of various types of cancers. However, the mechanisms by which HGF/c-Met signaling mediates cancer progression and metastasis are unclear. This study was designed to investigate the roles of HGF/c-Met in tumor progression and metastasis in HepG2 and Hep3B hepatoma cell lines. Treatment with HGF increased c-Met phosphorylation in a dose-dependent manner. Activity of c-Met phosphorylation peaked 1-3 min after HGF treatment and then declined. HGF enhanced the protein level and the activity of uPA in HepG2 and Hep3B cells, and the uPAR protein level also increased in a HGF dose-dependent manner. HGF increased cell invasion through the Matrigel. A monoclonal antibody against human uPA receptor, mAb 3936, inhibited HGF-mediated tumor cell invasion in a dose-dependent manner. Down-regulation of uPA using uPA-shRNA induced a decrease in in vitro cell invasion. These results suggest that hepatoma cells express functional c-Met, which may provide a target for a therapeutic basis to interfere with metastases of cancer cells by inhibiting uPA system-mediated proteolysis.

Identification of replicative senescence-associated genes in human umbilical vein endothelial cells by an annealing control primer system.

Cellular senescence is regulated by specific genes in many organisms. The identification and functional analysis of senescence-associated genes could provide valuable insights into the senescence process. Here, we employed a new and improved differential display reverse transcription-polymerase chain reaction (DDRT-PCR) method that involves annealing control primers (ACPs) to identify genes that are differentially expressed in human umbilical endothelial cells during replicative senescence. Using 120 ACPs, we identified 31 differentially expressed genes (DEGs). Basic local alignment search tool (BLAST) search revealed 29 known genes and two unknown genes. Expression levels of the 29 known genes were confirmed by real-time quantitative RT-RCR and by Western blotting for eight of these genes. CD9 antigen, MHC class I chain-related sequence A (MICA) and cell division cycle 37 homolog (CDC37) were up-regulated, and bone morphogenetic protein 4 (BMP4), dickkopf-1 (DKK1), and transcription factor 7-like 1 (TCF7L1) were down-regulated in old cells. Treatment with recombinant human MICA caused a decrease in cell proliferation and an increase in senescence-associated beta-galactosidase staining. Further analysis of differentially expressed genes may provide insights into the molecular basis of replicative senescence and vascular diseases associated with cellular senescence.

Regulation of replicative senescence by insulin-like growth factor-binding protein 3 in human umbilical vein endothelial cells.

Insulin/insulin-like growth factor (IGF) signaling pathways are among the most conserved processes in aging in organisms ranging from yeast to mammals. Previously, using cDNA microarray technology, we reported that expression of IGF-binding protein 3 (IGFBP3), one of the IGF-binding proteins, was increased with age in human dermal fibroblasts. In this study, the role of IGFBP3 on cellular senescence was studied in human umbilical vein endothelial cells (HUVEC). The expression levels of IGFBP3 mRNA and protein were increased in HUVECs with age. Knockdown of IGFBP3 in old cells with IGFBP3 short hairpin RNA (shRNA) retrovirus resulted in the partial reduction of a variety of senescent phenotypes, such as changes in cell morphology, and decreases in population doubling times and senescence-associated beta-galactosidase (SA-beta-gal) staining. Down-regulation of IGFBP3 rescued the growth arrest induced by p53 overexpression in young HUVECs. In contrast, up-regulation of IGFBP3 in young cells and prolonged IGFBP3 treatment accelerated cellular senescence, confirmed by cell proliferation and SA-beta-gal staining. The FOXO3a (forkhead box O3a) protein level was increased in old IGFBP3 shRNA cells. The treatment of young HUVECs with IGFBP3 repressed the levels of FOXO3a protein. Furthermore, calorie restriction reduced IGFBP3 protein levels, which were found to be increased with age in the rat liver and serum. These results suggest that IGFBP3 might play an important role in the cellular senescence of HUVECs as well as in vivo aging.

Hepatocyte growth factor promotes cell survival by phosphorylation of BAD in gastric cancer cells.

Hepatocyte growth factor (HGF) is one of the survival factors with a potent ability to promote cell survival by inhibiting apoptosis. However, the mechanism by which HGF inhibits apoptosis is not completely understood. To explore the genes associated with stomach cancer cell survival by HGF, we used cDNA microarray technology and selected 26 genes up- or downregulated in NUGC-3 cells during HGF treatment. Among them, BAD was confirmed to be upregulated at the RNA and protein levels by HGF treatment. We investigated the effect of BAD induced by HGF on cell survival. HGF treatment inhibited apoptosis induced by BAD overexpression and enhanced BAD phosphorylation. Pretreatment of NUGC-3 cells with PI3K inhibitors, LY 294002, decreased HGF-induced BAD phosphorylation on Ser136 whereas an MEK inhibitor, PD 98059, decreased BAD phosphorylation on Ser112. In conclusion, increases in BAD levels as well as BAD phosphoryation by HGF might contribute to HGF-mediated cell survival in NUGC-3 cells.

Cytotoxicity of 1,2-diacetylbenzene in human neuroblastoma SHSY5Y cells is mediated by oxidative stress.

Environmental substances or metabolites induce neuronal damage through oxidative stress. Environmental organic solvent metabolite, 1,2-diacetylbenzene (1,2-DAB), treated rats develop limb weakness with neuropathological damage in both the central and peripheral nervous systems. In this experiment, we examined the relevance of 1,2-DAB-induced toxicity to increased oxidative stress using human dopaminergic neuroblastoma SHSY5Y cells. 1,2-DAB (4, 16, and 32 microM) disrupted cytoskeletal integrity and caused morphological changes. 1,2-DAB significantly decreased cell viability and induced cell cycle arrest in the G(1) phase in a concentration-dependent manner. At higher concentration, it produced apoptosis. Pre-treatment of cells with the antioxidants, GSH or N-acetylcysteine (NAC), effectively blocked 1,2-DAB-mediated cytotoxicity including cell viability, and morphological changes. These results therefore suggest that oxidative stress is involved in environmental metabolite 1,2-DAB-mediated neurotoxicity and that antioxidant treatment can effectively protect the nervous system from environmental hazards.

Cellular mechanisms of hepatocyte growth factor-mediated urokinase plasminogen activator secretion by MAPK signaling in hepatocellular carcinoma.

AIMS AND BACKGROUND: The hepatocyte growth factor, its receptor c-Met, and urokinase-type plasminogen mediate various cellular responses on activation, including proliferation, survival, invasion, and metastasis. The regulatory mechanisms for the proliferation and the particular invasive phenotypes of hepatocellular carcinoma are not yet fully understood. In order to clarify the intracellular downstream signal for hepatocyte growth factor/c-Met signaling in tumor progression and metastasis in hepatoma, we determined the effects of a specific MEK1 inhibitor (PD 098059) and a p38 kinase inhibitor (SB 203580) on hepatocyte growth factor-mediated cell proliferation and urokinase-type plasminogen expression in hepatoma cell lines (HepG2 and Hep3B). RESULTS: Hepatocyte growth factor treatment induced the phosphorylation of ERK and p38 kinase in a dose-dependent manner, resulting in an early peak of phosphorylation at 3 to 10 min, which then rapidly decreased to a near basal level. Pretreatment with PD 098059 reduced hepatocyte growth factor-mediated cell proliferation and urokinase-type plasminogen secretion. In contrast, SB 203580 pretreatment enhanced cell proliferation and urokinase-type plasminogen secretion due to induction of ERK phosphorylation. Treatment with PD 098059 and SB 203580 resulted in a decrease in phospho-ERK activity. Stable expression of dominant negative-MEK1 in HepG2 cells showed a decrease in hepatocyte growth factor-mediated urokinase-type plasminogen secretion. CONCLUSIONS: Such results suggest that interaction of an MEK/ERK and a p38 kinase might be critical in intrahepatic invasion and metastasis of human hepatoma cells.

Involvement of glycogen synthase kinase-3beta in hydrogen peroxide-induced suppression of Tcf/Lef-dependent transcriptional activity.

Hydrogen peroxide (H(2)O(2)) mediates induction of cytotoxicity in various cell types. GSK-3beta has been found to participate in a number of signaling pathways, including cell proliferation and cell death. In the present study, we show that GSK-3beta is rapidly dephosphorylated and activated in response to H(2)O(2) treatment. H(2)O(2) also dephosphorylates Akt/PKB in a dose- and time-dependent manner. Overexpression of Akt/PKB attenuates H(2)O(2)-induced dephosphorylation of GSK-3beta. Ectopic expression of Dvl-1, a component of Wnt signaling, stimulates Akt/PKB and inhibits dephosphorylation of GSK-3beta by H(2)O(2). Furthermore, H(2)O(2) causes the reduction of beta-catenin level and LiCl-mediated activation of Tcf/Lef-dependent transcription activity. These findings suggest that GSK-3beta is involved in H(2)O(2)-mediated inhibition of Tcf/Lef-dependent transcriptional activity.