NADPH oxidase produces a large amount of reactive oxygen species (ROS) in Helicobacter pylori (H. pylori)-induced gastric epithelial cells. Even though ROS mediate apoptotic cell death, direct involvement of NADPH oxidase on H. pylori-induced apoptosis remains unclear. Besides, H. pylori isolates show a high degree of genetic variability. The predominant genotype of H. pylori in Korea has been reported as cagA+, vacA s1b, m2, iceA genotype. Present study aims to investigate whether NADPH oxidase-generated ROS mediate apoptosis in human gastric epithelial AGS cells infected with H. pylori in a Korean isolate. AGS cells were pretreated with or without an NADPH oxidase inhibitor diphenyleneiodonium (DPI) and cultured in the presence of H. pylori at a bacterium/cell ratio of 300:1. Cell viability, hydrogen peroxide level, DNA fragmentation, and protein levels of p53, Bcl-2, and Bax were determined. Results showed that H. pylori inhibited cell viability with the density of H. pylori added to the cells. Inhibition of NADPH oxidase by DPI suppressed H. pylori-induced cell death, increased hydrogen peroxide, DNA fragmentation, and the ratio of Bax/Bcl-2, and p53 induction in AGS cells dose-dependently. The results suggest that targeting NADPH oxidase may prevent the development of gastric inflammation associated with H. pylori infection by suppressing abnormal apoptotic cell death of gastric epithelial cells.
Apoptosis ; Apoptosis Regulatory Proteins/metabolism ; Cell Survival ; Epithelial Cells/metabolism/microbiology ; Gastric Mucosa/metabolism ; Helicobacter Infections/*metabolism/microbiology ; Helicobacter pylori/drug effects/genetics/*isolation & purification ; Humans ; NADPH Oxidase/metabolism ; Onium Compounds/*antagonists & inhibitors/pharmacology ; Oxidative Stress/drug effects ; Reactive Oxygen Species/metabolism ; Republic of Korea ; Stomach/cytology/*metabolism/microbiology

OBJECTIVETo explore the molecular mechanism of moxibustion at stomach meridian acupoints for precancerous lesions of chronic atrophic gastritis (CAG).

METHODSFifty male SD rats were randomly divided into a normal group, a model group, a stomach meridian group, a control point group and a vitacoenzyme group, 10 rats in each group. The CAG precancerous lesion model was made in all the groups except the normal group. The rats in the normal group and model group were bundled for 30 min per day; the rats in the stomach meridian group and control point group were bundled and treated with moxibustion at stomach meridian acupoints or control points for 30 min per day; the rats in the vitacoenzyme group were treated with intragastric administration of vitacoenzyme, once per day. All the treatment was given for 20 weeks. The pathological morphological change of gastric mucosa was observed under optical microscope; the expression of epidermal growth factor (EGF), transforming growth factor alpha (TGF-alpha), vascular endothelial growth factor (VEGF), gastric mucosal proliferatig cell nuclear antigen (PCNA), argyrophilic protein of nucleolar organizer regions (Ag-NORs) in gastric mucosal cells were detected by enzyme linked immuno sorbent assay (ELISA).

RESULTSCompared with the normal group, in the model group the gastric mucosal cells showed dysplasia and the expression of EGF, TGF-alpha, PCNA, VEGF, Ag-NORs in gastric mucosa cells in the model group was increased significantly (all P < 0.05). Compared with the model group, the gastric mucosa lesion gradually recovered and the expression of EGF, TGF-alpha, PCNA, VEGF, Ag-NORs in gastric mucosal cells was gradually decreased in the stomach meridian group, control point group and vitacoenzyme group, in which the stomach meridian group had the most significant effects (all P < 0.05).

CONCLUSIONMoxibustion at stomach meridian acupoints can obviously decrease the expression of cell proliferative factors in gastric mucosa in rats with CAG precancerous lesions, inhibit the gastric mucosal cell dysplasia, and promote the recovery of gastric mucosa.

Acupuncture Points ; Animals ; Cell Proliferation ; Epidermal Growth Factor ; genetics ; metabolism ; Gastric Mucosa ; cytology ; Gastritis, Atrophic ; genetics ; metabolism ; physiopathology ; therapy ; Humans ; Hyperplasia ; genetics ; metabolism ; physiopathology ; therapy ; Male ; Moxibustion ; Proliferating Cell Nuclear Antigen ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Vascular Endothelial Growth Factor A ; genetics ; metabolism

BACKGROUND/AIMS: Doublecortin and CaM kinase-like-1 (DCAMKL1) is a marker of stem cells expressed predominantly in the crypt base in the intestine. However, DCAMKL1-positive cells have been shown to be differentiated tuft cells rather than quiescent progenitors. Tuft cells are the only epithelial cells that express cyclooxygenase 2 (COX-2) in the normal intestinal epithelium. We previously generated Cdx2-transgenic mice as model mice for intestinal metaplasia and gastric carcinoma. In the current study, we investigated the association between COX-2 and DCAMKL1 in gastric carcinoma. METHODS: We examined the association between COX-2 and DCAMKL1 expression in gastric carcinomas in clinical samples (early gastric well-differentiated adenocarcinoma) and Cdx2-transgenic mice; and the DCAMKL1-transgenic mouse stomach using immunohistochemistry and quantitative real-time polymerase chain reaction. RESULTS: The COX-2-expressing cells were scattered, not diffusely expressed, in gastric carcinomas from humans and Cdx2-transgenic mice. DCAMKL1-positive cells were also scattered in the gastric carcinomas, indicating that tuft cells could still be present in gastric carcinoma. COX-2 was expressed in DCAMKL1-positive tuft cells in Cdx2- and DCAMKL1-transgenic mouse stomachs, whereas the Sox9 transcription factor was ubiquitously expressed in gastric carcinomas, including COX-2-positive cells. CONCLUSIONS: COX-2 is expressed in DCAMKL1-expressing quiescent tuft cells in gastric carcinoma.
Adenocarcinoma/metabolism ; Animals ; Cyclooxygenase 2/genetics/*metabolism ; Epithelial Cells/metabolism ; Gastric Mucosa/metabolism ; Humans ; Intestinal Mucosa/cytology/*enzymology/metabolism ; Intracellular Signaling Peptides and Proteins/genetics/*metabolism ; Mice ; Mice, Transgenic ; Protein-Serine-Threonine Kinases/genetics/*metabolism ; SOX9 Transcription Factor/genetics/metabolism ; Stomach Neoplasms/*enzymology/genetics

OBJECTIVETo investigate the change of gastric cancer cell proliferation and the expression of gastric cancer related gene 213 (GCRG213), a long interspersed nuclear element-1 (LINE-1) endonuclease variant, during hypoxia.

METHODSNormal gastric mucosa cell GES-1 and gastric cancer cell BGC-823 were cultured in 20% or 3% oxygen concentrations, respectively. MTT test was used to analyze the proliferation of the GES-1 and BGC-823 cells. The change of GCRG213 mRNA and protein expression in GES-1 and BGC-823 cells was detected by using RT-PCR and Western blot analysis. Blast was used at the NCBI Blast server to identify GCRG213 sequence to any alignment in the GeneBank databases.

RESULTSCompared with 20% oxygen condition, 3% oxygen concentration could promote cell growth. Mean-while, the expression of GCRG213 at mRNA and protein levels was increased. GCRG213 sequence shared high homology with LINE-1 endonuclease sequence.

CONCLUSIONGCRG213 is a variant of LINE-1 endonuclease. Hypoxia as in 3% oxygen condition can promote cell proliferation and lead to GCRG213 overexpression.

Cell Line, Tumor ; Cell Proliferation ; Cells, Cultured ; Deoxyribonuclease I ; genetics ; Gastric Mucosa ; cytology ; Gene Expression ; Humans ; Hypoxia ; Peptide Hormones ; genetics ; Stomach Neoplasms ; genetics ; pathology

OBJECTIVETo investigate the effect of Helicobacter Pylori lipopolysaccharide (Hp-LPS) on expression of Gli and Ptch-1 proteins in sonic hedgehog (Shh) signaling pathway of gastric mucosa GES-1 cells.

METHODSThe LPS was extracted from Hp by hot phenol water method, and then the concentration of LPS was detected by the kinetic turbidimetric assay. GES-1 cells were stimulated by different concentrations of Hp-LPS (0, 1, 10, 20, 30 and 40 μg/ml). The inhibition rates of cell growth were measured by MTT assay after treated with Hp-LPS for 24 h. The expression of Gli and Ptch-1 proteins were determined by Western Blot.

RESULTSMTT assay showed that the inhibition rates of GES-1 cell growth after treatment by different concentrations of Hp-LPS (1, 10, 20, 30 and 40μg/ml) were 25.8% ± 2.7%, 34.2% ± 3.1 %, 46.3% 3.4%, 60.8% ± 2.1% and 82.9% ± 2.8% respectively (r=0.985, P<0.001). Western blot showed that the expressions of Gli and Ptch-1 proteins were decreased after Hp-LPS treatment (0, 1, 10, 20, 30 and 40 μg/ml): the relative expression values of Gli were 1.286 ± 0.180, 0.963 ± 0.067, 0.850 ± 0.085, 0.566 ± 0.058, 0.549 ± 0.056 and 0.377 ± 0.047, respectively (r=-0.945, P<0.001); those of Ptch-1 were 1.688 ± 0.088, 1.466 ± 0.061, 1.170 ± 0.065, 1.042 ± 0.064, 0.648 ± 0.057 and 0.482 ± 0.074, respectively (r=-0.985, P<0.001).

CONCLUSIONHp-LPS can decrease the related protein expression of Shh signaling pathway, which indicates that Hp may interfere with the function of Shh signaling pathway in gastric mucosa via the effect of its LPS.

Cells, Cultured ; Epithelial Cells ; drug effects ; Gastric Mucosa ; cytology ; Hedgehog Proteins ; metabolism ; Humans ; Lipopolysaccharides ; administration & dosage ; pharmacology ; Patched Receptors ; Patched-1 Receptor ; Receptors, Cell Surface ; metabolism ; Signal Transduction ; Transcription Factors ; metabolism ; Zinc Finger Protein GLI1

OBJECTIVE: To explore the effect of different Helicobacter pylori (H.pylori) clinical strains on the proliferation and apoptosis of gastric epithelial cells, and to observe the effect of H.pylori on gastric mucosa by Mongolian gerbil model infected H.pylori. METHODS: H.pylori isolates harvested from pathologically documented gastric carcinoma (GC, n=10) or chronic gastritis specimens (CG, n=10) were co-cultured with GES-1 cells individually. MTT assay and flow cytometry were used to determine the proliferation and apoptosis of GES-1 cells induced by H.pylori isolates. Mongolian gerbils were infected by the most (A strain) and the least (B strain) significantly proliferated H.pylori strains. Results When co-cultured with the cell/bacteria concentration ratio 1:1 and 1:50 for 12 h and the cell/bacteria concentration ratio 1:50 for 24 h, H.pylori clinical strains isolated from patients with gastric cancer promoted the proliferation of GES-1 cells, and there was significant difference in the absorbance compared with the group of gastritis strains(P<0.05). The apoptosis rate of the GC and CG groups increased significantly (P<0.05) compared with the control group when co-cultured with the cell/bacteria concentration ratio 1:50 and 1:200, and there was no significant difference between the GC group and the CG group (P>0.05). The incidences of intestinal metaplasia and dysplasia in the A strain group were significantly higher than those in the B strain group (P<0.05). CONCLUSION H.pylori strains from different disease sources have different effects on the proliferation of GES-1 cells. H.pylori isolated from gastric cancer can promote the proliferation of cells to different degrees and directly induce gastric precancerosis and gastric cancer.
Animals ; Apoptosis ; Cell Line ; Cell Proliferation ; Chronic Disease ; Gastric Mucosa ; cytology ; microbiology ; pathology ; Gastritis ; microbiology ; pathology ; Gerbillinae ; Helicobacter Infections ; pathology ; Helicobacter pylori ; pathogenicity ; Humans ; Metaplasia ; pathology ; Precancerous Conditions ; microbiology ; pathology ; Stomach Neoplasms ; microbiology ; pathology

OBJECTIVETo clone core promoter regions of iroquois homeobox gene 1 (IRX1) gene and evaluate the regulatory mechanism of IRX1 transcription.

METHODSUpstream sequence from transcriptional start site was predicted using bioinformatics methods. Serial deleted fragments from IRX1 promoter sequences were amplified by PCR and luciferase reporter plasmids were constructed. The luciferase intensity was analyzed after transferring reporters into GES-1 gastric mucosa cell line.

RESULTSThe promoter of IRX1 was predicted to be within 700 bp from the 5'-flanking region of IRX1 gene. Eight serial deleted luciferase reporter plasmids were constructed. The transcriptional activity of different fragments was expressed as following: p-416>p-584>p-715>p-350>p-687>p-320>p-188>p-92. Except p-320 and p-188, the transcriptional activity of other 6 fragments was higher than that of PGL3-basic plasmid. The transcriptional activity was the highest in p-416 and decreased sharply from p-320 to p-188.

CONCLUSIONSThe fragment p-416 shows the strongest promoter activity. The sequence from -320 bp to -188 bp is identified as core promoter region, which is focused as key sequence for further regulatory analysis, since some binding sites for important transcriptional factors such as Sp1 and TFII D are predicted.

Cell Line ; Cloning, Molecular ; Gastric Mucosa ; cytology ; Genes, Homeobox ; Homeodomain Proteins ; genetics ; Humans ; Promoter Regions, Genetic ; Transcription Factors ; genetics

OBJECTIVETo evaluate the effect of IL-1beta on the expression of CDX2 in human gastric epithelial cell line GES-1 and its role in the intestinal metaplasia.

METHODSGES-1 cells were treated with IL-1beta in different concentrations and the expressions of CDX2 mRNA and protein were detected by real-time PCR, immunocytochemistry and Western blot at different time points. GES-1 cells were then pre-treated with NF-KappaB pathway inhibitor PDTC, and the expression of CDX2 mRNA and protein induced by IL-1beta were detected. The cell ultra-structure of GES-1 cells was observed by electronic microscope after GES-1 being treated with IL-1beta for 25 days.

RESULTSLevels of CDX2 mRNA and protein were 0.0749 + or - 0.0021 and 0.56 + or - 0.04 in the cells treated with 1 microg/L IL-1beta(P<0.05). After pre-treatment with PDTC, levels of CDX2 mRNA and protein were 0.0006 + or - 0.0002 and 0.40 + or - 0.06(P<0.05). Some changes in the cell ultra-structure of GES-1 were found by electronic microscope when GES-1 was treated with IL-1beta for 25 days.

CONCLUSIONIL-1beta can stimulate CDX2 mRNA and protein expression in GES-1 cells through the NF-KappaB signal pathway, indicating that IL-1beta plays an important role in the intestinal metaplasia.

CDX2 Transcription Factor ; Cell Line ; Epithelium ; metabolism ; pathology ; Gastric Mucosa ; cytology ; metabolism ; pathology ; Homeodomain Proteins ; metabolism ; Humans ; Interleukin-1beta ; pharmacology ; Metaplasia ; RNA, Messenger ; genetics

BACKGROUND/AIMS: Ligands for peroxisome proliferator-activated receptor gamma (PPAR gamma), a member of the ligand-activated nuclear receptor superfamily, exhibit anti-tumoral effects and are associated with de novo synthesis of proteins involved in regulating the cell cycle and cell survival/death. Helicobacter pylori (H. pylori) is an etiologic agent for gastric adenocarcinoma, and raises the cell turnover of gastric epithelium. The aim of this study was to investigate the effect of PPAR gamma ligand rosiglitazone on the cell proliferation and the expressions of p27 and Skp2 protein in H. pylori infected gastric epithelial cells. METHODS: We examined the expression of PPAR gamma by Western blot in H. pylori infected AGS human gastric epithelial cells. The effect of rosiglitazone on the survival of H. pylori infected AGS cells was assessed by cell viability assay. After the treatment of rosiglitazone in H. pylori infected AGS cells, the expressions of p27 and Skp2 were assessed by Western blot. RESULTS: The expression of PPAR gamma protein was increased in H. pylori infected AGS cells. Cell growth was inhibited and decreased in dose- and time- dependent manner in H. pylori infected AGS cells treated with rosiglitazone. A decrease in Skp2 expression and a reciprocal increase in p27 expression were found in dose- and time-dependent manner in H. pylori infected AGS cells treated with rosiglitazone. CONCLUSIONS: Rosiglitazone inhibited the growth of H. pylori infected AGS cells. Rosiglitazone attenuated Skp2 expression, thereby promoting p27 accumulation in H. pylori infected human gastric epithelial cells. Further studies will be needed to find the effects of accumulation on cell turnover in H. pylori infection and the role in the H. pylori-associated gastric carcinogenesis.
Anti-Bacterial Agents/*pharmacology ; Cell Line ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p27/*metabolism ; Epithelial Cells/metabolism/*microbiology ; Gastric Mucosa/cytology/metabolism/*microbiology ; *Helicobacter pylori ; Humans ; PPAR gamma/antagonists &inhibitors/metabolism ; S-Phase Kinase-Associated Proteins/*metabolism ; Thiazolidinediones/*pharmacology

OBJECTIVECytotoxin-associated protein (CagA) of H. pylori has been confirmed to be closely associated with gastric inflammation and tumorigenesis, but the mechanism behind it is little understood. In this study, we try to determine roles of CagA(+) strain in activating PI3K/Akt1 signaling pathway, and affecting expression of p21(WAF1/CIP1) and p27(KIP1), and also in releasing IL-8 in host cells.

METHODSAkt1 phosphorylation and IL-8 levels of CagA(+) and CagA⁻ strain infected AGS cells were detected by ELISAs. Two quantitative RT-PCRs were established to measure p21(WAF1/CIP1) and p27(KIP1) mRNA levels in the CagA(+) and CagA⁻ strain infected cells. LY294002, an inhibitor of PI3K/Akt pathway, was used to define effect of the pathway in IL-8 release.

RESULTSCagA(+) strain could induce an obvious elevation of Akt1 phosphorylation in the infected AGS cells while CagA? strain failed to do so. The CagA(+) H. pylori strain infected AGS cells showed significant drops both in p21(WAF1/CIP1) and p27(KIP1) mRNA levels, whereas the CagA⁻ H. pylori strain caused a remarkable increase in p21(WAF1/CIP1) mRNA without affecting p27(KIP1) gene transcription in the AGS cells. Both the CagA(+) and CagA⁻ H. pylori strains enabled AGS cells to produce close elevated levels of IL-8, and the LY294002 block resulted in unexpected elevations of IL-8 levels.

CONCLUSIONSCagA can activate PI3K/Akt1 pathway that plays an inhibitory role in IL-8 release in H. pylori infected AGS cells. Activation of PI3K/Akt1 pathway and subsequent negative regulation of p21(WAF1/CIP1) and p27(KIP1) expression might be involved in CagA-associated carcinogenesis.

Antigens, Bacterial ; genetics ; physiology ; Bacterial Proteins ; genetics ; physiology ; Cell Line ; Cyclin-Dependent Kinase Inhibitor p21 ; biosynthesis ; Cyclin-Dependent Kinase Inhibitor p27 ; Gastric Mucosa ; cytology ; enzymology ; microbiology ; Helicobacter pylori ; metabolism ; pathogenicity ; physiology ; Humans ; Interleukin-8 ; secretion ; Intracellular Signaling Peptides and Proteins ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; Transcription, Genetic ; Virulence