Gastric Mucosal Epithelial Cells Research Articles

MicroRNA-194 inhibits the epithelial-mesenchymal transition in gastric cancer cells by targeting FoxM1.

We hypothesized that miR-194 may control Forkhead box protein M1 (FoxM1) expression in gastric cancer cells and therefore may have therapeutic potential in gastric cancer. The expression level of miR-194 was examined using real-time PCR in human gastric cancer and noncancerous gastric tissues, gastric cancer cell and normal gastric mucosal epithelial cell. We examined whether the miR-194 regulates cell migration and invasion, and the epithelial-mesenchymal transition Phenotype by inhibiting FoxM1 in gastric cancer cells. The expression of miR-194 was significantly lower in gastric cancer compared with non-cancerous gastric tissues and cells. Exogenous expression of miR-194 inhibited cell migration, invasion, and the epithelial-mesenchymal transition phenotype in gastric cancer cells. Moreover, we discovered a novel post-transcriptional regulatory mechanism of FoxM1 expression that is mediated by miR-194. Our study clearly demonstrates that miR-194 inhibits the acquisition of the EMT phenotype in gastric cancer cells by downregulating FoxM1, thereby inhibiting cell migration and invasion during cancer progression.

Telomerase and hTERT: Can they serve as markers for gastric cancer diagnosis?

To investigate telomerase activity and human telomerase reverse transcriptase (hTERT) expression in normal human gastric mucosal epithelial cells (nhGMECs) and fibroblasts (nhGMFs). nhGMECs and nhGMFs were isolated and cultured from specimens obtained during routine surgery for bleeding peptic ulcer. Telomerase activity in nhGMFs, nhGMECs, and the tumor cell lines BGC-823, SGC-7901 and MKN-28 cells was analyzed using the telomeric repeat amplification protocol assay. hTERT protein was determined in nhGMECs, nhGMFs, BGC-823, SGC-7901 and MKN-28 cells by indirect immunofluorescence. A similar level of telomerase activity was observed in nhGMECs, nhGMFs and BGC-823, SGC-7901, MKN-28 cell lines. Positive hTERT immunostaining was detected in nhGMECs, nhGMFs, BGC-823, SGC-7901 and MKN-28 cell lines. The use of telomerase or hTERT as diagnostic markers for gastric cancer may require further studies.

Index of Suspicion

The reader is encouraged to write possible diagnoses for each case before turning to the discussion. We invite readers to contribute case presentations and discussions. Please inquire first by contacting Dr. Deepak Kamat at DKamat@med.wayne.edu. A 2-year-old boy with a history of eczema and food allergies to nuts and soy presents to the emergency department with a 10-day history of generalized edema. The swelling began in the periorbital area but soon progressed to involve his entire body. There have been no fevers or any recent illnesses other than 1 day of cough and a few watery stools. He has had no new exposures to foods or other substances. His family history is remarkable for multiple allergies and eczema. Physical examination reveals a temperature of 98.8°F (37.1oC), heart rate of 98 beats per minute, respiratory rate of 36 breaths per minute, blood pressure of 103/65 mm Hg, and an oxygen saturation of 97% on room air. His weight is 12.6 kg (34th percentile). He is noted to have a moderate amount of periorbital edema, decreased breath sounds at the lung bases bilaterally, a protuberant abdomen, and 2+ pitting edema on his lower extremities. The rest of his physical examination findings are within normal limits. Laboratory evaluation reveals a white blood cell count of 23,800/μL (23.8 × 109/L), with 37% neutrophils, 49% lymphocytes, 4% bands, 7% monocytes, and 3% eosinophils; hemoglobin level of 13.3 g/dL (133 g/L); and platelet count of 427 × 103/μL (427 × 109/L). Serum electrolyte, blood urea nitrogen, and creatinine levels are normal. Sodium level is 132 mEq/L (132 mmol/L). Serum albumin level is 1.7 g/dL (17 g/L) (reference range, 3.4-5.4 g/dL [34-54 g/L]). Total protein level is 3.8 g/dL (38 g/L). Aspartate aminotransferase, alanine aminotransferase, and coagulation profiles …

Effects of Helicobacter pylori on the expression of catalytic subunit of the DNA-dependent protein kinase and Ku70/Ku80 heterodimer in gastric mucosa epithelial cells in vivo and in vitro

Objective To explore the effects of Helicobacter pylori (H.pylori) on the expression of catalytic subunit of the DNA-dependent protein kinase (DNA-PKcs) and Ku70/Ku80 heterodimer in gastric mucosa epithelial cells in vivo and in vitro.Methods After treated with H.pylori for one,three,six,12 and 24 hours,the expressions of DNA-PKcs and Ku70/Ku80 heterodimer in gastric epithelial cells (GES) 1 and gastric adenocarinoma cells (AGS) were detected by Western blot.Mongolian gerbils were gavaged with H.pylori,and were sacrificed after infected for six and 12 months.The gastric mucosa tissues were taken for immunohistochemistry to detect the expressions of DNA-PKcs and Ku70/Ku80 heterodimer at protein level.The data were analyzed by t test and chi-square test.Results After H.pylori infection for one hour,the relative quantity of the expression of DNA-PKcs in GES-1 was 1.16±0.09,which was higher than that of non infected group (1.04±0.31) and the difference was statistically significant (t=4.67,P＜0.05).After infected by H.pylori for one,three,six,12 and 24 hours,the relative quantities of the expressions of Ku70/Ku80 heterodimer in GES-1 were 1.58±0.32,1.84±0.40,1.97±0.35,3.72±1.42 and 3.74±1.56,respectively,all were higher than that of non infected group (1.24±0.31) and the differences were statistically significant (t=3.57,4.20,5.03,8.11 and 8.14,all P＜0.05).The relative quantities of the expressions of Ku70/Ku80 heterodimer in AGS were 4.69 ± 0.87,3.67 ± 0.67,2.41±0.24,1.35±0.35 and 1.32±0.10 after H.pylori infected for one,three,six,12 and 24 hours,respectively,all were lower than that of no H.pylori infected group (4.84 ± 0.76) and the differences were statistically significant (t=34.13,27.68,19.81,4.47 and 5.69,all P＜0.05).In Mongolian gerbil models,DNA-PKcs did not express in H.pylori negative group (0/25),the total positive rate of H.pylori infected group was 98.1％ (53/54),the difference between the two groups was statistically significant (x2 =74.55,P＜0.01).The total positive rate of Ku70/Ku80 heterodimer in H.pylori negative group was 92.0％ (23/25) and in H.pylori infected group was 68.5％ (37/54),the difference between the two groups was statistically significant (x2=5.16,P＜0.05).Conclusion H.pylori infection affected cellular DNA damage repair through changing the expression of DNA-PKcs and Ku70/Ku80 heterodimer in gastric mucosa in vivo and in vitro,which may cause gastric mucosal lesions. Key words: DNA-binding proteins; Catalytic domain; Protein kinases; Fibrin fibrinogen degradation products; DNA damage; Helicobacter pylori; Gerbillinae

Expression of apoptosis-associated microRNAs in ethanol-induced acute gastric mucosal injury via JNK pathway

MicroRNAs (miRNAs) have been shown to be closely associated with cellular apoptosis, but their involvement in response to ethanol-induced gastric mucosal epithelial cell apoptosis remains largely unknown. The purpose of this study was to investigate the expression profile of apoptosis-associated miRNAs in ethanol-induced acute gastric mucosal injury and the mechanisms underlying injury. Gastric mucosal injury was induced in rats by oral administration of ethanol, and gastric tissues were collected for analysis of gastric ulcer index, apoptosis ratio, caspase-3 activity, and miRNAs expression. Cell cultures of human gastric mucosal epithelial cells (GES-1) were incubated with ethanol to induce apoptosis. Mimics or inhibitors of miRNAs or c-Jun N-terminal kinase (JNK) inhibitor were added to the cell culture medium. GES-1 cells were collected for analysis of apoptosis ratio, caspase-3 activity, miRNAs expression, and protein phosphorylation levels of JNK, p38 mitogen-activated protein kinase (p38MAPK), or extracellular signal-regulated kinase (ERK). In the animal experiments, gastric ulcer index, cellular apoptosis, and caspase-3 activity were significantly increased, accompanied by up-regulation of miR-145 and down-regulation of the microRNAs miR-17, miR-19a, miR-21, miR-181a, and miR-200c. In the human cell culture experiments, the anti-apoptotic effects of miR-19a and miR-21 or pro-apoptotic effect of miR-145 were confirmed by their corresponding mimics or inhibitor; the ethanol-induced GES-1 apoptosis as well as the changes in miRNAs expression were significantly attenuated in the presence of JNK inhibitor. These results demonstrated that miR-145, miR-19a, and miR-21 were the apoptosis-associated miRNAs in gastric mucosal epithelial cells. The regulation of expression of these 3 miRNAs in ethanol-induced GES-1 apoptosis involved the JNK pathway.

Synergistic antitumor effects of dasatinib and oxaliplatin in gastric cancer cells

The aim of this study is to investigate whether dasatinib, a Src inhibitor, has the synergistic effect with oxaliplatin in treating gastric cancer cells. The baseline levels of total Src and p-Src in 10 human gastric cancer cell lines and gastric mucosa epithelial cell line GES-1 were detected by Western blot (WB). The changes of Src and p-Src expression after oxaliplatin exposure were evaluated by WB. The combination indices and clonogenic assay were used to evaluate the synergistic effects of dasatinib with oxaliplatin on cell growth and proliferation in vitro. Gastric cancer xenografts in nude mice were established and treated by oxaliplatin with or without dasatinib. The tumor growth curves were calculated and the impacts of different treatment on the tumor proliferation and src protein expression in gastric cancer xenografts were determined by immunohistochemistry staining and WB. The different levels of Src expression in gastric cancer cells were related with their different sensitivity to oxaliplatin. The expression of p-Src, but not total Src, was elevated after oxaliplatin exposure both in vitro and in vivo. Dasatinib could dramatically inhibit p-Src expression, and combination indices demonstrated that dasatinib and oxaliplatin were synergistic in inhibiting gastric cancer cell growth. Dasatinib plus oxaliplatin were more effective in inhibiting clone formation than oxaliplatin or dasatinib monotherapy in clonogenic assay. The tumor volume and tumor weight of xenografts were significantly lower in doublet treatment group than those in single-agent treatment groups. Dasatinib plays synergistic role with oxaliplatin in inhibiting gastric cancer cell growth both in vitro and in vivo, via inhibiting Src activity stimulated by oxaliplatin.

Anticancer effects of 4-vinyl-2,6-dimethoxyphenol (canolol) against SGC-7901 human gastric carcinoma cells

Gastric cancer remains the fourth most commonly diagnosed cancer and is the second leading cause of cancer-related mortality worldwide. The aim of this study was to investigate the effects of canolol on the proliferation and apoptosis of SGC-7901 human gastric cancer cells and its relevant molecular mechanisms. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to observe the effect of canolol on the proliferation of SGC-7901 human gastric adenocarcinoma cells. The results showed that SGC-7901 cells exhibited a marked dose-dependent reduction in the proliferation rate. The survival rate of the cells was 88.86±1.58% at 50 μmol/l, decreasing to 53.73±1.51% at 800 μmol/l (P<0.05). By contrast, canolol had no significant toxicity on the human gastric mucosal epithelial cell line GES-1. The vivid images of cell morphology using an inverted microscope provided confirmation of the MTT assay. Treatment of SGC-7901 cells with canolol resulted in apoptosis demonstrated by flow cytometry. Furthermore, canolol downregulated the mRNA levels of COX-2, but had no significant effect on the mRNA expession of the Bax and Bcl-2 genes. These findings suggest that canolol has potential to be developed as a new natural anti-gastric carcinoma agent.

Local protective effects of oral 45S5 bioactive glass on gastric ulcers in experimental animals

Bioactive glass has been shown to stimulate bone regeneration and soft tissue healing. In this study, we evaluated the local protective effects of bioactive glass on experimental gastric ulcers, in comparison with omeprazole and hydrotalcite. Single and multiple gavage of 45S5 bioactive glass dose-dependently protected stress ulcers in mice and chronic ulcers in rats. Multi-daily gavage of bioactive glass for 7 days prevented chronic ulcer recurrence by 50 %. Bioactive glass ionic dissolution produced marked proliferation of ethanol-injured GES-1 human gastric mucosa epithelial cells 48 and 72 h after exposure. Bioactive glass was shown to be hardly absorbed after single or multi-daily gavage. This study, for the first time, demonstrates that bioactive glass is effective in protecting against gastric ulcers, with its high efficacy comparable to omeprazole and superior to hydrotalcite. The lack of oral absorption makes bioactive glass a potential for treatment of peptic ulcers omitting systemic toxicity or side-effects.

Clopidogrel delays gastric ulcer healing in rats

Clopidogrel is not safe enough for the gastric mucosa in patients with high risk of peptic ulcer. This study aimed to explore if clopidogrel delays gastric ulcer healing and elucidate the involved mechanisms. Gastric ulcer was induced in rats and the ulcer size, mucosal epithelial cell proliferation of the ulcer margin, expression of growth factors [epidermal growth factor (EGF), basic fibroblast growth factor] and their receptors, and signal transduction pathways for cell proliferation were measured and compared between the clopidogrel-treated group and untreated controls. For the in vitro part, rat gastric mucosal epithelial cell line (RGM-1 cells) was used to establish EGF receptor over-expressed cells. Cell proliferation and molecular change under EGF treatment (10ng/ml) with and without clopidogrel (10−6M) were demonstrated. Ulcer size was significantly larger in the clopidogrel-treated group compared to the control and mucosal epithelial cell proliferation of the ulcer margin was significantly decreased in the clopidogrel-treated group (P<0.05). Clopidogrel (2mg and 10mg/kg/day) significantly decreased ulcer-induced gastric epithelial cell proliferation and ulcer-stimulated expressions of EGF receptor and phosphorylated extracellular signal-regulated kinase (PERK) at the ulcer margin (P<0.05). Clopidogrel (10−6M) also inhibited EGF-stimulated EGF receptor, PERK expression, and cell proliferation in RGM-1 cells (P<0.05), and caused much less inhibition of EGF-stimulated cell proliferation in EGF receptor over-expressed RGM-1 cells than in RGM-1 cells (22% vs. 32% reduction). In conclusion, clopidogrel delays gastric ulcer healing in rats via inhibiting gastric epithelial cell proliferation, at least by inhibition of the EGF receptor-ERK signal transduction pathway.

The protective of hydrogen on stress-induced gastric ulceration

Stress ulceration frequently occurs as a result of major stressful events and hydroxyl radical (⋅OH) is one of the major causative factors for it. Recently, it has been proved that hydrogen, a potent selectively ⋅OH scavenger, can effectively protect animals against ROS-induced tissue damage. In like manner, we hypothesize that hydrogen may have a protective effect against stress ulceration. Gastric ulceration was induced by the method of cold restraint stress. Rats in the hydrogen treatment group received hydrogen-rich saline (10mL/kg body weight) 5min before the stress. At 6h post-stress, gastric corpus mucosa was harvested for the measurement of malondialdehyde, protein carbonyl, 8-hydroxy-desoxyguanosine, glutathione, superoxide dismutase, myeloperoxidase, TNF-α, IL-1β and cytokine-induced neutrophils chemoattractant-1. In addition, western blotting was used to determine the expression of p38 MAPK, P-p38 MAPK, P-JNk, JNK, Bcl-xl, Bax and cleaved caspase-3. Nuclear translocation of NF-κB was assessed by electrophoretic mobility shift assay. Gastric mucosa structure and mucosal epithelial cells apoptosis were measured at 12h post-stress. Our present study showed that hydrogen treatment lessened the stress-induced lipid peroxidation, protein carbonyl and DNA oxidant and improved tissue antioxidant potential. In addition, hydrogen mitigated inflammatory response and neutrophils infiltration with suppressing the activity of P-p38 MAPK, P-JNk and NF-κB. Importantly, hydrogen ameliorated gastric mucosa damage with preventing cell apoptosis. Furthermore, the up-regulation of cleaved caspase-3, Bax and down-regulation of Bcl-xl expression were blocked by hydrogen treatment. In conclusion, hydrogen treatment effectively ameliorated stress-associated gastric mucosa damage via its anti-oxidant, anti-inflammatory and anti-apoptotic effects.

Effect of Bone Morphogenetic Protein-2 on Proliferation and Apoptosis of Gastric Cancer Cells

Objective: To investigate the effects of bone morphogenetic protein-2 (BMP-2) on the proliferation, differentiation and apoptosis of normal human gastric mucosal cells and gastric cancer cells.Methods: Poorly differentiated gastric cancer BGC823 cells, moderately differentiated gastric cancer cells and normal human gastric mucosal epithelial GES-1 cells were independently treated with recombinant human BMP-2 or its inhibitor Noggin. MTT assay was performed to detect the proliferation, flow cytometry done to measure the cell cycle and apoptosis and immunohistochemistry carried out to determine the expression of cyclin-dependent kinase 4 (CDK4).Results: BMP-2 exerted inhibitory effect on the growth of all types of cells and the inhibition become more evident with the increase of BMP-2 dose. After treatment with 200 ng/ml BMP-2, cancer cells arrested in G1 phase and those in S phase reduced. Gastric cancer cells had higher CDK4 expression than GES-1 cells. BMP-2 decreased CDK-4 expression in cancer cells but had no influence in GES-1 cells. Noggin conferred promotive effect on the growth of 3 types of cells. In 2 types of cancer cells, treatment with 2000 ng/ml Noggin significantly increased the proportion of cells in S phase but reduced that in G1 phase. However, Noggin did not affect the cell cycle of GES-1 cells. The CDK4 expression was markedly increased in 2 types of cancer cells but that of GES-1 remained unchanged after treatment with 2000 ng/ml Noggin.Conclusions: BMP-2 may inhibit the proliferation of both normal and malignant gastric epithelial cells, down-regulate CDK4 expression in gastric cancer cells and arrest gastric cancer cells in G1-phase in cell cycle. Through antagonizing BMP-2, Noggin, may accelerate the proliferation of gastric cancer cells. Thus, the abnormality of BMP signaling pathway may play an important role in the pathogenesis of gastric cancer.

Antisense inhibition of gene expression and growth in gram-negative bacteria by cell-penetrating peptide conjugates of peptide nucleic acids targeted to rpoD gene

Gram-negative bacteria (GNB) cause common and severe hospital- and community-acquired infections with a high incidence of multidrug resistance (MDR) and mortality. The emergence and spread of MDR-GNB strains limit therapeutic options and highlight the need to develop new therapeutic strategies. In this study, the peptide (RXR) 4XB- and (KFF) 3K-conjugated peptide nucleic acids (PPNAs) were developed to target rpoD, which encodes an RNA polymerase primary σ 70 that is thought to be essential for bacterial growth. Their antimicrobial activities were tested against different clinical isolates of MDR-GNB in vitro and in infection models. The (RXR) 4XB- and (KFF) 3K- conjugated PNAs were bactericidal against different strains of MDR-GNB in concentration-dependent and sequence-selective manner, whereas a PPNA with a scrambled base sequence had no effect on growth. Among tested PPNAs, (RXR) 4XB conjugate PPNA06 showed more potent and broad spectrum inhibition in multidrug-resistant Escherichia coli, Salmonella enterica, Klebsiella pneumoniae, and Shigella flexneri in vitro and in vivo. The results were associated with suppression of rpoD mRNA and σ 70 expression, as well as σ 70 downstream regulated genes including ftsZ, mazF, prfB, rpoS, seqA, turfB and ygjD. The treatment of PPNA06 on mono- or multiple MDR-GBN infected human gastric mucosal epithelial cells demonstrated the complete inhibition on bacterial growth and no influence on morphology and growth of human cells. Also, PPNA06 did not show the induction of antibiotic resistance as compared with classical antibiotics in GNB. These findings firstly demonstrate that rpoD is potential target for developing antisense antibiotics, and indicate that peptide conjugates of anti- rpoD PNA are active against GNBs in vitro and in vivo. Our results offer a feasible strategy for treating MDR-GNB infections.

A study of the single SGC7901 and GES1 cell using synchrotron infrared microspectroscopy and imaging

In order to obtain unique information of the single gastric cancer cell and investigate gastric cancer further at the cellular and subcellular level, synchrotron infrared (SR-IR) microspectroscopy and imaging was used to study human gastric adenocarcinoma cell line SGC7901 and normal gastric mucosal epithelial cell line GES1. When we compared the infrared micro-spectra of the SGC7901 cells with those of the GES1 cells, the peak height ratios of 1121 cm −1/1020 cm −1 (RNA/DNA) of the SGC7901 cells were significantly higher than those of the GES1 cells, which might be useful for distinguishing malignant cells from normal cells. Furthermore, chemical imaging reveals that the amide II/the amide I ratio of the SGC7901 cell is lower than that of the GES1 cell in the most intense absorption region of v as PO 2 - . The result indicates the study of the single gastric cancer cell at subcellular level by synchrotron infrared microspectroscopy and imaging can provide more detailed information which is very helpful for the research and diagnosis of gastric cancer.

Delayed production of arachidonic acid contributes to the delay of proteinase‐activated receptor‐1 (PAR1)‐triggered prostaglandin E2 release in rat gastric epithelial RGM1 cells

Proteinase-activated receptor-1 (PAR1), upon activation, exerts prostanoid-dependent gastroprotection, and increases prostaglandin E(2) (PGE(2)) release through cyclooxygenase-2 (COX-2) upregulation in rat gastric mucosal epithelial RGM1 cells. However, there is a big time lag between the PAR1-triggered PGE(2) release and COX-2 upregulation in RGM1 cells; that is, the former event takes 18 h to occur, while the latter rapidly develops and reaches a plateau in 6 h. The present study thus aimed at clarifying mechanisms for the delay of PGE(2) release after PAR1 activation in RGM1 cells. Although a PAR1-activating peptide, TFLLR-NH(2), alone caused PGE(2) release at 18 h, but not 6 h, TFLLR-NH(2) in combination with arachidonic acid dramatically enhanced PGE(2) release even for 1-6 h. TFLLR-NH(2) plus linoleic acid caused a similar rapid response. CP-24879, a Δ(5)/Δ(6)-desaturase inhibitor, abolished the PGE(2) release induced by TFLLR-NH(2) plus linoleic acid, but not by TFLLR-NH(2) alone. The TFLLR-NH(2)-induced PGE(2) release was not affected by inhibitors of cytosolic phospholipase A(2) (cPLA(2)), Ca(2+)-independent PLA(2) (cPLA(2)) or secretory PLA(2) (sPLA(2)), but was abolished by their mixture or a pan-PLA(2) inhibitor. Among PLA(2) isozymes, mRNA of group IIA sPLA(2) (sPLA(2)-IIA) was upregulated following PAR1 stimulation for 6-18 h, whereas protein levels of PGE synthases were unchanged. These data suggest that the delay of PGE(2) release after COX-2 upregulation triggered by PAR1 is due to the poor supply of free arachidonic acid at the early stage in RGM1 cells, and that plural isozymes of PLA(2) including sPLA(2)-IIA may complementarily contribute to the liberation of free arachidonic acid.

Gastric cryptosporidiosis in farmed Australian Murray cod, Maccullochella peelii peelii

Protozoa morphologically consistent with Cryptosporidium sp. were histologically-evident in the stomach of three cohorts of Murray cod ( Maccullochella peelii peelii) from a single aquaculture facility in Australia. One cohort was asymptomatic. A second cohort had shown low-level mortalities, reduced appetite, and slowed growth, and fluid distension of the stomach and small intestine. Fish of the third cohort, sampled a year following diagnosis of the second cohort, were of stunted size and had displayed abnormal swimming behaviour. Microscopically, infection was associated with mild to moderate gastric mucosal mononuclear leukocyte infiltrate and occasional gastric mucosal epithelial cell necrosis and sloughing. Cryptosporidium molnari was confirmed in one cohort using SSU rDNA phylogenetic reconstruction with all available Cryptosporidium genotypes in fish. This study is the first to report Cryptosporidium sp. infection in Murray cod. Associated pathology and clinical signs highlight the possibility of production losses for the affected industry.

The relationship between Helicobacter pylori infection and the expression of TGF-β1 and B7-H1 in gastric mucosal epithelial cells

Objective To explore the influence of different dose of Helicobacter pylori on the expression of transforming growth factorβ(TGF-β1) and B7-H1 in the infected gastric mucosal epithelial cell and the bacterial factors which influence the expression of TGF-β1.To confirm that H.pylorican induce the expression of TGF-β1 and B7-H1 to inhibit the host immune function in gastric mucosal epithelial cell.Methods (1) We investigated the expression of TGF-β1 of human gastric mucosal epithelial cells infected with different concentration(1.0 × 109 CFU/ml,4.0 × 109 CFU/ml,8.0 × 109 C FU/ml) of H.pylori(NCTC 11637) in different time-point(0 h,0.5 h,1 h,1.5 h,2 h,4 h,8 h,12 h),and compared with the expression of TGF-β1 between the deactivated H.pylori group and activated H.pylori group.The blank group is the gastric mucosa epithelial cells which does not infect H.pylori.To detect expression of TGF-β1 in infected cell culture supernatant by enzyme-linked immunosorbent assay(ELISA) and the expression of B7-H1 mRNA by in situ hybridization.(2)At the same time,the middle concentration of deactivated H.pyloriand in vitro gastric mucosal cells were incubated for 2 h and 12 h,to detect expression of TGF-β1 in the cells and cell culture supernatant.(3)In vitro gastric mucosal cells were incubated with H.pylori bacterial supernatant and sedimentation by ultrasonic crushing and centrifugation and with H.pyloribacterial supernatant and sedimentation after boiling respectively,to detect expression of TGF-β1 in the cells and cell culture supernatant after 2 h,12 h.Results (1)Compared to the control group,the expression of TGF-β1 was significantly increased after stimulation with different concentration of activated H.pylori in different time-point(P ＜0.05).The expression of TGF-β1 secretion group has a similar dynamic trend,and the highest expression is the middle concentration group(P ＜0.05).(2)There was no difference between the middle concentration of deactivated H.pylori group and the same concentration of activated H.pylorigroup(P ＞ 0.05).(3) The expression of TGF-β1 in the H.pylori bacterial supernatant group was significantly increased higher than the blank group and the H.pylori bacterial sedimentation group(P ＜0.05),and the H.pylori bacterial supernatant group after boiling was significantly lower than the H.pylori bacterial supernatant group(P ＜ 0.05),but there was no difference between H.pylori sedimentation group after boiling and not boiling(P ＞ 0.05).The B7-H1 expression of different concentration groups which the H.pylori and gastric mucosal epithelial cells cocultured 12 h are higher than the blank group(P ＜ 0.05) by in situ hybridization,and the middle concentration group is the highest expression.TGF-β1 and B7-H1 mRNA are positively correlated(r,=0.628,P ＜0.01).Conclusion H.pylori can induce the gastric mucosal epithelial cells to express the TGF-β1,the factor was the soluble protein in the H.pylori thalline.At the same time,H.pylorican induce the B7-H1 expression increased.In gastric mucosal epithelial cells,TGF-β1 and B7-H1 mRNA are positively correlated.So H.pylori can inhibit the host immune response and participate the process of immune escape by increased the expressions of TGF-β1 and B7-H1. Key words: Helicobacter pylori; Transforming growth factor β1; B7-H1; Gastric mucosal epithelial cells; Immune escape

Selective gene expression by rat gastric corpus epithelium

The gastrointestinal (GI) tract is divided into several segments that have distinct functional properties, largely absorptive. The gastric corpus is the only segment thought of as largely secretory. Microarray hybridization of the gastric corpus mucosal epithelial cells was used to compare gene expression with other segments of the columnar GI tract followed by statistical data subtraction to identify genes selectively expressed by the rat gastric corpus mucosa. This provides a means of identifying less obvious specific functions of the corpus in addition to its secretion-related genes. For example, important properties found by this GI tract comparative transcriptome reflect the energy demand of acid secretion, a role in lipid metabolism, the large variety of resident neuroendocrine cells, responses to damaging agents and transcription factors defining differentiation of its epithelium. In terms of overlap of gastric corpus genes with the rest of the GI tract, the distal small bowel appears to express many of the gastric corpus genes in contrast to proximal small and large bowel. This differential map of gene expression by the gastric corpus epithelium will allow a more detailed description of major properties of the gastric corpus and may lead to the discovery of gastric corpus cell differentiation genes and those mis-regulated in gastric carcinomas.

CCN1 induces a reversible epithelial–mesenchymal transition in gastric epithelial cells

CCN1 is a matricellular protein that activates many genes related to wound healing and tissue remodeling in fibroblasts, but its effect on epithelial cells remains unclear. This study examined the role of CCN1 in epithelial wound healing using rat gastric epithelial cells and rat stomach ulcer as in vitro and in vivo models, respectively. We found that CCN1 expression is highly upregulated in the epithelial cells adjacent to a wound and remains high until the wound is healed. Upregulation of CCN1 activates a transient epithelial–mesenchymal transition in the epithelial cells at the migrating front and drives wound closure. Once the wound is healed, these epithelial cells and their progeny can resume their original epithelial phenotype. We also found that CCN1-induced E-cadherin loss is not due to transcriptional regulation but rather protein degradation due to the collapse of adherens junctions, which is contributed by β-catenin translocation. CCN1-activated integrin-linked kinase mediates this process. Finally, our in vivo study showed that locally neutralizing CCN1 drastically impairs wound closure, whereas local injection of recombinant CCN1 protein induces expression of vimentin and smooth muscle α-actin in normal gastric mucosal epithelial cells and accelerates re-epithelialization during ulcer healing. In conclusion, our study indicates that CCN1 can induce reversible epithelial–mesenchymal transition, and this feature may have great value for clinical wound healing.

Suppression of PTP1B in gastric cancer cells in vitro induces a change in the genome‐wide expression profile and inhibits gastric cancer cell growth

PTP1B (protein tyrosine phosphatase 1B) is a member of the superfamily of PTPs (protein tyrosine phosphatases) and has been implicated in cancer pathogenesis. However, the role of PTP1B in gastric cancer is still unknown. Here, we first detected the PTP1B expression in six gastric cancer cell lines and in the immortalized gastric mucosal epithelial cell line GES-1 by RT-PCR and Western blot. Then, we measured the change of the genome-wide expression profile in MKN28 gastric cancer cells transfected with a plasmid expressing PTP1B-specific small interfering RNA by microarray analysis. Our results showed that PTP1B was overexpressed in gastric cancer cells, and inhibition of PTP1B expression dramatically inhibited gastric cancer cell growth in vitro and in vivo. In addition, microarray analysis revealed that inhibition of PTP1B induced changes in the genome-wide expression profile. These changes may be related to cell growth. Taken together, our data suggested that PTP1B may be a candidate oncogene in gastric cancer.

Influence of IL1B polymorphism on CpG island hypermethylation in Helicobacter pylori-infected gastric cancer

Helicobacter pylori infection can induce aberrant CpG island hypermethylation in gastric mucosal epithelial cells. Single nucleotide polymorphisms of proinflammatory cytokine genes encoding for interleukin 1B (IL1B), IL6, and IL8 have been demonstrated to be associated with an increased risk of gastric cancer. To identify the influence of host genetic factors in CpG island hypermethylation induced by H. pylori infection, we analyzed H. pylori-infected chronic gastritis (n = 111) and gastric cancer samples (n = 78) for the methylation status of eight genes previously shown to be hypermethylated in chronic gastritis and single nucleotide polymorphisms of IL1B, IL6, and IL8. The methylation levels were then compared between different genotypes. Gastric cancers from patients with the IL1B-511T/T allele showed significantly higher methylation levels in five genes as compared with gastric cancers from IL1B-511 C carriers (P < 0.05). An increased level of hypermethylation in association with the IL1B-511T/T allele was observed in chronic gastritis samples, but the association was not statistically significant. These findings suggest that the IL1B-511T/T allele is associated with enhanced hypermethylation of multiple CpG island loci, which might contribute to an increase in the risk for gastric cancer in individuals with H. pylori infection and IL1B-511T/T allele.