Bile acids inhibit ferroptosis sensitivity through activating farnesoid X receptor in gastric cancer cells

BACKGROUND Gastric cancer(GC)is associated with high mortality rates.Bile acids(BAs)reflux is a well-known risk factor for GC,but the specific mechanism remains unclear.During GC development in both humans and animals,BAs serve as signaling molecules that induce metabolic reprogramming.This confers additional cancer phenotypes,including ferroptosis sensitivity.Ferroptosis is a novel mode of cell death characterized by lipid peroxidation that contributes universally to malignant progression.However,it is not fully defined if BAs can influence GC progression by modulating ferroptosis.AIM To reveal the mechanism of BAs regulation in ferroptosis of GC cells.METHODS In this study,we treated GC cells with various stimuli and evaluated the effect of BAs on the sensitivity to ferroptosis.We used gain and loss of function assays to examine the impacts of farnesoid X receptor(FXR)and BTB and CNC homology 1(BACH1)overexpression and knockdown to obtain further insights into the molecular mechanism involved.RESULTS Our data suggested that BAs could reverse erastin-induced ferroptosis in GC cells.This effect correlated with increased glutathione(GSH)concentrations,a reduced GSH to oxidized GSH ratio,and higher GSH peroxidase 4(GPX4)expression levels.Subsequently,we confirmed that BAs exerted these effects by activating FXR,which markedly increased the expression of GSH synthetase and GPX4.Notably,BACH1 was detected as an essential intermediate molecule in the promotion of GSH synthesis by BAs and FXR.Finally,our results suggested that FXR could significantly promote GC cell proliferation,which may be closely related to its anti-ferroptosis effect.CONCLUSION This study revealed for the first time that BAs could inhibit ferroptosis sensitivity through the FXR-BACH1-GSHGPX4 axis in GC cells.This work provided new insights into the mechanism associated with BA-mediated promotion of GC and may help identify potential therapeutic targets for GC patients with BAs reflux.

Ellagic acid inhibits gastric cancer cells by modulating oxidative stress and inducing apoptosis

Objective:To evaluate the anticancer effect of ellagic acid on gastric cancer cells.Methods:MTT assay was used to evaluate the effect of ellagic acid at different concentrations(0.5-100μg/mL)on gastric cancer AGS cells.RT-qPCR and Western blot analyses were applied to assess apoptosis(BCL-2,CASP-3,and BAX)and autophagy(LC3,ATG5,and BECN1)in AGS cells treated with ellagic acid.The expression of invasion-related markers including TP53,CDKN2A,and PTEN was determined.In addition,cell cycle markers including cyclin A,B,D,and E were measured by ELISA.Oxidative stress markers were evaluated using spectrophotometry.Results:Ellagic acid inhibited the proliferation of AGS cells in a concentration-and time-dependent manner.The expression of BCL-2 was significantly decreased(P<0.05)and CASP-3 and BAX were markedly increased(P<0.01)in AGS cells treated with ellagic acid.However,this compound induced no significant changes in the expression levels of LC3,ATG5,and BECN1(P>0.05).Moreover,the oxidative stress markers including SOD,TAC,and MDA were increased by ellagic acid(P<0.01).Conclusions:Ellagic acid can inhibit cell proliferation,induce apoptosis,and modulate oxidative stress in AGS cells.However,further in vivo and molecular studies are needed to verify its anticancer efficacy.

Mechanism of pachymic acid in the treatment of gastric cancer based on network pharmacology and experimental verification

BACKGROUND Pachymic acid(PA)is derived from Poria cocos.PA has a variety of pharmacological and inhibitory effects on various tumors.However,the mechanism of action of PA in gastric cancer(GC)remains unclear.AIM To investigate the mechanism of PA in treating GC via the combination of network pharmacology and experimental verification.METHODS The GeneCards and OMIM databases were used to derive the GC targets,while the Pharm Mapper database provided the PA targets.Utilizing the STRING database,a protein-protein interaction network was constructed and core targets were screened.The analyses of Gene Ontology,Kyoto Encyclopedia of Genes and Genomes(KEGG),and gene set enrichment analysis were conducted,and molecular docking and clinical correlation analyses were performed on the core targets.Ultimately,the network pharmacology findings were validated through in vitro cell assays,encompassing assessments of cell viability,apoptosis,cell cycle,cloning,and western blot analysis.RESULTS According to network pharmacology analysis,the core targets were screened,and the PI3K/AKT signaling pathway is likely to be the mechanism by which PA effectively treats GC,according to KEGG enrichment analysis.The experimental findings showed that PA could control PI3K/AKT signaling to prevent GC cell proliferation,induce apoptosis,and pause the cell cycle.CONCLUSION Network pharmacology demonstrated that PA could treat GC by controlling a variety of signaling pathways and acting on a variety of targets.This has also been supported by in vitro cell studies,which serve as benchmarks for further research.

Naloxone or Vagotomy Does Not Influence Centrally Octreotide-induced Inhibition of Gastric Acid Secretion in Rats

Summary： To investigate the effect of preceding naloxone injection into the third cerebroventricle or acute subdiaphragmatic vagotomy on the gastric acid secretion inhibited by the somatostatin analogue octreotide given by intracerebroventricular （icv） injection. The third ventricles were cannulated in male Wistar rats anesthetized with sodium pentobarbital. One week later, acute gastric lumen perfusion was carried out. The gastric perfusion samples were collected every 10 min and were titrated by 0.01 mol/L NaOH to neuter. On the basis of subcutaneous injection of pentagastrin （G-5, 160 g/kg）, icv injection of physiological saline （group A, n=20）, icv injection of octreotide （0.05 μ g） （group B, n=20）, icv injection of naloxone （2.5 μ g）＋octreotide （0.05 μg） （group C, n=20）, acute subdiaphragmatic vagotomy＋ icv injection of physiological saline （group D, n=20）, or acute subdia- phragrnatic vagotomy＋icv injection of octreotide （0.05 μg） （group E, n=20） were conducted. Before and after icv injection, 1-h total acid output （TAO） was determined and compared. The experimental data were expressed in change rate （%） of TAO. The change rates （%） of TAO were 4.60 % in group A, -20.35 % in group B, - 18.06 % in group C, 5.01% in group D and -21.59 % in group E, respectively. Comparison of group B or C versus group A showed that P〈0.01 and comparison between the group E versus group D showed that P〈0.01. Whereas the differences between group C and group B, group E and group B were not statistically significant （P〉0.05 for all）. The results indicate that the central inhibition of gastric acid secretion by octreotide may not be mediated by the endogenous opi- ate substance or its receptor and the peripheral pathway for icv injection of octreotide to suppress gastric acid secretion is via extra-vagus route.

Peripheral mechanism of inhibitory effect of centrally administrated histamine on gastric acid secretion

AIM To study the peripheral mechanism of the inhibitory effect of intra third ventricular administration (icv) of histamine (HA) on gastric acid secretion in rats. METHODS Gastric acid was continuously washed with 37℃ saline by a perfusion pump in male adrenalectomized SD rats. Drugs were injected intravenously (iv) by a syringe pump and their effect on pentagastrin induced (10μg·kg·h, iv) gastric acid secretion was observed. RESULTS The inhibitory effect of HA (1μg, icv) on gastric acid secretion was blocked by subdiaphragmatic vagotomy, and pretreatment with atropine (0 005mg·kg·h, iv). Pretreatment with somatostatin antagonist, cyclo [7 aminoheptanoyl Phe D Trp Lys Thr(Bzl)], ( 2μg - 4μg ·kg· 100min , iv) could also block the inhibitory effect of HA on gastric acid secretion in a dose dependent manner. CONCLUSION The inhibitory effect of centrally administrated HA on gastric acid secretion may be mediated by vagi, acetylcholine M receptor and somatostatin.

Ghrelin and gastric acid secretion

Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when administered peripherally or centrally. Ghrelin is also known to stimulate the gastric motility and the secretion of gastric acid. In the previous studies, the action of ghrelin on acid secretion was shown to be as strong as that of histamine and gastrin in in-vivo experiment. In the studies, the mechanism for the action of ghrelin was also investigated. It was shown that vagotomy completely inhibited the action of ghrelin on the secretion of gastric acid suggesting that vagal nerve is involved in the mechanism for the action of ghrelin on acid secretion. As famotidine did not inhibit ghrelin-in-duced acid secretion in the study by Masuda et al, they concluded that histamine was not involved in the action of ghrelin on acid secretion. However, we have shown that famotidine completely inhibited ghrelin-induced acid secretion and histidine decarboxylase (HDC) mRNA was increased in gastric mucosa by ghrelin injection which is inhibited by vagotomy Our results indicate that histamine is involved in the action of ghrelin on acid secretion. Furthermore synergistic action of gastrin and ghrelin on gastric acid secretion was shown. Although gastrin has important roles in postprandial secretion of gastric acid, ghrelin may be related to acid secretion during fasting period or at night. However, further studies are needed to elucidate the physiological role of ghrelin in acid secretion.

No relationship between IL-1B gene polymorphism and gastric acid secretion in younger healthy volunteers

AIM: To investigate the influence of IL-1B-511 gene polymorphism on IL-1B mRNA expression and gastric acid output in individual with or without Helicobacter pylori (H pylori) infection.METHODS: IL-1B mRNA expression and gastric acid secretion in 117 health volunteers were assayed using semi-quantitative RT-PCR and gastric juice assay, respectively. Pepsinogen (PG) Ⅰ and Ⅱ of 255 subjects (including 117 health volunteers) were also examined.RESULTS: T/T genotype individuals with H pylori infection had a more decreased PG Ⅰ/Ⅱ ratio. In gastric antrum mucosa, the individuals with H pylori infection had higher IL-1B expression than those without H pylori infection, but there was no obvious difference among each genotype. In gastric corpus, the individuals with H pylori infection had a significantly higher IL-1B expression than those without H pylori infection. IL-1B-511T/T genotype was markedly higher as compared with the other two genotypes. Both maximal acid output and basic acid output were similar among each genotype in IL-1B-511 gene locus, regardless of H pylori infection.CONCLUSION: IL-1B-511 T allele does not decrease gastric acid output, although it has a stimulated influence on IL-1B expression. Consequently, the pathway,through which IL-1B plays a central role in gastric cancer development, might not depend on low acid, but on the other regulation mechanisms.

Influence of gastric inhibitory polypeptide on pentagastrinstimulated gastric acid secretion in patients with type 2 diabetes and healthy controls

AIM： Gastric inhibitory polypeptide is secreted from intestinal K-cells in response to nutrient ingestion and acts as an incretin hormone in human physiology. While animal experiments suggested a role for GIP as an inhibitor of gastric secretion, the GIP effects on gastric acid output in humans are still controversial. METHODS： Pentagastrin was administered at an infusion rate of 1 μg . kg^-1 . h^-1 over 300 min in 8 patients with type 2 diabetes （2 female, 6 male, 54± 10 years, BMI 30.5 ± 2.2 kg/m^2; no history of autonomic neuropathy） and 8 healthy subjects （2/6, 46 ± 6 years., 28.9 ± 5.3 kg/ m^2）. A hyperglycaemic clamp （140 mg/dl） was performed over 240 min. Placebo, GIP at a physiological dose （1 pmol . kg^-1 . min^-1）, and GIP at a pharmacological dose （4 mol . kg^-1 . min^-1） were administered over 60 min each. Boluses of placebo, 20 pmol GIP/kg, and 80 pmol GIP/kg were injected intravenously at the beginning of each infusion period, respectively. Gastric volume, acid and chloride output were analysed in 15-min intervals. Capillary and venous blood samples were drawn for the determination of glucose and total GIP. Statistics were carried out by repeated-measures ANOVA and one-way ANOVA. RESULTS： Plasma glucose concentrations during the hyperglycaemic clamp experiments were not different between patients with type 2 diabetes and controls. Steady-state GIP plasma levels were 61 ±8 and 79 ± 12 pmol/I during the low-dose and 327±35 and 327± 17 pmol/I during the high-dose infusion of GIP, in healthy control subjects and in patients with type 2 diabetes, respectively （P= 0.23 and p 0.99）. Pentagastrin markedly increased gastric acid and chloride secretion （P〈 0.001）. There were no significant differences in the rates of gastric acid or chloride output between the experimental periods with placebo or any dose of GIP. The temporal patterns of gastric acid and chloride secretion were similar in patients with type 2 diabetes and healthy controls （P= 0.86 and P= 0.61, respectively）. CONCLUSION： Pentagastrin-stimulated gastric acid secretion is similar in patients with type 2 diabetes and healthy controls. GIP administration does not influence gastric acid secretion at physiological or pharmacological plasma levels. Therefore, GIP appears to act as an incretin rather than as an enterogastrone in human physiology.

Effect of somatostatin analogue octreotide injected into the third cerebral ventricle on pentagastrin-induced gastric acid secretion in rats

AIM： To investigate the effect of long-lasting somatostatin analogue octreotide （Oct） injected into the third cerebral ventricle （TCV） on gastric acid secretion in rats. METHODS： TCVs were cannulated in male Wistar rats anesthetized with sodium pentobarbital. One week later acute gastric lumen perfusion was carried out and gastric acid was continuously washed with 37℃ saline by a perfusion pump. Gastric perfusion samples were collected every 10 min and titrated by 0.01 moL/L NaOH to neutral. On the basis of subcutaneous （sc） injection of pentagastrin （G-5, 160 μg/kg）, Oct （0.025 μg, 0.05 μg, 0.1 μg, n=12 in each group） or vehicle （pyrogen-free physiological saline, n = 10） was injected into the TCV, Before and after the TCV injection, 1 h total acid output （TAO） was determined and experimental data were expressed in change rate （%） of TAO. RESULTS： Oct （0.025, 0.05 and 0.1 μg） injected into the TCV resulted in change rate of 1.56% （P〉0.05）, 20.21% （P〈 0.01） and 37.82% of TAO （P〈 0.001）, respectively. Moreover, comparison in change rate of TAO among these 3 doses showed P〈 0.05 between 0.025μg and 0.05 μg, P〈 0.01 between 0.025 μg and 0.ling, and P〈 0.05 between 0.05μg and 0.1 μg. However, sc injection of 0.05 μg Oct had no effect on G-5 stimulated gastric acid secretion. CONCLUSION： Octreotide injected into the third cerebral ventricle inhibits gastrin-induced gastric acid secretion in a dose-dependent manner.

Bravo capsule system optimizes intragastric pH monitoring over prolonged time:Effects of ghrelin on gastric acid and hormone secretion in the rat

AIM: To evaluate measurements of intragastric pH with the Bravo capsule system over a prolonged time.METHODS: A Bravo capsule was placed inside the rat gastric body and pH was studied for periods up to five consecutive days.For comparison,a gastric fistula model was used.Effects of ghrelin and esomeprazole,with or without pentagastrin,on gastric pH were studied.In addition,effects of esomeprazole on plasma ghrelin,gastrin and somatostatin were analyzed.RESULTS: All rats recovered after surgery.The average 24-h pH during free feeding was 2.3 ± 0.1 (n = 20) with a variation of 18% ± 6% over 5 d.Ghrelin,2400 pmol/kg,t.i.d.increased pH from 1.7 ± 0.1 to 3.1 ± 0.3 (P < 0.01) as recorded with the Bravo system.After esomeprazole (1 mg/kg,3 mg/kg and 5 mg/kg) there was a dose-dependent pH increase of maximally 3.4 ± 0.1,with day-to-day variation over the entire period of 8% ± 3%.The fistula and pH studies generated similar results.Acid inhibition with esomeprazole increased plasma ghrelin from 10 ± 2 pmol/L to 65 ± 26 pmol/L (P < 0.001),and somatostatin from 10 ± 2 pmol/L to 67 ± 18 pmol/L (P < 0.001).CONCLUSION: pH measurements with the Bravo capsule are reliable,and comparable to those of the gastric fistula model.The Bravo system optimizes accurate intragastric pH monitoring over prolonged periods and allows both short-and long-term evaluation of effects of drugs and hormones.

Effect of gastric acid secretion for L-pantoprazole sodium in rats

Aim To observe the effect of L-pantoprazole sodium on gastric acid secretion in rats. Methods The rats single injection to the drug on tail after fasting but help water 48h, then threading the pyloric ligation at the junction of the pylorus and duodenum, and the animals were fasted and ban water 5h. We remove the total gastrec- tomy, gastric juice was collected and the amount of the volume, and the determination of total acidity、total acidity secretion^pH value. Results L-pantoprazole sodium and pan pantoprazole sodium can significantly reduce the to- tal acidity secretion volume （P 〈 0.05）, increased gastric pH （P 〈 0.01 ）. D-pantoprazole sodium on gastric acid secretion of gastric juice and total PH had no significant effect （ P 〉 0. 05 ）. Conclusion L-pantoprazole sodiumhas significant inhibition of gastric acid secretion, the mechanism of the treatment of peptic ulcer may be through inhibition of proton pump discharge acid effect, to play a role in the protection of gastric mucosa.

Construction and Expression of Recombinant Ghrelin Plasmid and Effects on Growth Performance and Gastric Acid Secretion of Rats

The paper was to study construction and expression of rGhrelin （pcDNA3 -Ghrelin） and its effect on growth performance and gastric acid secretion of rats. Ghrelin amplified from gastric mucosa of weaned piglets was cloned into the expression vector pcDNA3 to get recombinant plasmid pcDNA3 - Ghrelin. Twelve weaning rats were randomly divided into two groups, six rats each group. The rats in each treatment group were individually injected with 100pg of naked plasmid pcDNA3 -Ghrelin, and the rats in control group were injected with empty plasmid. The weights and feed consumption of rats were measured after injection for 7, 14 and 29 d, respectively. The rats were sacrificed at the end of the experiment, and their stomach was separated and weighed, the pH value of gastric juice was measured as well. The results showed that the average daily gain of rats at 7 and 29 d were significantly higher than that in control group, respectively （P〈0.05）, and feed consumption did not have significant chan- ges; the feed meat ratio of rats in the treatment groups was significantly lower than that in control group （ P 〈0.05） ; the gastric relative weight and gastric weight did not change significantly, while the pH value of gastric juice of rats in treatment groups was significantly lower than that in control group （P 〈 0.05）. This indicated that after transfected expression of muscle tissue, ghrelin played an important regulatory role in growth and gastric acid secretion of rats.

Gastric Mucosal Blood Flow and Acid Secretion in Rats

The relationship between gastric mucosal blood flow (GMBF) and gastric acid secretionwere studied in rats by using secretory stimulant (pentagastrin)and inhibitor(cimetidine). GMBFwas measured by Laser Doppler flowmetry (LDF) and gastric mucosal pH determined by microglasspH electrode. GMBF increased and gastric mucosal pH decreased significantly after intravenous injec-tion of 6μg/kg of pentagastrin; nevertheless GMBF decreased and gastric mucosal pH increasedmarkedly after intravenous administration of 100mg/kg of cimetidine. This indicates that pentagastrincan increase GMBF and gastric acid secretion, and cimetidine can decrease GMBF and gastric acidsecretion in rats, proving the close relationship between GMBF and gastric acid secretion in rats.

Effects of ventromedial hypothalamic somatostatin on gastric somatostatin and acid secretion in rats

The effects of somatostatin and cysteamine injected into theventromedial nucleus of hypothalamus(VMH)on somatostatin-likeimmunoreactivity(SLI)concentration in the gastric antral mucosa and portal veinplasma,as well as the gastric acid secretion were studied in anesthetized rats.TheSLI concentration in the gastric antral mucosa and portal vein plasma and thegastric acid output were significantly increased one hour after the injection ofsomatostatin(0.5μg/0.5μ1)into the VMH.Four hours later,the SLI concentrationin the mucosa was still higher than the control level,while the SLI level in theplasma and the acid secretion were close to those of controls.On the contrary,the SLI concentration in the mucosa and plasma and the acid output weremarkedly decreased at four hours after the injection of cysteamine(15μg/0.5μ1)into the VMH.The present results suggest that both exogenous and endogenoussomatostatin in the VMH have a facilitatory action on the gastric somatostatinconcentration and its release as well as on the gastric acid secretion,thus provid-ing evidence for hypothalamic control of gastric somatostatin and acid secretion.

Effects of Supplemental Histamine on Gastric Acid Secretion, Digestive Enzyme Activities, Intestinal Microfloral of Early Weaned Piglets

Two experiments were conducted to study the effect of supplemental histamine in the diet of early-weaned piglets. In experiment A, 24 cross bred piglets with an average body weight of 6.10±0. 40 kg, weaned at the age of 28 days, were divided into four groups, fed with basal diet of low dietary copper without (control) or with supplemental histamine at 60, 120, 180μg kg-1 BW. During the two weeks and the third week after weaning, ADG(average daily gain) of piglets were increased by 15.8%(P<0. 05), 9.5%(P< 0.10) by addition of 60μg kg-1 BW histamine, but decreased by addition of 180μg kg-1BW histamine, which also increased the amount of E. coli in colon and the scour incidence. The secretion of gastric acid and pepsin were improved by both dose of supplemental histamine (60, 180μg kg-1BW) and gastric digesta pH were decreased by both. Addition of 60 μg kg-1 BW histamine improved the activities of trypsin, amylase in duodelum digesta. In experiment B, 12 cross bred piglets with an average body weight of 6. 85±0.35 kg, weaned at the age of 28 days, were divided into two groups, fed with basal diet of high dietary copper without (control) or with supplemental 60 μg kg-1 BW histamine. During the two weeks and the third week after weaning, ADG of piglets were increased by 9. 8% (P<0.05), 7. 0% (P<0. 10). The secretion of gastric acid, activities of trypsin and amylase in duodelum digesta, were also improved by addition of 60 μg kg-1BW histamine. The results showed that addition of histamine (60μg kg-1BW) in early weaned piglets could increase the secretion of gastric acid and pepsin, reduce gastric digesta pH and scour incidence, improve activities of trypsin, amylase in duodelum digesta, and the growing performance of early weaned piglets.

Physiological and clinical significance of enterochromaffin-like cell activation in the regulation of gastric acid secretion

Gastric acid plays an important role in digesting food （especially protein）, iron absorption, and destroying swallowed micro-organisms. H＋ is secreted by the oxyntic parietal cells and its secretion is regulated by endocrine, neurocrine and paracrine mechanisms. Gastrin released from the antral G cell is the principal physiological stimulus of gastric acid secretion. Activation of the enterochromaffin-like （ECL） cell is accepted as the main source of histamine participating in the regulation of acid secretion and is functionally and trophically controlled by gastrin, which is mediated by gastrin/CCK-2 receptors expressed on the ECL cell. However, longterm hypergastrinemia will induce ECL cell hyperplasia and probably carcinoids. Clinically, potent inhibitors of acid secretion have been prescribed widely to patients with acid-related disorders. Long-term potent acid inhibition evokes a marked increase in plasma gastdn levels, leading to enlargement of oxyntic mucosa with ECL cell hyperplasia. Accordingly, the induction of ECL cell hyperplasia and carcinoids remains a topic of considerable concern, especially in long-term use. In addition, the activation of ECL cells also induces another clinical concem, i.e., rebound acid hypersecretion after acid inhibition. Recent experimental and clinical findings indicate that the activation of ECL cells plays a critical role both physiologically and dinically in the regulation of gastric acid secretion.

Changes of gastric acid secretion after cholangioduodenostomy with artificial papilla and interposed jejunum

The changes of gastric acid secretion and the levels of gastrin(Gn) and somatostatin(SS) in the serum, gastric juice and mucous membrane of pyrolic antrum were determined in 10 cases with cholangioduodenostomy with artificial papilla and interposed jejunum(Inter-JCD) and 28 cases with cholangiojenunostomy with Roux-en-Y (CJR-Y). It was found that the secondary gastric hypersecretion did not occur and the levels of Gn and SS showed no significant changes after Inter-JCD but there was secondary high secretion of gastric acid, significant reduction of the synthesis and release of SS and significant elevation of the synthesis and release of Gn after CJR-Y. These findings indicate that Inter-JCD is superior to CJR-Y since it induces no disturbance of gastric acid secretion postoperatively.

18β-glycyrrhetinic acid inhibits proliferation of gastric cancer cells through regulating the miR-345-5p/TGM2 signaling pathway

BACKGROUND Gastric cancer(GC)is a common gastrointestinal malignancy worldwide.Based on cancer-related mortality,the current prevention and treatment strategies for GC still show poor clinical results.Therefore,it is important to find effective drug treatment targets.AIM To explore the molecular mechanism of 18β-glycyrrhetinic acid(18β-GRA)regulating the miR-345-5p/TGM2 signaling pathway to inhibit the proliferation of GC cells.METHODS CCK-8 assay was used to determine the effect of 18β-GRA on the survival rate of GES-1 cells and AGS and HGC-27 cells.Cell cycle and apoptosis were detected by flow cytometry,cell migration was detected by a wound healing assay,the effect of 18β-GRA on subcutaneous tumor growth in BALB/c nude mice was investigated,and the cell autophagy level was determined by MDC staining.TMT proteomic analysis was used to detect the differentially expressed autophagy-related proteins in GC cells after 18β-GRA intervention,and then the protein-protein interaction was predicted using STRING(https://string-db.org/).MicroRNAs(miRNAs)transcriptome analysis was used to detect the miRNA differential expression profile,and use miRBase(https://www.mirbase/)and TargetScan(https://www.targetscan.org/)to predict the miRNA and complementary binding sites.Quantitative real-time polymerase chain reaction was used to detect the expression level of miRNA in 18β-GRA treated cells,and western blot was used to detect the expression of autophagy related proteins.Finally,the effect of miR-345-5p on GC cells was verified by mir-345-5p overexpression.RESULTS 18β-GRA could inhibit GC cells viability,promote cell apoptosis,block cell cycle,reduce cell wound healing ability,and inhibit the GC cells growth in vivo.MDC staining results showed that 18β-GRA could promote autophagy in GC cells.By TMT proteomic analysis and miRNAs transcriptome analysis,it was concluded that 18β-GRA could down-regulate TGM2 expression and up-regulate miR-345-5p expression in GC cells.Subsequently,we verified that TGM2 is the target of miR-345-5p,and that overexpression of miR-345-5p significantly inhibited the protein expression level of TGM2.Western blot showed that the expression of autophagy-related proteins of TGM2 and p62 was significantly reduced,and LC3II,ULK1 and AMPK expression was significantly increased in GC cells treated with 18β-GRA.Overexpression of miR-345-5p not only inhibited the expression of TGM2,but also inhibited the proliferation of GC cells by promoting cell apoptosis and arresting cell cycle.CONCLUSION 18β-GRA inhibits the proliferation of GC cells and promotes autophagy by regulating the miR-345-5p/TGM2 signaling pathway.

Effect of Lanthanum on Acid Secretion from Isolated Mouse Stomach in Vitro

To explore the effect and the mechanism of La^(3+) on gastric acid secretion (GAS) of isolated mouse stomach with perfused lumen, 12 cm H_2O column intragastric pressure-provided, whole stomach preparations from mice were incubated in buffer at 37 ℃ in vitro, and perfusate was measured for pH with a pHS-3 type pH meter. The results show that La^(3+) (0.41～820×10^(-6) mol·L^(-1)) significantly promotes GAS in a concentration-dependant manner. Proglutamine, a blocker of gastrin receptor, potently inhibits GAS, and it may block the promotive effect of La^(3+) on GAS, and this effect increases with the increase of proglutamin concentration. Cimetidine, a blocker of histamine H_2 receptor, also potently inhibits GAS, and blocks the promotive effect of La^(3+) on GAS in the same manner with proglutamine. These results suggest that La^(3+) promotes GAS in isolated stomach possibly by stimulating the releases of gastrin from G cell and Histamine from ECL cell or by activating the gastrin receptors and Histamine H_2 receptors on the parietal cell, thereby accelerating the acid secretion of parietal cells in stomach.

Aberrant methylation of secreted protein acidic and rich in cysteine gene and its significance in gastric cancer

BACKGROUND Aberrant methylation in DNA regulatory regions could downregulate tumor suppressor genes without changing the sequences.However,our knowledge of secreted protein acidic and rich in cysteine(SPARC)and its aberrant methylation in gastric cancer(GC)is still inadequate.In the present research,we performed fundamental research to clarify the precise function of methylation on SPARC and its significance in GC.AIM To investigate promoter methylation and the effects of the SPARC gene in GC cells and tissues and to evaluate its clinical significance.METHODS Plasmids that overexpressed the SPARC gene were transfected into human GC BGC-823 cells;non-transfected cells were used as a control group(NC group).Quantitative real-time polymerase chain reaction and western blotting(WB)were then used to detect the expression of SPARC.Methylation-specific polymerase chain reaction was executed to analyze the gene promoter methylation status.Cell viability was measured by the cell counting kit-8 assay.The migration and invasion ability of cells were detected by scratch assays and transwell chamber assays,respectively.Cell cycle events and apoptosis were observed with a flow cytometer.RESULTS The expression of SPARC mRNA in GC tissues and cells was significantly lower and showed differing degrees of hypermethylation,respectively,than that in normal adjacent tissues and control cells.Treatment with 5-Aza-2’-deoxycytidine(5-Aza-Cdr)was able to restore the expression of SPARC and reverse promoter hypermethylation.Overexpression of the SPARC gene significantly inhibited proliferation,migration,and invasion of GC cells,while also causing cell cycle arrest and apoptosis;the NC group exhibited the opposite effects.CONCLUSION This study demonstrated that SPARC could function as a tumor suppressor and might be silenced by promoter hypermethylation.Furthermore,in GC cells,SPARC inhibited migration,invasion,and proliferation,caused cell cycle arrest at the G0/G1 phase,and promoted apoptosis.