Human Gastric Adenocarcinoma Epithelial Cell Research Articles

In vitro and in vivo inhibition of Helicobacter pylori by Lactobacilllus paracasei HP7

The efficacy of standard therapeutic strategies for Helicobacter pylori (H. pylori) infection is decreasing over time due to the emergence of drug-resistant strains. As an alternative, the present study investigated the capacity of Lactobacilllus paracasei (L. paracasei) HP7, isolated from kimchi, to inhibit H. pylori growth. The effects of L. paracasei HP7 on H. pylori adhesion and H. pylori-induced inflammation were examined in ACS human gastric adenocarcinoma epithelial cells and a mouse model of H. pylori SS1 infection. L. paracasei HP7 reduced H. pylori adhesion to ACS cells and suppressed the inflammatory response in infected cells by downregulating interleukin-8. H. pylori colonization in the stomach of C57BL/6 mice was demonstrated by rapid urease test, and results showed significant decrease in mice post-treated with L. paracasei HP7. Additionally, L. paracasei HP7 decreased gastric inflammation and epithelial lesions in the stomach of H. pylori-infected mice. These results demonstrate that L. paracasei HP7 treatment can inhibit H. pylori growth and is thus a promising treatment for patients with gastric symptoms such as gastritis that are caused by H. pylori infection.

Apoptotic effect of sodium acetate on a human gastric adenocarcinoma epithelial cell line.

The objective of this study was to investigate the effect of sodium acetate on the viability of the human gastric adenocarcinoma (AGS) epithelial cell line. AGS cells were exposed to a range of concentrations of sodium acetate for different periods of time, and the sodium acetate-induced cytotoxic effects, including cell viability, DNA fragmentation, apoptotic gene expression, and caspase activity, were assessed. The changes in these phenotypes were quantified by performing a lactate dehydrogenase cell viability assay, annexin V staining, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL), and several caspase activity assays. In vitro studies demonstrated that the cytotoxicity of sodium acetate on the AGS cell line were dose- and time-dependent manners. No differences were found between the negative control and sodium acetate-treated cells stained with annexin V and subjected to the TUNEL assay. However, caspase-3 activity was increased in AGS cells exposed to sodium acetate. Overall, it was concluded that sodium acetate exerted an apoptotic effect in AGS cells via a caspase-dependent apoptotic pathway.

Purification and characterization of two bacteriocins from Lactobacillus brevis BK11 and Enterococcus faecalis BK61 showing anti-Helicobacter pylori activity

The aim of this study was to investigate the antimicrobial effects of purified bacteriocins isolated from Lactobacillus brevis BK11 and Enterococcus faecalis BK61 on Helicobacter pylori. After the final purification step, the molecular weights of the purified bacteriocins from L. brevis BK11 and E. faecalis BK61 were estimated to be approximately 6.5 and 4.5 kDa, respectively. Significant decrease in the antimicrobial activity of these bacteriocins was observed when they were treated with several proteolytic enzymes. However, their antimicrobial activity was stable over long periods of storage and a wide range of pH and was relatively heat resistant. The inhibitory spectrum of the bacteriocin produced by L. brevis BK11 strain was quite narrow, whereas the bacteriocin produced from E. faecalis BK61 strain exhibited a broad antimicrobial spectrum against various foodborne pathogens such as Listeria monocytogenes, Escherichia coli O157, and Salmonella enteritidis. Treatment of H. pylori with these bacteriocins significantly reduced the number of cells of the pathogen found adhering to the monolayers of cultured human gastric adenocarcinoma epithelial cell line (p 0.05).

Inhibition of Helicobacter pylori adhesion to human gastric adenocarcinoma epithelial cells by aqueous extracts and pectic polysaccharides from the roots of Cochlospermum tinctorium A. Rich. and Vernonia kotschyana Sch. Bip. ex Walp

In Malian traditional medicine infusions of the roots of Vernonia kotschyana or Cochlospermum tinctorium in water are used for treating gastric ulcer. Helicobacter pylori is known to play a major role in gastric ulcer development, and it was of interest to evaluate a potential anti-adhesive activity towards H. pylori by crude water extracts and isolated polysaccharide fractions from the roots of V. kotschyana and C. tinctorium. The inhibitory effects were examined by an in vitro flow cytometric assay using human gastric adenocarcinoma epithelial cells, where fluorescent-labeled H. pylori were pre-treated with the test fractions. The crude extract Ctw50 from C. tinctorium, containing a mixture of inulin, pectic polysaccharides, phenols and protein, led to a 43% reduction of bacterial attachment. The isolated pectic type fractions CtwA1 and CtwA2 from C. tinctorium, and Vko-I from V. kotschyana resulted in approximately 30% inhibition of H. pylori adhesion. These fractions consist of rhamnogalacturonan backbones with side chains of arabinogalactans and/or arabinans. The low degree of uronic acids in the fractions compared to anti-adhesive polysaccharides reported previously, suggests that the neutral side chains might play a role in the binding of bacterial adhesins. The fraction Vko-III.1 from V. kotschyana consisting mainly of galacturonic acid resulted only in a 19% inhibition of H. pylori adhesion. The anti-adhesive properties shown by the crude water extracts and isolated polysaccharide fractions in the present study might partly explain the anti-ulcer activities by the roots of V. kotschyana and C. tinctorium.

Mitochondrial DNA mutations in gastric endothelial cells induced by extract of helicobacter pylori in vitro

To investigate the relationship between the helicobacter pylori (HP) infection and the genetic instability of mitochondrial DNA (mtDNA) in human gastric adenocarcinoma epithelial cells (AGS). After treated with extracts of HP11638 (CagA+, VacA+) or Hp11638 mutant strain (CagA+, VacA-), AGS cells were collected, and mitochondrial DNA was extracted and Cox-I, Cox-II, Cox-III, ATPase6, ATPase8 and Cytb genes and the D-Loop region were amplified by PCR and then sequenced. The mutation rates of the mtDNA in AGS cells were correlated with the extracts of the two HP strains in a concentration- and time-dependent manner. But the mtDNA mutation rate in AGS cells treated with the HP11638 extract was higher than that treated with the Hp11638 mutant extract. Total of 616 mutations in D-Loop region were detected, including 489 point mutations, 81 insertions and 46 deletions. Among them, 70.9% (437/616) belonged to GC to AT and AT to GC transition. Seventeen out of 20 (85%) AGS cells treated with extract of HP had mutations in 303PolyC, 16184PolyC and 514CA regions of mtDNA D-Loop. No mutation was detected in Cox-I, Cox-II, Cox-III, ATPase6 and ATPase8 genes, three point mutations were found in the Cytb gene. HP can cause the accumulation of mutations in mtDNA, in particular, in the D-Loop region, and the VacA participated in the process.

Modification of Alternative Splicing of Mcl-1 Pre-mRNA Using Antisense Morpholino Oligonucleotides Induces Apoptosis in Basal Cell Carcinoma Cells

Myeloid cell leukemia-1 (Mcl-1, Mcl-1L) is an anti-apoptotic protein of the Bcl-2 family that acts as a critical molecule in apoptosis control. Mcl-1 pre-mRNA can undergo alternative splicing to yield the short isoform, Mcl-1S, which resembles BH3-only pro-apoptotic proteins and induces apoptosis. Overexpression of Mcl-1 may play a role in various human tumors, and Mcl-1 may serve as a target in cancer therapy. In this study, we found an imbalance between the expression levels of Mcl-1L and Mcl-1S in the skin basal cell carcinoma (BCC) cell line when compared with primary keratinocytes. We showed that overexpression of Mcl-1S induces apoptosis in BCC cells. Finally, we showed that Mcl-1 antisense morpholino oligonucleotides (AMOs) can specifically target Mcl-1 pre-mRNA and shift the splicing pattern from Mcl-1L to Mcl-1S mRNA and protein. This shift increases the level of pro-apoptotic Mcl-1S and reduces the level of anti-apoptotic Mcl-1L, which induces apoptosis in BCC cells and AGS cells, a human gastric adenocarcinoma epithelial cell line. Thus, this report provides a strategy for cancer therapy in which AMOs change the alternative splicing pattern of Mcl-1 pre-mRNA and thereby induce apoptosis.

Phosphoproteomic analysis of differential expression of AGS cellular proteins in response to Helicobanter pyiori infection

Objective To research the differential expression of trace phosphorylated proteins in human gastric adenocarcinoma epithelial (AGS) cells infected by Helicobacter pylori. Methods H. pylori 26695 strain infected AGS cells 4 h and AGS cells was cultivated for 4 h as a comparison. The proteins of AGS and comparison AGS cells were extracted. Their phosphorylated proteins were enriched by metal ion af-finity adsorption enrichment techniques. After desalinated and purified the phosphorylated proteins samples were separated by 2-dimensional polyacrylamide gel electrophoresis (2-DE) technique. Computer assisted image analysis was used to analyze the differential proteomic expression. The significantly differentially ex-pressed proteins were unambiguously assigned identities by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF/TOF). Results Fifteen kinds of proteins were down-regulated, 4 kinds of new proteins were observed, 1 kind of proteins were up-regulated, 1 kind of proteins unexpression. The 21 proteins that were significantly differentially expressed , including cellular calcium ion homeostasis, transcription, interpretation, protein folding and transport, ribosomal assembly, centrosome replication, chromosome stability, cellular structure, cellular proliferation and apoptosis. Conclusion H. priori can cause a wide range change to human gastric adenocarcinoma epithelial cell protein pheshorylation. This change character has great significance to further comprehensive understanding of the pathogenesis of H. pylori. Key words: Affinity adsorption; Phosphorylated proteins; 2-DE; Pathogenic mechanism

Sodium nitrite-induced cytotoxicity in cultured human gastric epithelial cells

To investigate the effect of sodium nitrite on the viability of the human gastric adenocarcinoma epithelial cell line, AGS, cultured AGS cells were exposed to various concentrations of sodium nitrite for 24, 48 or 72 h. The cytotoxic response was assessed using a cell proliferation assay, and the extent of the response was evaluated on the basis of intracellular and extracellular levels of interleukin 1β (IL-1β), interleukin 6 (IL-6), interleukin 8 (IL-8) and tumor necrosis factor (TNF-α). Both mRNA and protein levels were measured for each cytokine. Sodium nitrite had a significant effect on AGS cell proliferation after a 72-h exposure. At low sodium nitrite concentrations (up to 6.25 mM), cell proliferation increased in a dose-dependent manner; however, exposure to higher concentrations resulted in a dose-dependent decrease in cell proliferation. Sodium nitrite at a low concentration (6.25 mM) increased IL-8 release, whereas IL-1β, IL-6, and TNF-α release increased only after exposure to high sodium nitrite concentration (25 mM). Our data demonstrate that sodium nitrite can induce the release of these inflammatory cytokines and that high concentrations of sodium nitrite decrease AGS cell proliferation.

Inhibition of Helicobacter pylori adhesion to human gastric adenocarcinoma epithelial cells by acidic polysaccharides from Artemisia capillaris and Panax ginseng.

Helicobacter pylori specifically adheres to host cells, mainly based on carbohydrate-mediated cell-cell interactions. Previously, we investigated the anti-adhesive effect of polysaccharide fractions from Artemisia capillaris and Panax ginseng, using hemagglutination and enzyme-linked glycosorbent assays. In the present study, each active polysaccharide fraction was further purified, resulting in a single peak (fraction F2) using gel filtration FPLC, in which no protein content was detectable. Using scanning electron microscopy, we examined the inhibitory effects of these polysaccharides on the attachment of H. pylori to the human gastric adenocarcinoma epithelial cell line. The bacterial attachment to the cell line was inhibited by these polysaccharides in the range of the concentrations studied (0.2 - 2.8 mg/mL), showing their minimum inhibitory concentration at as low as 0.2 mg/mL. The bacterial binding was inhibited more effectively by P. ginseng polysaccharides, than by those from A. capillaris. The purified polysaccharides contain similar sugar compositions and have high amounts of uronic acids. Our results suggest that acidic carbohydrates may play an important role in the inhibitory activity on H. pylori adhesion to host cells and that our established purification protocol can be applied to obtain active acidic polysaccharides from plant sources.