Human AGS Cells Research Articles

Lycopene induces apoptosis by inhibiting nuclear translocation of β-catenin in gastric cancer cells.

Reactive oxygen species (ROS) promote the development and progression of cancer by their effects on several signaling pathways. Lycopene, a major carotenoid natural product, is known to display antioxidant activity and to induce apoptosis of cancer cells. The aim of the present study was to investigate the mechanism by which lycopene induces apoptosis of the human gastric cancer AGS cells. In the present study, we showed that lycopene reduces the viability of AGS cells by inducing DNA fragmentation and increasing the Bax/Bcl-2 ratio. To determine the mechanistic basis for these effects, studies were conducted to assess the effects of this carotenoid on activation and nuclear translocation of β-catenin, and the expression of β-catenin target genes in AGS cells. The results showed that lycopene reduces the levels of ROS. It also inhibits activation of β-catenin signaling by changing the Wnt/β-catenin multi-protein complex such as a reduction in phosphorylation of glycogen synthase kinase 3β [GSK3β] and an increase in adenomatous polyposis coli [APC] and β-transducin repeats-containing proteins [β-TrCP]). It suppresses nuclear translocation of β-catenin and the expression of the β-catenin target survival genes c-myc and cyclin D1. Lycopene induces apoptosis by reducing ROS levels and suppressing β-catenin-c-myc/cyclin D1 axis. Thus, lycopene induces apoptosis of gastric cancer cells by disrupting nuclear translocation of β-catenin and expression of key cell survival genes.

In vitro effects of two major phenolic compounds from the family Lamiaceae plants on the human gastric carcinoma cells.

Phenolic compounds of essential oils from the family Lamiaceae are commonly used substances in the food industry because of their flavouring, antimicrobial and antioxidant properties. In this context, it has become important to have healthy and safe products for consumers who are exposed to these phenolic compounds. The present study was aimed to investigate the toxic effects of carvacrol, thymol and their mixture on human gastric carcinoma (AGS) cells. Cells were analyzed after 24 h of exposure to different concentrations of carvacrol, thymol and their mixture by the ATP cell viability, 2',7' dichlorodihydrofluorescein diacetate (H2DCF-DA), reducte glutatione/oxide glutathione((GSH)/GSSG-Glo) and comet assays. Apoptosis induction was studied by acridine orange/ethidium bromide staining and western blotting. Carvacrol, thymol and their mixture induced cytotoxicity, genotoxicity, apoptosis, increased reactive oxygen species (ROS) and decreased GSH levels after 24 h of their exposure in a dose-dependent manner. A close negative relationship was found between cell viability and ROS generation. We examined dose-dependent cytotoxic effects of carvacrol, thymol and their mixture in human AGS cells. Increased intracellular ROS causes oxidative stress in cells. The results indicated that these compounds should be used carefully in the food industry.

Discovery of 9H-purins as potential tubulin polymerization inhibitors: Synthesis, biological evaluation and structure−activity relationships

Two series of N-(4-methoxyphenyl)-N-methyl-9H-purin-6-amines (9a-d and 10a-h) and 9-substituted benzyl-6-chloro-9H-purines (11a-h) were designed and synthesized. Their antiproliferative activities against human myelogenous leukemia (K562), human neuroblastoma (SH-SY5Y) and gastric cancer (AGS) cell lines were evaluated using the MTT assay. The preliminary results indicated that compounds 9d and 11e-h displayed low-micromole GI50 values against all tested cell lines. In addition, compounds 10b and 10d showed wonderful antiproliferative activities towards SH-SY5Y cells with selectivity of >230-fold over K562 and AGS cells. Among them, compounds 9d, 10b, 10d and 11g with good antitumor activities exhibited high selectivity for tumor cell lines over immortalized mouse hippocampal (HT22) cell line. Moreover, compound 9d with sub-micromole GI50 values toward AGS cells exhibited moderate tubulin polymerization inhibitory activity, and induced apoptosis at G2/M phase arrest with a dose-dependent manner in the human AGS cells.

Phenolics from the Patagonian currants Ribes spp.: Isolation, characterization and cytoprotective effect in human AGS cells

The South American currants (Ribes spp.) are native species occurring in southern Chile and Argentina. Ripe fruits from Ribes cucullatum, Ribes magellanicum, Ribes punctatum and Ribes trilobum were investigated for antioxidant activity and phenolic constituents. The fruit extracts were submitted to membrane chromatography to separate the anthocyanins and copigments. Individual anthocyanins were isolated by high-performance counter-current chromatography and were identified as cyanidin-3-rutinoside, cyanidin-3-glucoside, delphinidin-3-glucoside and delphinidin-3-rutinoside. The main compound in the copigment fraction was 3-caffeoylquinic acid. Around 60 compounds were tentatively identified by HPLC-DAD-MS/MSn. The fruit phenolics comprise 23 anthocyanins, 13 hydroxycinnamic acids (HCA) and 23 flavonols. From the polymeric fraction, (epi)-gallocatechin and (epi)catechin tetramers were identified after thiolytic depolimerization.Significant cytoprotection was exhibited by the extracts, anthocyanins and copigments against oxidative and dicarbonyl-induced stress in human gastric AGS cells. This study provides evidence on the potential of native Chilean currants as functional foods.

Sulforaphene promotes Bax/Bcl2, MAPK-dependent human gastric cancer AGS cells apoptosis and inhibits migration via EGFR, p-ERK1/2 down-regulation.

Gastric cancer migration and invasion considered as main causes of this cancer-related death around the world. Sulforaphene (4-isothiocyanato-4R-(methylsulfinyl)-1-butene), a structural analog of sulforaphane, has been found to exhibit anticancer potential against different cancers. Our aim was to investigate whether dietary isothiocyanate sulforaphene (SFE) can promote human gastric cancer (AGS) cells apoptosis and inhibit migration. Cells were treated with various concentrations of SFE and cell viability, morphology, intracellular ROS, migration and different signaling protein expressions were investigated. The results indicate that SFE decreases AGS cell viability and induces apoptosis in a dose-dependent manner. Intracellular ROS generation, dose- and time-dependent Bax/Bcl2 alteration and signaling proteins like cytochrome c, Casp-3, Casp-8 and PARP-1 higher expression demonstrated the SFE-induced apoptotic pathway in AGS cells. Again, SFE induced apoptosis also accompanied by the phosphorylation of mitogen-activated protein kinases (MAPKs) like JNK and P-38. Moreover, dose-dependent EGFR, p-ERK1/2 down-regulation and cell migration inhibition at non-toxic concentration confirms SFE activity in AGS cell migration inhibition. Thus, this study demonstrated effective chemotherapeutic potential of SFE by inducing apoptisis as well as inhibiting migration and their preliminary mechanism for human gastric cancer management.

Dexosome from dendritic cells treated with heat-CO2 pneumoperitoneum induced apotosis of human gastric adenocarcinoma AGS cells

Objective To observe the effects of heat-CO2-treated dendritic cells (DC)-derived dexosomes (DEXs) on apoptosis of human gastric adenocarcinoma cell line AGS and investigate the applied value of heat-CO2 pneumoperitoneum during laparoscopic surgery.Methods An in vitro heat-CO2 pneumoperitoneum experimental box was built.After heat-CO2 pneumoperitoneum treatment,the DC-derived DEXs were isolated and identified through TEM and Western blotting.AGS cells were co-cultured with DEXs,apoptosis was examined by Annexin V/propidium iodide (PI) flow cytometry and Hoechst 33258 fluorescent microscopy,and relative Caspase-3 activity was determined by using colorimetric assay.Results DEXs were successfully isolated.Heat-CO2-treated DC-derived DEXs produced evident anti-proliferative effect and the cell proliferation inhibition rate at 1st,2nd,3rd and 4th day was 31.13％,43.28％,51.34％ and 50.32％ respectively.The heat-CO2-treated CD-derived DEXs induced apoptosis of AGS cells.The early apoptosis rate induced by DEXs was 2.3％,5.6％,15.7％ and 36.8％ respectively.The relative viability of AGS cells in heat-CO2-treated DC-derived DEXs group was 171.37％.Conclusion Heat-CO2 treated DC-derived DEXs could significantly inhibit proliferation and induce apoptosis of AGS cells,which may be related to the activation of Caspase-3. Key words: Heat-CO2 ; Dendritic cell; Gastric adenocarcinoma; Apotosis

Peptides from Pisum sativum L. enzymatic protein digest with anti-adhesive activity against Helicobacter pylori: structure-activity and inhibitory activity against BabA, SabA, HpaA and a fibronectin-binding adhesin.

Identification of anti-adhesive peptides against Helicobacter pylori obtained by enzymatic hydrolysis of seed proteins from Pisum sativum L. (Fabaceae). Bioassay-guided fractionation of protein tryptic digest by ultrafiltration, size exclusion chromatography (SEC) and reversed phase chromatography (RPC) were used. Identification of bioactive peptides was achieved by MALDI-TOF-MS. Adhesion of H. pylori was monitored by two different assays, using a quantitative in vitro assay on human AGS cells with evaluation of bacterial binding by flow cytometry, beside a semi-quantitative in situ adhesion assay using FITC-labelled H. pylori on human stomach tissue sections. From two highly active fractions (F3, F3.3) two anti-adhesive peptides (S3, S5) were identified. Neither F3 nor S3 or S5 had any cytotoxic effect against H. pylori. By hemagglutination assay and semiquantitative dot blot overlay assay with immobilized ligands it was shown that F3 interacts specifically with H. pylori adhesins BabA, SabA, HpaA and a fibronectin-binding adhesin, while S3 and S5 inhibit only BabA. It was demonstrated that BabA, usually interacting with carbohydrate motifs such as fucosylated blood group antigens, interacts with the peptide moieties. Bioactive peptides from pea protein could be applied as functional ingredients for protecting infants and children against infections such as H. pylori.

Antibiotic amoxicillin induces DNA lesions in mammalian cells possibly via the reactive oxygen species

Amoxicillin is a commonly prescribed drug for anti- bacterial infection. In this study, we are interested in the effect of the drug on the cellular DNA integrity. Amoxicillin was added to the human or hamster cells in culture, and the DNA lesions induced by the drug were assessed by a comet assay with nuclear extract incubation (Wang et al., 2005 Anal Biochem 337: 70–75). Amoxicillin at 5 mM rapidly induced DNA lesions in human AGS cells. The level of DNA lesions attained a maximum at about 1 h, and then declined steadily and reached almost the basal level at 6 h following the drug treatment. Similar induction pattern of DNA lesions was found with amoxicillin-related antibiotics such as ampicillin but not with the unrelated antibiotics such as kanamycin. For studying the repair kinetics, the cells were treated with amoxicillin for only 1 h and continued culture in the absence of the drug for a certain period of time before subsequent analysis. Repair of the amoxicillin-induced DNA lesions was essentially completed within 4 h. Such repair may not involve nucleotide excision repair (NER) pathway because the repair was completed with similar kinetics in both NER proficient Chinese hamster CHO-K1 cells and its isogenic NER deficient UV24 cells. Instead, the repair may involve base excision repair (BER) pathway because immunodepletion of OGG1/2, glycosylases involved in BER rendered the nuclear extract unable to excise DNA lesions induced by amoxicillin in the modified comet assay. Furthermore, amoxicillin induced intracellular reactive oxygen species (ROS) at the tempo similar to that of DNA lesions induction. Thus, we hypothesize that amoxicillin causes oxidative DNA damage in mammalian cells via ROS.

Expression of 12-lipoxygenase and its inhibitor's effect on proliferation of human AGS cell line

AIM: To investigate the expression of 12-lipoxygenase (12LOX) and the possible effect of its inhibitor on proliferation of human gastric cancer cell line AGS. METHODS: AGS cells were cultured in RPMI-1640 medium with 100 mL/L fetal bovine serum (FBS), 100 kU/L penicillin and 100 kU/L streptomycin. 12-LOX mRNA was analyzed by reverse transcription polymerase chain reaction (RT-PCR). The effect of baicalein on the proliferation of the cells was detected by thiazolyl blue tetrazolium bromide (MTT) method. The morphological changes of cellular and subcellullar structures were observed under inverted microscope and electron microscopy. AO-EB double and TUNEL staining were used to evaluate the apoptotic index of AGS cells.