Search

Epithelial-mesenchymal transition (EMT) plays a crucial role in cancer metastasis. In this study, we evaluated the effect of heat treatment on tumor growth factor-β1 (TGF-β1)-induced EMT in pancreatic cancer cells and tried to ascertain the mechanism related to any observed effects. Human pancreatic cancer cell lines (BxPC-3, PANC-1 and MIAPaCa-2) were stimulated by TGF-β1, and evaluated for morphological changes using immunofluorescence and EMT-related factors (i.e., E-cadherin, Vimentin, Snail or ZEB-1) using RT-PCR. To examine the effect of heat on EMT, the cancer cells were heat-treated at 43°C for 1 h then stimulated with TGF-β1. We then evaluated whether or not heat treatment changed the expression of EMT-related factors and cell migration and also whether Smad activation was inhibited in TGF-β signaling. After being treated with TGF-β1, pancreatic cancer cells resulted in EMT and cell migration was enhanced. Heat treatment inhibited TGF-β1-induced changes in morphology, inhibited the expression of EMT-related factors, and attenuated TGF-β1-induced migration in pancreatic cancer cells. Additionally, we observed that heat treatment blocked TGF-β1-induced phosphorylation of Smad2 in PANC-1 cells. Our results suggest that heat treatment can suppress TGF-β1-induced EMT and opens the possibility of a new therapeutic use of hyperthermia as a potential treatment for cancer metastasis.

We investigated the effects of anticancer agents on peripheral blood mononuclear cells for the purpose of providing data to support new translational chemoimmunotherapy regimens. Peripheral-blood mononuclear cells were treated with one of four anticancer agents (5-fluorouracil, irinotecan, cisplatin, and gemcitabine) for 2 h, after which cell viability was determined. For assessment of effects of each drug on proliferation and cytokine production, cells were stimulated with phytohemagglutinin for 48 h. As a result, the anticancer agents did not affect cell viability. Cell proliferation was unaffected by 5-fluorouracil and irinotecan but inhibited by cisplatin and gemcitabine. Treatment with gemcitabine enhanced the production of IFN-γ and decreased the number of regulatory T cells. gemcitabine treatment increased IFN-γ production among CD4 T cells but not among CD8 T cells. The results indicated that GEM had immunoregulatory properties that might support immune response against cancer. This finding has implications for designing chemoimmunotherapy strategies.

The beneficial effects by peroxisome proliferator-activated receptor-γ (PPAR-γ) on gastric injury induced by ischemia-reperfusion have been confirmed, however, the precise mechanism of its cytoprotection is not elucidated thoroughly. The aim of the present study was to determine the gastric localization of PPAR-γ expression in the rat gastric mucosa, and to clarify the mechanism of its cytoprotective properties. The gastric expression of PPAR-γ was confirmed by RT-PCR and western blot, and localized on gastric epithelial cells. The protective effect of PPAR-γ ligands, pioglitazone or 15-deoxy-Δ(12,14)-prostaglandin J(2), on gastric ischemia-reperfusion injury was reversed by the co-administration with PPAR-γ antagonist. The gastric expression of tumor necrosis factor-α and cytokine-induced neutrophil chemoattractant-1 increased significantly in rats treated ischemia-reperfusion, and these increases were significantly inhibited by treatment with pioglitazone. Among the 1,032 probes, 18 probes were up-regulated at least 1.5-fold, 17 were down-regulated at least 1.5-fold by pioglitazone. The network including calnexin, endoplasmic reticulum stress protein, heat shock proteins, and proteasome genes was induced by pioglitazone treatment. In conclusion, activation of gastric epithelial PPAR-γ receptor by its ligands may represent a novel therapeutic approach for gastric inflammation via up-regulation of heat shock proteins and endoplasmic reticulum-related proteins.

Neutrophils activation and tumor necrosis factor-α (TNF-α) induction play critical roles in aspirin-induced gastric mucosal injury. The aim of the present study was to determine whether electrolyzed alkaline water (EAW) can ameliorate aspirin-induced gastric mucosal injury in rats, and whether EAW can inhibit the increased gastric TNF-α expression associated with neutrophil accumulation and gastric epithelial cell apoptosis. EAW (pH 10.5, oxidation-reduction potential -450mW) was produced by electricity resolution of tap water with a device that used a platinum electrode. EAW was administered to rats via free drinking for 14 days. Aspirin-induced injury was produced by the intragastric administration of aspirin (200mg/kg) and HCl (0.15N, 8.0ml/kg). After 3h the animals were killed, and the gastric mucosal tissue was used for the assessment of macroscopic damage and tissue-associated myeloperoxidase (MPO) activity, the quantitation of TNF-α protein, and the assay of epithelial cell apoptosis. The expression of TNF-α mRNA was determined by reverse transcription polymerase chain reaction (RT-PCR) 1h after aspirin administration. In the group drinking tap water, intragastric administration of acidified aspirin induced hyperemia and hemorrhagic erosions in rat stomachs. The increase in the total gastric erosive area after aspirin administration was significantly inhibited by pretreatment with EAW. The increases in MPO activity and epithelial cell apoptosis after aspirin administration were significantly inhibited by treatment with EAW. The gastric content of TNF-α increased and the expression of TNF-α mRNA was up-regulated after aspirin treatment. However, the peak TNF-α mRNA expression 1h after aspirin administration was inhibited by EAW. Based on these data, we conclude that the beneficial effects of EAW on aspirin-induced gastric mucosal injury may be attributed to its anti-inflammatory properties via inhibition of TNF-α expression.

Oxygen radical-mediated lipid peroxidation is involved in the tissue injury of inflammatory bowel disease. The present study investigated the effects of a novel water-soluble vitamin E derivative, 2-(α-D-glucopyranosyl) methyl-2, 5, 7, 8-tetramethylchroman-6-ol (TMG), on dextran sulfate sodium-induced olonic inflammation in mice. Acute colitis was induced in female mice by giving 8% dextran sulfate sodium orally in drinking water for 7 days. Animals were randomized to different concentrations of TMG (1, 10, and 100mg/kg) or physiologic saline (vehicle) by daily intraperitoneal injection. After days of dextran sulfate sodium administration, mice had severe colonic nflammation characterized by significant decreases in total colon length, increases in luminal hemoglobin content and colonic myeloperoxidase activity. TMG at doses of 10 and 100mg/kg reduced colonic injury and inflammation. The contents of thiobarbituric acid-reactive substances were significantly increased by dextran sulfate sodium administration, and this increase was reduced by TMG. These results indicate that the protective effect of TMG against colonic injury induced by dextran sulfate sodium may result, in part, from its inhibitory action toward lipid peroxidation, as well as from reducedneutrophil recruitment into the inflammatory site.

The effect of green tea extract on acute gastric mucosal damage induced by ischemia-reperfusion injury was investigated in rats. Ischemia-reperfusion injury was produced by applying a small vascular clamp to the celiac artery for 30min followed by removal of the clamp with reperfusion for 60min. An anti-ulcer effect of the green tea extract was demonstrated in this model. The increase seen in the lipid peroxide level in the gastric mucosa after ischemia-reperfusion was significantly inhibited by the extract. Tissue-associated myeloperoxidase activity, an index of neutrophil accumulation, was increased significantly in the gastric mucosa after reperfusion; this increase of activity was significantly inhibited by the green tea extract and paralleled the increase in the total area of gastric erosions. An electron spin resonance spin trapping study showed that the extract scavenged superoxide radicals generated by the hypoxanthine-xanthine oxidase system and that diphenyl-p-picryl-hydrazyl radicals were also eliminated in a concentration-dependent manner. In an in vitro study, the green tea extract significantly inhibited the increase in lipid peroxide in brain homogenates. Incubation of whole blood cells with interleukin-8 increased the expression of CD11b/CD18 by neutrophils, whereas co-incubation with the extract did not cause this upregulation. Human umbilical vein endothelial cells stimulated with interleukin-1β showed increased expression of E-selectin and intercellular adhesion molecule-1, but co-incubation with the extract significantly inhibited this upregulation. These results suggest that the protective effect of green tea extract against ischemia/reperfusion-induced gastric mucosal injury may be related to its antioxidant activity and inhibition of neutrophil accumulation.

The objective of the present study was to investigate the role of oxygen radicals in the acute gastric mucosal injury induced by taurocholate combined with serotonin (TCA-5HT) in rats. Just after taurocholate had been given intragastrically at a dose of 30mM/rat, serotonin was injected subcutaneously at a dose of 20mg/kg. Superficial hemorrhagic erosions were observed on the glandular stomach 2h after administration of TCA-5HT. The level of lipid peroxides and that of α-tocopherol in the gastric mucosa significantly increased and decreased, respectively, with time after TCA-5HT treatment. Myeloperoxidase (MPO) activity, an index of neutrophil infiltration, in the gastric mucosa also increased significantly. Pretreatment with the combination of recombinant human Cu, Zn-superoxide dismutase (hSOD) and catalase significantly inhibited the gastric mucosal injury, accumulation of lipid peroxides, and the decrease in α-tocopherol content in the gastric mucosa. Polaprezinc, a new synthetic antioxidant, significantly inhibited gastric mucosal injury and the accumulation of lipid peroxides in the gastric mucosa. All these results suggest that oxygen radicals and lipid peroxidation are involved in the pathogenesis of the acute gastric mucosal injury induced by TCA-5HT.

Protection of the small intestine from mucosal injury induced by nonsteroidal anti-inflammatory drugs including acetylsalicylic acid is a critical issue in the field of gastroenterology. Polaprezinc an anti-ulcer drug, consisting of zinc and L-carnosine, provides gastric mucosal protection against various irritants. In this study, we investigated the protective effect of polaprezinc on acetylsalicylic acid-induced apoptosis of the RIE1 rat intestinal epithelial cell line. Confluent rat intestinal epithelial cells were incubated with 70 µM polaprezinc for 24 h, and then stimulated with or without 15 mM acetylsalicylic acid for a further 15 h. Subsequent cellular viability was quantified by fluorometric assay based on cell lysis and staining. Acetylsalicylic acid-induced cell death was also qualified by fluorescent microscopy of Hoechst33342 and propidium iodide. Heat shock proteins 70 protein expression after adding polaprezinc or acetylsalicylic acid was assessed by western blotting. To investigate the role of Heat shock protein 70, Heat shock protein 70-specific small interfering RNA was applied. Cell viability was quantified by fluorometric assay based on cell lysis and staining and apoptosis was analyzed by fluorescence-activated cell sorting. We found that acetylsalicylic acid significantly induced apoptosis of rat intestinal epithelial cells in a dose- and time-dependent manner. Polaprezinc significantly suppressed acetylsalicylic acid-induced apoptosis of rat intestinal epithelial cells at its late phase. At the same time, polaprezinc increased Heat shock protein 70 expressions of rat intestinal epithelial cells in a time-dependent manner. However, in Heat shock protein 70-silenced rat intestinal epithelial cells, polaprezinc could not suppress acetylsalicylic acid -induced apoptosis at its late phase. We conclude that polaprezinc-increased Heat shock protein 70 expression might be an important mechanism by which polaprezinc suppresses acetylsalicylic acid-induced small intestinal apoptosis, a hallmark of acetylsalicylic acid-induced enteropathy.

Previous studies have shown that activated neutrophils and their myeloperoxidase (MPO)-derived products play a crucial role in the pathogenesis of non-steroidal anti-inflammatory drug (NSAID)-related small intestinal injury. The aim of the present study is to identify dihalogenated proteins in the small intestine on indomethacin administration. Intestinal damage was induced by subcutaneous administration of indomethacin (10 mg/kg) in male Wistar rats, and the severity of the injury was evaluated by measuring the area of visible ulcerative lesions. Tissue-associated MPO activity was measured in the intestinal mucosa as an index of neutrophil infiltration. The dihalogenated proteins were separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) using novel monoclonal antibodies against dibromotyrosine (DiBrY), and they were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) peptide mass fingerprinting and a Mascot database search. Single administration of indomethacin elicited increased ulcerative area and MPO activity in the small intestine. 2D-PAGE showed an increased level of DiBrY-modified proteins in the indomethacin-induced injured intestinal mucosa and 6 modified proteins were found. Enolase-1 and albumin were found to be DiBrY modified. These proteins may be responsible for the development of neutrophil-associated intestinal injury induced by indomethacin.

The clinical efficacy of gastroprotective drugs or low-dose H(2) receptor antagonists in the prevention of nonsteroidal anti-inflammatory drug (NSAID)-induced gastropathy is limited. The aim of the present study was to investigate efficacy of rebamipide and famotidine in Helicobacter pylori (H. pylori)-negative healthy volunteers taking NSAID. This study was a randomized, two way crossover study comparing the preventive effect rebamipide 100 mg, t.i.d. and famotidine 10 mg, b.i.d against indomethacin (25 mg, t.i.d.)-induced gastric mucosal injury in H. pylori-negative healthy volunteers. 12 subjects satisfied criteria and were randomized. Endoscopy was performed at baseline and again after the treatment for 7 days, and symptoms were recorded during the treatment. Tissue levels of lipid peroxides and myeloperoxidase and serum indomethacin concentrations were also measured. Subjective symptoms were developed in 58% (7/12) of the rebamipide group, and in 75% (9/12) of the famotidine group (no significant differences). The incidence of gastric lesions (modified Lanza score 2 or higher) was 17% (2/12) in the rebamipide group and 25% (3/12) in the famotidine group. Peptic ulcers did not occur in both groups. There were no significant differences in tissue levels of lipid peroxide and myeloperoxidase and serum level of indomethacin between two groups after the treatment. In conclusion, these data recommend rebamipide (100 mg, t.i.d.) or famotidine (10 mg, b.i.d.) for the prevention of acute gastric injury induced by NSAID in patients without a particular risk factor.