E. Surrenti

Antidiabetic thiazolidinediones inhibit invasiveness of pancreatic cancer cells via PPARγ independent mechanisms

Background/Aims: Thiazolidinediones (TZD) are a new class of oral antidiabetic drugs that have been shown to inhibit growth of some epithelial cancer cells. Although TZD were found to be ligands for peroxisome proliferators activated receptor γ (PPARγ) the mechanism by which TZD exert their anticancer effect is currently unclear. Furthermore, the effect of TZD on local motility and metastatic potential of cancer cells is unknown. The authors analysed the effects of two TZD, rosiglitazone and pioglitazone, on invasiveness of human pancreatic carcinoma cell lines in order to evaluate the potential therapeutic use of these drugs in pancreatic adenocarcinoma. Methods: Expression of PPARγ in human pancreatic adenocarcinomas and pancreatic carcinoma cell lines was measured by reverse transcription polymerase chain reaction and confirmed by western blot analysis. PPARγ activity was evaluated by transient reporter gene assay. Invasion assay was performed in modified Boyden chambers. Gelatinolytic and fibrinolytic activity were evaluated by gel zymography. Results: TZD inhibited pancreatic cancer cells’ invasiveness, affecting gelatinolytic and fibrinolytic activity with a mechanism independent of PPARγ activation and involving MMP-2 and PAI-1 expression. Conclusion: TZD treatment in pancreatic cancer cells has potent inhibitory effects on growth and invasiveness suggesting that these drugs may have application for prevention and treatment of pancreatic cancer in humans.

Eradication of helicobacter pylori reduces the rate of duodenal ulcer rebleeding: a long-term follow-up study

Objectives:The long-term efficacy of Helicobacter pylori eradication to reduce the rate of recurrence of peptic ulcer bleeding is still uncertain. We evaluated the rate of duodenal ulcer rebleeding for 48 months after H. pylori eradication.Methods:Thirty-two male patients with H. pylori infection and duodenal ulcer bleeding were treated with omeprazole (40 mg/day for 4 wk), colloidal bismuth (480 mg/day for 2 wk), amoxicillin (2 g/day for 1 wk), and metronidazole (750 mg/day for 1 wk), and followed up for 48 months. Endoscopy and tests for H. pylori infection were repeated every year.Results:Ulcer healed in all patients, but H. pylori infection persisted or recurred in 11 patients. Within 48 months, rebleeding occurred in nine (81.8%) of these patients, whereas the 21 patients who were persistently negative for H. pylori infection remained asymptomatic without rebleeding (0/21 = 0%, p < 0.002) during the whole follow-up.Conclusions:Eradication of H. pylori can reduce the rate of duodenal ulcer rebleeding for at least 4 yr, thus potentially modifying the natural history of the disease.

The potential of antidiabetic thiazolidinediones for anticancer therapy

The thiazolidinediones (TZDs) are a class of synthetic compounds for treatment of insulin-resistant Type 2 diabetes mellitus. TZDs are known activators of the peroxisome proliferator-activated receptor-γ (PPAR-γ), and exert their antidiabetic action largely through this nuclear receptor family. Moreover, increasing experimental evidences of PPAR-γ-independent effects are accumulating. Apart from the established metabolic actions, TZD treatment exerts additional biological effect such as control of cell growth, differentiation, motility and programmed cell death. In this context, considerable interest has focused on TZDs as potential chemopreventive agents in oncology; however, despite encouraging observation on the potential anticancer effect of these drugs in several in vitro experimental models, controversial results have been obtained with animal models and in pilot clinical trials. This review summarises the molecular mechanisms of the antineoplastic actions of TZDs and the relevance of these findings in human pathology and therapy.

Colonic vasoactive intestinal polypeptide in ulcerative colitis.

Vasoactive intestinal polypeptide (VIP) is a 28 amino acid peptide which is localised in both the central and peripheral nervous system. In the human colon VIP is found in all layers and the highest concentrations have been found in the myenteric plexus. It is known that VIP has various effects on intestinal functions: i) it is a potent stimulant of mucosal water and electrolyte secretion; ii) it is involved in the peristaltic reflex; and iii) plays an inhibitory role on immune cell function. Based on these biological effects it has been hypothesized that the intestinal mucosal immune system and inflammation may be influenced by alterations in the tissue concentrations of VIP. Some authors have demonstrated no changes in the VIP colonic content of patients with ulcerative colitis, whereas others have demonstrated a reduction. Our results, using specific radioimmunoassay, showed that there is a significant decrease of VIP in both rectal and colonic mucosa of patients with ulcerative colitis as compared to controls. The VIP decrease is selective since substance P and calcitonin gene-related peptide were unchanged in the mucosal tissue of ulcerative colitis patients and furthermore the VIP alteration is correlated to the degree of mucosal inflammation. These findings suggest that the reduction of VIP mucosal content, even if it represents a non-specific event, could influence local inflammatory response and the activity of the disease.

Expression of epidermal growth factor, transforming growth factor-alpha and their receptor in the human oesophagus.

SummaryIncreasing evidence indicates that epidermal growth factor and transforming growth factor-α are involved in the maintenance of oesophageal mucosal integrity. However, their cellular origin and the exact localization of their receptor in the oesophagus are still unclear. Therefore, we examined the expression of the two growth factors and their shared receptor in the normal human oesophagus at both mRNA and protein level, by immunohistochemistry, in situ hybridization and reverse transcription-polymerase chain reaction. In addition to being expressed in the proliferative compartment of the oesophageal epithelium, the receptor was found in a variety of cells, including smooth muscle cells, submucosal gland cells and the epithelium lining their ducts. Immunohistochemically, the pattern of distribution of epidermal growth factor paralleled that of its receptor. In situ hybridization demonstrated epidermal growth factor mRNA expression in the oesophageal epithelium and submucosal glands. Additionally, amplified transcripts of predicted size were detected by reverse transcription-polymerase chain reaction, thus confirming that authentic transcripts of the growth factor exist in the normal human oesophagus. Transforming growth factor-α mRNA and protein expression, while similar to that of epidermal growth factor, predominated in the more differentiated cell layers of the stratified squamous epithelium. These results demonstrate that the normal oesophagus can synthesize both growth factors. Moreover, the peculiar distribution of these peptides and the concomitant expression of their receptor in multiple cell types suggest that the two growth factors may exert diverse physiological functions in the oesophagus and participate in defence and reparative events following mucosal injury.

Helicobacter pylori cag Pathogenicity Island Is Associated with Reduced Expression of Interleukin-4 (IL-4) mRNA and Modulation of the IL-4δ2 mRNA Isoform in Human Gastric Mucosa

ABSTRACT Interleukin-4 (IL-4) and IL-4δ2 mRNA gastric expression was evaluated in healthy subjects and patients who did not have ulcers but were infected with Helicobacter pylori with or without the cag pathogenicity island (cag PAI). IL-4 mRNA was physiologically expressed by gastric epithelium and negatively influenced by H. pylori. Also, nonepithelial cells in the lamina propria of H. pylori-infected patients expressed IL-4 mRNA, whereas IL-4δ2 mRNA was found only in cag PAI-negative patients. Thus, gastric IL-4 takes part in the local immune response to H. pylori.

Helicobacter pylori cag pathogenicity island is associated with enhanced interleukin-8 expression in human gastric mucosa.

BACKGROUND In vitro studies showed that Helicobacter pylori strains carrying the cag pathogenicity island are able to induce epithelial secretion of Interleukin-8. AIMS To evaluate the assessment of cag pathogenicity island and the expression of Interleukin-8 in the gastric mucosa of Helicobacter pylori-infected patients and correlate these data with the activity of gastritis and Helicobacter pylori density. METHODS cag status was determined by polymerase chain reaction directly on gastric biopsies from 13 Helicobacter pylori+ patients with non-ulcer dyspepsia and 13 Helicobacter pylori+ with duodenal ulcer. Interleukin-8 gene transcription and protein expression were analysed by in situ hybridization and immunofluorescence, respectively. Gastritis activity and Helicobacter pylori density were also investigated. RESULTS cag was present in 20/26 of Helicobacter pylori+ patients: in 7/13 non-ulcer dyspepsia (53.8%] and in 13/13 duodenal ulcer patients (100%), (p<0.05). Interleukin-8 mRNA and protein expression in epithelial and inflammatory cells was higher in cag+ than in cag- patients (p<0.005). Gastritis activity significantly correlated with cag (p<0.05) and Interleukin-8 expression (p<0.005]. Helicobacter pylori density was enhanced in cag+ [p<0.005] and correlated with Interleukin-8 expression (p<0.0051. CONCLUSIONS The present study demonstrates that in Helicobacter pylori-infected human gastric mucosa, cag+ infection is associated with enhanced Interleukin-8 expression, higher levels of active gastritis and bacterial density, and presence of duodenal ulcer.

Serologic Detection of CagA Positive Helicobacter pylori Infection in a Northern Italian Population: Its Association with Peptic Ulcer Disease

About 60–70% of Helicobacter pylori strains possess cagA (cytotoxin associated gene A) gene and express its product CagA, a highly immunogenic 128–140kD protein. Patients infected with CagA positive strains develop serum IgG anti‐CagA. A serologic response to CagA has been detected in Helicobacter pylori infected patients with peptic ulcer more frequently than in those with gastritis alone. It is unclear whether this finding is consistent in different geographical populations. We investigated the relationship between anti‐CagA seropositivity and peptic ulcer disease in a Northern Italian population.

Regression of duodenal gastric metaplasia in Helicobacter pylori positive patients with duodenal ulcer disease

BACKGROUND It is unclear whether the extent of duodenal gastric metaplasia is due to Helicobacter pylori and/or acid. AIMS To investigate the role of Helicobacter pylori eradication in the regression of duodenal gastric metaplasia in patients with duodenal ulcer maintained in acid suppression conditions. METHODS . Duodenal (anterior, superior inferior walls of first part of duodenum) and gastric antrum biopsies were obtained from 44 Helicobacter pylori positive duodenal ulcer patients. Helicobacter pylori infection was diagnosed by rapid urease test, histology and 13C-Urea Breath Test. Patients were treated with 20 mg omeprazole tid associated with 250 mg clarithromycin and 500 mg amoxycillin four times daily for 10 days and maintained with 20 mg omeprazole daily for 18 weeks. Control endoscopies were performed at 6 and 18 weeks after beginning treatment. RESULTS Duodenal gastric metaplasia regression was observed in all (32/32) patients in whom Helicobacter pylori was eradicated, but in only 3 out of 6 patients in whom eradication was not achieved (p<0. 001). CONCLUSIONS . The present results suggest that Helicobacter pylori eradication associated with prolonged acid suppression may represent a good therapeutic strategy to achieve duodenal gastric metaplasia regression and highlight the combined role of acid and Helicobacter pylori in the pathogenesis of duodenal gastric metaplasia.

Human gastric epithelium produces IL-4 and IL-4delta2 isoform only upon Helicobacter pylori infection.

Recent evidence suggests that interleukin-4 (IL-4) is related to mucosal tolerance by which an injurious immune response is prevented, suppressed or shifted to a non-injurious response. We investigated the expression of IL-4 and its splice variant isoform IL-4δ2 in gastric epithelial cells of healthy subjects and gastritis patients infected with Helicobacter pylori (H. pylori) with or without the cag pathogenicity island (cag-PAI). IL-4 and IL-4δ2 mRNAs were evaluated in microdissected gastric epithelium and in AGS cell lines co-cultured with H. pylori B128 or SSI strains. IL-4 mRNA was consistently detected in microdissected gastric epithelial cells from healthy subjects. The IL-4 mRNA expression was low in H. pylori-infected patients, and markedly reduced in cag-PAI-positive ones. IL-4δ2 mRNA was expressed on gastric epithelium of H. pylori-infected patients, but not in healthy subjects. The IL-452 expression was lower in cag-PAI-positive than in cag-PAI-negative H. pylori infected patients. AGS cells also produced IL-4 mRNA upon SSI strain stimulation, whereas IL-4δ2 mRNA expression was detected in AGS co-cultured with either SSI or B128 strains. An inverse correlation was documented between IL-4 and IL-482 mRNA expression by microdissected gastric epithelial cells and the score of gastritis. IL-4, but not IL-452, is expressed by gastric epithelium of healthy subjects, whereas IL-452 and lesser IL-4 mRNA are detectable in the gastric epithelium of H. pylori-infected patients. Data suggest that gastric epithelial cells might regulate the balance between tolerance and immune response by the fine tuning of IL-4 and IL-4δ2 expression.