BACKGROUND: Helicobacter pylori (H. pylori) is a gram-negative bacterium associated with the etiology of several gastrointestinal tract pathologies, and cagA-positive (cagA+) strains are found in populations with gastric ulcers and precancerous lesions, inducing pro-inflammatory responses. The development of neoplasms is related to microRNA (miRNA) dysregulation, indicating highly expressed miRNA-629. The article aims to correlate the expression level of miRNA-629 with the presence of H. pylori and the pathogenicity marker cagA. METHODS: 203 gastric biopsy samples were evaluated from individuals with normal gastric tissue (n=60), gastritis (n=96), and gastric cancer (n=47) of both genders and over 18 years old. The samples were subdivided according to the presence or absence of H. pylori, detected by polymerase chain reaction (PCR). RNA was extracted using a commercial kit and quantified. Complementary DNA (cDNA) was synthesized using commercial kits, and the relative expression was calculated using the 2-ΔΔCt method. RESULTS: Individuals infected with H. pylori are nine times more likely to develop gastric cancer. Cancer patients appeared to have decreased expression of miRNA-629; however, the presence of the bacterium would not influence this reduction. Individuals in the cancer group showed lower miRNA-629 expression when cagA+; however, in the control group, the expression was higher when cagA+. CONCLUSION: H. pylori is a factor involved in the etiology and progression of gastric diseases. Reduction in miRNA-629 expression in cancer patients occurs independent of the presence of the bacterium, but when the cagA pathogenicity marker is present, it induces changes in the gene expression of the respective miRNA.
Antigens, Bacterial , Bacterial Proteins , Helicobacter Infections , Helicobacter pylori , MicroRNAs , Stomach Neoplasms , Humans , Helicobacter pylori/genetics , Helicobacter pylori/pathogenicity , Stomach Neoplasms/microbiology , Stomach Neoplasms/genetics , Antigens, Bacterial/genetics , Bacterial Proteins/genetics , MicroRNAs/genetics , MicroRNAs/analysis , Female , Male , Helicobacter Infections/microbiology , Middle Aged , Adult , Aged , Gastritis/microbiology
PURPOSE: The aim of this study was to evaluate the expression of miR-125a-5p in patients with dyspeptic symptoms and gastric cancer, correlating them with the development of this cancer and H. pylori. METHODS: Patients were divided in groups according to histopathological analysis (control, gastritis, and cancer groups). Polymerase chain reaction was performed to detect H. pylori and real-time quantitative PCR to determine miR-125a-5p expression. RESULTS: H. pylori was detected in 44% of the patients, with prevalence in the gastritis and cancer groups. A statistically significant decrease of miR-125a-5p expression was found in the control positive (p = 0.0183*), gastritis positive (p = 0.0380*), and cancer positive (p = 0.0288*) groups when compared with the control negative group. CONCLUSION: We suggest that decreased expression of the miRNA-125a-5p associated with the presence of the H. pylori is an important mechanism in gastric diseases and could be a possible marker for early diagnosis of gastric cancer.
Biomarkers, Tumor/metabolism , Gastritis/genetics , Helicobacter Infections/genetics , MicroRNAs/metabolism , Stomach Neoplasms/genetics , Adult , Aged , Biomarkers, Tumor/analysis , Brazil/epidemiology , Cell Line, Tumor , Cell Proliferation , Early Detection of Cancer/methods , Female , Gastric Mucosa/microbiology , Gastric Mucosa/pathology , Gastritis/microbiology , Gastritis/pathology , Gene Expression Profiling , Genetic Predisposition to Disease , Helicobacter Infections/epidemiology , Helicobacter Infections/microbiology , Helicobacter Infections/pathology , Helicobacter pylori/isolation & purification , Humans , Male , MicroRNAs/analysis , Middle Aged , Prevalence , Stomach Neoplasms/diagnosis , Stomach Neoplasms/microbiology , Stomach Neoplasms/pathology
PURPOSE: Analyze the expression of caspase-9, Smac/DIABLO, XIAP, let-7a, and let-7b in patients with normal gastric tissue, chronic gastritis, and gastric adenocarcinoma. METHODS: The expression of caspase-9, Smac/DIABLO, XIAP, let-7a, and let-7b by qRT-PCR was analyzed in 158 samples from 53 patients with normal gastric mucosa, 86 with chronic gastritis, and 19 with gastric cancer. RESULTS: The comparison between the gastric cancer and the control group revealed a decreased expression of caspase-9 in gastric cancer tissues; considering the Helicobacter pylor presence, comparable results were revealed. Smac/DIABLO was increased in gastric cancer cells, while XIAP demonstrated no significant difference in the gene expression. The microRNA analysis revealed a decreased expression of let-7a and let-7b in samples positive to H. pylori infection and in gastric cancer group, regardless of the presence of the bacterium. CONCLUSION: Our study provided some evidence of low activity of the intrinsic apoptosis pathway, as well as the influence of H. pylori on let-7a and let-7b expression.
Adenocarcinoma/genetics , Apoptosis/genetics , Biomarkers, Tumor/genetics , Carcinogenesis/genetics , Stomach Neoplasms/genetics , Adenocarcinoma/pathology , Adult , Aged , Apoptosis Regulatory Proteins/genetics , Biopsy , Caspase 9/genetics , Female , Gastric Mucosa/microbiology , Gastric Mucosa/pathology , Gastritis/genetics , Gastritis/microbiology , Gastritis/pathology , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Helicobacter Infections/genetics , Helicobacter Infections/microbiology , Helicobacter Infections/pathology , Helicobacter pylori/isolation & purification , Humans , Male , MicroRNAs/genetics , Middle Aged , Mitochondrial Proteins/genetics , Stomach Neoplasms/microbiology , Stomach Neoplasms/pathology , X-Linked Inhibitor of Apoptosis Protein/genetics
