Persistent infection of the gastric mucosa by Helicobacter pylori (H. pylori), promotes a chronic inflammation, providing favorable microenvironment to atrophic gastritis with possible progression to gastric cancer. It is estimated that 50 % of the world population is infected by H. pylori, but the clinical outcome of the infection depends not only on the presence of the bacterium, but also genetic factors of H. pylori and host. CagA and vacA genes are the main virulence markers of H. pylori and may influence the immune response and chronic inflammation, favoring epithelial changes; which in turn, stimulates apoptosis, and the imbalance between cell proliferation and death, main factor related to progression to gastric cancer. Deregulation in the expression of genes involved in this control event can contribute to the development of gastric disorders and changes in gene expression may be influenced by microRNAs. Several studies have shown the importance of miRNAs in tissue homeostasis, as well as their deregulation due to H. pylori infection. In this way, using gastric biopsies of dyspeptic patients and patients with gastric cancer, the purpose of this study are: (I) analyses the gene expression of microRNAs miR-146, miR-155, miR-let-7a e miR-let-7b; (II) analyses the gene expression of mRNA: Smac/Diablo, Caspase 9 e XIAP, TNF-± e IL-2; (III) Correlate the gene expression of microRNAs and mRNA studded; (IV) Correlate the gene expression of microRNAs and mRNA with presence of H. pylori and genes cagA, vacA e dupA. The development of this approach may open new perspectives for the characterization of factors involved in peptic disease, gene regulation, as well as clarification on the interaction among genes involved in gastric diseases, seeking a better understanding of the pathophysiological mechanisms of these diseases. Together these data may suggest biomarkers and groups at risk for progression to gastric cancer. (AU)
Articles published in Agência FAPESP Newsletter about the research grant:
ZABAGLIA, LUANNA MUNHOZ;
BARTOLOMEU, NICOLE CHIUSO;
DOS SANTOS, MONICA PEZENATTO;
PERUQUETTI, RITA LUIZA;
CARDOSO SMITH, MARILIA DE ARRUDA;
MARQUES PAYAO, SPENCER LUIZ;
RASMUSSEN, LUCAS TREVIZANI.
Decreased MicroRNA miR-181c Expression Associated with Gastric Cancer.
JOURNAL OF GASTROINTESTINAL CANCER,
Web of Science Citations: 9.