Differential phospho and glyco proteomic analysis in gastric adenocarcinoma and the eventual correlation with clinic-pathological parameters of prognosis

Abstract

Gastric cancer is the 4th most frequent type of cancer and is the second most common cause of cancer death in the World. Brazil is in 4th place concerning higher prevalence of gastric cancer in Latin America and Pará State presents a high incidence of this neoplasia. The etio-pathology of gastric carcinogenesis gastric is still fragmented. The modification of this panorama may rely on the detection of protein alterations in tumor development, which would allow an accurate approach for prognosis, diagnosis and therapeutic management. Few studies on protein expression, glycosylation and phosphorylation profiles in primary gastric cancer samples were done. In the present study, proteic expression, glycosylation and phosphorylation profiles will be investigated in 24 gastric cancer and 24 normal gastric tissue samples. To study the protein expression profile, samples will be separate by bidimensional gel electrophoresis and proteins sub or superexpressed will be identified by mass spectrometry. Glycosylation and phosphorylation profiles will be evaluated by Pro-Q® 300 Emerald glycoprotein stain and Pro-Q® Diamond Phosphoprotein Gel Stain respectively. Proteins with difference in glycosylation and phosphorylation status will be identified by mass spectometry. These profiles will be compared considering presence or absence of neoplasia, presence or absence of Helicobacter pylori, clinical stage, gastric adenocarcinoma type and differentiation degree, as well as presence or absence of lymph node metastases. Proteins found with superexpression in neoplastic samples will be evaluated by Western Blotting in 50 serum samples of gastric cancer patients and 50 of volunteers, aiming investigate circulating diagnostic markers and a less invasive assay. All samples will be collected in University Hospital João of Barros Barreto of Pará State. This study will generate new and additional biological informations to provide etio and physiopathology understanding of this neoplasia with potential therapeutic use.