Objective: To identify the different proteins of Helicobacter pylori (H. pylori) in gastric cancer, peptic ulcer, and gastritis initially.
Methods: H. pylori in the endoscopic biopsy specimens of gastric mucosa of patients with gastric cancer, peptic ulcer, or gastritis, 3 specimens for each disease, were separated and cultured. The whole-cell protein of the H. pylori was extracted by lysis buffer and sonication. The protein concentration of the bacteria cell lysates was measured by the Bradford method. The protein maps of H. pylori were obtained by two-dimensional gel electrophoresis (2-DE) and the different proteins in gastric cancer, peptic ulcer and gastritis were analyzed by Image Master v 5.0. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS) were performed to identify the different proteins. The differential proteins were searched by the Mascot database at www.matrixscience.com.
Results: Four protein spots of H. pylori were over-expressed in the protein maps from gastric cancer in comparison with those from peptic ulcer and gastritis. Mass identification showed that the 4 proteins were thioredoxin, adenylate kinase, single-stranded DNA-binding protein, and ribosomal protein 50S L7/L12, with the Mowse scores of 94, 286, 139 and 132, and with the sequence coverage rates of 77%, 33%, 33%, and 28% respectively.
Conclusion: Anti-oxidant and inhibiting apoptosis, thioredoxin may be related to gastric carcinogenesis induced by H. pylori. Proteomics technology has a widespread perspective in the field of relationship between pathogenic bacteria and gastric cancer.