Identification Of Tumor-associated Proteins In Human Gastric Carcinoma

Objective: Gastric carcinogenesis is generally believed to be a multi-step progression from normal gastric mucosa to preneoplastic lesions and ultimately cancer and multiple genetic and molecular alterations involved in this progression. The study of gene expression profiles in different stages of this progression may bring new insight into the process of carcigenesis and becoming hot. While gene expression profiling of this progression has been performed, no comparable protein analysis has been reported. Encoded proteins carry out most biological functions, and to understand how cells work, one must study what proteins are present, how they interact with each other and what they do. Proteomics research offers new tools for studying proteins, and is poised to boost our understanding of systems-level cellular behaviour. Comparative proteomics was applied to identify cancer-associated proteins in human gastric carcinoma.Methods: The total proteins of normal gastric mucosa, dysplasia and gastric cancinoma were seperated by two-dimensional electrophoresis (2-DE). After a modified Neuhoff s colloidal coomassie blue G-250 staining, image scanning and PDquest software analysis, the differentially expressed protein spots were incised from gels and digested by trypsin in gel. Then matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) were used for peptides mass analysis. The acquired peptide mass fingerprints (PMFs) were used to search for matches in SWISS-PROT and NCBI databases with Mascot software. The functions and subcellular locations of identified proteins were further analysed according to bioinformatic resources.Results: Through comparative proteomic analysis of gastric mucosa among normal,dysplasia and carcinoma tissue, we obtained 43 differential proteins, 11 of which were identified by MS. The identified proteins could be divided into five groups based on their functions: redox-status regulatory proteins, Aflatoxin B₁ aldehyde reductase member 3, Peroxiredoxin 5, Acyl-CoA dehydrogenase(short-chain specific), Cytochrome c oxidase...