Quantitative Proteome Identification Of Tumor-associated Proteins In Gastric Carcinoma With LCM

Objective: Gastric carcinoma (GC) is a disease related to multiple genetic and multi-step progressions from normal gastric mucosa. Early diagnosis is the key to treatment of GC. But in the current, diagnosis methods of GC can not do in early. The purpose of this study was identified the differentially expression proteins between gastric adenocarcinoma cells (GAC) and normal gastric adenoepithelial cells (NGAC), to look for early diagnosis of GC specific proteins.Methods: The glandular tissue was purified from GAC and NGAC with laser capture microdissection (LCM). The total proteins were extracted from the tissues. After the total proteins labeled with different iTRAQ stable isotope, labeled total proteins were segregated with Nano-RPLC-MS/MS, to obtain relative abundance of peptides information. The differentially expression proteins were identified through SWISSPORT database.Results:Through Quantitative proteomic analysis of GAC and NGAC, 319 proteins were identified with MS, 88 of which were differentially expression proteins. There were 12 Up-regulation and 76 Down-regulation proteins in GAC. The identified proteins can be divided into seven groups according to protein function: biological oxidation, signal transduction, protein composition and metabolism, molecular chaperones, cytoskeleton, apoptotic and others. There were 12 up-regulated proteins mainly related to cytoskeleton and Secreted protein, such as vimentin, CK18, Decorin, Lumican,etc. These proteins were associated with signal transduction proteins such as septin 9, ras-related protein rab-44, S100P, etc, and biological oxidation such as Peroxiredoxins-1, cytochrome c oxidase subunit 5B, etc, and protein composition and metabolism: 60S ribosomal protein L8, histone H1x, etc. and cytoskeleton: CK19, Cofilin-1, etc, and apoptotic: microtubule-associated protein 1S, protein-glutamine gamma glutamyltransferase 2, etc. and molecular chaperones: HSP60, HSP70, HSP90βin 76 down-regulation proteins. The change of protein expression might participate in generation and development of gastric carcinoma.Conclusion:1. In the study of gastric adenocarcinoma,we were first successfully identify differentially expressed protein used by LCM and Quantitative proteomics technology using iTRAQ^TM stable isotope labeling.319 proteins were identified by MS and in which There were 12 Up-regulation and 76 Down-regulation differential proteins in gastric adenocarcinoma tissue.2. The differentially expressed protein find by us such as Ezrin,Septin9, Prdx1, Prdx6 provides a large of valuable information, not only in the discovery of gastric cancer biomarkers and drug targets but also exploration of gastric cancer molecular mechanisms.