Proteomics of differentially-expressed proteins between human primary and lymph node metastatic gastric adenocarcinoma

Abstract

Objective To identify the differentially-expressed proteins of human gastric adenocarcinoma cell in primary or metastatic lymph node tissues by comparative proteomics technology, and to screen the specific metastatic-associated proteins so as to investigate the metastatic molecular mechanism of lymph node metastasis in gastric cancer. Methods 11differential proteins were acquired previously from primary and metastatic lymphnode tissues in gastric adenocarcinoma patients by 2D-DIGE. Some selected differential protein spots were identified by PMF based on MALDI-TOF-MS and database search. Immunohistochemical staining of HSP70 was used to evaluate the reliability of the proteomic analysis results. Results After analyzed on 11 differential proteins by in-gel trypsin digestion and MALDI-TOF-MS-based PMF analysis, a total of 5 differential proteins were identified by searching Mascot-database, HSP70's 8 isoform 2 variant, chaperonin, chaperonin, leucine aminopeptidase, predicted: hypothetical protein XP_515584. Among the differential proteins identified, the levels of HSP70, chaperonin, leucine aminopeptidase expression had a significant up-regulation in gastric primary cancer compared with metastatic lymph node. HSP70 expression rate increased with the metastasis of lymph node and the progress of gastric cancer, agreed with the proteomics results. Conclusions They are similar in differentially-expressed proteins in primary or metastatic lymph node tissues because of the uniformity in source and differention. There are few protein changes in cancer cells between them, taking part in the metastatic of gastric cancer. HSP70 takes part in the progress of gastric cancer and relates to the metastasis of lymph node and malignant degree. Key words: Stomach neoplasms; Adenocarcinoma; Lymphatic metastasis; Microdissection; Spectrometry, mass, matrix-assisted laser desorption-ionization; Proteomics