Proteome Analysis of Gastric Cancer Metastasis by Two-Dimensional Gel Electrophoresis and Matrix Assisted Laser Desorption/Ionization-Mass Spectrometry for Identification of Metastasis-Related Proteins

Abstract

A well-described animal model was used to understand the molecular mechanisms of carcinogenesis and metastasis of gastric cancer at the protein level. Gastric cancer was induced in 12 Wistar rats by oral administration of N-methyl-N'-Nitro-N-Nitrosoguanidine (MNNG). The protein expression patterns of normal gastric tissue, gastric cancer, and corresponding metastases were analyzed by proteomics in matched tissues of 3 rats. Proteins in the region of molecular masses of 15-75 kDa and an isoelectric point of 3-7 were separated by two-dimensional electrophoresis (2-DE) and identified by peptide fingerprinting with matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS). Twenty-seven spots corresponding to 25 different proteins served as landmarks for comparison between tissues. The identified proteins included cytoskeletal proteins, stress associated proteins, proteins involved in signal transduction, cell proliferation and differentiation, and metabolism. Eleven proteins were up-regulated and 2 proteins were down-regulated in tumor tissue when compared with normal tissue. Twelve proteins were up-regulated and 8 proteins were down-regulated in the metastases when compared with the primary tumor. The overexpression of HSP27 in gastric cancer was confirmed by immunohistochemical analysis of human gastric cancer specimens. Combining well-defined animal models with proteome analysis will improve our understanding of the fundamental changes that contribute to the process of carcinogenesis and the formation of metastases in gastric cancer.

Heat shock protein 27 is over-expressed in tumor tissues and increased in sera of patients with gastric adenocarcinoma

“…The over-expression of HSP27 in gastric cancer has been observed by several studies (8,25,26). In gastric cancer, over-expression of HSP27 may be associated with metastasis to the lymph nodes, advanced stage (III and IV) cancer, and shorter overall survival of patients (27,28), indicating that HSP27 has prognostic significance for gastric cancer.…”

“…Additionally, HSP27 expression was closely related to gastric tumor size, and the presence of organ metastases (29). However, another study found that HSP27 was not present in metastatic gastric tumors, and was only detectable in samples from non-metastatic gastric cancer tissue (26). None of these studies measured HSP27 serum concentrations to investigate if there is a link between intracellular and extracellular HSP27 concentrations in gastric neoplasia.…”

Two-dimensional differential in-gel electrophoresis for identification of gastric cancer-specific protein markers

“…These conflicting results may suggest that shock protein abundance varies in different stages of gastric cancer, which needs further study. Chen et al (23) reported that HSP27 was expressed in human gastric cancer, whereas non-tumorous, non-regenerative human foveolar epithelium did not express HSP27. In our research, HSP27 was down-regulated on DIGE.…”

Protein Profiling of Microdissected Pancreas Carcinoma and Identification of HSP27 as a Potential Serum Marker

“…In primary breast cancer samples, DJ-1 negatively regulates the PTEN tumor suppressor and thus produces overexpressed hyperphosphorylation of PKB/Akt and increased cell survival (27 ). In a proteomic analysis of gastric cancer, DJ-1 was detectable only in metastatic tumor tissue vs nonmetastatic tumor tissue and healthy gastric tissue (28 ). Based on this fact, it seems likely that DJ-1 contributes to the metastatic potential of a tumor.…”