A proteomics approach to characterizing human submandibular gland cell lines by fluorescent two-dimensional differential in-gel electrophoresis

The human salivary glands have a variety of histologic features such as intercalated duct cells, myoepithelial cells and acinar cells. A neoplastic human salivary intercalated duct cell line (HSG) and its derivatives, HSG with a myoepithelial cell phenotype (HSG-AZA1) and HSG with an acinar cell phenotype (HSG-AZA3) induced by 5-aza-2'-dC treatment of HSG cells, have been reported. To identify characterization of intercalated duct cells, myoepithelial cells and acinar cells in the salivary gland, we selected HSG, HSG-AZA1 and HSG-AZA3 cell lines to perform two-dimensional electrophoresis analysis. We used a fluorescent two-dimensional differential in-gel electrophoresis (2-D-DIGE) for comparative proteomics, which improved the reproducibility and reliability of differential protein expression analysis between the samples. Furthermore, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) peptide mass fingerprinting (PMF) was used to identify the proteins. These methods were combined to approach the protein profiles associated with characterization between HSG, HSG-AZA1 and HSG-AZA3 cells. Using these strategies, we identified seven HSG associated proteins, such as actin-beta, hydrocephalus inducing protein, L-plastin, KIAA0657 protein, septin 6 isoform A, lamin A/C isoform 2 and superoxide dismutase 2, three HSG-AZA1 associated proteins such as ubiquitin carboxyl-terminal esterase L1, myosin light chain 2 and muscle creatine kinase, and two HSG-AZA3 associated proteins, microtubule-associated protein 6 and Annexin A3. These results suggest that the proteins are associated with characterization of the salivary gland.