Analysis of protein profiles in human epithelial ovarian cancer tissues by proteomic technology

Screening in ovarian cancer is progressively finding out candidate genes and proteins which may work as screening biomarkers and play a role in tumor progression. We examined the protein expression patterns of ovarian cancer tissues using two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization-time of fight mass spectrometry (MALDI-TOF MS).

Tissues from 36 ovarian cancers and 20 normal ovaries were examined by 2-DE. The images of silver stained gels were analyzed by ImageMaster 2D Elite. The peptide mixtures, after in-gel digestion, were determined by MALDI-TOF MS for fingerprinting. The de-isotope tryptic peptide profiles were matched by using the Mascot search engine based on the entire NCBI and Swiss-Prot protein databases. Western/dot blots were then applied to verify the findings.

In ovarian cancer, 12 proteins that showed differential expressions were identified unequivocally. Among these proteins, five proteins (galectin-1, cathepsin B, ubiquitin carboxy-terminal hydrolase L1, HLA class II antigen DRB1-11 and heat shock protein 27) were up-regulated and seven proteins (cellular retinol-binding protein, transthyretin, SH3 binding glutamic-rich-like protein, tubulin-specific chaperone A, DJ-1, gamma-actin and tropomyosin 4) were down-regulated.

The present study is the first to report the up-regulation of ubiquitin carboxy-terminal hydrolase L1 and the down-regulation of SH3 binding glutamic-rich-like protein, tubulin-specific chaperone A, and tropomyosin 4 in human ovarian cancer tissues. Further cloning and functional analysis of these salient proteins will provide more information on their pathophysiologic roles in ovarian cancer.