Comprehensive proteome analysis of ovarian cancers using liquid phase separation, mass mapping and tandem mass spectrometry: a strategy for identification of candidate cancer biomarkers.
A two-dimensional (2-D) liquid phase separation method, liquid isoelectric focusing followed by nonporous reversed-phase high performance liquid chromatography (HPLC), was used to separate proteins from human ovarian epithelial whole cell lysates. HPLC eluent was interfaced on-line to an electrospray ionization (ESI) time of flight (TOF) mass spectrometer to obtain accurate intact protein molecular weights (Mr). 2-D protein expression maps were generated displaying protein isoelectric point (pI) versus intact protein Mr. Resulting 2-D images effectively displayed quantitative differential protein expression in ovarian cancer cells versus non-neoplastic ovarian epithelial cells. Protein peak fractions were collected from the HPLC eluent, enzymatically digested, and analyzed by matrix-assisted laser desorption/ionization (MALDI) TOF-mass spectrometry (MS) peptide mass fingerprinting and by MALDI-quadrupole TOF tandem mass spectrometry peptide sequencing. Interlysate comparisons of differential protein expression between two ovarian adenocarcinoma cell lines, ES2 and MDAH-2774, and ovarian surface epithelial cells was performed. Five pI fractions from each sample were selected for comparative study and over 300 unique proteins were positively identified from the 2-D liquid expression maps using MS, which covered around 60% of proteins detected by on-line ESI-TOF-MS. This represents one of the most comprehensive proteomic analyses of ovarian cancer samples to date. Protein bands with significant up- or down-regulation in one cell line versus another as viewed in the 2-D expression maps were identified. This strategy may prove useful in identifying novel ovarian cancer marker proteins.
Department of Chemistry, The University of Michigan, Ann Arbor 48109-1055, USA.
Haixing
H
Wang
Maureen T
MT
Kachman
Donald R
DR
Schwartz
Kathleen R
KR
Cho
David M
DM
Lubman
D014408:Biomarkers, Tumor / Q000032:analysis*; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005260:Female; D006801:Humans; D007525:Isoelectric Focusing / Q000379:methods*; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000032:analysis*; D010051:Ovarian Neoplasms / Q000737:chemistry*; D010449:Peptide Mapping; D020543:Proteome / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D020543:Proteome