Idetification of Glycoprotein Biomarkers in Prostate Cancer by Quantitative Proteomics

摘要

Lectin enrichment (WGA-cell lysates and serum; SNA-serum) and quantitative methods (SILAC, N-acetylation and ~(18)(O) labeling) were successfully applied for the identification of potential glycoprotein biomarkers that are associated with prostate cancer. Several glycoproteins were identified and found to be differentially expressed in LNCAP and PC3 prostate cancer tumor cell lysates and some of the cell surface glycoproteins (ex: PODXL, CD55, ITGA2) were found to be up-regulated in androgen refractory prostate cancer cell lysate. Employing N-terminal acetylation and ~(18)(O) labeling methods, many glycopeptides were identified with NXS(T) consensus sequence with altered sialylation in prostate cancer serum glycoproetins. This method not only avoids serious in-vivo/in-vitro deamidation problems, but also enables the ID of glycan specific glycopeptide when specific lectins are used.