Identification of candidate biomarkers with cancer‐specific glycosylation in the tissue and serum of endometrioid ovarian cancer patients by glycoproteomic analysis

Abstract

Epithelial ovarian cancer is diagnosed less than 25% of the time when the cancer is confined to the ovary, leading to 5-year survival rates of less than 30%. Therefore, there is an urgent need for early diagnostics for ovarian cancer. Our study using glycotranscriptome comparative analysis of endometrioid ovarian cancer tissue and normal ovarian tissue led to the identification of distinct differences in the transcripts of a restricted set of glycosyltransferases involved in N-linked glycosylation. Utilizing lectins that bind to glycan structures predicted to show changes, we observed differences in lectin-bound glycoproteins consistent with some of the transcript differences. In this study, we have extended our observations by the use of selected lectins to perform a targeted glycoproteomic analysis of ovarian cancer and normal ovarian tissues. Our results have identified several glycoproteins that display tumor-specific glycosylation changes. We have verified these glycosylation changes on glycoproteins from tissue using immunoprecipitation followed by lectin blot detection. The glycoproteins that were verified were then analyzed further using existing microarray data obtained from benign ovarian adenomas, borderline ovarian adenocarcinomas, and malignant ovarian adenocarcinomas. The verified glycoproteins found to be expressed above control levels in the microarray data sets were then screened for tumor-specific glycan modifications in serum from ovarian cancer patients. Results obtained from two of these glycoprotein markers, periostin and thrombospondin, have confirmed that tumor-specific glycan changes can be used to distinguish ovarian cancer patient serum from normal serum.

Cell Surface Nucleolin Facilitates Enterovirus 71 Binding and Infection

“…Proteins that contain the desired glycans were enriched from cell lysates or a protein mixture and quantitatively analyzed by mass spectrometry. Glycoproteomic approaches have been applied to identify new tumor markers (25,41,42). In this study, we successfully identified 16 EV71-interacting proteins by glycoproteomic approaches.…”

“…Glycoproteomics coupled with mass spectrometric analyses have been used to identify the functions of glycoproteins, such as tumor markers (19)(20)(21)(22)(23)(24)(25)(26). Although cell surface glycoproteins are known to participate in the recognition, binding, and infection of pathogens (27), this advanced methodology has never been applied to the discovery of virus receptors prior to this study.…”

Proteomics and the search for biomarkers of female reproductive diseases

“…Using specific affinity enrichment for glycoproteins (Table 1), recent analyses of the serum glycoproteome to identify biomarkers of ovarian cancer have been undertaken (Abbott et al 2009). A number of tumour-specific glycan changes have been identified to date that can distinguish ovarian cancer patients from controls (Li et al 2008a, Abbott et al 2009), or predict response or resistance to chemotherapy (Di Michele et al 2009b). Other studies have identified several aberrantly glycosylated proteins with potential as biomarkers for ovarian cancer (Imre et al 2008).…”

“…In addition to the large glycoprotein CA 125, numerous other glycoproteins have been proposed as potential markers for ovarian cancer including osteopontin, human epididymis protein 4 (HE4; recently approved for clinical use), CA 15-3, CA 19-9, inhibin and several members of the kallikrein family (kallikreins 5, 6, 8,10, 11 and 14;Giuntoli et al 1998, Kim et al 2002, Drapkin et al 2005, Borgono et al 2006, Luo et al 2006, Shan et al 2006, McIntosh et al 2007, Shih Ie et al 2007). Using specific affinity enrichment for glycoproteins (Table 1), recent analyses of the serum glycoproteome to identify biomarkers of ovarian cancer have been undertaken (Abbott et al 2009). A number of tumour-specific glycan changes have been identified to date that can distinguish ovarian cancer patients from controls (Li et al 2008a, Abbott et al 2009), or predict response or resistance to chemotherapy (Di Michele et al 2009b).…”

“…A number of strategies are applicable (Table 1); some of these include isoelectric focusing, chromatography, immunodepletion , Hannan et al 2009a or affinity depletion (e.g. glycoprotein enrichment via lectin chromatography (Imre et al 2008, Li et al 2008a, Abbott et al 2009, Di Michele et al 2009b.…”