title: Clusterin glycopeptide variant characterization reveals significant site-specific glycan changes in the plasma of clear cell renal cell carcinoma.
abstract: Cancer-related alterations in protein glycosylation may serve as diagnostic or prognostic biomarkers or may be used for monitoring disease progression. Clusterin is a medium abundance, yet heavily glycosylated, glycoprotein that is upregulated in clear cell renal cell carcinoma (ccRCC) tumors. We recently reported that the N-glycan profile of clusterin is altered in the plasma of ccRCC patients. Here, we characterized the occupancy and the degree of heterogeneity of individual N-glycosylation sites of clusterin in the plasma of patients diagnosed with localized ccRCC, before and after curative nephrectomy (n = 40). To this end, we used tandem mass spectrometry of immunoaffinity-enriched plasma samples to analyze the individual glycosylation sites in clusterin. We determined the levels of targeted clusterin glycoforms containing either a biantennary digalactosylated disialylated (A2G2S2) glycan or a core fucosylated biantennary digalactosylated disialylated (FA2G2S2) glycan at N-glycosite N374. We showed that the presence of these two clusterin glycoforms differed significantly in the plasma of patients prior to and after curative nephrectomy for localized ccRCC. Removal of ccRCC led to a significant increase in the levels of both FA2G2S2 and A2G2S2 glycans in plasma clusterin. These changes were further confirmed by lectin blotting of plasma clusterin. It is envisioned that these identified glycan alterations may provide an additional level of therapeutic or biomarker sensitivity than levels currently achievable by monitoring expression differences alone.
authors: †Barnett Institute and Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States.
authors: Francisca O
authors: FO
authors: Gbormittah
authors: §NIBRT-The National Institute for Bioprocessing Research and Training, Foster Avenue, Mount Merrion, Blackrock, Co. Dublin, Ireland.
authors: Jonathan
authors: J
authors: Bones
authors: ∥Genzyme, a Sanofi Company, 45 New York Avenue, Framingham, Massachusetts 01701, United States.
authors: Marina
authors: M
authors: Hincapie
authors: †Barnett Institute and Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States.
authors: Fateme
authors: F
authors: Tousi
authors: †Barnett Institute and Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States.
authors: William S
authors: WS
authors: Hancock
authors: ⊥Center for Cancer Research at Massachusetts General Hospital Cancer Center, Charlestown, Massachusetts 02129, United States.|#Division of Hematology-Oncology, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.
authors: Othon
authors: O
authors: Iliopoulos
mesh_terms: D002292:Carcinoma, Renal Cell / Q000378:metabolism* / Q000473:pathology; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D051152:Clusterin / Q000737:chemistry / Q000378:metabolism*; D006020:Glycopeptides / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007680:Kidney Neoplasms / Q000378:metabolism* / Q000473:pathology; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism*; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry
chemical_list: D051152:Clusterin; D006020:Glycopeptides; D011134:Polysaccharides
keywords: Clear cell renal cell carcinoma; N-glycan; clusterin; collision-induced dissociation; glycoforms; site-specific analysis