Glycosylation status of haptoglobin in sera of patients with prostate cancer vs. benign prostate disease or normal subjects

Abstract

We studied chemical level and glycosylation status of haptoglobin in sera of patients with prostate cancer, as compared to benign prostate disease and normal subjects, with the following results. (i) Haptoglobin level was enhanced significantly in sera of prostate cancer. (ii) Sialylated bi-antennary glycans were the dominant structures in haptoglobins from all 3 sources, regardless of different site of N-linked glycan. The N-linked glycans at N184 were exclusively bi-antennary, and showed no difference between prostate cancer vs. benign prostate disease. (iii) Tri-antennary, N-linked, fucosylated glycans, carrying at least 1 sialyl-Lewis x/a antenna, were predominantly located on N207 or N211 within the amino acid 203-215 sequence of the b-chain of prostate cancer, and were minimal in benign prostate disease. Fucosylated glycans were not observed in normal subjects. A minor tri-antennary N-linked glycan was observed at N241 of the b-chain in prostate cancer, which was absent in benign prostate disease. (iv) None of these N-linked structures showed the expected presence of disialylated antennae with GalNAcb4(NeuAca3)Galb3(NeuAca6)GlcNAcbGal, or its analogue, despite cross-reactivity of prostate cancer haptoglobin with monoclonal antibody RM2. (v) Minor levels of O-glycosylation were identified in prostate cancer haptoglobin for the first time. Monoand disialyl core Type 1 O-linked structures were identified after reductive b-elimination followed by methylation and mass spectrometric analysis. No evidence was found for the presence of specific RM2 or other tumor-associated glycosyl epitopes linked to this Oglycan core. In summary, levels of haptoglobin are enhanced in sera of prostate cancer patients, and the N-glycans attached to a defined peptide region of its b-chain are characterized by enhanced branching as well as antenna fucosylation. ' 2007 Wiley-Liss, Inc.

Haptoglobin Levels in Turkish Patients with Bladder Cancer and its Association with Clinicopathological Features

“…Several studies have associated serum haptoglobin concentration with many cancers, including ovarian cancer, breast cancer, small cell lung cancer, esophageal squamous cell carcinoma, pancreatic cancer, liver cancer and prostate cancer (Ahmed et al, 2004;Awadallah et al, 2004;An et al, 2005;Ang et al, 2006;Okuyama et al, 2006;Fujimura et al, 2008;Shah et al, 2010). Furthermore, Dunzendorfer et al (1980) found increased serum haptoglobin levels in patients with urogenital tumors.…”

Targeted High-Throughput Glycoproteomics for Glyco-Biomarker Discovery

“…Since altered glycosylation of secreted and/or cell surface proteins reflects cell function and hence disease progression (Pan et al 2011;Packer et al 2008), this approach is likely to discover disease-relevant glyco-biomarkers. Previous studies aimed to find glyco-biomarkers have identified high abundance proteins in the blood as potential biomarker candidates, such as haptoglobin (Yoon et al 2010;Fujimura et al 2008), hemopexin (Comunale et al 2009), transferrin (Zeng et al 2011;Bones et al 2010) and alpha-1B-glycoprotein (Zeng et al 2011). LeMBA results will be trading low abundance for high specificity as glycosylation changes detected by multiple lectins will be unique for the altered glycan structure.…”

N-glycosylation status of β-haptoglobin in sera of patients with prostate cancer vs. benign prostate diseases

“…Recently, the N-glycosylation status of haptoglobin from sera of patients with cancer has been studied in detail (16)(17)(18). The N-glycosylation sites of haptoglobin were found exclusively in the ß-subunit and the level of N-glycosylation was enhanced at Asn 207 and 211 as compared to Asn 241 or Asn 184 of the ß-subunit isolated from prostate cancer, as compared to benign prostate disease (16).…”

“…The N-glycosylation sites of haptoglobin were found exclusively in the ß-subunit and the level of N-glycosylation was enhanced at Asn 207 and 211 as compared to Asn 241 or Asn 184 of the ß-subunit isolated from prostate cancer, as compared to benign prostate disease (16). Haptoglobin isolated from sera of patients with pancreatic cancer was found to show enhanced reactivity with Aleuria aurantia lectin (AAL), suggesting the presence of Fuc·6GlcNAc linked to Asn (17).…”

“…Haptoglobin isolated from sera of patients with pancreatic cancer was found to show enhanced reactivity with Aleuria aurantia lectin (AAL), suggesting the presence of Fuc·6GlcNAc linked to Asn (17). However, the fucosylation site of haptoglobin in prostate cancer may be different from that in pancreatic cancer, since extensive mass spectrometry of released N-linked glycans from prostate cancer cases indicated that the fucosylation site was at the peripheral GlcNAc through ·3 or ·4 fucosylation at Asn 207 and 211, rather than ·6 fucosylation at the core GlcNAc (16). Similarly, site-specific expression of sialyl-Le x in the tri-antennary N-linked glycan at the Asn 211 site of haptoglobin in pancreatic cancer was clearly demonstrated recently (18).…”