Pancreatic Cancer Serum Detection Using a Lectin/Glyco-Antibody Array Method

Abstract

Pancreatic cancer is a formidable disease and early detection biomarkers are needed to make inroads into improving the outcomes in these patients. In this work lectin antibody microarrays were utilized to detect unique glycosylation patterns of proteins from serum. Antibodies to four potential glycoprotein markers that were found in previous studies were printed on nitrocellulose coated glass slides and these microarrays were hybridized against patient serum to extract the target glycoproteins. Lectins were then used to detect different glycan structural units on the captured glycoproteins in a sandwich assay format. The biotinylated lectins used to assess differential glycosylation patterns were Aleuria aurentia lectin (AAL), Sambucus nigra bark lectin (SNA), Maackia amurensis lectin II (MAL), Lens culinaris agglutinin (LCA), and Concanavalin A (ConA). Captured glycoproteins were evaluated on the microarray in situ by on-plate digestion and direct analysis using MALDI QIT-TOF mass spectroscopy. Analysis was performed using serum from 89 normal controls, 35 chronic pancreatitis samples, 37 diabetic samples and 22 pancreatic cancer samples. We found that this method had excellent reproducibility as measured by the signal deviation of control blocks as onslide standard and 41 pairs of pure technical replicates. It was possible to discriminate cancer from the other disease groups and normal samples with high sensitivity and specificity where the response of Alpha-1-β glycoprotein to lectin SNA increased by 69% in the cancer sample compared to the other non-cancer groups (95% confidence interval 53% to 86%). These data suggest that differential glycosylation patterns detected on high throughput lectin microarrays are a promising biomarker approach for the early detection of pancreatic cancer.

Probing the O-Glycoproteome of Gastric Cancer Cell Lines for Biomarker Discovery*

“…Several O-glycoproteome studies of serum have been undertaken in the past using PNA (35,52), and these have provided insight into the general presence of O-glycoproteins and O-glycosites in serum. Our interest was to isolate the small subfraction of circulating O-glycoproteins with aberrant STn O-glycosylation, which are predicted to exist from studies with the CA72-4 assay (53, 54) and lectin arrays (55)(56)(57)(58). High levels of STn are detectable in sera of patients with different cancer types (59 -61) and this is associated with lower survival (62,63).…”

Markers of Ovarian Cancer Using a Glycoprotein/Antibody Array

“…39,40 However, the expression of SAP in plasma of ovarian cancer patients has not been studied. Furthermore, in our previous study, 41 glycosylation of SAP was found significantly changed in pancreatic cancer. Thus, SAP was also included in our biomarker testing.…”

Glycans and Galectins: Sweet New Approaches in Pancreatic Cancer Diagnosis and Treatment

“…Importantly, some of the aberrantly glycosylated proteins have been suggested as biomarkers (Lacunza et al, 2007;Okuyama et al, 2006;Peracaula et al, 2008). Lectin antibody microarrays have been used to detect unique glycosylation patterns in pancreatic cancer serum in high throughput strategies (Li et al, 2009;Wu et al, 2009). These assays proved efficient specificity and sensitivity and shed some light in distinguishing between www.intechopen.com Pancreatic Cancer -Molecular Mechanism and Targets 308 pancreatic cancer and chronic pancreatitis, a matter that has been for long unresolved.…”