Abstract 1768: A practical tool for probing protein glycosylation in clinical samples: Application to characterizing subtypes of MUC5AC glycosylation in distinct subsets of pancreatic cancer patients

Abstract

Glycans are critical to protein biology and are useful as disease biomarkers. Many studies of glycans rely on clinical specimens, but the low amount of sample available for some specimens limits the experimental options. We have a method to obtain information about protein glycosylation using a minimal amount of protein, and we applied it to the study of biomarkers in the blood plasma of pancreatic cancer patients. The method works by treating proteins that were captured by antibody microarrays (2.2 x 2.2 mm) with exoglycosidases to successively expose underlying features, and then probing the native or exposed features using a panel of lectins or glycan-binding antibodies. We use an algorithm to interpret the data and provide predictions about the glycan motifs that are present in the sample. We applied the method to the analysis of the glycosylation of a biomarker, MUC5AC, found in the plasma of patients with pancreatic cancer. An O-linked glycan on MUC5AC that is elevated in the plasma of about 75% of patient had mostly 2,3 linked sialic acid on type-1 N-acetyl-lactosamine (LacNAc), whereas other glycans on MUC5AC had a 2,6 linkage of sialic acid on type-2 LacNAc. Another glycan, fucosylated and sialylated/sulfated type-2 LacNAc, which is elevated in distinct subset of patients, was on N-linked glycans, representing an unusual finding of N-linked glycans on mucins associated with cancer. Further developments are enabling the testing for consistent structural features associating with subtypes of cancer, which could improve our ability to detect and target the subtypes. The on-chip glycan modification and probing (on-chip GMAP) method provides a platform for analyzing protein glycosylation in clinical specimens and could facilitate the characterization and discovery of glycan biomarkers.

Citation Format: Peter Y. Hsueh. A practical tool for probing protein glycosylation in clinical samples: Application to characterizing subtypes of MUC5AC glycosylation in distinct subsets of pancreatic cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1768. doi:10.1158/1538-7445.AM2017-1768