Oral Presentation 25th Annual Lorne Proteomics Symposium 2020

Deciphering the stage-specific glycoprotein signatures of colorectal cancer using integrated mass spectrometry-based omics (#45)

Rebeca Kawahara Sakuma 1 , Sayantani chatterjee 1 , Nicolle Packer 1 , Giuseppe Palmisano 2 , Seong Beom Ahn 1 , Morten Thaysen-Andersen 1
  1. Macquarie University, Sydney, NSW, Australia
  2. Departament of Parasitology, University of Sao Paulo, Sao Paulo, SP, Brazil

Glycobiology plays central roles in colorectal cancer (CRC) as exemplified by the aberrant glycosylation decorating immune and CRC-derived glycoproteins. Previous efforts have explored the changes in protein glycosylation in CRC, but the site-specific information of the proteins carrying altered glycosylation as well as their cellular origin is crucially missing. In this study, we used integrated mass spectrometry-based quantitative glycomics and glycoproteomics to characterise the N-glycosylation of non-depleted plasma proteins and peripheral blood mononuclear cell (PBMC) obtained from CRC patients spanning four disease stages (Dukes I-IV, n=7/stage) and age-matched healthy donors (n=8). Porous graphitised carbon (PGC)–LC-MS/MS N-glycomics revealed a total of 74 and 44 biosynthetically-related N-glycans from plasma and PBMC, respectively, across the sample cohort. The plasma N-glycome showed 26 N-glycans including the abundant biantennary mono- and bi-α2,6-sialylated glycans with and without α1,6-fucosylation and the related but less abundant tri- and tetra-antennary core-fucosylated sialoglycans. The N-glycome displayed stage-specific expression profiles that also differed quantitatively from the N-glycan profile of plasma proteins from healthy blood. The PBMC N-glycome data displayed a high abundance of paucimannosidic structures in particular in late stages of CRC. Integrated glycomics and glycoproteomics data analysis and adjustment for stage-specific protein level variations revealed that the CRC stage-specific plasma N-glycome changes were recapitulated at the individual glycosylation site level of the ten most abundant plasma glycoproteins including haptoglobin, Ig gamma-1 chain C region and fibrinogen. The glycoproteome of PBMC revealed that myeloperoxidase is an important contributor to the elevation of paucimannose observed in PBMCs from patients with advanced CRC. This study demonstrates the immense yet often under-utilised potential of employing integrated MS-based glycomics and glycoproteomics to deconstruct the regulation of the cell-, protein- and tumour-stage-specific glycosylation associated with CRC onset and development.