Poster Presentation HUPO 2019 - 18th Human Proteome Organization World Congress

Antibody Panel Based N-glycan imaging of patient serum for cancer biomarker discovery (#432)

Alyson P Black 1 , Peggi M Angel 1 , Richard R Drake 1 , Anand S Mehta 1
  1. Medical University of South Carolina, Charleston, SC, United States

The vast majority of biomarkers used in the detection of cancer are glycoproteins, and studies indicate that the N-glycan component of the glycoprotein can act as a better marker of cancer than the protein component. However, accurate glycoprotein biomarker assays are lacking, and there is a need for higher throughput biomarker discovery. We have developed a new platform for multiplexed N-glycoprotein biomarker analysis from patient serum. This platform combines matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) workflows with antibody slide arrays. Antibody Panel Based (APB) N-glycan imaging allows for specific capture of N-glycoproteins by antibodies and N-glycan analysis in a protein-specific and multiplexed manner. Development of this technique has focused on human serum glycoproteins alpha-1-antitrypsin, haptoglobin, hemopexin, immunoglobulin G, low molecular weight kininogen, and transferrin. Using purified standard solutions and human serum samples, glycoproteins were specifically captured and followed by enzymatic release of N-glycans. N-glycans are detected with a MALDI mass spectrometer in a localized manner along the array. Glycoproteins were captured in a concentration-dependent manner while maintaining specificity of capture. As a proof of concept, cirrhotic patient serum samples were compared to healthy serum, and a previously shown increase in an IgG N-glycan was observed corresponding to disease status. This novel approach to protein-specific N-glycan analysis from an antibody panel can be further expanded to include any glycoprotein for which a validated antibody exists, allowing analysis of potentially 100s of individual glycoprotein targets from a patient sample in just one imaging run. Additionally, this platform can be adapted for analysis of any biofluid or biological sample that can be analyzed by antibody arrays. This technique has exciting potential to be applied in the clinic as both a biomarker discovery tool as well as a screening tool in readily available clinical biofluid samples with minimal consumption.