MALDI imaging mass spectrometry profiling of N-glycans in formalin-fixed paraffin embedded clinical tissue blocks and tissue microarrays

PLoS One. 2014 Sep 3;9(9):e106255. doi: 10.1371/journal.pone.0106255. eCollection 2014.

Abstract

A recently developed matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) method to spatially profile the location and distribution of multiple N-linked glycan species in frozen tissues has been extended and improved for the direct analysis of glycans in clinically derived formalin-fixed paraffin-embedded (FFPE) tissues. Formalin-fixed tissues from normal mouse kidney, human pancreatic and prostate cancers, and a human hepatocellular carcinoma tissue microarray were processed by antigen retrieval followed by on-tissue digestion with peptide N-glycosidase F. The released N-glycans were detected by MALDI-IMS analysis, and the structural composition of a subset of glycans could be verified directly by on-tissue collision-induced fragmentation. Other structural assignments were confirmed by off-tissue permethylation analysis combined with multiple database comparisons. Imaging of mouse kidney tissue sections demonstrates specific tissue distributions of major cellular N-linked glycoforms in the cortex and medulla. Differential tissue distribution of N-linked glycoforms was also observed in the other tissue types. The efficacy of using MALDI-IMS glycan profiling to distinguish tumor from non-tumor tissues in a tumor microarray format is also demonstrated. This MALDI-IMS workflow has the potential to be applied to any FFPE tissue block or tissue microarray to enable higher throughput analysis of the global changes in N-glycosylation associated with cancers.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Animals
  • Carbohydrate Sequence
  • Carcinoma, Hepatocellular / chemistry*
  • Carcinoma, Hepatocellular / pathology
  • Female
  • Formaldehyde
  • Humans
  • Hydrolysis
  • Kidney / anatomy & histology
  • Kidney / chemistry
  • Liver Neoplasms / chemistry*
  • Liver Neoplasms / pathology
  • Male
  • Mice
  • Middle Aged
  • Molecular Sequence Data
  • Pancreatic Neoplasms / chemistry*
  • Pancreatic Neoplasms / pathology
  • Paraffin
  • Paraffin Embedding
  • Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase / chemistry
  • Polysaccharides / analysis*
  • Polysaccharides / chemistry
  • Prostatic Neoplasms / chemistry*
  • Prostatic Neoplasms / pathology
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Tissue Array Analysis
  • Tissue Fixation

Substances

  • Polysaccharides
  • Formaldehyde
  • Paraffin
  • Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase