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

TW Powers, BA Neely, Y Shao, H Tang, DA Troyer… - PloS one, 2014 - journals.plos.org
TW Powers, BA Neely, Y Shao, H Tang, DA Troyer, AS Mehta, BB Haab, RR Drake
PloS one, 2014journals.plos.org
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 …
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.
PLOS