PROTEOMICS 2016* High-Speed Imaging Mass Spectrometry of N-Linked Glycans Provides a new approach to Molecular Histology and Tissuetyping of Tumors (#211)
Introduction: Imaging mass spectrometry (IMS) is a unique
analytical tool that allows simultaneous label-free visualization of hundreds
of compounds expressed in tissue. When applied to tumor samples, IMS provides a
means of correlating many lipids/peptides/proteins to histological features
thereby creating a multi-dimensional scale for molecular histology. N-linked
glycosylation of proteins is an important subset of the molecular mechanisms
important for cellular homeostasis, and disease state alters certain
glycosylation mechanisms. The aim of this study was to use a new high-speed IMS
tissuetyping platform to map and identify N-glycan markers from prostate and
breast tumor samples to determine the suitability using the high-speed platform for N-glycan tissuetyping.
Experimental: Sections were cut at 5 micron from a tissue microarray of breast cancer, 48 HER2+/HER2- cores, and FFPE prostate biopsies. These were mounted onto conductive microscope slides. Each slide was processed with standard antigen retrieval methods, followed by aerosol applications of peptide N-glycanase to release N-linked glycans and matrix for matrix-assisted laser desorption (MALDI). Imaging mass spectrometry analysis of the released N-glycans was done on a Bruker rapifleX at image resolutions of 10-50 um/spot.
Results: Results from the high-speed imaging measurements were found to correlate with data generated from previous studies. A number of histopathology-specific glycan distributions were identified. The high-speed imaging system provided acquisition times similar to that of standard histology, ranging from seconds for each TMA core to a few minutes for the larger biopsies. Images of the most abundant N-glycans (15-20 species) distinguish tumor-related stroma vs normal stroma in the prostate biopsies. In the breast cancer TMA, images show that N-glycan abundances correlate with HER2 status of cancer regions in the cores.
Conclusion: High-speed images of N-glycosylation patterns are characteristic of tissue pathology, making it possible to create large-cohort databases.
Experimental: Sections were cut at 5 micron from a tissue microarray of breast cancer, 48 HER2+/HER2- cores, and FFPE prostate biopsies. These were mounted onto conductive microscope slides. Each slide was processed with standard antigen retrieval methods, followed by aerosol applications of peptide N-glycanase to release N-linked glycans and matrix for matrix-assisted laser desorption (MALDI). Imaging mass spectrometry analysis of the released N-glycans was done on a Bruker rapifleX at image resolutions of 10-50 um/spot.
Results: Results from the high-speed imaging measurements were found to correlate with data generated from previous studies. A number of histopathology-specific glycan distributions were identified. The high-speed imaging system provided acquisition times similar to that of standard histology, ranging from seconds for each TMA core to a few minutes for the larger biopsies. Images of the most abundant N-glycans (15-20 species) distinguish tumor-related stroma vs normal stroma in the prostate biopsies. In the breast cancer TMA, images show that N-glycan abundances correlate with HER2 status of cancer regions in the cores.
Conclusion: High-speed images of N-glycosylation patterns are characteristic of tissue pathology, making it possible to create large-cohort databases.