This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The expression of glycosaminoglycans (GAGs) is critical to normal cellular growth and development. Remodeling of GAG structure also occurs with disease related changes in cell growth patterns. In order for a tumor to grow, cells must escape from normal growth controls. In order to do so, cells alter their responses to growth factor signals and degrade and remodel the extracellular matrices. GAGs on cell surfaces bind many families of growth factors and growth factor receptors. Thus, by altering the structures of cell surface GAG, the manner in which cells respond to growth factor stimuli are altered. By degrading extracellular matrix, growth factors formerly immobilized may be made available to stimulate cellular growth. The expression levels of extracellular GAG modifying enzymes including heparanases and sulfatases are correlated with a variety of human cancers. Thus, there is strong evidence that structures of GAGs correlated with the phenotype of the cell by which it is synthesized. With developments in mass spectrometric methods for analysis of glycosaminoglycans (GAGs), it is possible to determine GAG structure from small tissue quantities. It is important to be able to associate this structural information with the phenotype of the cells in question. Given that there is an abundance of histological specimens on human cancers available, there would be considerable value in developing methods for analysis of GAGs directly off tissue surfaces. In preliminary work, we have demonstrated feasibility by enzymatically digesting GAGs from surfaces of histological slides and detecting the disaccharides released using size exclusion chromatography-mass spectrometry. Experiments are underway to determine the define the analytical reproducibility and biological variation seen in normal tissues. It will be necessary to develop a more sensitive and rapid disaccharide analysis platform to enable tissue profiling with appropriate spot-to-spot resolution.
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