Characterization of Glycans Derived from Biological Samples Using LC-MS/MS

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Proteins are intricate compounds that play vital roles in biological activities. One of the most prevalent post-translational modifications (PTMs) is protein glycosylation, which enhances several biological functions, such as protein stability, localization, cellular communication, inflammation, immune responses, and host-pathogen interactions. Unusual protein glycosylation has been linked to numerous diseases, including different types of cancer. Given the essential nature of glycans in crucial biological functions and their association with various health conditions when their expressions are altered, glycomics are becoming leading areas in the development of biomarkers. These biomarkers present unique opportunities to refine clinical diagnostics and achieve more precise disease phenotyping. Such enhanced diagnostics and characterization will facilitate more specific treatment approaches. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) stands as one of the most potent tools which is available currently for comprehensive structural analysis of biomolecules. Nanoflow-based reverse-phase liquid chromatography (RPLC) is a powerful and sensitive separation method often coupled with MS/MS for the isolation of permethylated glycans. In addition, there are a variety of dissociation methods utilized to facilitate the extensive fragmentation of precursor ions, aiding in the structural confirmation of biomolecules via MS/MS. Despite the presence of powerful and effective methodologies for the identification of biomarkers, more studies which lead to discovery of glycan biomarkers in cancers and infectious diseases are still needed. The focus of the current thesis is on the biomedical application of a liquid chromatography-tandem mass spectrometry platform to identify and quantify the glycans for potential biomarker discovery in breast cancer brain metastasis and SARS-CoV-2. The presented studies investigate the glycan analysis from breast cancer cells for identifying potential biomarkers. On top of that, glycan biomarker studies are discussed for exploring potential biomarkers candidates for SARS-CoV-2. Moreover, the thesis introduces future strategies for improving and developing biomarker studies. These research strategies and achieved results are considered to extensively enhance the future biomarker discovery studies for cancers and infectious diseases such as Covid 19 pandemic.

Embargo status: Restricted until 01/2027. To request the author grant access, click on the PDF link to the left.

SARS-CoV-2, Breast Cancer Brain Metastasis, O-Glycans, N-Glycans