Comparative glycoproteomics analysis in cancer
Abstract
Increased fucosylation of cell surface glycoproteins has been correlated with malignancy and metastatic potential. Tumor-associated fucosylated proteins are often liberated from the cell surface and can be detected in the blood stream; therefore, pathological changes in the blood or tissues are likely to be reflected in serum proteins. Recent advances in proteomics technologies have made it possible to analyze for panels of serum proteins, providing a means to screen for multiple protein biomarkers relevant to disease. Because high abundance proteins, such as serum albumin, can obscure detection of diagnostically important glycoproteins, our first study was to evaluate the ability of lectin affinity selectors to efficiently deplete serum albumin. Using three different lectin affinity selectors, each lectin was observed to deplete serum albumin by 99%. Our second goal was to develop a serum-based glycoproteomics method that could be used to isolate and quantitate changes in fucosylated serum peptides and apply these techniques in animal cancer models. Using canine malignant lymphoma and canine transitional cell carcinoma (TCC) of the urinary bladder as our cancer models, Lotus tetragonolobus lectin affinity selection, combined with GIST isotope coded labeling strategies, was used to generate patterns of peptide profiles from each type of cancer. In the lymphoma study, serum from three dogs were analyzed and compared. In one dog, pre-chemotherapy (lymphoma), post-chemotherapy (remission), and relapse (recurrence of lymphoma) serum samples were analyzed and compared. These data indicated that the majority of the fucosylated peptides that increased with lymphoma (pre-chemotherapy) decreased following chemotherapy when the dog was in clinical remission, and subsequently increased during relapse of the cancer. When the pre-chemotherapy serum of this and two other dogs with lymphoma were analyzed and compared to normal serum, nearly all of the peptides identified in all three dogs increased with lymphoma. In the TCC study, sera from two dogs were analyzed and compared. When the sera from these two dogs were compared to normal serum, greater than 70% of the peptides that changed increased with TCC. These results emphasize the potential of glycoproteomics for use in the diagnosis of cancer, monitoring patient response to chemotherapy, and indicating recurrence of the disease.
Degree
Ph.D.
Advisors
Hooser, Purdue University.
Subject Area
Analytical chemistry
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