Aberrant Fucosylation is a Critical Feature of Neuroblastoma Immune Evasion

Technical Summary Neuroblastoma is a childhood cancer of the sympathoadrenal axis. Children with high risk disease have 40-50% 5-year survival despite aggressive treatment with chemotherapy, surgery, and radiation. These poor outcomes highlight the need to identify new therapeutic strategies and define mechanisms of therapeutic resistance. Neuroblastomas have demonstrated limited responses to many recent advances in cancer immunotherapy. Limited tumor cell antigen presentation machinery and presence of an immunosuppressive tumor microenvironment containing tumor-supporting myeloid cells are key contributors to neuroblastoma therapeutic resistance. Glyconjugates are an understudied component of the tumor microenvironment. Glycosylation a critical post-translation modification that impacts the functions of cell surface and secreted proteins. Aberrant glycosylation is a hallmark of adult cancers and plays a critical role in cell adhesion, metastasis, and immune evasion but few studies have been completed in pediatric solid tumors. Our laboratory believe that aberrant glycosylation is an understudied contributor to the immunosuppressive microenvironment of neuroblastomas and may regulate therapeutic resistance. Few studies have evaluated the role of glycosylation in pediatric solid tumors. Matrix-assisted laser desorption/ionization-mass spectroscopy imaging (MALDI-MSI) is a new technology that permits near single cell resolution of metabolites in situ. We have developed a workflow to detect N-linked glycans from FFPE human neuroblastoma tumor samples. This strategy is made possible through a multi-disciplinary team of glycobiologists, pathologists, and bioinformaticians. Our initial studies suggest that core fucosylated n-linked glycans are depleted in neuroblastic tumor populations compared to normal and less aggressive controls. Fucosylation is a specific type of glycosylation where fucose is added to proteins. GDP-mannose-4,6-dehydratase (GMDS) is a key enzyme for de novo fucose production. Genetic knockdown demonstrates that GMDS is a key regulator of core fucosylation which enhances monocyte recruitment in vitro. These findings led us to hypothesis that fucosylation is a key regulator of monocyte cell recruitment and activity in neuroblastoma. Herein, we propose to investigate the role of neuroblastoma tumor cell fucosylation on monocyte recruitment and macrophage differentiation. These studies will provide critical information on delineating the role of aberrant glycosylation in regulating non-cancerous constituents of the tumor microenvironment that contribute to therapeutic response.