Model
Digital Document
Publisher
Florida Atlantic University
Description
In recent decades, developments in glycobiology have enabled the use of glycopeptides as tools for studying complex diseases such as cancer. Mucin 1 (MUC1) is a heavily glycosylated transmembrane protein, altered in both expression and glycosylation pattern in human carcinomas of the epithelium. The presence of incomplete or truncated glycan structures, often capped by sialic acid, commonly known as tumor-associated carbohydrate antigens (TACAs), on the cell surface is a well-known cancer biomarker and therapeutic target for different types of cancer. Accumulating evidence suggests that TACAs are recognized by the endogenous carbohydrate binding proteins (lectins). These interactions frequently result in the development of a protumor microenvironment, favoring tumor initiation, progression, metastasis, and immune evasion. Macrophage galactose binding lectin (MGL) is a C-type lectin receptor found on antigen-presenting cells (APCs) which facilitates the uptake of carbohydrate antigens for antigen presentation, modulating the immune response in homeostasis, autoimmunity, and cancer. Considering the crucial role of tumor-associated forms of MUC1 and MGL in tumor immunology, a thorough understanding of this interaction is essential for it to be exploited for cancer vaccine strategies. The specific goal of this research is to synthesize structurally well-defined chemical probes, mono and multiple glycosylated MUC1 glycopeptide models bearing the Tn or sTn antigens, that provide control over the complexity of the chemical space of multivalent ligands. For this purpose, a concise scheme was developed for the large-scale synthesis of the Tn and sTn antigen building blocks in a relatively high yield with moderate stereoselectivity. Thiophenyl glycoside donors, in the presence TfOH/NIS or TMSOTf/NIS as promoter systems, were used for the galactosylation and sialylation steps of the amino acid building block synthesis, respectively. We explored the effect of the activator, temperature, solvent, and excess equivalent of sialic acid thioglycoside donor on the sialylation reaction.
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