Prof. Jia Niu¹

¹Boston College

E-mail: jia.niu@bc.edu

O-Sulfation is an important chemical code widely existed in bioactive molecules, but the scalable and facile synthesis of complex bioactive molecules carrying O-sulfation remains challenging. Herein, we developed a general approach to O-sulfation via the Sulfur (VI) Fluoride Exchange (SuFEx) reaction between aryl fluorosulfates and silylated hydroxyl groups. Efficient sulfate diester formation was achieved through systematic optimization of the electronic properties of aryl fluorosulfates. The versatility of this O-sulfation strategy was demonstrated in the scalable syntheses of a variety of complex molecules carrying sulfate diesters at various positions, including monosaccharides, disaccharides, amino acid, and steroid. Selective hydrolytic and hydrogenolytic removal of the aryl masking groups from sulfate diesters yielded the corresponding O-sulfated products in excellent yields. This strategy provides a powerful tool for the synthesis of O-sulfated bioactive compounds.

Dr. Supriya Dey¹

¹Harvard University

E-mail: supriyadey86@gmail.com

In this talk, I will discuss the development and application of Computer-Program in the synthesis of complex oligosaccharides. Over the years the synthesis of complex oligosaccharide has been a challenging task for the synthetic chemist. The development of the computer program, namely, Optimer (1999) and Auto-CHO (2019) by Wong’s group simplified the synthesis of complex oligosaccharides. The program is based on the Relative Reactivity Value (RRV) of thioglycoside donor and was successfully employed for the one-pot synthesis of various oligosaccharides including heparin sulfate, heparin-based anticoagulants Fondaparinux and Idraparinux.

Samir Ghosh

University of Toledo

E-mail: samir.ghosh@utoledo.edu

Oligosaccharides and glycoconjugates play crucial roles in various biological processes and thus have attracted tremendous attention in the synthetic and biological communities over the past number of decades. As a contribution along these lines, we have developed efficient synthetic routes to access anomeric aminooxy Globo H, a hexasaccharide which is a tumor associated carbohydrate antigen (TACA). Globo H hexasaccharide was synthesized in an overall 7.8% yield employing a convergent [3+3] strategy that revealed an anomeric aminooxy group used for conjugation to oxidized PS A1 via an oxime linkage. Globo H-PS A1, formulated with adjuvants monophosphoryl lipid A and Titer Gold. After immunization an antigen specific immune response was observed in ELISA with anti-Globo H IgG/IgM antibodies. Specificity of the corresponding antibodies was determined by FACS showing cell surface binding to Globo H-positive cancer cell lines MCF-7 and OVCAR-5. The anti-Globo H antibodies also exhibited complement-dependent cellular cytotoxicity against MCF-7 and OVCAR-5 cells.

Ashley DeYong

Indiana University

E-mail: adeyong@iu.edu

The O-linked fucose post-translational modification has been shown to play an important role in the Notch signaling pathway. Despite knowing the importance of this modification, there still remains information to be gained through chemical synthesis, in that this can allow for higher quantities of pure material. This work primarily focuses on the chemical syntheses of fucosylated amino acid building blocks. These building blocks can then be incorporated into larger biomolecular structures to probe the structure and function of these systems to gain further insight regarding the importance of these modifications. These building blocks will also be used directly in SPPS. Chemical syntheses of these targets can be challenging because of the acid-labile linkage of fucose, and a fast and effective way to synthesize these targets is yet to be determined. An automated flow chemistry approach can address the long reaction times of the previous syntheses of these targets and can also address the high commercial cost of these building blocks and make them more accessible. Automating the syntheses of these building blocks will allow for more straightforward optimization and reproducibility. Herein we present the progress towards developing an automated flow method using minimal steps to synthesize O-linked fucosylated amino acid building blocks.

“An Unnatural ≤-Linked Mucin-1 Glycopeptide Vaccine Can Elicit Protective Antibodies Towards the Native Antigen”

Hunter McFall-Boegeman,^†,° Zahra Rashidijahanabad,^†,° Xuanjun Wu,^¬‚† Kunli Liu,^†,° Christian Pett,^•,# Jin Yu,^• Manuel Schorlemer,^•,# Sherif Ramadan,^†,°∂ Sandra Behren,^•,# Ulrika Westerlind,^•,# and Xuefei Huang*,^†,°,*

†Department of Chemistry, ‚°Institute for Quantitative Health Science and Engineering, and *Department of Biomedical Engineering, Michigan State University, East Lansing, Michigan 48824, USA

^¬National Glycoengineering Research Center, Shandong University, Qingdao, Shandong 266237, China

^•Leibniz-Institut for Analytische Wissenschaften‚ SAS.V., 44227, Dortmund, Germany

^#Department of Chemistry, Ume• University, 901 87 Ume•, Sweden

^∂Chemistry Department, Faculty of Science, Benha University, Benha, Qaliobiya 13518, Egypt

E-mail: mcfallbo@chemistry.msu.edu

Cancer is one of the leading causes of death in the United States. Because of its overexpression and adherent glycosylation on multiple types of cancer, Mucin-1 (MUC1) has emerged an attractive antigen for vaccine development. Vaccination studies have found that the peptide sequence SAPDTRPAP, from the tandem repeat region, is an important epitope. This region includes an O-glycosylation site. The stability of O-glycosylated antigen containing vaccines has long been a concern. In an attempt to increase the stability of the glycopeptide we synthesized a MUC1 glycopeptide containing the Thomsen-Friedenreich (Tf) antigen linked to the peptide backbone through the unnatural a-linkage. Compared to the a-natural linkage the MUC1-a, Tf antigen was more stable to enzymatic degradation. Upon conjugation to the carrier bacteriophage Qa and vaccination in clinically relevant transgenic mice, high titers of IgG antibodies capable of recognizing the natural MUC1-a±Tf antigen were elicited. Additionally, these cross-reactive antibodies were able to kill MUC1 expressing tumor cells. Taken together, the evidence points to a simple switch of glycopeptide stereochemistry can improve design of vaccines targeting glycopeptides.

“Profiling Gangliosides Expression in THP-1 macrophages upon LPS stimulation in”

Sonia Tomar¹, Xue-Long Sun^*1

¹Department of Chemistry, Chemical and Biomedical Engineering and Center for Gene Regulation in Health and Disease (GRHD), Cleveland State University, Cleveland, OH 44115

E-mail: s.tomar@vikes.csuohio.edu

Glycosphingolipids (GSLs), consisting of hydrophilic oligosaccharides and hydrophobic ceramide, are crucial components of plasma membranes and play key roles in fundamental biological processes such as development, cell adhesion, and signaling. In particular, sialo glycosphingolipids (gangliosides containing one or more sialic acid residues) are involved in cell-cell recognition and adhesion and signal transduction within specific cell surface microdomains, lipid rafts, and glycosphingolipid-enriched microdomains. Alteration of GSL expression are involved in the pathogenesis of many human diseases, including cancer and inflammatory diseases. More importantly, gangliosides are involved in LPS induced macrophage activation, which further involved in inflammation and production of cytokines. In this research, we investigate ganglioside expression changes, especially GM1, GM3, GD3 of THP-1 macrophages LPS stimulation using HPLC-fluorescence method. Specifically, we found that GM3, GM1 and GD3 decreased upon LPS stimulation. In comparison, GM3 is present in THP-1 macrophages in higher amount than GM1, GD3. GM3 present on cell membrane is 50% of total cell lysate. Cell lysate GM3 decreased to 32% after LPS stimulation at 6hrs. Cell membrane GM3 reduced to 42% at 6hr after LPS stimulation. Overall, GM3 at in cell lysate and cell membrane showing significant decrease with LPS stimulation at 6hr than other time interval. GM1 which is present less than GM3 in THP-1 macrophages. 75% of GM1 present on cell membrane as compared to total cell lysate GM1in cell lysate reduced to 37% at 24hr after LPS stimulation. GM1 showed maximum decrease at 6hr on cell membrane to 35% after LPS stimulation. GD3 is present least in THP-1 macrophages in comparison to GM3 and GM1. 87% of total cell lysate GD3 was present on cell membrane. GD3 on cell membrane decreased to 38% at 24hr after LPS stimulation and GD3 in cell lysate decreased to 24% at 48hr after LPS stimulation. In cell lysate, maximum decrease of GM3 observed at 6hr, GM1 at 24hr and GD3 at 48hr was observed after LPS stimulation while on cell membrane, maximum decrease for GM3, GM1 observed at 6hr and GD3 at 24hr. Overall, we observed significant GM1, GM3, GD3 decrease of THP-1 macrophages LPS stimulation at particular time interval, indicating they may play important role in LPS induced macrophage activation.