Synthesis of Human Cancer Associated Globo-H (MBr1) Glycosylamino Acid: Some Mechanistic and Conformational Reinvestigations

Synthetic carbohydrate-based anticancer vaccines: the Memorial Sloan-Kettering experience

Malignantly transformed cells can express aberrant cell surface glycosylation patterns, which serve to distinguish them from normal cells. This phenotype provides an opportunity for the development of carbohydrate-based vaccines for cancer immunotherapy. Synthetic carbohydrate-based vaccines, properly introduced through vaccination of a subject with a suitable construct, should be recognized by the immune system. Antibodies induced against these carbohydrate antigens could then participate in the eradication of carbohydrate-displaying tumor cells. Advances in carbohydrate synthetic capabilities have allowed us to efficiently prepare a range of complex, synthetic anticancer vaccine candidates. We describe herein the progression of our longstanding carbohydrate-based anticancer vaccine program, which is now at the threshold of clinical evaluation in several contexts. Our carbohydrate-based anticancer vaccine program has evolved through a number of stages: monomeric vaccines, monomeric clustered vaccines, unimolecular multi-antigenic vaccines and dual-acting vaccines. This account will focus on our recently developed unimolecular multi-antigenic constructs and potential dual-acting constructs, which contain clusters of both carbohydrate and peptide epitopes.

A practical total synthesis of globo-H for use in anticancer vaccines

An improved synthesis of the hexasaccharide MBr1 antigen (globo-H) is reported. Enhanced efficiency in the synthesis was necessary for the scale-up production of globo-H, in order to advance globo-H-based anticancer vaccines to clinical trials. The key features of the improved synthesis include preactivation-based glycosylations and a revised iodosulfonimidation/rearrangement.

Biologics through chemistry: total synthesis of a proposed dual-acting vaccine targeting ovarian cancer by orchestration of oligosaccharide and polypeptide domains

Carbohydrate and peptide-based antitumor vaccine constructs featuring clusters of both tumor associated carbohydrate antigens and mucin-like peptide epitopes have been designed, synthesized, and studied. The mucin-based epitopes are included to act, potentially, as T-cell epitopes in order to provoke a strong immune response. Hopefully the vaccine will simulate cell surface architecture, thereby provoking levels of immunity against cancer cell types displaying such characteristics. With this central idea in mind, we designed a new vaccine type against ovarian cancer. Following advances in glycohistology, our design is based on clusters of Gb(3) antigen and also incorporates a MUC5AC peptide epitope. The vaccine is among the most complex targeted constructs to be assembled by chemical synthesis to date. The strategy for the synthesis employed a Gb(3)-MUC5AC thioester cassette as a key building block. Syntheses of both nonconjugate and KLH-conjugated vaccines constructs have been accomplished.