Abstract: Agents having cytotoxic activity, as well as compositions, uses, and methods relating thereto, are described herein. Certain steroid acid-peptide conjugates or moieties have the ability to induce killing or inhibition of proliferation of mammalian cells, in vitro or in vivo upon administration to a subject. The steroid acid-peptide conjugates include bile acids and bile acid analogs and peptides that may include a nuclear localisation signal or a portion thereof. Also described herein is a method for treating cancer, an autoimmune disease, or any other disease or disorder ameliorated by treatment with an antiproliferative drug in a subject in a subject with the cytotoxic agents described herein.

Abstract: Immunogen enhancers for admixture with an antigen of interest are described herein. The enhancers generally comprise a steroid acid and/or a steroid acid-peptide conjugate in an amount sufficient to improve or modify the adaptive immune response to antigens admixed therewith. In embodiments, the steroid acid may be a bile acid and the peptide may comprise one or more functional domains, such as a nuclear localization signal, which may facilitate antigen-presentation and/or antigen cross-presentation, thereby triggering improved cellular immunity, or improved cellular and humoral immunity, against the antigen.

Abstract: The present description relates to a conjugated compound comprising cholic acid (ChAc) or a variant thereof, the ChAc conjugated to a non-cell penetrating peptide comprising a nuclear localization sequence (NLS) conjugated to a compound of interest.

Abstract: Covalently modified polypeptide antigens having improved immunogenicity and/or stability, as well as compositions, cells, and methods relating thereto, are described herein. Polypeptide antigens are covalently conjugated to a one or more of steroid acid moieties to improve their stability and/or to trigger improved cellular immunity, or improved cellular and humoral immunity, against the antigen upon administration to a subject. The steroid acids include bile acids and bile acid analogs that enhance endocytosis and/or endosomal escape of endosomally trapped cargoes by potentiating enzymatic cleavage of sphingomyelin to ceramide within endosomal membranes. The steroid acid moieties may be pre-conjugated to a peptide, and the steroid acid-peptide moiety subsequently conjugated to the polypeptide antigen. The peptide may comprise one or more domains that impart an additional functionality to the modified polypeptide antigen.