Abstract 598: Utilization of Meditope Biosciences SnAP technology to enhance antibody internalization

Abstract

Abstract Therapeutic antibodies can bind to cell-surface receptors, prompting receptor internalization and effectively blocking further stimulation by the cognate receptor ligands. Receptor internalization is also exploited by antibody-drug conjugates (ADC) to promote effective delivery of cytotoxic payload to the inside of the cell. Meditope Biosciences has developed a way to use its SnAP (Site-specfi novel Antibody Platform) technology to promote enhanced internalization of antibody receptor complexes. The Meditope's SnAP technology functionally enables antibodies to bind to specific peptides, termed “meditopes’, and this property can be used to directly facilitate receptor crosslinking when meditope enabled antibodies are bound to cell surface receptors. Here we show that the affinity of the meditope enabled antibodies (trastuzumab anti-HER2 and gemtuzumab anti-CD33) for cell surface receptors results in the formation of an antibody receptor complex that can be detected by native gel electrophoresis and gel filtration. Binding of the meditope peptide to the enabled antibody does not interfere with normal antigen-antibody interaction and the formation of the peptide bound antibody:receptor complexes results in accelerated internalization of the complex, as shown by decreased surface fluorescence of Alexa 488-labeled SnAP peptides as well as by increased pHrodo-Red increased fluorescence of internalized antibodies when they reach the endosomal compartment. Finally, as a result this increased internalization, the downregulation of specific antibody mediated signaling events are much more effectively downregulated in the presence of the meditope peptide complex as compared to the antibody alone. Citation Format: Calin D. Dumitru, Elisabeth Gardiner, John Williams, Cindy Zer. Utilization of Meditope Biosciences SnAP technology to enhance antibody internalization. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 598.