Physician Assistant M.S.
Targeted antibody therapeutics are currently being developed for treatment of a wide variety of cancers. By extending the scope of targeted antibody therapeutics into a bispecific design, it has been shown that simultaneous targeting of the CD3 T cell receptor and cancer cell receptors is possible. While great success has been achieved with the use of bispecific agents, many of these agents are genetically fused antibody fragments that can only target one type of cancerous receptor. Here we describe a simple and straightforward method of spontaneously assembling bispecific antibody therapeutics. Using fusion proteins consisting of two dihydrofolate reductase proteins and an antibody single chain variable fragment (DHFR-DHFR-scFv), and a dimeric methotrexate species were are able to take advantage of the high binding affinity between DHFR and methotrexate to create varying sized Chemically Self-Assembled Antibody Nanorings (CSANs). By combining two different DHFR-DHFR-scFv proteins with our dimeric methotrexate species we are able to quickly and efficiently assemble bispecific rings of varying degrees of valance. Herein we describe the synthesis of a novel DHFR-DHFR-antiEpCAM protein and show that it selectively binds the EpCAM receptor overexpressed on the surface of MCF-7 breast cancer cells. We further show that combining the DHFR-DHFR-antiEpCAM and our previously described DHFR-DHFR-antiCD3 protein into a bispecific CSAN, we can successfully target both CD3+ T cells and MCF-7+ breast cancer cells simultaneously. Furthermore, we show that through simultaneous targeting we are able to induce specific cell lysis of the target MCF-7+ cells by the activated CD3+ T cells.
Masters of Science in Physician Assistant
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Gabrielse, K. A. (2015). Chemically Self-assembled Antibody Nanorings: A Novel Approach to Bispecific Design for Cancer Therapeutics [Masterʼs thesis, Bethel University]. Spark Repository. https://spark.bethel.edu/etd/221