A Novel Biphasic Antibody Targeting TFRC and HER2 in Breast Cancer Treatment 9417

Abstract Description Brain metastases remain a significant challenge with no currently successful therapies. Our recent work identified a “ferrophilic” phenotype in breast cancer cells, with reliance on iron to support growth and metastasis. This dependency is a promising therapeutic target, particularly as endothelial cells within the brain express higher levels of the transferrin receptor (TFRC). To achieve this, we developed a biphasic antibody designed to target TFRC and HER2. Using three breast cancer cell lines (ZR75-30, SK-BR-3, MDAMB-231), we demonstrated biphasic antibody-mediated disruption of iron metabolism, reduced proliferation, and increased apoptosis. Iron uptake, quantified using FerroOrange fluorescence, revealed altered homeostasis following a seven-day coculture with the biphasic antibody concentrations from 10 µg/mL to 1 ng/mL. TUNEL assays confirmed increased DNA fragmentation, demonstrating apoptosis induction in response to treatment. Efficacy of the biphasic antibody was further amplified by immune system engagement, as antibody-dependent cellular cytotoxicity assays revealed that NK cells enhanced therapeutic outcomes. This interaction underscores the dual functionality of the biphasic antibody: direct tumor targeting and recruitment of immune components to amplify antitumor effects. Our findings suggest biphasic antibodies targeting TFRC and HER2 are a promising therapeutic strategy to inhibit breast cancer metastasis, particularly within the blood-brain barrier. Funding Sources TTU New Faculty Startup Fund Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)