Dual-Targeting Strategy to Repurpose Cetuximab with HFn Nanoconjugates for Immunotherapy of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a highly aggressive and treatment-resistant malignancy characterized by the lack of targeted therapies and poor clinical outcomes. Here, we present a dual-targeting strategy combining the anti-EGFR monoclonal antibody cetuximab (CTX) with H-ferritin (HFn), a nanoparticle targeting transferrin receptor 1 (TfR1), for potential immunotherapy in CTX-resistant tumors. The HFn–CTX nanoconjugate exhibited favorable biophysical properties and good tumor accumulation and significantly enhanced antibody-dependent cellular cytotoxicity (ADCC) in TNBC spheroids compared to CTX alone. Conversely, glioblastoma spheroids did not exhibit comparable reactivity. This effect correlated with elevated cell-surface EGFR expression and plasma-membrane lingering of the nanoconjugate in TNBC cells, facilitating robust immune activation. Biodistribution studies showed selective accumulation of the HFn–CTX nanoconjugate in TNBC tumors in vivo. These findings highlight the potential of HFn–CTX nanoconjugates to repurpose CTX for refractory cancers that express EGFR at high levels, such as TNBC, leveraging dual-receptor targeting to amplify immune-mediated cytotoxicity and overcome resistance.