Medina-Kauwe, L. K. | bioRxiv Science

bioRxiv2026

Next generation protein-corrole bio-assemblies provide effective tumoricidal treatment in a metastatic triple-negative breast cancer model

Assemblies that combine chemotherapeutics with tumor-targeting proteins are promising agents for treating resistant cancers but require full biochemical characterization before therapeutic deployment. We developed and optimized a HER3-targeting capsomere, HPK2.0, which forms stable nanoscale assemblies with cytotoxic corroles via electrostatic neutralization and shape complementarity. These nanocomplexes exhibit durable serum stability, HER3-dependent tumor invasion, and efficient endosomal escape, resulting in potent and selective cytotoxicity in triple-negative breast cancer (TNBC) cells. In an orthotopic metastatic TNBC model, systemic treatment with HPK2.0-corrole assemblies achieved 67-83% tumor regression, near-complete suppression of spontaneous lung metastasis, and a [~]2-fold improvement in survival relative to mock treatment, with minimal off-target toxicity. By integrating tumor specificity with therapeutic potency, this next-generation protein-corrole platform establishes a clinically scalable strategy for treating metastatic HER3-positive TNBC. SignificanceTriple-negative breast cancer (TNBC) is an aggressive disease with high rates of metastasis and mortality, largely because it lacks molecular targets for precision therapy. As a result, patients rely primarily on chemotherapy, which causes systemic toxicity and frequently fails to control metastatic spread. Here, we introduce a targeted therapeutic strategy in which a bioengineered protein selectively recognizes a receptor highly expressed in metastatic TNBC and delivers a potent cytotoxic payload directly into tumor cells. In mouse models, this approach produced robust tumor regression, markedly reduced lung metastases, extended survival, and showed minimal off-target toxicity. These findings establish a versatile platform for targeted treatment of TNBC and highlight a strategy that may be broadly applicable to other HER3-expressing cancers.

cancer biology↗

bioRxiv2021

Systemic ligand-mimicking bioparticles cross the blood-brain barrier and reduce growth of intracranial triple-negative breast cancer using the human epidermal growth factor receptor 3 (HER3) to mediate both routes

Crossing the blood-brain barrier (BBB) and reaching intracranial tumors is a significant clinical challenge for targeted therapeutics and contributes to the poor prognosis for most patients with brain malignancies. Triple-negative breast cancer (TNBC) has a high propensity for metastasis to the brain and lacks cell surface markers that can be recognized by current targeted therapies used in the clinic, thus limiting therapeutic options. The human epidermal growth factor receptor HER3 (or ErbB3) has emerged as a biomarker of therapeutic resistance and metastasis in a growing range of tumor types and may serve as a possible therapeutic target for TNBC. Accordingly, we have developed HER3-targeted biological particles (bioparticles) that assume polyhedral capsid shapes when encapsulating nucleic acid cargo, forming nano-nucleocapsids (NNCs). The NNCs exhibit systemic homing to resistant and metastatic breast tumors, including TNBC, due to the high cell surface densities of HER3 on these tumors. Here we describe our discovery that HER3 is also prominently expressed on the brain endothelium and can mediate the passage of HER3-targeted NNCs across the BBB and into triple-negative breast tumors localized in the brain. Our findings show that HER3 is present at high levels on the vasculature (but not extravascular parenchyma) of both mouse and human adult brain specimens and associates with the extravasation of systemic HER3-targeted NNCs in mice and in a human model of the BBB (BBB chip). Furthermore, systemically delivered NNCs carrying tumoricidal agents reduced the growth of intracranial TNBC tumors in mice (representing metastatic breast tumors that have established in the brain) and exhibited improved therapeutic profile compared to current therapeutic interventions (liposomal doxorubicin) used in the clinic. This study addresses the major clinical problem of systemically delivering targeted therapeutics across the blood-brain barrier (BBB), and demonstrates a new route for not only accomplishing this but also for reaching tumors localized in the brain.

cancer biology↗