Chemotherapeutic drug scavenger-based combination therapy toward treating triple-negative breast cancer.

Abstract

Triple-negative breast cancer (TNBC) is resistant to most antitumor treatments, leaving chemotherapy as the primary option. Although doxorubicin (Dox) in combination with other therapies is promising for TNBC management, the combined effect is still compromised by the dose-limiting toxicities of Dox. Here, we developed a chemotherapeutic drug scavenger (CDS) by encapsulating GC-rich DNA-preferred binding targets of Dox-within an erythrocyte membrane functionalized with a normal tissue-targeting (NTT) peptide. Mimicking the structure of the cell nucleus, CDS selectively absorbs and neutralizes Dox in susceptible normal organs while sparing tumor tissues. This targeted detoxification allows for safe escalation of the Dox dose to 15 mg/kg, three times the standard 5 mg/kg, without observable toxicity. Such a high Dox dose enabled by CDS pretreatment significantly inhibited the post-operative residual/metastasized 4T1 tumor growth, regardless of the early or later stages of the tumor. Also, delivery of a high dose of Dox into the 4T1 tumor could profoundly increase the G2/M arrest, facilitating the combination therapy with a low-powered radiation of 2 Gy. Further, tumor exposure to high Dox amounts could convert the 4T1 tumor microenvironment from 'cold' to 'hot', leading to improved infiltration of immune cells, including T cells, dendritic cells, and macrophages. Overall, this study demonstrates how the safe injection of high amounts of Dox enabled by CDS detoxification could augment and extend Dox's functionality combined with surgery, radiotherapy, and cell therapy for TNBC treatment.