Biomimetic Prussian blue nanocomplexes for chemo-photothermal treatment of triple-negative breast cancer by enhancing ICD

Drug-induced immunogenic cell death (ICD) can efficiently inhibit tumor growth and recurrence through the release of tumor-associated antigens which activate both local and systemic immune responses. Pyroptosis has emerged as an effective means for inducing ICD; however, the development of novel pyroptosis inducers to specifically target tumor cells remains a pressing requirement. Herein, we report that Cinobufagin (CS-1), a main ingredient of Chansu, can effectively induce pyroptosis of triple-negative breast cancer (TNBC) cells, making it a potential therapeutic agent for this kind of tumor. However, the application of CS-1 in vivo is extremely limited by the high dosage/long-term usage and non-selectivity caused by systemic toxicity. To address these drawbacks, we developed a new nanomedicine by loading CS-1 into Prussian blue nanoparticles (PB NPs). The nanomedicine can release CS-1 in a photothermal-controlled manner inherited in PB NPs. Furthermore, hybrid membrane (HM) camouflage was adopted to improve the immune escape and tumor-targeting ability of this nanomedicine, as well. In vitro assays demonstrated that the chemo-photothermal combination treatment produced high-level ICD, ultimately fostering the maturation of dendritic cells (DCs). In vivo anti-tumor assessments further indicated that this strategy not only efficiently inhibited primary growth of MDA-MB-231 cells and 4T1 cells-bearing models but also efficiently attenuated distant tumor growth in 4T1 xenograft model. This was mechanistically achieved throuh the promotion of DCs maturation, infiltration of cytotoxic T lymphocyte into the tumor, and the inhibition of Treg cells. In summary, this work provides a novel strategy for efficient TNBC therapy by using nanomaterials-based multimodal nanomedicine through rational design.