Self-Delivery Nanotherapeutics for Tumor Low-Temperature Photothermal Immunotherapy through Cascade Heat Shock Protein and Inflammation Inhibition.

The clinical efficacy of immunotherapy in triple-negative breast cancer (TNBC) faces dual barriers: poor immunogenicity and a suppressive tumor microenvironment. While low-temperature photothermal therapy (LTPTT) has emerged as a potential immunostimulatory strategy, its efficacy is counteracted by heat shock protein (HSP) induction and COX-2/PGE2-mediated immunosuppression. To address these challenges, we developed a multifunctional immunophotothermal nanoplatform (IAC NPs) through rational engineering of human serum albumin for combinatorial delivery of indocyanine green as a photothermal converter, atovaquone for HSP70-mediated thermoresistance blockade, and celecoxib for COX-2/PGE2 pathway inhibition. The IAC NPs achieved tumor-targeted delivery and NIR-activated immunogenic phototherapy while coinhibiting HSP70 (via atovaquone's mitochondrial complex III blockade) and the COX-2/PGE2 immunosuppressive axis (via celecoxib). The triple medications' synergistic action improved the expression of effector memory T cells, boosted the maturation of dendritic cells, encouraged the infiltration of CD4+ and CD8+ T cells, and reduced regulatory T cells. In vivo, the IAC NPs mediated profound suppression of both primary tumors and metastatic dissemination while exhibiting optimal biocompatibility for clinical translation. Our work validates a nanoenabled self-delivery system that augments the efficacy of LTPTT immunotherapy against TNBC by orchestrating coordinated inhibition of HSPs and inflammatory responses.