Near-infrared light triggered multi-hit therapeutic nanosystem for tumor specific photothermal effect amplified signal pathway regulation and ferroptosis.

The high therapeutic resistance of tumor is the primary cause behind tumor recurrence and incurability. In recent years, scientists have devoted themselves to find a variety of treatments to solve this problem. Herein, we propose a multi-hit strategy that is based on the biodegradable hollow mesoporous Prussian blue (HMPB)-based nanosystem for tumor-specific therapy that encapsulated the critical heat shock protein 90 (HSP90) inhibitor 17-dimethylamino-ethylamino-17-demethoxydeldanamycin (17-DMAG). The nanosystem was further modified using thermotropic phase transition material star-PEG-PCL (sPP) and hyaluronic acid (HA), which offers near infrared light (NIR) responsive release characteristic, as well as enhanced tumor cell endocytosis. Upon cell internalization of 17-DMAG-HMPB@sPP@HA and under 808 nm laser irradiation, photothermal-conversion effect of HMPB directly kills cells using hyperthermia, which further causes phase transition of sPP to trigger release of 17-DMAG, inhibits HSP90 activity and blocks multiple signaling pathways, including cell cycle, Akt and HIF pathways. Additionally, the down-regulation of GPX4 protein expression by 17-DMAG and the release of ferric and ferrous ions from gradual degradation of HMPB in the endogenous mild acidic microenvironment in tumors promoted the occurrence of ferroptosis. Importantly, the antitumor effect of 17-DMAG and ferroptosis damage were amplified using photothermal effect of HMPB by accelerating release of ferric and ferrous ions, and reducing HSP90 expression in cells, which induced powerful antitumor effect