Dual tumor microenvironment-responsive albumin nanoplatform integrates conditional PROTAC activation with starvation and ferroptosis for synergistic cancer therapy.

[BACKGROUND] Proteolysis-targeting chimeras (PROTACs) have emerged as a promising cancer therapeutic approach by targeting protein degradation to address undruggable targets and drug resistance associated with conventional therapies, yet their clinical translation is hindered by poor solubility and non-specific toxicity. Additionally, tumor heterogeneity and biological complexity frequently limit the efficacy of monotherapies, necessitating the development of multifunctional delivery systems.

[RESULTS] We engineered a dual microenvironment-responsive albumin to integrate conditional PROTAC activation with metabolic starvation and ferroptosis for synergistic antitumor efficacy within a unified therapeutic cascade. Ferrocene (Fc)-modified human serum albumin (HSA) via coupling chemistry was electrostatically complexed with glucose oxidase (GOD) and co-assembled with an azobenzene (AZO)-caged ARV-771 prodrug to yield HSA-Fc-GOD@ARV-771(AZO) nanoparticles that exhibited pH-triggered disassembly in acidic tumor environments. the released GOD consumes glucose and oxygen to generate hydrogen peroxide while inducing metabolic starvation and exacerbating hypoxia. The intensified hypoxia triggers nitroreductase to cleave the prodrug linker and release the active ARV-771, which subsequently degrades bromodomain containing protein 4. This degradation directly suppresses tumor cell proliferation and downregulates glutathione peroxidase 4 expression to sensitize cancer cells to oxidative damage. Concurrently, the ferrocene component converts the generated hydrogen peroxide into hydroxyl radicals via the Fenton reaction to amplify lipid peroxidation and ferroptotic cell death. The nanoplatform suppressed lung cancer cell viability to 10.8% in vitro and achieved 94.3% tumor growth inhibition in xenograft models without observable systemic toxicity.

[CONCLUSIONS] This study demonstrates a precision therapeutic paradigm. It exploits tumor microenvironment characteristics to couple conditional drug activation with starvation and ferroptosis. This strategy offers a translatable framework for next generation's cancer treatment.