Bioresponsive cisplatin crosslinked albumin hydrogel served for efficient cancer combination therapy

Combination therapy is one of the potential strategies for tackling complicated tumor treatments like drug resistance. In this work, we have generated a therapeutic cisplatin-crosslinked albumin hydrogel (BC-Gel) that allows the local release of L-Buthionine-sulfoximine (BSO), cisplatin, and glucose oxidase (GOx) with distinct release kinetics. The BC-Gel with favorable biostimuli degradability and injectability could release therapeutic agents in a programmed manner within the tumor microenvironment (TME). The preferentially released BSO significantly suppressed the glutathione (GSH)-related cisplatin resistance and sensitized the tumor cells to cisplatin by inhibiting the γ-glutamylcysteine synthetase. Meanwhile, cisplatin achieved a sequential release and long-term treatment following the bioresponsive gel degradation under the combined action of chloride ions (Cl⁻) and proteinase in the body. In addition, the overproduced H₂O₂ of GOx-catalyzed glucose oxidation accelerated the depletion of existed GSH within cells and further weakened the cisplatin resistance, achieving enhanced tumor treatment together with a strong cell-killing effect. The above sequential drug release strategy based on the dual GSH depletion effect breaks the balance of the GSH-mediated redox TME and enhances the sensitivity of A549 cells to cisplatin forcefully, and provides a promising way for temporal control of drug release as well as efficient cancer combination therapy.