Chemo-photothermal nanoplatform with diselenide as the key for ferroptosis in colorectal cancer

Colorectal cancer (CRC) is a prevalent clinical malignancy of the gastrointestinal system, and its clinical drug resistance is the leading cause of poor prognosis. Mechanistically, CRC cells possess a specific oxidative stress defense mechanism composed of a significant number of endogenous antioxidants, such as glutathione, to combat the damage produced by drug-induced excessive reactive oxygen species (ROS). We report on a new anti-CRC nanoplatform, a multifunctional chemo-photothermal nanoplatform based on Camptothecin (CPT) and IR820, an indocyanine dye. The implementation of a GSH-triggered ferroptosis-integrated tumor chemo-photothermal nanoplatform successfully addressed the poor targeting ability of CPT and IR820 while exhibiting significant growth inhibitory effects on CRC cells. Mechanistically, to offset the oxidative stress created by the broken SeSe bonds, endogenous GSH was continuously depleted, which inactivated GPX4 to accumulate lipid peroxides and induce ferroptosis. Concurrently, exogenously administered linoleic acid was oxidized under photothermal conditions, resulting in an increase in LPO accumulation. With the breakdown of the oxidative stress defense system, chemotherapeutic efficacy could be effectively enhanced. In combination with photoacoustic imaging, the nanoplatform could eradicate solid tumors by means of ferroptosis-sensitized chemotherapy. This study indicates that chemotherapy involving a ferroptosis mechanism is a viable method for the treatment of CRC.