In vivo imaging of ferroptosis through nanodynamic changes in lipid membranes.

Ferroptosis emerged as a cell death modality for drug resistant cancer cells, but there are currently no available biomarkers for imaging ferroptosis based therapies. To address this gab, we evaluated the nanodynamic changes in lipid membranes occurring during cell death to explore potential targeting opportunities to image cell death. We nano-sized gaps at late stages of ferroptosis can serve as entry points for dyes that can bind to cellular structures. These changes were accompanied with cellular signaling components similar to platelet activation, with phosphatidyl serine emerging on the surface of the cells and therefore as a potential target for imaging of programed cell death, including ferroptosis. Taking advantage of these changes in cell membrane dynamics, we employed a novel tumor-seeking dye CJ215 that can label apoptotic cells as recently described by us. We show that CJ215 accumulates in ferroptotic cells both in vitro and in vivo by binding to phosphatidyl serine, a process that is prevented by inhibition of ferroptosis. Since phosphatidyl serine exposure also occurs during apoptosis, CJ215 can serve to image both apoptosis and ferroptosis based therapy.