A mitochondria-targeted AIE photosensitizer for enhancing specificity and efficacy of ferroptosis inducer

Ferroptosis is a form of regulated cell death characterized by iron-dependent accumulation of lipid peroxidation and lethal reactive oxygen species (ROS). To date, misregulated ferroptosis has been implicated in several types of cancers, and ferroptosis inducers can be used to promote ferroptosis in tumor cells and play an anti-tumor role. However, the specificity and efficacy of ferroptosis inducers remain unsatisfactory. Here, a new mitochondria-targeted photosensitizer (PS) with aggregation-induced emission (AIE) characteristic named TCSVP was designed, which efficiently generates ROS in mitochondria after light exposure. TCSVP administration significantly sensitizes tumor cells to ferroptosis inducer (RSL3)-mediated cell death by specifically and light-dependently triggering a moderate ROS generation in vitro and in vivo. Mechanically, the expression levels of ferroptosis related proteins Acyl-CoA synthetase long-chain family member 4 (FACL4/ACSL4) and cyclooxygenase-2 (COX2) were increased in TCSVP/RSL3-treated cells after light exposure, coupled with decreased Glutathione peroxidase 4 (GPX4) activity and excessive malondialdehyde (MDA) accumulation. This study declared that light-induced moderate ROS generation within mitochondria in cancer cells by AIE-PS can be used to enhance the specificity and efficacy of ferroptosis inducers, bringing a new synergistic strategy for tumor intervention.