Synergistic induction of ferroptosis by targeting HERC1-NCOA4 axis to enhance the photodynamic sensitivity of osteosarcoma.

Over the past 30 years, the survival rate for osteosarcoma (OS) has remained stagnant, indicating persistent challenges in diagnosis and treatment. Photodynamic therapy (PDT) has emerged as a novel and promising treatment modality for OS. Despite apoptosis being the primary mechanism attributed to PDT, it fails to overcome issues such as low efficacy and resistance. Ferroptosis, a Fe-dependent cell death process, has the potential to enhance PDT's efficacy by increasing reactive oxygen species (ROS) through the Fenton reaction. In this study, we investigated the anti-tumor mechanism of PDT and introduced an innovative therapeutic strategy that synergistically induces apoptosis and ferroptosis. Furthermore, we have identified HERC1 as a pivotal protein involved in the ubiquitination and degradation of NCOA4, while also uncovering a potential regulatory factor involving NRF2. Ultimately, by targeting the HERC1-NCOA4 axis during PDT, we successfully achieved full activation of ferroptosis, which significantly enhanced the anti-tumor efficacy of PDT. In conclusion, these findings provide new theoretical evidence for further characterizing mechanism of PDT and offer new molecular targets for the treatment of OS.