Synthesis and Bio-evaluation of Aminoferrocene-Based Anticancer Prodrugs as Potent Ferroptosis Inducers

Glutathione peroxidase 4 (GPX4) plays a critical role in the ferroptosis pathway, emerging as a promising drug target for the treatment of refractory tumors. However, the poor selectivity and toxicity problem of current GPX4 covalent inhibitors have hampered the development of GPX4-targeted cancer therapy. Benefiting from the reactive oxygen species (ROS)-initiated activation of N-alkylaminoferrocenes (NAAF), a series of NAAF-appended GPX4 inhibitors have been developed as novel ferroptosis-inducing prodrugs, particularly RSL3-NAAF hybrid I-1 and ML162-NAAF hybrid II-1. These two complexes displayed comparable anticancer activities with those of their precursor compounds, but with superior ferroptosis selectivity and exceptional safety profiles on normal cells. In this study, the efficient release of the GPX4 inhibitor from II-1 under high ROS conditions along with its significant ROS-inducing ability at both the molecular and cellular levels have been evidenced, leading to its potent inhibition on GPX4 and remarkable ferroptosis inducing potency. These data indicate promising aminoferrocene-based anticancer agents for further evaluation. The effectiveness of NAAF-based prodrug strategy may not only advance the development of ROS-responsive prodrugs for ferroptosis-related anticancer treatments, but also highlight the significance of metallocene-containing bioorganometallics for potential disease therapies.