ABSTRACT Ferroptosis is a form of regulated cell death that is characterized by iron‐dependent lipid peroxidation. This process is regulated by specific metabolites, the lipid composition of the cells, redox‐active iron, and antioxidant mechanisms. Although numerous regulators have been identified over the past decade, exploring other mechanisms, particularly from non‐coding genomic regions, can build a thorough understanding of the multifaceted regulatory processes underlying ferroptosis. MicroRNAs (miRNAs) play a crucial role in gene regulation and cellular functions. Through a CRISPR KO screen, we identified miR‐940 as a negative regulator of ferroptosis. Overexpression of miR‐940 in several cell lines consistently suppressed ferroptosis induced by system x c − inhibition. Notably, multiple cancer patient cohorts with elevated miR‐940 levels exhibit reduced survival. Integrated bioinformatic, transcriptomic, and proteomic analyses revealed that miR‐940 decreases the expression of ACSL4, LPCAT3, DMT1, and NCOA4, and simultaneously increases levels of GPX4. Pharmacological inhibition of GPX4 attenuated the protective effect of miR‐940, indicating that its primary anti‐ferroptotic activity is mediated through GPX4. Overall, these mechanistic insights link gene rewiring to reduced levels of redox‐active iron and diminished lipid peroxidation, mediating ferroptosis suppression. These findings provide a defined regulatory network, presenting a novel target for therapeutic exploration in susceptible cancers.
Kolak et al. (Fri,) studied this question.