RSL3 promotes PARP1 apoptotic functions by distinct mechanisms during ferroptosis.

backgroundThe classical ferroptosis activator RSL3 targets enzymes with nucleophilic active sites, primarily acting on glutathione peroxidase 4 (GPX4) to trigger ferroptosis. Recent studies identify RSL3 as a potential pro-apoptotic agent. However, the mechanism by which RSL3 induces apoptosis during ferroptosis remains elusive. Poly(ADP-ribose) polymerase (PARP1) determines cell fate in response to DNA damage, where its loss or cleavage by activated caspase-3 induces apoptosis to attenuate tumor progression. We elucidate a novel mechanism underlying PARP1 regulation, encompassing both its caspase-dependent cleavage and full-length depletion during RSL3-mediated ferroptosis-apoptosis crosstalk.

methodsTo investigate the role of RSL3 during ferroptosis, we treated several cancer cells of different histological types with varying doses of RSL3 to induce apoptosis. The regulatory proteins of PARP1 were analyzed using real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot analysis. The N

resultsRSL3 triggers two parallel apoptotic pathways via increasing reactive oxygen species (ROS) production during ferroptosis: (1) caspase-dependent PARP1 cleavage and (2) DNA damage-dependent apoptosis resulting from reduced full-length PARP1. The latter occurs through inhibition of METTL3-mediated m

conclusionsRSL3 orchestrates ferroptosis-apoptosis crosstalk via PARP1, demonstrating therapeutic potential against tumorigenesis, particularly in PARPi-resistant malignancies.