Licochalcone A promotes SP1/DNA-PKcs-dependent NHEJ repair to prevent ferroptosis and attenuate hepatic ischemia-reperfusion injury.

BACKGROUND

Ferroptosis, an iron-dependent form of cell death driven by lethal lipid peroxidation, is implicated in various pathological conditions. Despite its clinical significance, the development of effective ferroptosis inhibitors remains challenging, necessitating the exploration of novel therapeutic candidates. Natural plant products, with their structural diversity, represent a promising source of such compounds.

PURPOSE: Our previous screening identified licochalcone A (LA), a flavonoid derived from Glycyrrhiza uralensis, as a potent ferroptosis inhibitor. In this study, we further investigate its underlying molecular mechanisms.

STUDY DESIGN AND

METHODS

We investigated the mechanism of LA in RSL3-treated HT1080 cells. Using RNA-sequencing and bioinformatic analysis, we identified the candidate gene PRKDC and its transcriptional factor SP1. To determine whether LA inhibits ferroptosis through the SP1/DNA-PKcs axis, we generated PRKDC knockout HT1080 cells and inhibited SP1 expression. Finally, we validated LA's function and mechanism in a ferroptosis model induced by liver ischemia-reperfusion (I/R) injury.

RESULTS

We elucidate a previously unrecognized mechanism by which LA inhibits ferroptosis, independent of radical scavenging or iron chelation. RNA-seq and bioinformatics revealed LA activates transcription factor SP1, which upregulates PRKDC to enhance DNA-PKcs-mediated NHEJ repair, thereby suppressing ferroptosis-associated DNA damage. Additionally, SP1 inhibition or PRKDC knockout abolished LA's protective effects in RSL3-treated HT1080 cells. Importantly, the therapeutic potential of LA via the SP1/DNA-PKcs axis was validated in a clinically relevant model of liver ischemia-reperfusion (I/R) injury. LA treatment significantly mitigated hepatic damage by reducing lipid peroxidation and γ-H2AX accumulation, with these effects dependent on DNA-PKcs activity.

CONCLUSIONS

Our findings establish a novel connection between DNA repair pathways and ferroptosis suppression, positioning LA as a unique therapeutic candidate. By targeting the SP1/DNA-PKcs axis, this study not only provides a mechanistic foundation for LA-based therapies but also highlights its translational potential for treating ferroptosis-related diseases.