Mechanism of Saikosaponin D in regulating ferroptosis in patient-derived lung adenocarcinoma organoids via upregulation of ATF3/CHOP/CHAC1 signaling.

Lung adenocarcinoma (LUAD) is associated with high morbidity and mortality, making the discovery of novel and effective drugs treatment crucial.This study aimed to identify and evaluate antitumor saponin monomers with better effects using patient-derived organoid (PDO) models from patients with LUAD. We successfully constructed LUAD PDO models and confirmed their similarity to original tissues using immunohistochemistry and immu-nofluorescence staining. We performed drug sensitivity screening using the CCK-8 assay on five kinds of saponin monomers. saikosaponin D (SSD) was identified as having the highest antitumor potential and we then validated its efficacy. The antitumor mechanism of the saponin monomer was elucidated using RNA sequencing and confirmed using flow cytometry, ferrous ion determi-nation, RT-qPCR, western blotting, molecular docking and drug affinity responsive target stability experiment. SSD exhibited concentration-dependent inhibition of PDO viability in LUAD and inhibited proliferation and mi-gration of A549 lung cancer cells. Mechanistically, the results from the PDO and A549 cell ex-periments were consistent with those of the RNA sequencing analysis, indicating that SSD upreg-ulated the ATF3/CHOP/CHAC1 pathway, triggered endoplasmic reticulum stress, and induced ferroptosis. We demonstrate that SSD exerted stronger antitumor effects than cis-platin. These findings lay the groundwork for the potential application of SSD in the treatment of LUAD.