Corosolic acid inhibits EMT in lung cancer cells by promoting YAP-mediated ferroptosis.

Background: Corosolic acid (CA), a naturally occurring pentacyclic triterpenoid is renowned for its anticancer attributes. Previous studies have predominantly centered on the anticancer properties of CA in lung cancer, specifically its role in inducing apoptosis, however, investigations regarding its involvement in ferroptosis have been scarce.

Methods: The apoptotic and proliferative effects were evaluated by CCK8 and colony formation assay. Cell death and ROS generation were measured to assess the response of CA to iron death induction. Scratch and invasion assays were performed to verify the effect of CA on the invasive ability of lung cancer cells. Protein and mRNA expression were analyzed using Western blotting and qPCR. The CHX assay was carried out to detect protein half-life. Metabolite levels were measured with appropriate kits. Protein expression was detected through IF and IHC. A xenograft tumor model was established to investigate the inhibitory effect of CA on lung cancer in vivo.

Results: The current findings revealed that CA exerts its anticancer effect by inducing cell death, accompanied by the accumulation of lipid reactive oxygen species (ROS), hinting at the possible involvement of ferroptosis. Our experimental results further substantiated the significance of ferroptosis in the CA anticancer mechanism, as ferroptosis inhibitors were found to effectively rescue CA-induced cell death. Significantly, we demonstrated for the first time that CA could induce ferroptosis further by suppressing EMT in lung cancer cells. Additionally, CA could regulate GPX4 to induce ferroptosis, interestingly, CA downregulated GSH synthetase by inhibiting YAP rather than GPX4, thereby reducing GSH, inducing ferroptosis, and further suppressing EMT in lung cancer cells.We also discovered that GSS is a crucial downstream target of YAP in regulating GSH. Moreover, a xenograft mouse model indicated that CA could trigger ferroptosis in lung cancer cells by regulating YAP expression and GSH levels.

Conclusion: CA inhibited lung cancer cell metastasis by inducing ferroptosis. Our data offer the first evidence that CA induces ferroptosis in lung cancer cells by regulating YAP/GSS to modulate GSH, thereby further suppressing EMT. These results imply the potential of CA as an inducer of ferroptosis to inhibit lung cancer metastasis.