Morusin targeting GDF15 enhances ferroptosis and overcomes cisplatin resistance in NSCLC.

BACKGROUND

The natural compound morusin (Mor) acts as a potent tumor suppressor in non-small cell lung cancer (NSCLC), but its potential to sensitize DDP and its direct targets are less understood. This work aims to investigate the DDP-sensitizing effects of Mor and the underlying mechanisms.

METHODS

Cell viability and drug synergy were assessed in NSCLC cells. Ferroptosis was evaluated by measuring lipid reactive oxygen species (ROS), iron accumulation, and the expression of ferroptosis markers. GDF15 was identified as a target via transcriptome sequencing. Its direct binding with Mor was confirmed by molecular docking. The ubiquitin-mediated degradation mechanism and its functional role in ferroptosis were validated using the proteasome inhibitor MG132, alongside GDF15 overexpression and knockdown models. Clinical relevance was assessed using TCGA database analysis.

RESULTS

Mor induces ferroptosis and significantly augments DDP sensitivity in both NSCLC and cisplatin-resistant A549 cells (A549/DDP). Mechanistically, Mor directly binds to GDF15 and promotes its ubiquitin-mediated degradation. Consequently, GDF15 overexpression reversed Mor-induced cytotoxicity and DDP sensitization. Furthermore, DDP exposure impairs intracellular GDF15 protein levels, and the Mor/DDP combination synergistically suppresses GDF15 in A549 cells. Notably, GDF15 expression is elevated in NSCLC cells compared to normal lung epithelial cells. However, A549/DDP cells exhibit diminished intracellular GDF15 protein relative to parental cells, while GDF15 transcription is upregulated. Knockdown of GDF15 augmented DDP sensitivity in resistant cells.

CONCLUSION

Mor reverses DDP resistance by inducing GDF15 degradation and ferroptosis, suggesting that Mor-based combination therapy holds promise in treating NSCLC.