4‑Methoxydalbergione inhibits the tumorigenesis and metastasis of lung cancer through promoting ferroptosis via the DNMT1/system Xc‑/GPX4 pathway.

Lung cancer is responsible for the highest number of tumor‑related deaths worldwide. A flavonoid extracted from the heartwood of Dalbergia sissoo Roxb., 4‑methoxydalbergione (4‑MD), exhibits potent anticancer activity in multiple malignancies; however, the potential anticancer activity of 4‑MD in lung cancer has not yet been elucidated. In the present study, A549 cells were treated with increasing concentrations of 4‑MD, and cell viability was assessed using a Cell Counting Kit‑8 assay. In addition, colony formation, 5‑ethynyl‑2'‑deoxyuridine, wound healing and Transwell assays were conducted to evaluate cell proliferation, migration and invasion, respectively. Cell morphology was observed using transmission electron microscopy, and ferroptosis was determined using thiobarbituric acid reactive substance, lipid reactive oxygen species (ROS) and iron assays. Moreover, molecular docking was used to verify the potential interaction between 4‑MD and DNA methyltransferase 1 (DNMT1). Tumor‑bearing mice were established and treated with 10 or 30 mg/kg 4‑MD, and tumor volume and weight were recorded. Immunohistochemistry and Prussian blue staining were conducted to examine Ki‑67 expression and iron deposition in tumor tissues, and protein expression was further explored using western blot analysis. The results of the present study revealed that 4‑MD significantly inhibited cell proliferation, migration, invasion and epithelial‑mesenchymal transition in a concentration‑dependent manner. Notably, 4‑MD induced ferroptosis via increased lipid peroxidation, lipid ROS and Fe2+ levels. In addition, it was revealed that 4‑MD can directly bind to DNMT1 to inhibit expression, and inhibit solute carrier family 7 member 11 (SLC7A11; also known as cystine‑glutamate antiporter) and glutathione peroxidase 4 expression. Following DNMT1 overexpression, the observed antitumor activity and ferroptosis‑promoting effects of 4‑MD were partially reversed. Furthermore, 4‑MD significantly inhibited tumor growth in vivo, and reduced tumor volume and weight. In addition, Ki‑67 expression was reduced while iron deposition was increased in the tumor tissues of mice following treatment with 4‑MD. In conclusion, 4‑MD may exhibit anticancer activity through the promotion of DNMT1‑mediated cell ferroptosis. Thus, 4‑MD may have potential as a novel therapeutic agent in the treatment of lung cancer.