Lapatinib induces ferroptosis in osteosarcoma via the SLC1A5-GPX4 axis

Osteosarcoma (OS) continues to have a poor prognosis, underscoring the urgent need for novel therapeutic strategies. Ferroptosis, an iron-dependent form of regulated cell death, offers a promising alternative to circumvent apoptosis resistance. Lapatinib (Lap), a well-known EGFR/HER2 inhibitor, exhibits potential beyond its canonical targets.

The anti-OS effects of Lap were evaluated in U2OS and HOS cell lines using CCK-8, colony formation, Transwell, and flow cytometry assays. Its potential target was identified through molecular docking, molecular dynamics simulations, CETSA, and DARTS. Ferroptosis induction was assessed by measuring key markers (MDA, GSH, Fe²⁺, lipid ROS) and related proteins (SLC1A5, GPX4). An in vivo xenograft mouse model was used to confirm ferroptosis induction.

Lap significantly inhibited OS cell proliferation, migration, and invasion, and induced cell death predominantly via ferroptosis. It elevated lipid peroxidation and triggered characteristic ferroptotic events (Fe²⁺ accumulation, lipid ROS, GSH depletion), all of which were reversed by the ferroptosis inhibitor DFO. Moreover, SLC1A5 knockdown attenuated lapatinib-induced ferroptosis, whereas SLC1A5 overexpression rescued it, confirming that SLC1A5 is a functional target. Molecular docking, CETSA, and DARTS supported a potential interaction between lapatinib and SLC1A5. Mechanistically, lapatinib disrupted glutamine uptake and GSH synthesis, leading to GPX4 suppression and ferroptosis. In vivo, lapatinib suppressed tumor growth and downregulated SLC1A5/GPX4, effects that were reversible by DFO.

This study reveals a novel mechanism by which lapatinib inhibits OS via the SLC1A5-GPX4 axis to induce ferroptosis, providing a preclinical rationale for further evaluation of lapatinib repurposing in osteosarcoma.