Isoalantolactone induces apoptosis of non-small cell lung cancer cells by targeting EGFR and MET kinases and ROS generation

Extensive research efforts are necessary to develop effective treatments for non-small cell lung cancer (NSCLC), one of the most lethal malignancies. To address limitations of gefitinib (GEF) in NSCLC treatment, we investigated the anticancer activity of isoalantolactone (IAL) in HCC827 cells with or without GEF resistance. MTT cell viability and soft agar assays were performed to evaluate cytotoxicity of IAL. In vitro kinase assays and molecular docking were used to assess the inhibition of EGFR and MET kinases. Western blot analysis was conducted to examine protein levels involved in apoptosis signaling, cell cycle regulation, and mitochondrial membrane permeability. Flow cytometry was utilized to analyze cell cycle, reactive oxygen species (ROS) generation, apoptosis, and caspase activation. IAL exhibited cancer-selective cytotoxicity. The in vitro kinase assay demonstrated that IAL significantly inhibited EGFR and MET kinase activities. This finding was further supported by molecular docking. Western blot analysis revealed that IAL treatment downregulated phosphorylation of EGFR, MET, and AKT kinases. In addition, IAL induced G2/M phase cell cycle arrest, ROS generation, and caspase activation. Z-VAD-FMK pretreatment confirmed the crucial role of caspase activation in IAL-induced cytotoxicity. Further investigation into the therapeutic potential of IAL for treating NSCLC with various resistance mechanisms is warranted.