The novel thioredoxin reductase inhibitor butaselen suppresses lung cancer by inducing oxidative stress

Lung cancer is one of the leading causes of cancer-related deaths worldwide with limited treatment options available. The anti-tumor effects of the TrxR inhibitor Butaselen (BS/BS1801) on lung cancer and its underlying mechanisms remain unknown. This study utilized lung cancer cell lines, LLC1-bearing mice models, and organoids to detect the inhibitory effects of BS on lung cancer. The ROS-induction and apoptotic role of BS on lung cancer cells and molecular mechanisms were assessed with flow cytometry, western blot, Co-IP, real-time PCR, ChIP, reporter gene assay, ELISA, and bisulfite pyrosequencing. BS can effectively inhibit lung cancer both in vitro and in vivo, by triggering ROS-induced apoptosis. The inactivation of NF-κB and MAPK signaling pathways, along with the activation of PI3K-Akt and HBP1 signaling pathways, are involved in BS's suppression of lung cancer. HBP1 is a novel downstream target of the Trx system. The activation of HBP1 by BS is dependent on ROS accumulation and further leads to the transcriptional inhibition of DNMT1 and the demethylation of the whole genome, as well as the promoters of p21 and HOXA9. The TrxR/Trx inhibitor butaselen suppresses lung cancer by triggering ROS-induced apoptosis. This study provides a novel and effective regimen for treating lung cancer.