Abstract

Ibrutinib (IBT), the first-in-class inhibitor of Bruton’s tyrosine kinase (BTK), has demonstrated clinical activity against various B-cell malignancies. Aside from its therapeutic mechanism through BTK inhibition, IBT has other target sites reported for cancer therapy, leading us to investigate whether IBT has unreported targets. Our study revealed that IBT can inhibit SMMC-7721 cells through irreversible inhibition of mammalian thioredoxin reductase enzymes. Further study demonstrated that IBT can cause cellular reactive oxygen species elevation and induce cancer cell apoptosis. The discovery of a new target of IBT sheds light on better understanding its anticancer mechanisms and provides a theoretical foundation for its further use in clinical therapy.