Targeting USP18 overcomes acquired resistance in hepatocellular carcinoma by regulating NCOA4 deISGylation and ferroptosis
Shengtao Ye, Junxin Chen, Ying Zheng, Mengmeng He, Yanqiu Zhang, Cheng Yang, Yingrong Leng, Enyi Wu, Lingyi Kong, Hao Zhang
Abstract
Targeted therapy resistance has become a major challenge for hepatocellular carcinoma (HCC) treatment. Triggering ferroptosis emerges as a promising strategy to overcome therapeutic resistance. Here, we have identified ubiquitin-specific protease 18 (USP18), a member of the deubiquitinating enzyme family, contributing to HCC resistance by inhibiting sorafenib-induced ferroptosis. Nuclear receptor coactivator 4 (NCOA4), a crucial regulator of ferroptosis, turned out to be a novel downstream effector of USP18 and is posttranslationally suppressed. Such regulation is based on the USP18-mediated deISGylation and degradation process. Additionally, we have demonstrated that sorafenib promotes USP18 accumulation in HCC via the STING/IRF3/ISG15 axis. Importantly, we screened and identified hyperoside (HYP) as a new USP18 enzyme activity inhibitor, which sensitizes cancer cells to existing targeted therapies (sorafenib and regorafenib) by inhibiting USP18 and following deISGylation of NCOA4. Collectively, our study has uncovered a novel mechanism of acquired sorafenib resistance and offers a promising combination therapy strategy for overcoming therapeutic resistance in HCC.