OTUD1-mediated deubiquitination stabilizes SLC7A11 to suppress ferroptosis in hepatocellular carcinoma.

BACKGROUND

Evasion of ferroptosis has been increasingly recognized as an important mechanism underlying lenvatinib resistance in hepatocellular carcinoma (HCC). However, the roles of deubiquitinating enzymes in ferroptosis regulation and the post-translational control of key ferroptosis regulators in HCC remain poorly understood.

METHODS

Public lenvatinib resistance-related and ferroptosis-related datasets were analyzed to identify candidate deubiquitinating enzymes associated with HCC therapeutic resistance and ferroptotic stress. Loss- and gain-of-function assays were performed to evaluate the effects of OTUD1 on lenvatinib sensitivity, erastin-induced ferroptosis, and HCC cell growth. Subcutaneous xenograft and orthotopic tumor models were used to assess the role of OTUD1 in tumor growth and ferroptosis resistance in vivo. Western blotting, RT-qPCR, co-immunoprecipitation, cycloheximide chase, MG132 rescue, ubiquitination, SLC7A11 rescue, and ERK1/2 pathway modulation assays were conducted to investigate the underlying mechanism. Clinical HCC specimens and public datasets were analyzed to determine OTUD1 expression and its association with patient prognosis.

RESULTS

OTUD1 was identified as a gene associated with lenvatinib resistance in HCC. Knockdown of OTUD1 sensitized HCC cells to lenvatinib, and this effect was abolished by ferroptosis inhibition. OTUD1 knockdown enhanced ferroptosis in HCC cells, whereas OTUD1 overexpression suppressed it. Moreover, OTUD1 promoted HCC growth and conferred ferroptosis resistance in mice. Mechanistically, OTUD1 interacted with solute carrier family 7 member 11 (SLC7A11) and removed its K48-linked polyubiquitin chains, thereby stabilizing SLC7A11 protein levels. In addition, ERK1/2-dependent phosphorylation of OTUD1 at Ser216 strengthened its interaction with SLC7A11, further enhancing SLC7A11 stability and promoting ferroptosis resistance. Analysis of clinical samples and public datasets further revealed that OTUD1 was upregulated in HCC tissues and correlated with poor prognosis.

CONCLUSIONS

Our findings identify the ERK1/2-OTUD1-SLC7A11 axis as a key mechanism mediating ferroptosis resistance in HCC. These results suggest that OTUD1 may serve as a potential therapeutic target for HCC.