Abstract

Background: Ferroptosis is a unique form of regulated cell death that provided a new opportunity for cancer therapy. Ferroptosis suppressor protein 1 (FSP1) is a key regulator in the NAD(P)H/FSP1/CoQ10 antioxidant system, which sever as an oxide redox enzyme to scavenge harmful lipid hydroperoxides and escape from ferroptosis in cells. This study aimed to investigate the role of FSP1 on sorafenib-induced ferroptosis and disclosed the underlying mechanisms.

Methods: Cell viability, malondialdehyde (MDA), glutathione (GSH), and lipid reactive oxygen species levels were assessed using indicated assay kits. The levels of FSP1 and glutathione peroxidase 4 (GPX4) in the patients with HCC were analyzed based on the database. Western blot and quantitative real-time PCR were performed to detect the protein and mRNA expression. Co-immunoprecipitation was applied to detect the interaction between proteins. Tumor xenograft experiments were used to evaluate whether overexpression of FSP1-inhibited sorafenib-induced ferroptosis in vivo.

Results: We verified that sorafenib-induced ferroptosis in HCC. Furthermore, we found that sorafenib decreased the protein level of FSP1, and knockdown FSP1 rendered HCC cells susceptible to sorafenib-induced ferroptosis. Co-immunoprecipitation and ubiquitination assays showed that sorafenib accelerated the TRIM54-mediated FSP1 ubiquitination and degradation. Sorafenib-induced ferroptosis was abrogated by TRIM54 suppression. Mechanically, sorafenib-promoted TRIM54 ubiquitinated and degraded FSP1 by means of the ERK pathway. Moreover, FSP1 enhanced tumor development and decreased HCC cellular susceptibility to sorafenib in vivo.

Conclusions: Sorafenib facilitated the TRIM54-mediated FSP1 ubiquitination through the ERK pathway, thereby inducing ferroptosis in HCC cells.