MicroRNA-214-3p enhances erastin-induced ferroptosis by targeting ATF4 in hepatoma cells

Primary liver cancer is the second most frequent cause of cancer-related deaths. Ferroptosis, a recognized form of regulated cell death, recently gains attention. MicroRNA-214-3p (miR-214) plays a regulatory role in hepatocarcinogenesis. However, the role of miR-214 in cellular ferroptosis is unclear. This study aimed at elucidating whether miR-214 could regulate ferroptosis of liver cancer. In vitro, HepG2 and Hep3B cancer cells were treated with erastin, a ferroptosis inducer, and then erastin was demonstrated to suppress the cell viability. Moreover, pre-miR-214 overexpression caused that HepG2 and Hep3B cells were more susceptible to erastin, whereas anti-miR-214 sponge showed the opposite effect. Additionally, pre-miR-214 overexpression increased the malondialdehyde and reactive oxygen species levels, upregulated Fe2+ concentration, and decreased glutathione levels in cancer cells exposed to erastin. Further, erastin enhanced the activation of transcription factor 4 (ATF4) in HepG2 and Hep3B cells, and pre-miR-214 overexpression inhibited ATF4 expression. The luciferase reporter data validated ATF4 as a direct target of miR-214. Cancer cells transfected with ATF4 overexpression plasmid rendered lower susceptible to miR-214-induced ferroptotic death. In vivo, erastin significantly reduced the size and weight of xenografted tumors, and miR-214 elevated the ferroptosis-promoting effects of erastin and decreased ATF4 expression. In summary, our study demonstrates that the ferroptosis-promoting effects of miR-214 in hepatoma cells are attributed at least to its inhibitory effects on ATF4, which may provide a new target for therapy of hepatoma regarding ferroptosis.