miR-122-5p Regulates Ferroptosis through Targeting the Glutamine Transporter SLC1A5 in Hepatocellular Carcinoma

Background: Hepatocellular carcinoma (HCC) typically begins inconspicuously and progresses swiftly, leading to most patients being diagnosed at an advanced stage. Accordingly, a pressing priority is to clarify the development mechanisms of HCC and devise efficient intervention and treatment protocols. Methods: An upstream miRNA of solute carrier transporter family 1 member 5 (SLC1A5) was predicted to be miR-122-5p by various databases, and a dual-luciferase reporter gene assay was used to verify the SLC1A5- and miR-122-5p-targeting relationship. SLC1A5 and miR-122-5p expression in HCC cells was quantitatively assessed using quantitative reverse transcription polymerase chain reaction (qRT–PCR). Western blotting was used to evaluate SLC1A5 expression in HCC cells. To determine the effects of the ferroptosis inducers erastin and L-g-glutamyl-p-nitroanilide (GPNA) on Huh-7 and HepG2 cell viability, a Cell Counting Kit-8 assay was performed. Additionally, various assay kits were used to assess malondialdehyde (MDA), Fe2+, and reactive oxygen species (ROS) levels in HCC cells. Moreover, an HCC tumor model was established in nude mice to investigate the growth of HCC tumors overexpressing miR-122-5p. Results: miR-122-5p downregulated SLC1A5 levels. MiR-122-5p knockdown inhibited erastin-promoted ferroptosis, whereas miR-122-5p overexpression promoted ferroptosis. After knocking down miR-122-5p, the MDA, Fe2+, and ROS levels in Huh-7 and HepG2 cells decreased, whereas overexpressing miR-122-5p increased the MDA, Fe2+, and ROS levels. Following the addition of GPNA, the cells experienced decreased viability and increased MDA levels, which in turn inhibited ferroptosis. Knockdown of SLC1A5 partially reversed the ferroptosis-inhibiting effect induced by knocking down miR-122-5p. Additionally, the overexpression of miR-122-5p hindered HCC development in vivo. Conclusion: miR-122-5p downregulates SLC1A5, which promotes lipid peroxidation and iron accumulation and inhibits glutamine transport, ultimately causing ferroptosis in HCC cells.