MicroRNA-15a promotes prostate cancer cell ferroptosis by inhibiting GPX4 expression

Ferroptosis is a novel form of regulated cell death characterized by accumulated lipid reactive oxygen species (ROS) and inactivation of glutathione peroxidase 4 (GPX4). The present study aimed to investigate the role of microRNA (miRNA/miR)-15a in ferroptosis of prostate cancer cells. Bioinformatics analysis was performed to predict the potential interaction between miR-15a and the 3'-untranslated region (UTR) of GPX4 mRNA. The prostate cancer cell line, LNCAP was transfected with miR-15a mimics or small interfering (si)-GPX4. Reverse transcription-quantitative PCR and western blot analyses were performed to detect the mRNA and protein expression levels of GPX4, respectively. Biotin-RNA pull-down and dual-luciferase reporter assays were performed to verify the interaction between miR-15a and GPX4 mRNA. The Cell Counting Kit-8 assay was performed to assess cell proliferation, while lactate dehydrogenase (LDH) and intracellular ferrous iron levels were detected via ELISA. Lipid ROS and mitochondrial membrane potential (MMP) were assessed via flow cytometry and staining with C11-BIODIPY probes or JC-1. Furthermore, lipid peroxidation was identified by measuring malondialdehyde (MDA) levels. The results demonstrated that transfection with miR-15a mimics decreased GPX4 protein expression. Bioinformatics analysis revealed potential binding sites between miR-15a and the 3'-UTR region of GPX4, and RNA pull-down and the dual-luciferase reporter assays further confirmed the interaction between miR-15a and GPX4 mRNA. Both transfection with miR-15a mimics and si-GPX4 suppressed cell proliferation, elevated LDH release, accumulated intracellular ferrous iron and ROS, disrupted MMP and increased MDA levels. Taken together, the results of the present study suggest miR-15a induces ferroptosis by regulating GPX4 in prostate cancer cells, which provides evidence for investigating the therapeutic strategies of prostate cancer.