MicroRNA-1287-5p promotes ferroptosis of osteosarcoma cells through inhibiting GPX4

Osteosarcoma is the most prevalent primary bone malignancy in adolescents, and ferroptosis is implicated in its pathogenesis. MicroRNA (miR)-1287-5p plays critical roles in multiple human cancers, and the present study aims to investigate the role and underlying mechanisms of miR-1287-5p in regulating ferroptosis and osteosarcoma progression. Human osteosarcoma cell lines were treated with the mimic, inhibitor or matched controls of miR-1287-5p. Cell viability, colony formation, cell death ratio and ferroptosis were determined. miR-1287-5p expression was downregulated in human osteosarcoma, but upregulated upon ferroptotic stimulation. Overexpression of miR-1287-5p significantly induced, while inhibition of miR-1287-5p suppressed ferroptosis of osteosarcoma cells, thereby modulating cell viability and colony formation. Mechanistic studies indicated that miR-1287-5p directly bound to the 3'-untranslated region of glutathione peroxidase 4 (GPX4) to inhibit its protein level and activity, and that GPX4 overexpression completely abolished the miR-1287-5p mimic-mediated ferroptotic induction and tumor suppression. Moreover, the miR-1287-5p mimic dramatically sensitized human osteosarcoma cells to cisplatin chemotherapy. Our findings prove that miR-1287-5p promotes ferroptosis of osteosarcoma cells through inhibiting GPX4, identifying an adjuvant and even alternative method for the treatment of human osteosarcoma.