LncRNA-PVT1 Inhibits Ferroptosis through Activating STAT3/GPX4 Axis to Promote Osteosarcoma Progression.

ABSTRACT

BACKGROUND: Osteosarcoma (OS) is a primary malignant bone tumor in the pediatric and adolescent populations. Long non-coding RNAs (LncRNAs), such as plasma-cytoma variant translocation 1 (PVT1), have emerged as significant regulators of OS metastasis. Recent studies have indicated that activation of signal transducer and activator of transcription 3 (STAT3) signaling, which might be controlled by PVT1, inhibits ferroptosis to promote the malignant progression of cancer. Therefore, the present study aimed to determine the role of PVT1 in OS pathogenesis and investigate whether PVT1 affects OS progression by regulating STAT3/GPX4 pathway-mediated ferroptosis. METHODS: The human OS cell line MG63 were transfected with sh-PVT1 plasmid to inhibit PVT1 expression, with or without co-transfection with a STAT3 overexpression plasmid. The expression of PVT1 was determined by real-time quantitative polymerase chain reaction (RT-qPCR). The proliferation, migration, invasion, and apoptosis of MG63 cells were determined using the cell counting kit-8 (CCK8), Transwell assay, and flow cytometry. The levels of malondialdehyde (MDA), Fe2+, and glutathione (GSH) were determined by ELISA kits, whereas reactive oxygen species (ROS) level was determined by immunofluorescence. The protein expression levels of STAT3, p-STAT3, and glutathione peroxidase 4 (GPX4) were detected by western blot (WB). RESULTS: PVT1 expression was significantly increased in MG63 cells. When knocking down PVT1 with sh-PVT1 plasmid, the proliferation, migration, and invasion of MG63 cells were markedly inhibited, while the rate of apoptosis was upregulated. Further investigation revealed that MG63 cells with PVT1 knockdown exhibited elevated levels of MDA, Fe2+, and ROS. In addition, the inhibition of PVT1 expression resulted in decreased levels of GSH and inhibited expression of p-STAT3 and GPX4. When sh-PVT1 was co-transfected with STAT3 overexpression plasmid in MG63 cells, the increased levels of MDA, Fe2+, and ROS were downregulated, and the decreased expressions of GSH, p-STAT3, and GPX4 were upregulated. CONCLUSION: PVT1 promotes OS metastasis by activating the STAT3/GPX4 pathway to inhibit ferroptosis. Targeting PVT1 might be a novel therapeutic strategy for OS treatment.