FBXO17 promotes osteosarcoma progression by regulating glycolysis and macrophage polarization

Osteosarcoma (OS) is the most common primary malignant bone tumor, characterized by high aggressiveness and poor prognosis. Glycolytic reprogramming and immune microenvironment imbalance contribute to OS progression, but the role of E3 ubiquitin ligases in coordinating glycolysis and macrophage polarization remains unclear. This study aimed to identify key E3 ubiquitin ligases regulating glycolysis and immune microenvironment in OS. Differentially expressed genes (DEGs) were identified from the GSE309091 lncRNA-sequencing dataset using DESeq2. Glycolysis-related genes from GeneCards and E3 ubiquitin ligases from UbiBrowser were integrated with DEGs, and Random Forest machine learning was applied to select core genes. Immune cell infiltration was assessed using CIBERSORT. Key gene expression was analyzed across the GSE309091 and GSE36001 datasets, with protein expression validated via Western blot. OS cell proliferation, cell cycle, apoptosis, invasion, and glycolysis were evaluated using colony formation, EdU, flow cytometry, Transwell assays, and glucose/lactate measurements. THP1-derived macrophages co-cultured with OS cell-conditioned medium were used to assess M1/M2 polarization. The expression of inflammatory cytokines was detected using ELISA. Potential FBXO17 substrates were predicted using UbiBrowser 2.0, and its regulatory relationship with PGC-1α was examined using Co-IP, ubiquitination, CHX-chase. Xenograft mouse models determined in vivo effects of FBXO17. FBXO17, SIAH2, BRCA1, and TRIM32 were identified as core genes associated with glycolysis and ubiquitination. Immune infiltration analysis showed their expression correlated with immune cell composition in OS. FBXO17 was highly expressed in GSE309091 and GSE36001 datasets, as well as in OS cell lines. FBXO17 knockdown inhibited OS cell proliferation, invasion, and glycolytic activity, induced G0/G1 arrest, promoted apoptosis, and enhanced M1 polarization of THP1 macrophages. FBXO17 interacted with PGC-1α and promoted its polyubiquitination and degradation. FBXO17 knockdown slowed PGC-1α degradation, whereas FBXO17 overexpression in FBXO17-knockdown cells reduced PGC-1α protein accumulation and partially restored lactate production. In vivo, FBXO17 silencing significantly suppressed tumor growth. FBXO17 promotes OS progression and glycolytic reprogramming, at least in part, by facilitating the ubiquitination and degradation of PGC-1α and is also involved in regulating macrophage polarization. Therefore, FBXO17 may represent a potential therapeutic target for OS.