FBXO22 promotes glioblastoma malignant progression by mediating VHL ubiquitination and degradation

Glioblastoma (GBM) is the most common malignant primary brain tumor. Despite comprehensive treatment with traditional surgery, radiotherapy, and chemotherapy, the median survival rate is <14.6% and the 5-year survival rate is only 5%. FBXO22, a substrate receptor of the SCF ubiquitin ligases, has been reported to play a promoting role in melanoma, liver cancer, cervical cancer, and other cancers. However, the function of FBXO22 in GBM has not been reported. In the present study, we demonstrate that FBXO22 is highly expressed in glioma and is positively correlated with worse pathological features and shorter survival of GBM patients. We revealed that FBXO22 promotes GBM cell proliferation, angiogenesis, migration, and tumorigenesis in vitro and in vivo. In terms of mechanism, we reveal that FBXO22 decreases VHL expression by directly mediating VHL ubiquitination degradation, which ultimately increases HIF-1 alpha and VEGFA expression. In addition, our data confirm that there are positive correlations among FBXO22, HIF-1 alpha, and VEGFA expression, and there is a negative correlation between FBXO22 and VHL protein expression in glioma patients. Our study strongly indicates that FBXO22 is a promising diagnostic marker and therapeutic target for glioma patients.