Knockdown of FBXO22 inhibits melanoma cell migration, invasion and angiogenesis via the HIF-1α/VEGF pathway

F-box proteins, a type of substrate-recognition complexes consisting of SKP1-cullin 1-F-box protein (SCF) E3 ligase, can critically affect many cellular processes because of the ubiquitylation and subsequent degradation of target proteins. This study investigated the effect of FBXO22 on melanoma angiogenesis, migration, and invasion. Results showed that FBXO22 staining intensity was increased in malignant melanoma (MM) compared with that in skin tissue (P˂0.001). The percentage of high FBXO22 expression in MM (74.3%) was markedly higher than that in paracancerous and skin tissues (0%) (P˂0.001). FBXO22 was also overexpressed in MM tissues compared with that in normal skin tissues. FBXO22 knockdown in vitro inhibited MM cell migration, invasion, and angiogenesis (P < 0.001). In vivo studies confirmed that using nude mice with knocked down FBXO22 reduced the formation of blood vessels and decreased the positive rate of CD31 (P < 0.05). HIF-1α expression varied with FBXO22, indicating that FBXO22 regulated the expression of HIF-1α and VEGFA and that FBXO22 was a regulator of HIF-1α and VEGF for the control of tumor angiogenesis. In conclusion, FBXO22 promoted the migration and invasion of tumor cells and melanoma angiogenesis via HIF-1α upregulation. This study demonstrated that FBXO22 knockdown suppressed tumor progression and metastasis, suggesting that FBXO22 might be developed as a novel target for treating patients with MM.