IGF1 3'UTR functions as a ceRNA in promoting angiogenesis by sponging miR-29 family in osteosarcoma

Osteosarcoma is one of the most common malignant bone tumors in human worldwide. Angiogenesis is a pivotal process during osteosarcoma development. Insulin-like growth factor 1 (IGF1) has been reported to promote angiogenesis. However, the role of 3' untranslational region (3'UTR) of IGF1 mRNA in angiogenic activity in osteosarcomas is still unknown. In the present study, we performed gain-of-function assays to investigate the role of IGF1-3'UTR in angiogenesis. For the first time, we demonstrated that IGF1 3'UTR increased VEGF expression and promotes angiogenesis in osteosarcoma cells. In addition, RNA-immunoprecipitation and luciferase reporter assays showed that IGF1 3'UTR was a direct target of miR-29s. Our data also demonstrated that there existed a competition of miR-29s between IGF1-3'UTR and VEGF mRNA, and IGF1-3'UTR promoted angiogenesis at least in part via sponging miR-29s. Taken together, our study suggests that IGF1-3'UTR functions as a ceRNA in promoting angiogenesis by sponging miR-29s in osteosarcoma.