Insulin-like growth factor II mRNA-binding protein 3 promotes cell proliferation, migration and invasion in human glioblastoma

Background/Aims: Recently, the insulin-like growth factor mRNA-binding protein 3 (IMP3) has been reported to be involved in tumorigenesis. We aimed to study the expression and role of IMP3 in human glioblastoma. Methods: We analyzed the expression of IMP3 in 70 cases of glioma tissues, normal brain tissues and 5 kinds of cell lines using western blot. Immunohistochemistry (IHC) was used to evaluate the expression and distribution of IMP3 in glioma tissues. Colony formation, wound healing, migration and invasion assays and tumorigenesis in nude mice were used to explore the function of IMP3 in vitro and in vivo. The epithelial-mesenchymal transition (EMT)-related biomarkers were detected by western blot. Results: We found that the expression level of IMP3 was obviously higher in glioma tissues than that in normal brain tissues, and associated with glioma grade. In-vitro assays revealed that IMP3 overexpression significantly induced cell proliferation, migration, and invasion. Mechanically, IMP3 over-expression downregulated the expression of E-cadherin, but upregulated the expressions of N-cadherin, vimentin, snail, slug and MMP9. However, the inhibition of IMP3 impaired these oncogenic effects. In vivo assay also demonstrated that silencing of IMP3 inhibited tumor growth and improved survival of tumor-bearing xenograft nude mice. Conclusion: IMP3 can promote cell proliferation, migration and invasion by inducing EMT in glioblastoma. Thus, targeting IMP3 pathway may be a novel way to treat patients with glioblastoma.