Long non-coding RNA FOXD2-AS1 promotes cell proliferation, metastasis and EMT in glioma by sponging miR-506-5p

Long non-coding RNA forkhead box D2 adjacent opposite strand RNA 1 (FOXD2-AS1) has emerged as a potential oncogene in several tumors. However, its biological function and potential regulatory mechanism in glioma have not been fully investigated to date. In the present study, RT-qPCR was conducted to detect the levels of FOXD2-AS1 and microRNA (miR)-506-5p, and western blot assays were performed to measure the expression of CDK2, cyclinE1, P21, matrix metalloproteinase (MMP)7, MMP9, N-cadherin, E-cadherin and vimentin in glioma cells. A luciferase reporter assay was performed to verify the direct targeting of miR-506-5p by FOXD2-AS1. Subsequently, cell viability was analyzed using the CCK-8 assay. Cell migration and invasion were analyzed using Transwell and wound healing assays, respectively. The results demonstrated that FOXD2-AS1 was significantly overexpressed in glioma cells, particularly in U251 cells. Knockdown of FOXD2-AS1 in glioma cells significantly inhibited cell proliferation, migration, invasion and epithelial–mesenchymal transition (EMT) and regulated the expression of CDK2, cyclinE1, P21, MMP7 and MMP9. Next, a possible mechanism for these results was explored, and it was observed that FOXD2-AS1 binds to and negatively regulates miR-506-5p, which is known to be a tumor-suppressor gene in certain human cancer types. Furthermore, overexpression of miR-506-5p significantly inhibited cell proliferation, migration, invasion and EMT, and these effects could be reversed by transfecting FOXD2-AS1 into the cells. In conclusion, our data suggested that FOXD2-AS1 contributed to glioma proliferation, metastasis and EMT via competitively binding to miR-506-5p. FOXD2-AS1 may be a promising target for therapy in patients with glioma.