Long non-coding RNA DANCR facilitates glioma malignancy by sponging miR-33a-5p.

Glioma is among the most fatal brain tumors characterized by a highly malignancy and rapid progression and early metastasis. Dysregulation of long non-coding RNA differentiation antagonizing non-protein coding RNA (LncRNA DANCR) is associated with the development, progression and metastasis of various cancers. In the present study, we investigated functional role of LncRNA DANCR in the malignancy of glioma. The results showed that LncRNA DANCR was increased in glioma tissues and cells compared with normal brain tissues and cells. DANCR expression was positively correlated with the malignancy and poor prognosis of glioma patients. DANCR contained a binding site of miR-33a-5p. miR-33a-5p was decreased in glioma tissues and cells compared with normal brain tissues and cells. Downregulation of miR-33a-5p was positively correlated with the malignancy and poor prognosis of glioma patients. In glioma tissues, the expression of DANCR was negatively correlated with the expression of miR-33a-5p. Downregulation of DANCR increased miR-33a-5p expression. miR-33a-5p mimic reduced the luciferase of DANCR-WT but not DANCR-MUT. DANCR pull-down showed the expression of miR-33a-5p. miR-33a-5p mimic enhanced knockdown of DANCR -induced inhibition of cell proliferation, migration, and EMT, and increase of apoptosis. Anti-miR-33a-5p reversed the effects of si- DANCR on cell malignancy. Knockdown of DANCR remarkably reduced the increase of tumor volumes in xenograft mouse models. In tumor tissues, knockdown of DANCR increased the expression of miR-33a-5p, reduced EMT and increased apoptosis. Our study provides novel insights in the functions of LncRNA DANCR-miR-33a-5p axis in tumorigenesis of glioma.