Silencing lncRNA GIHCG increases radiosensitivity of glioma cells by up-regulating miR-146a-3p

Objective To investigate the effect of lncRNA GIHCG on the radiosensitivity of glioma cells and its mechanism. Methods The expression levels of GIHCG and miR-146a-3p in human brain normal glial cells HEB and glioma cell lines U251, A172, SHG139 and U87 were quantitatively measured by qRT-PCR assay. U251 and SHG139 cells were used for subsequent experiment. After silencing the expression of GIHCG or overexpressing miR-146a-3p in U251 and SHG139 cells, cell proliferation was detected by MTT assay, cell apoptosis was detected by flow cytometry, cell radiosensitivity was detected by colony formation assay and the expression levels of CDK1, CyclinD1, Bcl-2 and Bax proteins were measured by Western blot. The bioinformatics software predicted the presence of a binding site for GIHCG and miR-146a-3p. Dual luciferase reporter gene assay and qRT-PCR assay were adopted to verify the targeting relationship between GIHCG and miR-146a-3p. Results Compared with HEB cells, the expression of GIHCG was significantly up-regulated in glioma U87, U251, A172 and SHG139 cells (all P<0.05), whereas that of miR-146a-3p was remarkably down-regulated (P<0.05). Silencing GIHCG expression or overexpression of miR-146a-3p significantly decreased the U251 and SHG139 cell survival rate, survival fraction and the expression of CDK1, CyclinD1 and Bcl-2 proteins (all P<0.05), whereas considerably increased the apoptotic rate and expression of Bax protein (both P<0.05). GIHCG performed targeted negative regulation of miR-146a-3p expression in U251 and SHG139 cells and inhibition of miR-146a-3p expression reversed the effect of silencing GIHCG on proliferation, apoptosis and radiosensitivity of glioma cells. Conclusion Silencing GIHCG expression up-regulates the expression of miR-146a-3p, thereby enhancing the radiosensitivity of glioma cells. Key words: Glioma; lncRNA GIHCG; miR-146a-3p gene; Radiosensitivity