Abstract
BACKGROUND Circular RNA (circRNA) is a stable non-coding RNA without 5'-3' polarity and without a poly-A tail, that contains response elements for microRNAs (miRNAs) such as miR-661. There have previously been few reported studies on the role of circRNAs in glioma. The aim of this study was to investigate the effects of the expression of the circRNA, hsa-circ-0012129, and miR-661 in human glioma tissue and human glioma cell lines. MATERIAL AND METHODS Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of hsa-circ-0012129 and miR-661 in glioma tissues from 31 patients (WHO grades I-IV), compared with adjacent normal tissue, and in human glioma cell lines, U373, A172, and SHG44, compared with the normal human astrocyte cell line, NHA. The MTT assay, colony formation assay, transwell and wound scratch assays were performed to analyze and compare cell viability, cell migration, and invasion. RESULTS Expression of hsa-circ-0012129 was significantly increased in glioma tissues and cell lines; hsa-circ-0012129 knockdown significantly suppressed the proliferation, migration, and invasion abilities of U373 and SHG44 cells. A dual-luciferase reporter assay showed that hsa-circ-0012129 contained the complementary binding region with miR-661 and that hsa-circ-0012129 expression negatively regulated miR-661. Rescue experiments showed that miR-661 could reverse the effects of hsa-circ-0012129 on cell viability, cell migration and invasion of glioma cells in vitro. CONCLUSIONS The findings of this study indicated that, in human glioma cells, the circRNA, hsa-circ-0012129 might act as a natural miR-661 sponge, and that miR-661 could have suppressive effects on the expression of circ-0012129.