Elevation of circ-PITX1 upregulates interleukin 17 receptor D expression via sponging miR-518a-5p and facilitates cell progression in glioma.

Glioma (GM) is one of the major global health problems across the world. Circular RNAs (circRNAs) have been increasingly identified and characterized in almost every aspect of biology, especially in cancer biology. This study desires to investigate the mechanism of circ-PITX1 on regulating GM development. Quantitative reverse-transcription polymerase chain reaction was carried out to measure the expression of circ-PITX1, which was upregulated in matched cancerous tissues and adjacent noncancerous tissues from 52 patients and four cell lines of GM. Fisher's exact indicated the upregulation of circ-PITX1 was associated with patients' tumor size and World Health Organization grade. Gain and loss-of-function assays demonstrated that circ-PITX1 could facilitate the growth, migration, and invasion and inhibit cell apoptosis in GM cell lines. What's more, circ-PITX1 sponges miR-518a-5p to release its repression on 3'-untranslated region (3'UTR) of interleukin 17 receptor D (IL17RD) messenger RNA to exert its oncogenic functions in GM cells proved by dual-luciferase reporter and rescue assays. Taken together, circ-PITX1 may play a critical role in GM and may be used as a therapeutic target for GM.