Background: Glioma is the most common and malignant tumor of central nervous system. The tumor initiation, self-renewal, and multi-lineage differentiation abilities of glioma stem cells (GSCs) are responsible for glioma proliferation and recurrence. Although circular RNAs (circRNAs) play vital roles in the progression of glioma, the detailed mechanisms remain unknown.
Methods: qRT-PCR, western blotting, immunohistochemistry, and bioinformatic analysis were performed to detect the expression of circATP5B, miR-185-5p, HOXB5, and SRSF1. Patient-derived GSCs were established, and MTS, EDU, neurosphere formation, and limiting dilution assays were used to detect the proliferation of GSCs. RNA-binding protein immunoprecipitation, RNA pull-down, luciferase reporter assays, and chromatin immunoprecipitation assays were used to detect these molecules' regulation mechanisms.
Results: We found circATP5B expression was significantly upregulated in GSCs and promoted the proliferation of GSCs. Mechanistically, circATP5B acted as miR-185-5p sponge to upregulate HOXB5 expression. HOXB5 was overexpressed in glioma and transcriptionally regulated IL6 expression and promoted the proliferation of GSCs via JAK2/STAT3 signaling. Moreover, RNA binding protein SRSF1 could bind to and promote circATP5B expression and regulate the proliferation of GSCs, while HOXB5 also transcriptionally regulated SRSF1 expression.
Conclusions: Our study identified the SRSF1/circATP5B/miR-185-5p/HOXB5 feedback loop in GSCs. This provides an effective biomarker for glioma diagnosis and prognostic evaluation.
Keywords: CircATP5B; Glioma stem cells; HOXB5; IL6; JAK2/STAT3 signaling; MiR-185-5P; SRSF1.