Circ_0000253 promotes the progression of osteosarcoma via the miR-1236-3p/SP1 axis

Abstract Objective Circular RNAs (circRNAs) play important roles in modulating tumour progression. This study investigated the role of circ_0000253 in osteosarcoma (OS). Methods We downloaded the chip dataset GSE140256 from the Gene Expression Omnibus database and the circRNAs differentially expressed in OS tissue and normal tissue samples were analysed. Quantitative real-time PCR (qRT-PCR) was carried out to examine circ_0000253 expression in OS tissues and cells. Cell counting kit-8, BrdU and flow cytometry assays were performed to verify the effects of circ_0000253 on OS cell growth and apoptosis. Bioinformatics analysis was conducted to predict, and RNA immunoprecipitation assay and dual-luciferase reporter gene assay were performed to verify the targeted relationships of miR-1236-3p with circ_0000253 and Sp1 transcription factor (SP1) mRNA 3ʹUTR. The effects of miR-1236-3p and circ_0000253 on SP1 expression in OS cells were detected through Western blot. Key findings Circ_0000253 was upregulated in OS tissues and cell lines. Circ_0000253 overexpression facilitated OS cell growth and suppressed apoptosis, whereas knocking down circ_0000253 inhibited OS cell growth and facilitated apoptosis. Circ_0000253 targeted miR-1236-3p directly and negatively modulated its expression. SP1 was miR-1236-3p’s target gene and positively regulated by circ_0000253. Conclusion Circ_0000253 promotes OS cell proliferation and suppresses cell apoptosis via regulating the miR-1236-3p/SP1 molecular axis.