Cell proliferation assay
The proliferation of human OS cells was evaluated by the CellTiter 96 AQueous One Solution cell proliferation assay. human OS cells were plated in 96-well culture plates (3 × 103 per well). After 24 h of incubation, the cells were transfected with 30 pmol of target gene (sh-circ_0001722 or miR-204-5p or negative control) for 24, 48, 72, and 96 h. Then 20 μl Cell Titer 96 Aqueous One Solution (Promega, USA) were added and cells incubated for another 1 h. Absorbance was read at 492 nm.