RAC1 and osteosarcoma: In order to verify whether circSRSF4 promoted the proliferation, invasion, and migration of osteosarcoma through the circSRSF4/miR-224/Rac1 axis, we co-transfected the Rac1 overexpression plasmid with the 3’UTR region and circSRSF4 siRNA into osteosarcoma cells for a rescue experiment.