Effects of Rap2c overexpression and knockdown on U2OS cell proliferation. (A) CCK-8 assay was performed with U2OS cells following transfection with the indicated siRNAs or a pcDNA3.1-Rap2c expression plasmid at 24, 48, 72 and 96 h. (B) Apoptotic cells were detected using Annexin V-FITC/PI staining using flow cytometry. siRNA, small interfering RNA; siCtrl, negative control siRNA; Rap2c, Ras-related protein Rap2c; Vector, empty vector; FITC, fluorescein isothiocyanate; PI, propidium iodide.