Fig. 2

circPTN promoted glioma growth in vitro. a. Left: Schematic illustration for minigene for circularizing circPTN in vitro: exons 2–4 of the PTN gene were cloned between splicing acceptor (SA) and splicing donor (SD) sequences with upstream and downstream flanking inverted repeat sequences; Middle: Stable overexpression for circPTN by lentiviral tranfection in U87 and U251 cells, n = 3, *p < 0.05, t test; Right: Sanger sequence indicated our overexpression system produced circPTN with correct junction. b. Left: Schematic illustration for siRNA specially targeted junction of circPTN; Middle: Nine siRNAs across the splice junction and one that can specifically target circPTN but not influence the linear spliced PTN product, (n = 3, mean ± SEM); Right: Stable interference system for circPTN by lentiviral transfection in U87 and U251 cells, n = 3,*p < 0.05, t test. c. Images of western blots between shControl and sh-circPTN in U87 and U251 cells. d. Results of CCK-8 assays indicated that circPTN significantly promoted proliferation of U87 and U251 cells. n = 3, *p < 0.05, t test. e. Upper: Results of EdU assays showed that circPTN significantly increased the percentage of EdU positive U87 and U251 cells; scale bar, 100 μm; Lower: Analyses of EdU assays results indicated circPTN promoted proliferation. n = 5, *p < 0.05, t test. f. Left: Cell cycle showed that circPTN increased proportion of S phase cells in U87 and U251 cells; Right: Analyses of cell cycle results indicated that circPTN significantly promoted shift of G1 → S, n = 3, *p < 0.05, t test