Fig. 3

CASC15 activates Wnt signaling in NSCLC via SOX4-mediated stabilization of β-catenin protein. a TOP-FLASH assay of A549 cells transfected with si-CASC15 or with concurrent overexpression of SOX4. TOP-FLASH (TOP) or FOP-FLASH (FOP) plasmids were used for the reporter assay. pRL-TK was co-transfected as an internal control. The results are presented as the TOP/FOP ratio. b Western blot analysis of β-catenin protein levels in A549 and H1299 cells with stable knockdown of CASC15 or with concurrent overexpression of SOX4. Blots were probed with an antibody against GAPDH to ensure equal loading. c Relative mRNA levels of CTNNB1 (mean ± SEM, n = 3) in A549 and H1299 cells with stable knockdown of CASC15 or with concurrent overexpression of SOX4. d A549 cells with stable knockdown of CASC15 were transfected with SOX4 expression plasmids or empty vector control. The cell lysates were collected 0, 60, 120, 180, or 240 min after cycloheximide treatment (CHX, 10 μg/ml), and the β-catenin protein levels were detected by Western blotting