Fig 2: Knockdown or functional inhibition of DDX3 activated MAPK pathway and β-catenin signal in CRC cells. (A) Protein expression of DDX3, E-cadherin, Snail, Slug, p-Erk1/2, Erk1/2, p-β-catenin (Ser675) and β-actin in DDX3-KD SW480 and HCT116 cells and DDX3-OE DLD-1 cells by western blot (upper left panel). Gray analysis of the protein expression in SW480 and HCT116 cells is shown in lower panel and that in DLD-1 cells is shown in upper right panel. **P<0.01, ***P<0.001, ns P>0.05 via Student's t-test. (B) SW480 cells were treated with RK33 in serial concentration gradient for 12 h, and the protein expressions of DDX3, p-Erk1/2, Erk1/2 and β-actin were detected by western blot (upper panel). The correlation between the protein expression of DDX3 and p-Erk1/2 and RK33 concentration is shown in lower panel. *P<0.05, ns P>0.05 via Pearson correlation test. (C) Crystal structure of the active catalytic core of DDX3. (D) SW480 and HCT116 cells were treated with 25 µmol/L RK33 for 12 h, and the protein expressions of K-Ras, p-Raf1, Raf1, p-MEK1/2, MEK1/2, p-Erk1/2, Erk1/2, p-β-catenin (Ser675) and β-actin were detected by western blot (left panel). Gray analysis of the protein expression in SW480 and HCT116 cells is shown in right panel. ***P<0.001 via Student's t-test. All graphs are drawn from the mean ± SD of three independent replicates. Abbreviation: CRC, colorectal cancer; EV, empty vector; KD, knockdown; NC, negative control; OE, overexpression.