Figure 5. Knockdown of NDRG1 induced epithelial-to-mesenchymal transition (EMT) and enhanced Smad2 signaling in 5–8F cells.
(A) Immunostaining of NDRG1 and EMT markers. Magnification: 1800×. (B) Western blotting analysis of NDRG1 and EMT marker expression. NDRG1 knock-down increased N-cadherin and vimentin expression and decreased E-cadherin expression. (C) Quantification of protein expression shown in B by normalized to α-Tubulin. *P<0.05 compared to the shCtrl group for each individual protein, n=3. (D–G) Smad2 signaling was activated in NDRG1-blocked NPC 5–8F and 5–8F-LN cells. (D) Western blotting analysis of Smad2 and Smad3 expression and phosphorylation. NDRG1 knock-down increased Smad2 signaling. (E) Smad2 or Smad3 phosphorylation was normalized to total protein levels, which was normalized to α-Tubulin. *P<0.05 compared to control shRNA (shCtrl)-treated group, n=3. (F) Smad2 expression and phosphorylation in 5–8F and 5–8F-LN cells were detected by western blot. (G) Smad2 expression and phosphorylation were significantly higher in 5–8F-LN cells compared to 5–8F cells. Smad2 total levels were quantified by normalized to α-Tubulin. Smad2 phosphorylation was normalized to Smad2 level. *P<0.01 compared to 5–8F cells, n=3.