Fig. 3

TRIB2 regulates p21 expression and cellular senescence in a p53-independent pathway. a Western blot of TRIB2, p53 and p21 in SW48 cells transfected with TRIB2- and or not p53-specific siRNA. b mRNA expression of p21 in SW48 cells transfected with TRIB2- and or not p53-specific siRNA. c Luciferase activity of p21 promoter in SW48 cells transfected with p21-Luc plus TRIB2- and or not p53-specific siRNA. d Silencing of TRIB2 inhibits cell proliferation in the absence of p53. SW48 cells were transfected with TRIB2- and or not p53-specific siRNA and the absorption (A450 nm) was detected at 0, 24, 48 and 72 h, respectively. e Silencing of TRIB2 promotes cellular senescence in the absence of p53. SW48 cells were transfected with TRIB2- and or not p53-specific siRNA and treated with dox (0.25 μmol/l) for 48 h. The percentage of SA-β-gal-positive cells was analyzed (right panel). f Western blot of TRIB2 and p21 in HCT116p53^−/− cells transfected with TRIB2-specific siRNA (#1 and #2) or TRIB2-expressing plasmid. g mRNA expression of p21 in HCT116p53^−/− cells transfected with TRIB2-specific siRNA (#1 and #2) or TRIB2-expressing plasmid. h Cell growth was analyzed by CCK8 in HCT116p53^−/− cells transfected with TRIB2-specific siRNA or TRIB2-expressing plasmid. i Cell cycle distribution was analyzed by flow cytometry in TRIB2-knockdown or -overexpressing HCT116p53^−/− cells. j SA-β-gal staining analysis in TRIB2-knockdown or –overexpressed HCT116p53^−/− cells treated with dox (0.25 μmol/l, 48 h). left panel, representative images of SA-β-gal staining; right panel, percentage of SA-β-gal-positive cells. Results are presented as mean ± SD from three independent assays, * p < 0.05, ** p < 0.01, *** p < 0.001, t-test