Figure 3

miR-26b suppresses NF-κB signaling by targeting TAK1 and TAB3. (A) Knockdown of TAK1 or TAB3 inhibited the TNFα-induced NF-κB reporter activity. QGY-7703 cells were treated and analyzed as in Figure 1A. (B) Knockdown of TAK1 or TAB3 attenuated the TNFα-induced phosphorylation of IκBα and p65. QGY-7703 cells transfected with siNC (lanes 1, 2), siTAK1 (lanes 3, 4) or siTAB3 (lanes 5, 6) were untreated (-) or treated with 20 ng/ml TNFα (+) for 3 minutes before immunoblotting. (C) miR-26b repressed the activity of the luciferase reporter containing the wild-type 3’UTR of TAK1 or TAB3. QGY-7703 cells were co-transfected with NC or miR-26b duplexes, pRL-TK and a firefly luciferase reporter plasmid carrying the wild-type (WT) or the mutant (MUT) 3’UTR of TAK1 or TAB3 before luciferase activity analysis. (D) Expression of miR-26b reduced the protein levels of cellular TAK1 and TAB3. HCC cells were transfected with NC or miR-26b duplexes for 48 hours before immunoblotting. (E) Antagonism of endogenous miR-26b enhanced the levels of TAK1 and TAB3 proteins. HCC cells were transfected with anti-NC or anti-miR-26b for 48 hours before immunoblotting. *, P < 0.05; **, P < 0.01.