Fig. 4.

(a) Effect of ATRA or 9CRA on the NF-κB binding to the human pIgR NF-κB binding site. Nuclear extracts were prepared from TNF-α treated (10 ng/ml) HT-29 cells with or without 1 µm of ATRA or 9CRA, or neither TNF-α nor RA (control) as described Materials and methods. Ten µg of nuclear extract was incubated with a κB2 probe for the detection of NF-κB. Arrow indicates the NF-κB. (b) Cellular NF-κB activity by ATRA treatment. Reporter plasmid pNF-κB-luc was treansfected into HT-29 cells, and then TNF-α and/or ATRA were added and incubated for 24 h. Luciferase activity was measured as indicated in Materials and methods.