Figure 4

CDDO-Me inhibits EGFP-Stat3 nuclear translocation in osteosarcoma cell line U-2OS. U-2OS cells which stably express the EGFP-Stat3 fusion protein were incubated for 4 h with either IL-6 alone (A-D) or CDDO-Me (1 μM) followed immediately thereafter with the addition of IL-6 to a final concentration of 30 ng/ml (A'-D'). To counterstain the nuclei, the cells were incubated with 1 μg/ml Hoechst 33342 (Invitrogen, Carlsbad, CA) for 1 minute. Cells were photographed 1 h later. Subcellular localization of the fusion protein was assessed by fluorescence microscopy.