γ-T3 down-regulates IL-6-induced phospho-STAT3. A, γ-T3 suppresses phospho-STAT3 levels in various cells. DU-145, PC3, and MiaPaCa-2 cells (1 × 106/ml) were treated with 60 μm γ-T3 for 6 h, after which whole-cell extracts were prepared, and protein was resolved on 7.5% SDS-polyacrylamide gel, electrotransferred onto nitrocellulose membrane, and probed for phospho-STAT3. B and C, γ-TP has no effect on activation of STAT3. U266 cells (2 × 106/ml) were treated with the indicated concentrations of either γ-TP or γ-T3 for 6 h, after which the whole-cell extracts were prepared, and phospho-STAT3 levels were detected by Western blot. The same blots were stripped and reprobed with STAT3 antibody to verify equal protein loading. D, γ-T3 suppresses IL-6-induced phospho-STAT3 levels in a dose-dependent manner. MM.1s cells (2 × 106) were treated with IL-6 (10 ng/ml) for the indicated times. Whole-cell extracts were prepared, and phospho-STAT3 level was detected by Western blot. E, γ-T3 suppresses IL-6-induced phospho-STAT3 levels in a time-dependent manner. MM.1s cells (2 × 106) were treated with 60 μm γ-T3 for the indicated times and then stimulated with IL-6 (10 ng/ml) for 30 min. Whole-cell extracts were then prepared and analyzed for phospho-STAT3 by Western blotting.