Figure 1.

Establishment of mesenchymal stem cells (MSCs) stably expressing NIS regulated by the IL-6 promoter

(A–C) Stimulation with cytokines IL-1β (0.5–5 ng/mL), IFN-γ (40–60 ng/mL), and TNF-α (1–15 ng/mL) showed NIS-specific ¹²⁵I-uptake that was reduced to background levels using perchlorate as NIS-specific inhibitor. (D) Treatment of IL-6-NIS-MSCs with IL-1β (1 ng/mL), IFN-γ (50 ng/mL), and TNF-α (10 ng/mL) revealed an increased radioiodide uptake as compared with single stimulation studies. (E) Stimulation with GL261-CM led to a significant increase of radioiodide uptake as compared with unstimulated IL-6-NIS-MSCs and was further increased by combined treatment with IL-1β (1 ng/mL), IFN-γ (50 ng/mL), and TNF-α (10 ng/mL). In contrast, stimulation with 4T1-CM was significantly lower as compared with stimulation with GL261-CM, but treatment with 4T1-CM and IL-1β (1 ng/mL), IFN-γ (50 ng/mL), and TNF-α (10 ng/mL) led to similar radioiodide uptake activity of IL-6-NIS-MSCs as treatment with GL261-CM and combined factors. Results are expressed as mean ± SEM of three independent experiments (two-tailed Student’s t test ∗p < 0.05, ∗∗p < 0.01; ∗∗∗p < 0.001; ∗∗∗∗p < 0.0001). CM = conditioned medium.