Fig. S4.

Inhibiting mTOR in senescent cells prevented iron accumulation. (A) Inhibiting mTOR does not cause escape from cell cycle arrest. Primary MEFs were treated with rapamycin (100 nM) while irradiated (10 Gy) to induce senescence and then subsequently for 10 days in culture. Treated MEFs were unable to proliferate when seeded in 6 well plates (100,000 cells/well) and cultured for additional 5 days. (B) Inhibiting mTOR in senescent MEFs after 10 days post-irradiation through rapamycin (100 nM) treatment for 4 days, had no effect on SA-βgal activity (>80%) (blue staining). (C) Primary MEFs were treated with torin 1 (50 nM) while irradiated (10 Gy) to induce senescence and then subsequently for 14 days in culture. Sustained torin 1 treatment significantly prevented intracellular iron accumulation, as determined by ICP-MS. Statistical analysis was performed by student-t-test: significant (*p < 0.05, **p < 0.01, ***p < 0.001). Data represented as mean ± SD (n = 3).