Fig. 6

Intracellular iron accumulation following induced FTH1 expression. a Prussian blue staining: In the presence of 0.2 μg/ml Dox and 500 μM FAC, a large number of blue iron particles were detected in the C3H10T1/2-FTH1 cells, but no iron particles were detected in the C3H10T1/2-WT cells. In the absence of Dox, neither C3H10T1/2-FTH1 nor C3H10T1/2-WT cells showed blue iron particles, regardless of FAC supplementation. b Transmission electron microscopy: In the presence of 0.2 μg/ml Dox and 500 μM FAC, numerous electron dense particles were detected in the cytoplasm of C3H10T1/2-FTH1 cells, but no particles were detected in C3H10T1/2-WT cells. In the absence of Dox, neither C3H10T1/2-FTH1 nor C3H10T1/2-WT cells showed electron dense particles, regardless of FAC supplementation. Scale bars: 50 μm (a) and 2 μm (b). FTH1 ferritin heavy chain, Dox doxycycline, FAC ferric ammonium citrate