Fig. 4
MRI contrast generated via the induced expression of FTH1. a C3H10T1/2-FTH1 cells were cultured for 72 h in the presence or absence of 0.2 μg/ml Dox and different concentrations of FAC for T2-weighted imaging. In the absence of Dox (Dox-), there was no significant MRI signal change. However, in the presence of Dox (Dox+), the MRI signal decreased with increasing iron concentrations, and the MRI signal was significantly decreased at iron concentrations of 500 μM and 800 μM. b C3H10T1/2-FTH1 cells were cultured in Dox at different concentrations in the presence or absence of 500 μM FAC for 72 h. Color-coded R2 maps from multi-echo measurements of the R2 relaxation rates showed a significant increase in the R2 rate in C3H10T1/2-FTH1 cells treated with Dox and FAC (0.2 μg/ml and 500 μM, respectively) compared to that in the other cells (P < 0.05). MRI magnetic resonance imaging, FTH1 ferritin heavy chain, Dox doxycycline, FAC ferric ammonium citrate