Study on ASTC-a-1 cells labeled with superparamagnetic iron oxide and its magnetic resonance imaging.

The aim of this preliminary study is to explore the feasibility of incorporating superparamagnetic iron oxide (SPIO) with poly-L-lysine (PLL) for labeling and magnetic resonance imaging (MRI) of human lung adenocarcinoma cells. Endorem (5-200 microg/mL) was incubated with ASTC-a-1 cells in the presence of PLL (1.5 microg/mL) for 0.5-24 h. The presence of SPIO in labeled cells was examined by Prussian blue stain. The effects of SPIO on cell proliferation, reactive oxygen species (ROS) generation and the mitochondria were also examined. In vitro MRI of SPIO-PLL-labeled cells was performed using a clinical 1.5 T MRI system. The labeling efficiency of >99% could be achieved after incubating for 0.5 h with 25 microg/mL of SPIO in the presence of PLL (1.5 microg/mL). Higher concentrations of SPIO (e.g. >50 microg/mL) could induce significant cell death, which might be mediated by changes in intracellular ROS level and mitochondrial membrane potential. In vitro MRI showed the decrease in MRI signal intensity on T(1)WI, T(2)WI and T(2)*WI sequences. In conclusion, MRI can trace SPIO-labeled cancer cells according to changes in T(1)WI, T(2)WI and T(2)*WI sequences. It should be noted that at higher concentrations, SPIO can cause cell damage.