The anti-
cancer activity of
metal ions in the
lanthanide group is being considered recently. It has been reported that
cerium salts might stimulate the metabolism and therefore, produce anti-
cancer effects. However, little is known about the effects of
protein-
cerium complex in controlling
cancer cell growth. The aim of the present study was to elucidate the possible pathways for the cytotoxic effect of
cerium in the presence of apo-
transferrin on two
cancer cell lines (Hela and MCF-7), that express
transferrin receptors 3-4 fold higher than normal cells. The effect of different concentrations of
cerium (0.1, 1, 10, 100 μM) in the presence and absence of
transferrin for 48 h and 72 h incubation periods (37°C, 5% CO2 and 95% humidity) was studied using the MTT assay. The results showed that
cerium has a cell-proliferation inhibitory activity which is significantly increased by
transferrin protein. Compared with the direct treatment of
cancer cells with
cerium, the presence of
transferrin assisted inhibition of cell proliferation by 20% and 40% in Hela and MCF-7 cells, respectively. Though apo-
transferrin could lightly induce cell growth particularly in MCF-7 cells by itself, this phenomenon could not overcome the
cerium-
protein cell-proliferation inhibition activity. In conclusion, our results indicate that at a certain concentration, the
cerium compounds could be possibly involved in the control of cell proliferation and inhibiting the growth of
cancer cells.