Growth stimulation of ferritin of human leukemia cells in vitro.

Ferritin has been reported to inhibit the growth of some leukemia cells in serum-supplemented culture. Recently we have found that ferritin stimulates the proliferation of human acute myeloblastic leukemia cells HL-60 and erythroleukemia cells K-562-T1 in serum-free medium. In this study, we examined the effect of ferritin against 14 human leukemia cell lines using human heart ferritin in serum-depleted culture medium. Among 14 cell lines tested, 10 were stimulated to proliferate by ferritin (maximum response at 30-300 ng/ml) with 0-1% fetal calf serum (FCS). The growth of all the cell lines was significantly inhibited by ferritin in the presence of 10% FCS. These results suggest that ferritin has dual functions; it promotes the growth of leukemia cells with low concentrations of FCS, but suppresses their growth with high concentrations of FCS.