Induction by chloroquine of differentiation of cultured mouse myeloid leukemia cells

The effect of chloroquine on differentiation of cultured mouse myeloid leukemia Ml cells was examined. On treatment with 5 approximately 25 microgram/ml of chloroquine diphosphate for 1 approximately 4 days, the cells were induced to phagocytize latex beads, to form Fc rosettes, to form dispersed colonies in soft agar, and to synthesize lysozyme, unlike untreated cells. The morphology of about 40% of the cells changed during treatment with 20 microgram/ml of chloroquine diphosphate for 4 days; some cells developed small eccentrically located nuclei, and others ring-shaped or segmented nuclei. These results show that Ml cells differentiate into cells resembling macrophages or granulocytes on treatment with chloroquine.