Induction of differentiation of human and murine myeloid leukemia cells in culture by tunicamycin.

Tunicamycin, an antibiotic that specifically blocks the synthesis of N-acetylglucosamine-lipid intermediates and thereby prevents glycosylation of glycoproteins, induced differentiation of both human (HL-60) and murine (M1) myeloid leukemia cell lines in culture. At 0.1-1.0 microgram/ml, it induced differentiation of both HL-60 and M1 cells, characterized by increase in phagocytic cells and changes to resemble mature myeloid cells. Fc receptors were also induced in M1 but not in HL-60 cells; induction of intracellular lysozyme activity was not detected in either HL-60 or M1 cells. With this concentration of tunicamycin, there was marked decrease in rate of incorporation of radioactive glucosamine into macromolecules and a decrease in the rate of DNA synthesis. These data show that glycosylation of cellular proteins has an important role in maintaining these myeloid leukemia cells in an undifferentiated state in culture. The results also indicate that induction of phagocytosis in both HL-60 and M1 myeloid leukemia cells and of Fc receptors in M1 cells does not require continued synthesis of the oligosaccharide portions of cellular proteins by the lipid-linked pathway.