Development of chemotactic responsiveness in myeloid precursor cells: studies with a human leukemia cell line

We have studied the events that occur during the development of chemotaxis in HL60, a promyelocytic leukemia cell line that acquires the features of mature neutrophils when exposed to dimethylformamide (DMF). Chemotactic function first appears between 48 and 96 hr of DMF induction and is associated not only with the coincidental development of deformability, spontaneous motility, greatly increased binding of fMet-Leu-Phe, and orientation but also with decreasing cell size and pleomorphism of nuclei. Surface adhesiveness develops earlier (36-48 hr) and is coincident with a 10-fold increase in protein synthesis not seen in other DMF-inducible cell lines. This burst of protein synthesis precedes the expression of chemotactic function. These studies show that the HL60 cell line can provide a useful model for delineating control mechanisms responsible for the development of complex cellular functions present in differentiated myeloid cells in humans.