Switch in differentiative response to maturation inducers of human promyelocytic leukemia cells by prior exposure to alkaline conditions.

The myeloid lineage to which HL-60 promyelocytic leukemia cells will differentiate in response to a chemical differentiation inducer can be switched by altering the pH of the growth medium. Cells passaged previously at pH 7.2 become neutrophiles, and those passaged previously at pH 7.6 become eosinophiles after 5 to 7 days of culture in the presence of 0.5 mM butyric acid. Butyric acid and its analogues are unique in that all other chemical maturation inducers tested, such as dimethyl sulfoxide and retinoic acid, promote neutrophilic differentiation regardless of the prior culture history of the cells. This suggests that lineage commitment and maturational commitment are mechanistically separate processes in this multipotential cell line and can be independently manipulated experimentally.