Relationship of c-myc expression to differentiation and proliferation of HL-60 cells.

We have compared changes in c-myc expression in HL-60 promyelocytic leukemia cells induced to differentiate by dimethyl sulfoxide or growth inhibited in an undifferentiated state. Under these conditions, c-myc expression did not correlate with the proportion of proliferating cells. The kinetics of the decrease in c-myc expression upon differentiation induction is paralleled closely by an increasing proportion of histochemically detected differentiated myeloid cells and by a decrease in clonogenic potential but not by changes in the proportion of proliferating cells. Changes in c-myc expression subsequent to differentiation induction can therefore be directly related to the differentiation process rather than to a cell cycle-related phenomenon.