Early effects of G- and GM-CSF upon HL-60 proliferation and differentiation

Effects of human recombinant G- and GM-CSF upon HL-60 myeloid leukemic cell differentiation and proliferation have been studied. Minimal morphologically apparent differentiation was noted with treatment up to 7 days and concentrations up to 1000 units/ml. Cell surface marker analysis disclosed modest increases of MO1 and HLA-Dr expression following treatment with G-CSF/GM-CSF, for 2-4 days. Macromolecular synthesis rates following 24-hr exposures to CSF disclosed stimulation of [3H]uridine greater than [3H]thymidine greater than [3H]leucine by GM-CSF only. Proliferation was also assessed by flow cytometric DNA histogram analysis which also disclosed greater increases in the percentage of S + G2/M cells following GM-rather than G-CSF treatment. This study documents subtle early effects of G- and GM-CSF upon HL-60 proliferation and differentiation. Differentiative effects were relatively more marked with G-CSF while proliferative effects were more marked with GM-CSF.