Macrophage-like cell transformation and CFU(c) fluctuations in normal and leukemic human marrow cultures treated by phorbol diester.

Bone marrow from normal and chronic myeloid leukemia donors was grown in liquid cultures without feeder layers and with and without 12-u-tetradecanoyl-phorbol-13-acetate (TPA). In 24-96 hours most of the cells (60-70%) cultured with 10(-7) M and 10(-8) M TPA stuck to the bottom of the flasks and had a peculiar shape resembling macrophages possessing strong phagocytizing activity and surface markers of monocyte-macrophage lineage of differentiation. 10(-7) M and 10(-8) M TPA fully inhibited CFU(c) in cultures of normal marrow as well as of chronic myeloid leukemia (CML) patients; 10(-9) M and 10(-10) M exhibited individually varied partial suppression. Cultivation of bone marrow with 10(-11) M to 10(-13) M TPA led in some cases to statistically significant increase of CFU(c) on day 4 and day 7.