Figure 2. Effects of HF on U937 cell growth.

U937 cells (10⁵/ml) were treated with HF (A) at the indicated concentrations for 72 h or (B) or with 0.5 and 1.4 µg/ml HF for the indicated times. Control EtOH (vehicle). Cell growth was measured by direct cell counting (in duplicates). Data are the mean ± SD of results from at least 6 independent experiments, each performed in duplicates. (C) U937 cells were incubated with 1.4 µg/ml HF for 72 h. Cells were stained with PI and DNA contents analyzed by flow cytometry. (D) DNA fragmentation in U937 cells treated for 72 h with 1.4 µg/ml HF, EtOH (vehicle) or 100 nM flavopiridol (F).