Figure 2.
Dose-response activity of IGFBP-3 on proliferation of myeloid leukemia cells. (A) Trypan blue exclusion test. NB4 cells (105/mL) were cultured in the presence of various concentrations of human recombinant IGFBP-3 (0.01-10 μg/mL) for 4 days. Results are expressed as a mean percentage of the cell count in the control plates. Each point represents the mean ± SD of 3 independent experiments performed in triplicate. (B) TUNEL assay. NB4 cells (105/mL) were cultured with human recombinant IGFBP-3 (5 or 10 μg/mL) for 2 days, and apoptosis was measured by TUNEL assay. Data represent the mean ± SD of triplicate cultures.