HB-EGF induction by GM-CSF treatment in AML blasts. Resting blasts were negative for HB-EGF mRNA and insensitive to DT, but after GM-CSF they acquired HB-EGF transcripts and sensitivity to DT-induced cytolysis (P = .002). (A) Dose-response curves testing the different sensitivity to DT in ex vivo myeloid blasts from case 6 in Table 1 before and after treatment with GM-CSF. Results were expressed as percentage of controls and represented the mean ± SD of 5 experiments. (B) The percentage of cell viability at the 10−8 mol/L DT concentration in two representative experiments is associated with the corresponding pattern of RT-PCR analysis, showing the induction of the transcripts for HB-EGF after exposure to GM-CSF (HB-EGF: 605 bp; vimentin: 266 bp).
