Figure 6.

(A) Mononuclear cells isolated from the bone marrow of MPN patients were incubated with different concentrations of JAK2 or STAT5 targeting drugs for 48 h. Thereafter, ³[H]-thymidine was added for 16 h and its incorporation was analyzed using a beta counter. The diagrams show the mean ± SD of three independent experiments for JAK2-targeting drugs (patients #07, #20 and #23) or five independent experiments for STAT5-targeting drugs (patients #20, #23, #37, #35 and #39). (B,C) Mononuclear cells isolated from the bone marrow of MPN patients were incubated with different concentrations of JAK2 or STAT5 targeting drugs for 24 h (B) or 48 h (C). Then, the numbers of putative MPN stem cells (MPN-SC), defined as CD34⁺/CD38⁻/CD45^dim, were assessed using counting beads. The graphs show MPN-SC as percent of control in four patients (#14, #29, #30 and #31) in (B) and in three patients (#31, #42 and #43) in (C). Horizontal lines indicate mean values. (D) pSTAT5 levels in CD34⁺/CD38⁻ MPN-SC determined by flow cytometry (same patients as in (C)) after an incubation with targeted drugs (as indicated) for 4 h. Values represent pSTAT5 levels relative to the control. The mean staining index is also shown (horizontal bars). Patient characteristics are shown in Table A1.