FLT3-JM-PMs induce IL-3-independent growth in Ba/F3 cells and hyperproliferation in response to FL. (A) Ba/F3 cells stably transduced with FLT3-WT, FLT3-ITD constructs (W51, NPOS, W78), FLT3-TKD constructs (D835Y, D835V) or one of the FLT3-JM-PM mutants (FLT3-V592A, FLT3-V579A, FLT3-F594L, and FLT3-F590GY591D) were seeded at a density of 4 × 104 cells/mL in the absence or presence of IL-3. Viable cells were counted after 72 hours. The growth of cells in the presence of IL-3 was defined as 100% (control). All FLT3-JM-PM mutants showed a significantly higher proliferation rate compared with FLT3-WT (*P < .05), although not as high as FLT3-ITD or FLT3-TKD. SD is indicated. (B) FLT3-WT and mutant-expressing Ba/F3 cells were seeded at a density of 4 × 104 cells/mL in the absence or presence of human recombinant FL (50 ng/mL). Viable cells were counted after 72 hours by trypan blue exclusion. The cell number of FLT3-WT cells after 72 hours was defined as 100%. SEM is indicated.
