Figure 2. The effect of stromal cells on the atiprimod-induced apoptosis of cells expressing mutant JAK2^V617F.

(A) FDCP-EpoR^V617F cells were cultured alone (control), or with atiprimod, with or without HS5 stromal cells. Following 48 hour culture cells were harvested, stained with annexing V and percentage of apoptotic cells determined by flow cytometry. Data from representative experiment are shown. Atiprimod-induced apoptosis was dramatically impaired when JAK2^V617F-positive cells were co-cultured with stromal cells (B) FDCP-EpoR^V617F and SET-2 cells were cultured without (control) or with three different stromal cell monolayers (HS5, NK.tert, TM-R1) in the absence or presence of atiprimod for 48 hours. The induction of apoptosis was then assessed by flow cytometry. Results represent the mean ± SD from 3 independent experiments.