INCB053914 synergizes with ruxolitinib to inhibit the growth of MPN model cell lines. UKE1 cells were cultured with dimethyl sulfoxide (DMSO; 0.1%), 0.5 μM INCB053914, 0.5 μM ruxolitinib (Rux), and both drugs together (A); SET2 cells were cultured with DMSO (0.1%), 0.02 μM INCB053914, 0.1 μM ruxolitinib, and both drugs together (B); and BaF3-JAK2^VF cells were cultured with DMSO (0.1%), 0.01 μM INCB053914, 0.025 μM ruxolitinib, and both drugs together, and viable cell numbers were determined by trypan blue exclusion over time (C). For panels A-B, drug and media were replenished at each time point. For panel C, drugs were added once and not replenished. (D) UKE1 cells were incubated with the indicated range of ruxolitinib in the absence or presence of 0.5 μM INCB053914, and relative viable cells were determined after 72 hours using CellTiter-Glo. The expected additive percent of relative viable cells at each ruxolitinib concentration in the presence of INCB053914 was determined by the Bliss model of independence and plotted as the blue dashed line. The reduced observed percent of relative viable cells (red line below the dashed line) demonstrates synergy between ruxolitinib and INCB053914.