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. 2023 Nov 22;30(3):586–599. doi: 10.1158/1078-0432.CCR-23-0163

Figure 5.

Figure 5. Targeting MAPK pathway abrogates acquired resistance to type II JAK2 inhibition in MPN cells. A, Proliferation of JAKi-r SET2 cells was effectively inhibited by combined JAK2/MAPK pathway inhibition with CHZ868/trametinib as shown by a representative graph of proliferation capacity upon 48 hours exposure of inhibitor exposure. B, IC50 was significantly reduced by combined CHZ868/trametinib in JAKi-r cells (n = 3). C, Synergy analysis of type II JAK2 inhibition with CHZ868 and MAPK pathway inhibition with trametinib showed positive synergy in JAKi-r cells. Mean of n = 3 experiments is shown for synergy score along with a representative graph D. Proliferation of JAKi-R SET2 cells was effectively inhibited by combined JAK2/MAPK pathway inhibition with CHZ868/trametinib as shown by a representative graph of proliferation capacity upon 48 hours of inhibitor exposure. E, IC50 was significantly reduced by combined CHZ868/trametinib in JAKi-R cells (n = 3). F, Synergy analysis of type II JAK2 inhibition with CHZ868 and MAPK pathway inhibition with trametinib showed positive synergy in JAKi-R cells. Mean of n = 3 experiments is shown for synergy score along with a representative graph G. Apoptotic cell death reflected by positivity for caspase-3 was induced by combined JAK2 / MAPK pathway inhibition by CHZ868/trametinib in JAKi-R cells upon 48 hours exposure to inhibitors (n = 3–4). H, Representative histograms of caspase-3 positivity in JAKi-R cells are shown. I, Immunoblotting showed dose-dependent suppression of MAPK pathway signaling reflected by pERK1/2 (arrowhead) in JAKi-r and JAKi-R SET2 cells upon exposure to increasing concentrations of trametinib combined with CHZ868. Data are presented as mean ± SD and analyzed by one-way ANOVA. ns, not significant; *, P ≤ 0.05; **, P ≤ 0.01; ***, P ≤ 0.001; ****, P ≤ 0.0001.

Targeting MAPK pathway abrogates acquired resistance to type II JAK2 inhibition in MPN cells. A, Proliferation of JAKi-r SET2 cells was effectively inhibited by combined JAK2/MAPK pathway inhibition with CHZ868/trametinib as shown by a representative graph of proliferation capacity upon 48 hours exposure of inhibitor exposure. B, IC50 was significantly reduced by combined CHZ868/trametinib in JAKi-r cells (n = 3). C, Synergy analysis of type II JAK2 inhibition with CHZ868 and MAPK pathway inhibition with trametinib showed positive synergy in JAKi-r cells. Mean of n = 3 experiments is shown for synergy score along with a representative graph D. Proliferation of JAKi-R SET2 cells was effectively inhibited by combined JAK2/MAPK pathway inhibition with CHZ868/trametinib as shown by a representative graph of proliferation capacity upon 48 hours of inhibitor exposure. E, IC50 was significantly reduced by combined CHZ868/trametinib in JAKi-R cells (n = 3). F, Synergy analysis of type II JAK2 inhibition with CHZ868 and MAPK pathway inhibition with trametinib showed positive synergy in JAKi-R cells. Mean of n = 3 experiments is shown for synergy score along with a representative graph G. Apoptotic cell death reflected by positivity for caspase-3 was induced by combined JAK2 / MAPK pathway inhibition by CHZ868/trametinib in JAKi-R cells upon 48 hours exposure to inhibitors (n = 3–4). H, Representative histograms of caspase-3 positivity in JAKi-R cells are shown. I, Immunoblotting showed dose-dependent suppression of MAPK pathway signaling reflected by pERK1/2 (arrowhead) in JAKi-r and JAKi-R SET2 cells upon exposure to increasing concentrations of trametinib combined with CHZ868. Data are presented as mean ± SD and analyzed by one-way ANOVA. ns, not significant; *, P ≤ 0.05; **, P ≤ 0.01; ***, P ≤ 0.001; ****, P ≤ 0.0001.