Fig. 2.

CB839 synergized with selumetinib to inhibit proliferation of KRAS-mutant NSCLC cells. KRAS-mutant cells A549, H23, H2122 and the KRAS wild-type cell line H1299, H838 were treated with selumetinib, CB839, or a combination of both at escalating doses that ranged from 10 to 10⁵ nM for 72 h. Subsequent cell proliferation experiments were carried out according to the following combinations and drug doses: control, selumetinib (SE, ½IC₅₀ concentration), CB839 (CB, IC₁₀ concentration), and selumetinib+CB839 (SE ½IC₅₀ concentration +CB IC₁₀ concentration). (A) CCK8 assay of A549,H23 and H1299 cells treated with monotherapy or a combination of selumetinib and CB839. (B) The combination index (CI) plots of selumetinib and CB839 in A549, H23, and H1299 cells. CI values <1 indicated a synergistic drug-drug interaction,CI values <0.3 indicated a strong synergistic effect. (C) IC₅₀ of selumetinib, CB839 alone, and selumetinib combined with CB839. (D) Fold change of IC₅₀ of selumetinib when combined with CB839. (E) Edu assay of cell proliferation of A549 and H1299 cells to test the short-term response to the combination therapy. (200x) (F) The colony formation assay of A549 and H1299 cells to test the long-term response. CI were presented as median (P25, P75), other data were presented as mean ± SD from three independent experiments. A p-value<0.05 was considered statistically significant (*p<0.05, **p<0.01,***p<0.001;* in red: compared with SE group, * in green: compared with CB group).