A, Analysis of the apoptotic sub-G1 cell population. H460 cells were treated with AZD6244 only or the combination of AZD6244 and JSI-124 for 48 hours, and cells were collected and stained with propidium iodide for cell cycle analysis. B, Effects of JSI-124 on PI3K/AKT, JNK, and p38MAPK pathways. H460 cells were treated with different doses of JSI-124 for 24 hours, and a Western blot was performed with the antibodies indicated. C, Combination treatment with AZD6244 and JSI-124 induced BIM expression in MEK inhibitor–resistant cells. H460 cells were treated with AZD6244 only or with AZD6244 and JSI-124 for 48 hours, and Western blotting was performed to determine the expression of proteins as indicated. D, Activation of the STAT3 pathway inhibited BIM expression induced by AZD6244. Calu6 cells were transfected with constitutively active STAT3 or control vector. Then, 48 hours after transfection, cells were treated with AZD6244 with different dosages as indicated for another 48 hours. Western blotting was performed to check the protein expression with specific antibodies as indicated. E, Effects of MAPK and STAT3 pathways on FoxO3A and BIM. H460 cells were treated with AZD6244 or JSI-124 alone for 48 hours, and a Western blot was performed with the antibodies indicated.