To investigate the molecular determinants of differences observed between KRAS-mutant and KRAS/LKB1–mutant cells, we treated NCI-H441 (KRASG12V), NCI-H1734 (KRASG13C), A549 (KRASG12S/LKB1mut), and NCI-H460 (KRASQ61K/LKB1mut) cells with JQ1 for 48 hours...Proliferation assays demonstrated that H441 cells were sensitive to JQ1 with an IC50 of 0.06 μmol/L, whereas A549 cells were resistant to JQ1 with an IC50 higher than 10 μmol/L (Supplementary Fig. S1A). Similarly, H460 cells harboring LKB1-mutant are resistant to JQ1 with IC50 around 10 μmol/L ...