Fig. 3

GSDMB-high cells are significantly more sensitive to the combination of lapatinib plus chloroquine. A-D The cytotoxic effect of the treatment with lapatinib and/or chloroquine in shNTC, shGB1 and shGB2 HCC1954 (A, B) and OE19 (C, D) cells was evaluated by cell viability assays and Annexin V-FITC plus PI. E–H The outcome in terms of cell viability and apoptosis of the different treatment regimens was analyzed in HCC1954 LR (E–F) and OE19 LR (G-H) cells compared to their corresponding control cells C. Statistical significance was determined by two-tailed unpaired t-test (*P < 0.05; **P < 0.01; ***P < 0.001). Data are shown as the mean ± s.e.m. Annexin V-FITC positive cells alone (A + /PI-) and Annexin V-FITC and PI doubled stained (A + /PI +) were defined as apoptotic cells. The number over the bars indicate the fold increase in cell death between the indicated conditions (B, D, F, H). Three independent experiments with similar results were performed. A, Annexin V; PI, propidium iodide; CQ, chloroquine. NTC, non-targeting control. LR, Lapatinib resistant cells. Lap, lapatinib, CQ, chloroquine