Fig. 2

Functional validation of CSK or PTEN null N87 and OE19 cells. a Cell viability of CSK or PTEN knockout OE19 cells treated with indicated doses of lapatinib. OE19 cells were transduced with lentiviruses carrying sgRNAs targeting CSK, PTEN, or non-targeting control sgRNA. The drug resistance of the cells from each group was measured by calculating the relative percentage of cell viability. CSK or PTEN protein expressions were evaluated by western blotting. b Cell viability of CSK or PTEN knockout N87 cells treated with different doses of lapatinib. N87 cells transduced with non-targeting sgRNA as control. Shift between control cells and gene knockout cells in the dose response curve displays the reduced sensitivity to lapatinib in the GC cell lines. CSK or PTEN protein expressions were evaluated by western blotting. c Caspase-Glo 3/7 assay analysis to examine lapatinib induced caspase-3/7 activity after 48 h treatment in CSK or PTEN null cells OE19 and N87 cells. OE19 or N87 cells transduced with virus carrying non-targeting sgRNA as control. Unpaired Student’s t test indicated the following: *significant difference from the control, p < 0.05; **significant difference from the control, p < 0.01