FIGURE 5.

Glycogen synthase kinase (GSK)‐3 inhibition induced apoptosis of epithelial‐mesenchymal transition‐associated resistant cells. A, Control and GSK‐3 siRNAs were transfected into H1975 parental cells and resistant clone cells. At 24 h posttransfection, cells were treated with 1 μmol/L osimertinib and cell viability was measured after 72 h using MTT assay (n = 3). Error bars represent SEM. *P < .0001. B, Control and GSK‐3 siRNAs were transfected into H1975 parental and resistant clone cells. Cell lysates were analyzed using western blotting with the indicated Abs at 48 h posttransfection. C, Control and GSK‐3 siRNAs were transfected into resistant clone cells. At 24 h post‐transfection, cells were treated with 1 μmol/L osimertinib and cell lysates were analyzed using western blotting with the indicated Abs after 72 h (n = 4). D, OR#1, OR#3, and OR#4 cells were pretreated with 0.03 μmol/L quisinostat for 48 h, followed by GSK‐3 siRNA for 72 h. Cell viability was measured using MTT assay (n = 3). Error bars represent SEM. *P < .0001. E, Control, GSK‐3α, and GSK‐3β siRNAs were transfected into OR#3 cells and cell viability was measured after 72 h using MTT assay (n = 3). Error bars represent SEM. *P < .0001