Figure 5.

RTK inhibition sensitizes the acquired PEM-resistant model of NSCLC. (A) NCI-H3122 P and NCI-H3122 R cells were treated with the indicated concentrations of PEM for 3 days. (B) Apoptosis was evaluated by flow cytometry of Annexin V-PI double-stained NCI-H3122 R cells after treatment with gefitinib or afatinib for 24 h. The Y-axis represents the PI-labeled population, whereas the X-axis represents the Annexin V positive cells. The left lower gating (Annexin V-, PI-) indicates normal cells, whereas the right lower gating (Annexin V+, PI−) and the right upper gating (Annexin V+, PI+) are the early and late apoptotic cells, respectively. (C) Data are presented as histograms (*** p < 0.001). (D) Caspase 3/7 activity was quantified 24 h after gefitinib or afatinib treatment in NCI-H3122 R cells. Means with different letters (a, b, c, and d) indicate statistically significant differences (p < 0.05; N.S., not significant).