Figure 2. Increased sensitivity to cisplatin in patient-derived xenograft (PDX) lung adenocarcinoma cell lines following DDR1 knockdown.

(A) Western blot validation of DDR1 knockdown in 2 patient-derived xenograft (PDX) cell lines (2 and 3) treated with 2 independent shRNAs (960 and 1358) against DDR1 in parallel with a shRNA control. α-Tubulin was used as loading control. Representative Western blots of 2 independent experiments are shown. (B) Comparison of IC₅₀ values upon 72 hours cisplatin treatment between control and DDR1-knocked down PDX cell lines maintained in 2D growth conditions. Data are shown as the mean ± SEM of 3 independent experiments. The table shows decreased IC₅₀ values (mean ± SD, n = 3) following DDR1 knockdown. (C) Cell number quantification following treatment with the indicated concentrations of cisplatin for 72 hours in control and DDR1-knocked down PDX cell lines maintained in 2D growth conditions. Data were analyzed using 2-way ANOVA followed by Bonferroni’s multiple comparison test. **P value < 0.01, ***P value < 0.001. Data are shown as the mean ± SEM of at least 3 independent experiments. (D) Comparison of IC₅₀ values upon 72 hours cisplatin treatment between control and DDR1-knocked down PDX cell lines maintained in 3D growth conditions. Data are shown as the mean ± SEM of 3 independent experiments. The table shows decreased IC₅₀ values (mean ± SD, n = 3) following DDR1 knockdown. (E) Cell number quantification following treatment with the indicated concentrations of cisplatin for 72 hours in control and DDR1-knocked down PDX cell lines maintained in 3D growth conditions. All values were normalized to their respective untreated controls. Data were analyzed using 2-way ANOVA followed by Bonferroni’s multiple comparison test. *P < 0.05, **P < 0.01, ***P < 0.001. Data are shown as the mean ± SEM of at least 3 independent experiments. (F) Quantification of apoptosis following treatment with the indicated concentrations of cisplatin for 72 hours in control and DDR1-knocked down PDX cell lines maintained in 2D growth conditions. Data were analyzed using 2-way ANOVA followed by Bonferroni’s multiple comparison test. *P < 0.05, **P < 0.01, ***P < 0.001. Data are shown as the mean ± SEM of 3 independent experiments. P value ns, nonsignificant.