Supplementary Figure 3: Enrichment of integrin ${\text{β}}_{3^{+}}$ cells during acquired resistance to erlotinib.

(a) Immunoblot of integrin β₃ in tumour lysates from Fig. 3a. (b) Representative Immunohistochemistry staining of integrin β₃ in mouse orthotopic lung tumours after systemic treatment with vehicle or erlotinib (58 days) shown in Fig. 3c. Scale bar, 50 μm. (c) Representative immunofluorescent staining of integrin α_vβ₃ in pancreatic human xenografts treated 4 weeks with vehicle or erlotinib shown in Fig. 3d. Scale bar, 40 μm. (d) Phase contrast images of self-renewal tumour spheres of HCC827 vehicle treated, erlotinib treated unsorted, ${\text{β}}_{3^{-}}$ and ${\text{β}}_{3^{+}}$ sorted population. Scale bar, 100 μm. (e) Limiting dilution experiments determining tumour-initiation efficiency (% tumour induction) shown in Fig. 3f. (f) Relative mRNA expression of ALDH1 in HCC827 vehicle-treated tumours (n = 5 tumours) or erlotinib-treated tumours (n = 7 tumours) from Fig. 3a. mean ± SEM. (g) Effect of integrin β₃ knockdown on ALDH1 expression in A549 in 3D culture. Results are represented as fold change in mRNA expression in A549 shβ₃ versus control. Data are mean ± s.d. n = 3 independent experiments. P value was estimated by χ² test in e. Students t-test in f,g. *P < 0.05, **P < 0.01. Uncropped western-blots are provided in Supplementary Figure 7. Original data for g are provided in the Statistical source data (Supplementary Table 3).