Fig. 4: Claudin1 knockdown inhibits cancer cell stemness in NSCLC cells.

A PC9/GR cells were infected with a lentivirus for 48 h. Then, total RNA were extracted and mRNA expression levels of CLDN1, POU5F1, Sox2, NANOG, and ALDH1A1 were detected by real-time PCR (mean ± SD; n = 6; *P < 0.05, **P < 0.01). B H1975 cells were infected with a lentivirus for 72 h and infection efficiency was detected by a laser scanning confocal microscope. Note: Numbers represent MOI values; lentivirus concentration: 3.0 × 10⁸ TU/mL. C, D PC9/GR and H1975 cells were infected with lentivirus for 48 h and the expression of claudin1, Nanog, Sox2, and Oct4 was evaluated by western blotting. E, F Sphere formation of H1975 cells was observed after claudin1 knockdown. Cell spheres that were characterized by tight, spherical, non-adherent colonies of >90 μm in diameter were counted (Scale bar: 100 μm; original magnification: ×100; representative images from three experiments; mean ± SD; **P < 0.01). G siRNA was transfected for 6 h, then PC9/GR cells were treated with gefitinib (1 μM) for another 48 h, the protein was extracted and expression levels of claudin1, Oct4, Sox2, Nanog, and CD133 were evaluated by western blotting. H H1975 cells were transfected with siCLDN1 or siCtrl for 6 h, and then treated with gefitinib (1 μM) for another 48 h, and the expression levels of claudin1, Oct4, Sox2, and CD133 were evaluated.