A) Cell count at day 0,1,2, and 3 after E2F1 depletion by siRNA (siE2F1) compared with control siRNA (siGL2), n = 4, +p<0,05 compared to siGL2. B) mRNA levels of KRT14, E2F1, cyclin E1 and cyclin D1 at day 2 after cell cycle arrest caused by E2F1 depletion (siE2F1), n = 6, *p<0.05 compared to siGL2. C) Protein levels of KRT14 and E2F1 in H441 assessed by Western blot at day 2 following E2F1 depletion by siE2F1; GAPDH level was used for normalization. D) Cell count at day 0,1,2, and 3 after E2F1 overexpression, n = 3, ^p<0.05 compared to pEGFP. E) mRNA expression levels of KRT14, E2F1, cyclin E1 and cyclin D1 at day 3 after cell cycle progression induced by E2F1 overexpression (pE2F1) compared with an unrelated transfection vector (pEGFP), n = 4, *p<0.05 compared to pEGFP. All data are reported as mean ± SD.