Fig. 3

a BDNF expression in HBE cells, two SCC cells (SK and LK2) and two ADC cells (A549 and LTE) by western blot analysis. The ratio between the optical density of BDNF and β-actin of the same cells was used to indicate the relative level of BDNF expression. The expression of BDNF was rare in HBE cells, and that was much higher in other 4 lung cancer cells. b The decreased expression of BDNF by specific shRNA was shown in LK2 or A549 cells. β-actin was used as a reference control to ensure the equal protein quantity in all lanes. The experiments for each cell line were completed in triplicates