Fig. 1. PD-L1 promotes lung cancer cell growth in vitro and in vivo.
a PD-L1 mRNA expression in different human lung cancer cell lines was analyzed by RT-PCR. b PD-L1 expression in human lung cancer cells was detected by western blot. c Colony formation assay in human lung cancer cells with PD-L1 knockdown or overexpression. d The xenografts were harvested at 18 days after injection and the morphology of tumor xenografts from each nude mouse was photographed. e The tumor weight of each nude mouse was measured. f The tumor volume of each mouse from different groups was measured and calculated as Volume = (Width2 × length)/2. g Growth kinetics (mean ± SD) of PD-L1-sh4, PD-L1-sh5 versus the negative control in BALB/c-nude mice (n = 6). The data are presented as mean ± SD of three independent tests. *P < 0.05, **P < 0.01, ***P < 0.001.