WDR1 promotes NSCLC growth in vitro. A: In A549, H1299 and H226 cell lines, we generated stable WDR1 knockdown (mediated by shRNA), and overexpressed cells, respectively. The efficiencies of WDR1 knockdown and overexpression were detected by western blotting analysis. The results showed that shWDR1 markedly down-regulated the expression levels of WDR1; and WDR1 was increased in cells transfected with PCDH-WDR1 plasmid (WDR1), relative to cells transfected with PCDH-GFP plasmid (control). The relative protein level was quantified, and the results were showed below the corresponding bands. B: CCK-8 assay showed that WDR1 knockdown significantly inhibited the proliferative rates in A549 and H1299 cells. C: CCK-8 assay in H226 cells. WDR1 knockdown significantly inhibited the proliferative rates, whereas WDR1 overexpression promoted the proliferative rates, compared to their corresponding controls. D: The cloning ability was determined by colony formation assay in A549 cells. Compared with shCTL cells, the colony formation was dramatically inhibited in shWDR1 cells. E-F: Western blotting analysis (E) and quantification (F) of protein levels of cell cycle regulators in A549 cells. Compared with shCTL, Cyclin A2, cyclin B1, cyclin D1, cyclin E, Cdk1 were decreased in shWDR1 cells, and p27 was significantly increased. Data are expressed as means ± SEM. *P < 0.05, **P < 0.01, and ***P < 0.001.