Figure 3. Effects of CDX2 on lung cancer cell proliferation and cell cycle distribution. (A) Confirmation of re-expression of CDX2 in H23 cells by western blotting. Actin was used as internal reference. (B) Typical colony formation assay for CDX2 and control vector are presented. H23 cells were transfected with pcDNA-CDX2 or control vector. After selection with G418 for 2–3 weeks, the surviving colonies were stained with 0.5% crystal violet and counted. (C) Quantitative analysis of colony formation assays. The numbers of G418 resistant colonies in control vector transfected cells were set to 100%. The results are given as the mean ± SD from triplicate experiments. (*P < 0.05). (D) Representative results of cell cycle distribution for CDX2 and control vector. H23 cells were transfected with the pEGFP-CDX2 or control vector. Transfected cells were sorted by GFP expression. Cell cycle distributions were measured by propidium iodide (PI) staining followed by flow cytometry after transfection for 48 h. (E) Quantitative analysis of cell cycle distribution. The percentages of G1, S and G2 cells transfected with control vector served as controls. The results are given as the mean ± SD from triplicate experiments. (**P < 0.01; ***P < 0.001).