BLU expression exerts growth inhibitory activity and cell cycle arrest. (A) NPC-derived CNE-2 line and esophageal carcinoma-derived EC109 line were transfected with empty pcDNA3.1 vector, tumor suppressor TP53 or BLU. Cells were cultured in complete medium supplemented with 500 μg/ml G418 for up to 2 weeks, harvested and stained with gentian violet. (B) Summary of the results in (A). The colonies obtained for each experimental condition were counted and the numbers were presented as mean ± standard deviation. (C) and (D) CNE-2 cells were transfected with vector or pCD316-BLU and stained with PI diluted in assay buffer. The DNA contents were measured with FACS and analyzed with Win Cycle32 software. (E) Results of FACS analysis. The numbers 1, 2, and 3 depict the populations of cells in G1, G2/M and S phases. BLU expression arrested the cells in G1 phase, as manifested by the increase in this population. The data is presented as mean ± SD derived from at least three independent experiments.