TRIB3 regulated cell growth and cell cycle progression in radioresistant MDA-MB-231 cells. Radioresistant MDA-MB-231 cells were transduced with lentivirus carrying TRIB3 specific shRNAs (KD1 or KD2) or control lentivirus (sh-LacZ, Ctrl) and selected for successfully transduced cells with 2 μg/ml puromycin for 48 h. (A) The selected cells were then harvested and plated into 12 well-plates at 1 × 105 cells/well, and cells were harvested by trypsin/ ethylenediaminetetraacetic acid (EDTA) every 24 h until 96 h passed, followed by counting under inverted microscopy. *, p < 0.05; **, p < 0.01. (B) The selected cells were plated into 6-cm cell culture dishes at 3 × 105 cells/dish and labeled with Bromodeoxyuridine (BrdU) at 46 h after plating. Cells were then harvested by trypsin/EDTA at 48 h and stained with BrdU incorporated cells as described in the Materials and Methods section. The percentage of each phase was calculated by WinMDI software.