Fig. 1.

Smad7 enhances DSB response. a The cells were treated with NCS (from 20 to 80 ng/ml) and incubated for 10–14 days in control or Smad7-overexpressing (S7OE) A549 and NCI-H292 cells. The surviving colonies were stained with 2 % methylene blue. The number of surviving colonies was counted. At least three independent experiments were performed for each analysis. b Single-cell electrophoresis was performed in control or S7OE A549 cells treated with or without 200 ng/ml NCS. The NCS-treated cells were allowed to recover for 0 or 4 h. To evaluate DNA damage repair, the % tail moment was calculated using the Cometscore16 program. Student’s t test showed that the % tail moment was significantly different in LPCX and S7OE cells at p < 0.0001 (****). c The activation of the G2/M checkpoint was examined in control and S7OE A549 cells at 3 h after treatment with 200 ng/ml NCS. The cells were fixed in 1 % formaldehyde and stained with Alexa Fluor 488-conjugated anti-phospho-histone H3 (S10) antibody and propidium iodide. The percentage of cells in M phase was calculated through FACS analysis. The percentage of phospho-H3-positive cells was significantly different between LPCX and S7OE cells at p < 0.05 (*), according to Student’s t test