Figure 4.

BORIS resists DDP-induced DNA damage. (A) Immunofluorescence stain of H1299 cells transfected by pBORIS (BORIS-flag) and then treated by 1 µg/ml DDP for 24 h. BORIS expression was detected by flag antibody and FITC conjugated secondary antibodies (green). γH2AX antibody and TRITC conjugated secondary antibodies were used to detected DNA damage (red). (B) Quantification of immune fluorescence signals inside the dotted cycles in panel A. The column demonstrates the γH2AX (DNA damage) signal difference between gated (BORIS-flag transfected) and ungated cells. (C) H1299 and A549/DDP cells were transfected by BORIS siRNA-1. The knockdown of BORIS induced TUNEL signals in both cell lines. (D) H1299 and H460 cells were transfected by pBORIS or BORIS siRNA-1. Expression levels of the DNA repair associated genes were tested by reverse transcription-quantitative PCR. MSH6 was regulated by the treatments. ***P<0.001. IOD, integral optical density; A549/DDP, DDP resistant A549 cell line; BORIS, Brother of Regulator of Imprinted Sites; NSCLC, non-small cell lung cancer; OD, optical density; si, small interfering; nc, negative siRNA control; MSH6, mutS homolog 6.