Figure 8.
Andrographolide improved homologous recombination pathway mediated DNA damage repair. (A) HCT116 cells (5 × 105) were seeded in 6-well plates co-transfected with 2 μg I-SceI expression plasmid (pCBASce) and either 4 μg pimEJ5-GFP or pHPRT-DR-GFP plasmid. Twenty-four hours post transfection, cells were incubated with andrographolide (3 μmol/L) for another 24 h. Cells were harvested and analyzed by flow cytometry analysis for GFP expression. (B, C) HCT116 were treated with CPT-11 (30 μmol/L) for 24 h and withdraw. Then the cells were cultured with or without andrographolide (3 μmol/L) for the indicated time. The cells were subjected to IF analysis for RAD51 and γH2AX foci (B) and Western blot for expression of RAD51 and γH2AX (C). (D) IHC staining of RAD51 in colon tissues resected from tumor-bearing mice. Data are expressed as mean ± SEM (n = 3). ∗P < 0.05, ∗∗P < 0.01. Scale bar: 100 μm.