Figure 7.

Effect of 3-BrOP on repair of DNA damage induced by BCNU and cytotoxicity in glioblastome stem cells. (A) Comet assay of DNA damage in GSC11 cells treated with BCNU, 3-BrOP, or their combination. Cells were treated with the indicated concentrations of compounds for 6 h, and then either immediately processed for comet assay or cultured in drug-free medium for additional 3–6 h for potential DNA repair. The bright green dots represent the positions of cellular nuclei; the “tail” length and intensity and on the right side of each nucleus represent the degree of DNA strand breaks eluted out from the cell during electrophoresis. Flow cytometry analysis (annexin-V/PI staining) was also used to measure cell death at 24 h (18 h after drug removal, lower panel). (B) Quantification of DNA damage in GSC11 cells treated with or without BCNU and 3-BrOP as indicated. At least 30 cells in each sample were quantitatively analyzed for % of DNA tail that eluted from the cellular nuclei. (C) Western blot analysis of γH₂AX and total H₂AX (tH₂AX) proteins in GSC11 cells treated with the indicated compounds for 2–6 h. *, p<0.05; **, p<0.01; ***, p<0.001.