Figure 5.

Down-Expression of SETDB1 Enhances HCC Cell Radiosensitivity In Vitro

(A) Expression of SETDB1 mRNA detected by real-time qPCR in HepG2 and Smmc-7721 cells transfected with SETDB1 siRNA or control. (B) Western blotting analysis of SETDB1 protein. (C) Quantification of SETDB1 protein. (D and E) HepG2 (D) and Smmc-7721 (E) cells transiently transfected with SETDB1 siRNA or control were irradiated with a range of 2- to 8-Gy IR doses. After 14 days, colonies were stained and scored for colony formation and the SF was plotted, as described in the Materials and Methods. (F) Western blotting analysis of γ-H2AX protein in HepG2 and Smmc-7721 cells transfected with SETDB1 siRNA or control treated with a 4 Gy dose of IR. (G) Quantification of γ-H2AX protein. (H) The comet assay was used to evaluate DNA damage in HepG2 and Smmc-7721 cells transiently transfected with SETDB1 siRNA or control. Quantification of tail moment is shown. (I and J) Treated cells were cultured for 24 hr, harvested, stained with Annexin V-FITC/PI, and then analyzed using flow cytometry. Representative images (I) and quantitative data (J) are shown. Each column is shown as the means of three separate experiments. *p < 0.05, **p < 0.01, ***p < 0.001.