Figure 2.

miR-621 Enhances HCC Cell Radiosensitivity In Vitro

(A and B) Expression of miR-621 was detected by real-time qPCR in HepG2 (A) and Smmc-7721 (B) cells transfected with miR-621 mimic or negative control (NC). (C and D) HepG2 (C) and Smmc-7721 (D) cells transiently transfected with miR-NC or miR-621 mimic 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. (E and F) Treated cells were cultured for 24 hr, harvested, stained with Annexin V-fluorescein isothiocyanate (FITC) and PI, and then analyzed using flow cytometry. Representative images (E) and quantitative data (F) are shown. Each column is shown as the means of three separate experiments. The late apoptotic cells are shown on the graph as PI+ Annexin V+ population. (G) Western blotting analysis of γ-H2AX protein in HepG2 and Smmc-7721 cells transfected with miR-621 mimic or miR-NC treated with a 4-Gy dose of IR. The expression of γ-H2AX protein was detected 6 hr after IR (4 Gy). (H) Quantification of γ-H2AX protein. (I) The comet assay was used to evaluate DNA damage in HepG2 and Smmc-7721 cells transiently transfected with miR-NC or miR-621 mimic. A representative cell nucleus fluorescent image is shown. (J) Quantification of tail moment. *p < 0.05, **p < 0.01, ***p < 0.001.