Figure 5.

OGE enhances cisplatin-induced DNA damage. (A) HepG2 cells, in the presence or absence of OGE (200 μg/mL), were treated with cisplatin (60 μM) for 4 h. After cisplatin removal (defined as 0 h post cisplatin treatment), HepG2 cells were collected at the indicated times. The expression of γH2AX was determined via Western blotting. Ratio, the relative protein level. β-actin, loading control. (B) After cell synchronization by culture with serum-free media for 24 h, HepG2 cells, in the presence or absence of OGE (200 μg/mL), were treated with cisplatin (60 μM) for 6 h. The cell cycle was determined using flow cytometric analysis of propidium iodide-stained cells with a FACSVerse flow cytometer (BD Biosciences). Cell cycle distribution was analyzed using BD FACSuite software (BD Biosciences). (n = 3). (C) HepG2 cells, in the presence or absence of OGE (200 μg/mL), were treated with cisplatin (60 μM) for 4 h. The expression of γH2AX (green) and Rad51 (red) in HepG2 cells at the indicated times post-cisplatin treatment was analyzed using confocal microscopy. The fluorescence signals were measured using ImageJ 1.54g software, and the relative fluorescence intensity was normalized to the control group. (D) BRCA1 expression was determined via Western blotting, and (E) cell viability assays were conducted using the MTT assay in HepG2 cells with or without BRCA1/KD in the presence or absence of OGE (200 μg/mL) at the indicated doses of cisplatin. The nuclei, DAPI (blue). Scale bar, 10 µm. For statistical analyses, one-way ANOVA with Tukey’s post hoc test (B,E). ^★★, p < 0.01.