Figure 1.

CoQ₀ inhibits growth of human ovarian carcinoma cells and induces G2/M cell-cycle arrest in SKOV-3 cells. (A) Structure of CoQ₀. (B–D) Human ovarian carcinoma (SKOV-3, A2870 and A2870/CP-70) and (E) human ovarian surface epithelial (IOSE) cells were treated with increasing concentrations of CoQ₀ (0–40 µM) for 24 h. Cell viability was determined using MTT assay. (F) Morphological changes in CoQ₀-treated (0–40 µM, 24 h) SKOV-3 cells were examined by phase-contrast microscope (200 × magnification). (G) SKOV-3 cells were treated with CoQ₀ (0–30 µM) for 24 h, stained with PI and analyzed for cell-cycle phase using flow cytometry. The cellular distributions (percentage) in different phases of cell-cycle (G1, S and G2/M) were determined after CoQ₀ treatment. Flow cytometry images shown here are from one representative analysis that was repeated three times with similar results. (H) SKOV-3 cells were treated with CoQ₀ (0–30 µM) for 24 h, and cell-cycle regulatory proteins, cyclin B1, CDK1, cyclin A and CDK2 were examined using Western blot. Relative changes in protein intensities were quantified by commercially available software, and presented as histogram, control being as 1-fold. Results expressed as mean ± SD of three independent assays (n = 3), and significant at **p < 0.01; ***p < 0.001 compared with untreated control cells.