Effects of cyproheptadine on the cell cycle in HCC cells. HepG2 (A) and Huh-7 (B) cells in 6-well plates were cultured for 24 h, starved in serum-free medium for 24 h, and then treated with cyproheptadine at 30 or 40 μM (HepG2) or at 25 or 35 μM (Huh-7) for 48 h. Treated cells were stained with propidium iodide and analyzed by flow cytometry. Data are presented as mean ± SD (n = 4). Significant differences from the no-treatment control, determined by one-way ANOVA and Dunnett’s comparison test, are indicated by asterisks: *p < 0.05; ***p < 0.001. No difference was observed between the no-treatment control and the DMSO-only control in all test groups, indicating the absence of confounding effects from the DMSO solvent.