Figure 1. Bufalin inhibits cell proliferation and clonogenic activity and induces apoptosis.

(A and B) Cells were treated with 20, 40, or 80 nM bufalin for 24 or 48 h, and the viability of cells was measured using CCK-8 (***P<0.001 vs untreated group). (C and D) Cells (2 × 10³ cells/well) were exposed to 20, 40, or 80 nM bufalin for 24 h, washed with PBS, and then allowed to grow for the next 7 to 10 days. The colonies were visualized by Crystal Violet staining (P<0.001 (H460), ^###P<0.001 (A549), vs untreated group). (E) Cells (3 × 10⁵ cells/ 60 mm dish) were exposed to 20, 40, or 80 nM bufalin for 24 h. The levels of PARP and γ-H2AX protein were determined by Western blot analysis.