Effects of lycorine on expression of p21 and downstream genes regulated by p21 in HL-60 cells. (A) Expression levels of p21 in HL-60 cells were analysed by real-time quantitative RT-PCR. Expression levels were standardised using expression of the housekeeping gene β-actin. (B) Effects of lycorine on expression of p21 protein, (C) Cdc2 and Cyclin B proteins, (D) Cdk2 and Cyclin E proteins. α-tubulin was used for normalisation and verification of the protein loading in B, C, and D in Western blotting. Lanes 1-4, HL-60 cells were treated with 0, 1.25, 2.5, and 5.0 μM lycorine, respectively. Results were presented as mean ± S.D. (n = 3, three independent experiments). Asterisk symbol (*) indicates significant difference (p < 0.05) compared with the control group.