FIGURE 3.

Actein inhibited cell proliferation and mediated cell arrest in G1 phase through the modulation of p21-cyclin D1/CDK4-pRb pathway. (A) Effect of actein on MDA-MB-231 cell proliferation was investigated by (methyl-³H)-thymidine incorporation assay after 24 or 48 h incubation with actein. Results are expressed as mean ± SD of 3 independent experiments. (B) Cell cycle of MDA-MB-231 cells treated with actein for (i) 24 and (ii) 48 h were evaluated by flow cytometry, and (C) Results were presented as mean + SD of 3 independent experiments in bar charts. (D) Western blot analysis of p21-cyclin D1/CDK4-pRb pathway related proteins in MDA-MB-231 cells upon (i) 24 or (ii) 48 h treatment with actein (10 – 40 μM). (E) Bar charts show the expression levels of proteins of (i) P21, (ii) CDK4, (iii) Cyclin D1, and (iv) phosphorylated Rb, which were adjusted with corresponding β-actin protein level and expressed as fold of control (mean fold of control + SD from 6 independent experiments). Differences among the treated and vehicle treated control groups were determined by one-way ANOVA. ^∗p < 0.05, ^∗∗p < 0.01, and ^∗∗∗p < 0.001 as compared to control group.