Figure 2. Berberine inhibits basal and EGF-stimulated proliferation in colon tumor cells.

(A) cells were treated with berberine at 50 µM under non-permissive condition for 24 hours in the presence or absence of EGF (30 ng/ml) treatment for 24 hours. Cell proliferation was detected by BrdU labeling and staining with FITC-conjugated anti-BrdU antibody and propidium iodide (PI) staining for flow cytometry. Density plots with BrdU-FITC vs PI and percentages of cells in G1, S, and G2 phase are shown. (B) cells were treated as described in (A). Cellular lysates was prepared for Western blot analysis to detect expression of the cell cycle checkpoint proteins. Data in this Figure are representative of three separate experiments.