Objective: To explore the possible mechanisms of Tanshinone IIA (TanIIA) on esophageal carcinoma cell lines.
Methods: Two human esophageal carcinoma cell lines (EC-1 cells and ECa-109 cells) were treated with different concentrations of TanIIA. Cell proliferation was measured by CCK-8, colony-forming efficiency was calculated, cell cycle and apoptosis were measured, and changes in cell cycle- and apoptosis-related gene expression were measured by Western blotting.
Results: The CCK-8 and colony formation assay indicated that TanIIA inhibited the cell proliferation of human esophageal cancer cells (IC50 below 1 μg/mL) at 48 h. Hoechst 33258 and flow cytometry showed that TanIIA induced apoptosis in both esophageal cancer cell lines. Flow cytometry showed that TanIIA arrested cell cycle in S phase and G2/M phase. Western blotting analysis showed that Akt1 and its phosphorylation were inhibited, the Bax/Bcl-2 ratio increased, and both caspase-9 and caspase-3 were activated after treatment with 1.3 μg/mL TanIIA at 48 h. Meanwhile, p53 and p21 protein levels increased, whereas cyclin B1, CDC2, and CDC2 phosphorylation were inhibited.
Conclusion: TanIIA inhibits the growth of esophageal cancer cells and induces apoptosis in a time-dependent and concentration-dependent manner, possibly by affecting cell cycle- and apoptosis-related signaling pathways.