In Vitro and In Vivo Effects of Xanthorrhizol on Human Breast Cancer MCF-7 Cells Treated With Tamoxifen

This study investigated the herb drug interaction of xanthorrhizol and tamoxifen in human breast cancer cells. Using MCF-7 cell line as an in vitro model, the herb drug interaction between xanthorrhizol and tamoxifen was measured by MTT assay, luciferase reporter assay, and cell cycle analysis. The effects of xanthorrhizol on growth/autophagy related signaling were determined by immunostaining, western blotting, and real time RT-PCR. Additionally, the in vivo effect of xanthorrhizol and tamoxifen on athymic nude mice implanted with MCF-7 cells was evaluated. When MCF-7 cells were co-treated with tamoxifen and xanthorrhizol, there were no significant changes in terms of cell number, luciferase activity, percentage S-phase cells and LC3-II expression. However, using the MCF-7 implanted nude mice model, it was possible to detect significantly increased tumor volumes, a larger tumor size, and increased protein expression of P38 and P27(Kip 1) in the xanthorrhizol + tamoxifen group compared to the tamoxifen-alone group. It can be concluded that while there is no significant herb drug interaction between xanthorrhizol and tamoxifen in vitro, there is such an interaction in tumor-bearing mice, which provides important information that affects breast cancer treatment translational research.