Calycosin Inhibits the Migration and Invasion of Human Breast Cancer Cells by Down-Regulation of Foxp3 Expression

Background/aims: Calycosin, a phytoestrogenic compound, has recently emerged as a promising antitumor drug. It has been shown that calycosin suppresses growth and induces apoptosis of breast cancer cells. However, the effect of calycosin on migration and invasion of breast cancer cells and the underlying molecular mechanisms have not been elucidated.

Methods: Human breast cancer cells MCF-7 and T47D were treated with, or without, different doses (0, 6.25, 12.5, 25, 50, 100 or 150 μM) of calycosin, and the viability of different groups was determined by MTT assay. Next, the inhibitory effect of higher doses (50, 100 or 150 μM) of calycosin on migration and invasion of the two cell lines was determined by wound healing and transwell assay. The relative expression levels of forkhead box P3 (Foxp3), vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) in MCF-7 and T47D cells were determined by quantitative RT-PCR and Western blot.

Results: Treatment with lower doses (6.25 or 12.5 μM) promoted proliferation of breast cancer cells, but with higher doses significantly reduced the viability of MCF-7 and T47D cells. Furthermore, higher doses of calycosin were found to inhibit migration and invasion of the two cell lines in a dose-dependent manner. Additionally, treatment with a higher dose of calycosin significantly reduced the expression levels of Foxp3, followed by down-regulation of VEGF and MMP-9 in both MCF-7 and T47D breast cancer cells.

Conclusion: Treatment with a higher dose of calycosin tends to reduce migration and invasion capacity of human breast cancer cells, by targeting Foxp3-mediated VEGF and MMP-9 expression.