Endocrine Abstracts

Triclosan (TCS) is one of endocrine disrupting chemicals (EDCs) derived from toothpastes, deodorant and cleaning supplies. As a phytoestrogen, kaempferol (Kaem) is found at variety of vegetables. In this study, we examined anti-proliferative effects of Kaem in TCS-induced cell growth in MCF-7 breast cancer cells. In MTT assay, TCS (10⁻⁶ M) increased the cell viability of MCF-7 cells, while Kaem (50 μM) significantly reduced the cell viability compared to a control (0.1% DMSO). Kaem reversed TCS-induced MCF-7 cell growth at 50 μM. To confirm that Kaem inhibited TCS-induced cell growth, we examined the transactional levels of cell growth and apoptosis-related markers using reverse transcription (RT)-PCR. The expression levels of cyclin D, cyclin E and were increased, while that of p21 and bax mRNAs was decreased by TCS in MCF-7 cells. In addition, Kaem treatment significantly reversed TCS-induced gene expressions. In parallel with its mRNA level, the protein level of cyclin E, cyclin D, cathepsin D, p-IRS1, p-AKT, p-ERK and p-MEK1/2 were induced by TCS while it was reversed by Kaem. The expression levels of p21 and bax genes was altered by TCS and reversed by Kaem treatment. For in vivo assay, a xenografted mouse model was generated following injection with MCF-7 breast cancer cells. In parallel with in vitro results, tumour volumes following treatment with E₂ and TCS were continually increased compared to a vehicle (corn oil). It was of interest that treatment of the mice with combination of E₂ plus Kaem or TCS plus Kaem showed less tumour formation rather than that of single treated mice with E₂ or TCS. Taken together, these results indicate that Kaem may inhibit the growth MCF-7 cells via regulating the expression of cell cycle, migration and apoptosis-related genes, suggesting that TCS-induced progression of breast cancer may be suppressed by a phytoestrogen (This work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (MEST) of the Republic of Korea (2014R1A1A2055295)).