Endocrine Abstracts

Triclosan is one of endocrine-disrupting chemicals (EDCs) which are scattered with environment agents, such as toothpastes, deodorant and cleaning supplies. As a phytoestrogen, kaempferol is one of bioflavonoids, which has been found at variety of vegetables including broccoli, tea and tomato. Although kaempferol may have anti-cancer activity, its exact mechanism is under investigation in the induction of apoptosis and inhibition of cell proliferation or angiogenesis. In this study, we examined the anti-proliferative effects of kaempferol in triclosan-induced cell growth in MCF-7 breast cancer cells. A proper concentration of kaempferol or triclosan was determined in MCF-7 cells measured by MTT assay. In this study, kaempferol significantly reduced the viability of MCF-7 cells compared to a negative control treated with DMSO, and that kaempferol reversed triclosan-induced MCF-7 cell growth at 50 μM. To confirm that kaempferol inhibited triclosan-induced cell growth, we examined the transactional levels of cell growth and apoptosis-related markers, i.e. cyclin D, p21, cyclin E, p27 and bcl-2, and bax genes, using RT-PCR. The expression levels of cyclin D, cyclin E and bax/bcl-2 ratio were increased, while that of p21 and p27 mRNAs was decreased by triclosan in MCF-7 cells. In addition, kaempferol reversed triclosan-induced gene expressions in an opposite manner. In parallel with its mRNA level, the protein level of cyclin E was induced by triclosanm while it was reversed by kaempferol as shown by western blot analysis. Taken together, these results indicated that kaempferol may inhibit the growth MCF-7 cells via regulating of cell cycle and apoptosis-related genes. In addition, EDCs-induced progression of breast cancer may be suppressed by a phytoestrigen, i.e. kaempferol, in a specific manner.