In vitro estrogenic activity of formononetin by two bioassay systems

Abstract

Aim. To study the estrogenic activity of formononetin in vitro.

Methods. We have established a highly sensitive bioassay system by placing estrogen-responsive elements upstream of the luciferase reporter gene, and used this assay to determine the estrogenic activity of formononetin. Cell growth was measured by the MTT (3-(4,5-dimethylthioazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and MG-63 cell function was studied by measuring alkaline phosphatase activity.

Results. Formononetin activated expression of the estrogen-responsive reporter gene in human breast cell line MCF-7 in a concentration-dependent manner (0.5–500 µM), and this activation was inhibited by estrogen antagonist (ICI 182780 at 100 nM). Furthermore, it induced the proliferation of MCF-7 breast cancer cells and MG-63 osteosarcoma cells, and it also increased the alkaline phosphatase activity in MG-63 cells.

Conclusion. Formononetin is a phytoestrogen that exhibits variable degrees of estrogen receptor agonism in different test systems.

Keywords:

• Formononetin
• transfection
• MCF7-ERE cell
• MG-63 cell estrogenic activity
• alkaline phosphatase