In vitro estrogenic activity of formononetin by two bioassay systems.
OBJECTIVE
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 microM), 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.


CONCLUSIONS
Formononetin is a phytoestrogen that exhibits variable degrees of estrogen receptor agonism in different test systems.
Ji
Zhao-Ning
ZN
Department of Oncology, Yijishan Hospital, Wannan Medical College, Wuhu, China. jzning@hotmail.com
Zhao
W Y
WY
Liao
G R
GR
Choi
R C
RC
Lo
C K
CK
Dong
T T X
TT
Tsim
K W K
KW
D001681:Biological Assay / Q000379:methods*; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004967:Estrogens / Q000494:pharmacology*; D017930:Genes, Reporter / Q000187:drug effects; D006801:Humans; D007529:Isoflavones / Q000494:pharmacology*; D008954:Models, Biological; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects; D048789:Phytoestrogens / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D014407:Tumor Cells, Cultured
D004967:Estrogens; D007529:Isoflavones; D048789:Phytoestrogens; C007768:formononetin