Ginsenoside-Rb1 acts as a weak phytoestrogen in MCF-7 human breast cancer cells.
Ginseng has been recommended to alleviate the menopausal symptoms, which indicates that components of ginseng very likely contain estrogenic activity. We have examined the possibility that a component of Panax ginseng, ginsenoside-Rb1, acts by binding to estrogen receptor. We have investigated the estrogenic activity of ginsenoside-Rb1 in a transient transfection system using estrogen-responsive luciferase plasmids in MCF-7 cells. Ginsenoside-Rb1 activated the transcription of the estrogen-responsive luciferase reporter gene in MCF-7 breast cancer cells at a concentration of 50 microM. Activation was inhibited by the specific estrogen receptor antagonist ICI 182,780, indicating that the estrogenic effect of ginsenoside-Rb1 is estrogen receptor dependent. Next, we evaluated the ability of ginsenoside-Rb1 to induce the estrogen-responsive gene c-fos by semi-quantitative RT-PCR assays and Western analyses. Ginsenoside-Rb1 increased c-fos both at mRNA and protein levels. However, ginsenoside-Rb1 failed to activate the glucocorticoid receptor, the retinoic acid receptor, or the androgen receptor in CV-1 cells transiently transfected with the corresponding steroid hormone receptors and hormone responsive reporter plasmids. These data support our hypothesis that ginsenoside-Rb1 acts a weak phytoestrogen, presumably by binding and activating the estrogen receptor.
Lee
Young Joo
YJ
College of Engineering, Institute of Biotechnology, Department of Bioscience and Biotechnology, Sejong University, Seoul, Korea. yjlee@sejong.ac.kr
Jin
Young Ran
YR
Lim
Won Chung
WC
Park
Wan Kyu
WK
Cho
Jung Yoon
JY
Jang
Siyoul
S
Lee
Seung Ki
SK
D000230:Adenocarcinoma / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism*; D004967:Estrogens / Q000096:biosynthesis; D004968:Estrogens, Non-Steroidal / Q000737:chemistry / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D036145:Ginsenosides / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D007529:Isoflavones; D048789:Phytoestrogens; D028321:Plant Preparations; D011960:Receptors, Estrogen / Q000096:biosynthesis; D014407:Tumor Cells, Cultured
D004967:Estrogens; D004968:Estrogens, Non-Steroidal; D036145:Ginsenosides; D007529:Isoflavones; D048789:Phytoestrogens; D028321:Plant Preparations; D011960:Receptors, Estrogen; C442759:ginsenoside Rb1