Effects of Cimicfuga racemosa (black cohosh) in MCF-7 cells

Extracts from the rhizome of Cimicifuga racemosa (black cohosh) are increasingly popular as herbal alternative to hormone replacement therapy (HRT) for the alleviation of postmenopausal disorders. However, the molecular mode of action and the active principles are presently not clear. Previously published data have been largely contradictory. We, therefore, investigated the effects of a lipophilic Cimicifuga rhizome extract on the ER+ breast cancer MCF-7 cells at transcriptional level in comparision to 17beta-estradiol and the ER antagonist tamoxifen. With the extract 431 genes were regulated more than 1.5 fold. The overall expression pattern differed from those of 17β-estradiol or the estrogen receptor antagonist tamoxifen. We observed an enrichment of genes in an anti-proliferative and apoptosis-sensitizing manner, together with an increase of mRNAs coding for gene products involved in several stress response pathways. Regulated genes of these functional groups were highly overrepresented among all regulated genes. Various transcripts coding for oxidoreductases were induced, as for example the cytochrome P450 family members 1A1 and 1B1. In addition, some transcripts associated with antitumor but also tumor-promoting activity were regulated. Keywords: treatment with black cohosh MCF-7 cells were treated for 24 h with a lipophilic (dichloromethane) Cimicifuga rhizome extract, 17beta-estradiol, tamoxifen and the solvent control (DMSO 0,1%) in duplicate