Research article

Gene expression profiling reveals effects of Cimicifuga racemosa (L.) NUTT. (black cohosh) on the estrogen receptor positive human breast cancer cell line MCF-7

Friedemann Gaube¹ , Stefan Wolfl^2,3 , Larissa Pusch² , Torsten C Kroll² and Matthias Hamburger^1,4

¹Institute of Pharmacy, Department of Pharmaceutical Biology, University of Jena, Semmelweisstr. 10, 07743 Jena, Germany

²Clinic of Internal Medicine II, University of Jena, Erlanger Allee 101, 07747 Jena, Germany

³Institute of Pharmacy and Molecular Biotechnology, University of Heidelberg, Im Neuenheimerfeld 364, 69120 Heidelberg, Germany

⁴Department of Pharmaceutical Sciences, Institute of Pharmaceutical Biology, University of Basel, Klingelbergstr. 50, CH-4053 Basel, Switzerland

author email corresponding author email

BMC Pharmacology 2007, 7:11doi:10.1186/1471-2210-7-11

Published:	20 September 2007

Abstract

Background

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 black cohosh rhizome extract and cycloartane-type triterpenoids on the estrogen receptor positive human breast cancer cell line MCF-7.

Results

Both extract and purified compounds clearly inhibited cellular proliferation. Gene expression profiling with the extract allowed us to identify 431 regulated genes with high significance. The extract induced expression pattern differed from those of 17β-estradiol or the estrogen receptor antagonist tamoxifen. We observed a significant enrichment of genes in an anti-proliferative and apoptosis-sensitizing manner, as well as an increase of mRNAs coding for gene products involved in several stress response pathways. These functional groups were highly overrepresented among all regulated genes. Also several 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. Real-Time RT-PCR analysis of 13 selected genes was conducted after treatment with purified compounds – the cycloartane-type triterpene glycoside actein and triterpene aglycons – showing similar expression levels compared to the extract.

Conclusion

No estrogenic but antiproliferative and proapoptotic gene expression was shown for black cohosh in MCF-7 cells at the transcriptional level. The effects may be results of the activation of different pathways. The cycloartane glycosides and – for the first time – their aglycons could be identified as an active principle in black cohosh.