Differential proliferative responses of estrogenic Chinese herbal medicines in breast cancer cells of different molecular subtypes

The potential risks of phytoestrogens consumption by breast cancer patients have been aroused since last decade. The role of estrogenic Chinese herbal medicines (eCHM) in breast cancer as a promotor or protector remains unclear [1]. However, some eCHM are still prescribed to breast cancer patients for reducing the side effects of chemotherapies [2]. CHM such as Angelica sinensis (AS), Astragalus membranaceus (AM), Dioscorea opposite (DO), Panax ginseng (PG), Glycyrrhiza uralensis (GU), Psoralea corylifolia (PC), Cuscuta chinensis (CS), Cistanche deserticola (CD), Ligusticum chuanxiong (LC) and Pueraria lobata (PL) were reported to have estrogenic effects. Breast cancer, a heterogeneous disease, is classified into various subtypes according to gene profiling or immunohistochemical markers such as estrogen receptor (ER) and human epidermal receptor 2 (HER2). With the lack of study revealing the safety of eCHM in breast cancer patients, this study aims to evaluate the proliferative effects of these eCHM in breast cancer cells of different molecular subtypes.

Human breast cancer cell lines, MDA-MB-361 (ER+, HER2+), MCF-7 (ER+, HER2-), SKBR3 (ER-, HER2+) and MDA-MB-231 (ER-, HER2-) were used to represent various molecular breast cancer subtypes. The proliferative effects of selected eCHM water extracts (0.4 – 6.4 mg/ml) on breast cancer cells viability were assessed by MTT assay. Our results demonstrated that AS, DO, PG, CS, CD and LC could increase cell viability in different breast cancer cells. In ER-positive cells, AS, DO, PG, CS and CD could increase cell viability in MDA-MB-361 cells, while DO, CD and LC could increase cell viability in MCF-7 cells. In ER-negative cells, only AS was shown to increase cell viability in both MDA-MB-231 and SKBR3 cells. In conclusion, our results revealed the differential responses of estrogenic CHM in breast cancer cells of different molecular subtypes, suggesting the action of some estrogenic CHM may also be ER-independent or HER2-related.

Acknowledgement: This work was supported by Food and Health Bureau HKSAR, Health and Medical Research Fund no. 12130471.

Keywords: Estrogenic, Chinese herbal medicines, breast cancer, estrogen receptor.

References:

[1] Rice S, Whitehead SA. Phytoestrogens and breast cancer – promoters or protectors? Endocr Relat Cancer 2006; 13: 995 – 1015

[2] Zhang M, Liu X, Li J, He L, Tripathy D. Chinese medicinal herbs to treat the side-effects of chemotherapy in breast cancer patients. Cochrane Database Syst Rev 2007; 2: CD004921