Nutraceuticals known to promote hair growth do not interfere with the inhibitory action of tamoxifen in MCF7, T47D and BT483 breast cancer cell lines

Background Hair loss/thinning is a common side effect of tamoxifen in estrogen receptor (ER) positive breast cancer therapy. Some nutraceuticals known to promote hair growth are avoided during breast cancer therapy for fear of phytoestrogenic activity. However, not all botanical ingredients have similarities to estrogens, and in fact, no information exists as to the true interaction of these ingredients with tamoxifen. Therefore, this study sought to ascertain the effect of nutraceuticals (+/- estrogen/tamoxifen), on proliferation of breast cancer cells and the relative expression of ER alpha/beta.Methods Kelp, Astaxanthin, Saw Palmetto, Tocotrienols, Maca, Horsetail, Resveratrol, Curcumin and Ashwagandha were assessed on proliferation of MCF7, T47D and BT483 breast cancer cell lines +/- 17 beta-estradiol and tamoxifen. Each extract was analysed by high performance liquid chromatography (HPLC) prior to use. Cellular ER alpha and ER beta expression was assessed by qRT-PCR and western blot. Changes in the cellular localisation of ER alpha:ER beta and their ratio following incubation with the nutraceuticals was confirmed by immunocytochemistry.Results Estradiol stimulated DNA synthesis in three different breast cancer cell lines: MCF7, T47D and BT483, which was inhibited by tamoxifen; this was mirrored by a specific ERa agonist in T47D and BT483 cells. Overall, nutraceuticals did not interfere with tamoxifen inhibition of estrogen; some even induced further inhibition when combined with tamoxifen. The ER alpha:ER beta ratio was higher at mRNA and protein level in all cell lines. However, incubation with nutraceuticals induced a shift to higher ER beta expression and a localization of ERs around the nuclear periphery.Conclusions As ER alpha is the key driver of estrogen-dependent breast cancer, if nutraceuticals have a higher affinity for ER beta they may offer a protective effect, particularly if they synergize and augment the actions of tamoxifen. Since ER beta is the predominant ER in the hair follicle, further studies confirming whether nutraceuticals can shift the ratio towards ER beta in hair follicle cells would support a role for them in hair growth. Although more research is needed to assess safety and efficacy, this promising data suggests the potential of nutraceuticals as adjuvant therapy for hair loss in breast cancer patients receiving endocrine therapy.