title: Rhodiola crenulata induces an early estrogenic response and reduces proliferation and tumorsphere formation over time in MCF7 breast cancer cells.
abstract: BACKGROUND
  Rhodiola crenulata is a Tibetan mountainous plant, commonly used in Eastern alternative medicine. Many phytochemicals possess estrogenic activity, a critical regulator of proliferation in mammary epithelial cells. We have previously characterized anti-cancer properties of R. crenulata in aggressive triple negative breast cancer cells, lacking the expression of estrogen receptor. Currently, it is unknown whether R. crenulata exerts estrogenic effects and as such consumption may be a concern for women with estrogen receptor positive breast cancer that use Rhodiola sp. to relieve mild to moderate depression.
  
  
  OBJECTIVE
  In this study, we wished to determine whether a hydroalcoholic fraction of the R. crenulata root extract exhibits estrogenic activity in estrogen receptor positive (ER+) breast cancer cells in vitro and whether it affects normal mammary epithelial ER target gene expression in vivo.
  
  
  METHODS
  ER transcriptional activity was analyzed in MCF7 cells expressing an ERE reporter construct and confirmed via qPCR of endogenous ER target genes. We also monitored cellular proliferation over time. Additionally, to assess stem-like properties in MCF7 cells, we performed a tumorsphere formation assay under anchorage independent conditions. We examined whether R. crenulata treatment reduced β-catenin levels via Western blotting and measured β-catenin transcriptional activity by a reporter assay. To examine the effects of R. crenulata on normal mammary epithelial cells, we performed immunohistochemical staining of ER and PR in the mammary glands of mice fed R. crenulata for 12 weeks.
  
  
  RESULTS
  We show an initial activation of ER transcriptional activity by dual reporter assay, qPCR and proliferation of MCF7 ER+ cells in response to 24 h of R. crenulata treatment. However, upon longer treatment basal and R. crenulata induced transcriptional activity was suppressed. There was a decrease in cell doubling times and a decrease in tumorsphere formation. In association with these changes, ERα transcript levels were decreased and active β-catenin levels were reduced in the cells treated for 2 weeks. Finally, we show no change in estrogen targets in normal mammary cells in vivo.
  
  
  CONCLUSIONS
  These data suggest that the R. crenulata extract contains components with estrogenic activity. However, R. crenulata treatment could still be protective in ER+ breast cancer cells, as longer treatment reduced the transcriptional activity of β-catenin and ER responses leading to reduced proliferation and tumorsphere formation. Furthermore, administration of 20 mg/kg/day R. crenulata to mice did not have an observable effect on mammary epithelial ERα target gene expression in vivo.
authors: Department of Veterinary and Animal Science, The University of Massachusetts Amherst, Amherst, MA, USA; Pioneer Valley Life Science Institute, Baystate Health, Springfield, MA, USA.
authors: Lotfi M
authors: LM
authors: Bassa
authors: Division of Science, Mathematics, and Computing, Bennington College, Bennington, VT, USA.
authors: Cody
authors: C
authors: Jacobs
authors: Pioneer Valley Life Science Institute, Baystate Health, Springfield, MA, USA; Biology Department, The University of Massachusetts Amherst, Amherst, MA, USA.
authors: Kelly
authors: K
authors: Gregory
authors: Pioneer Valley Life Science Institute, Baystate Health, Springfield, MA, USA; Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA.
authors: Elizabeth
authors: E
authors: Henchey
authors: Pioneer Valley Life Science Institute, Baystate Health, Springfield, MA, USA.
authors: Jennifer
authors: J
authors: Ser-Dolansky
authors: Department of Veterinary and Animal Science, The University of Massachusetts Amherst, Amherst, MA, USA; Pioneer Valley Life Science Institute, Baystate Health, Springfield, MA, USA. Electronic address: Sallie.Schneider@baystatehealth.org.
authors: Sallie S
authors: SS
authors: Schneider
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000473:pathology*; D049109:Cell Proliferation / Q000187:drug effects; D047628:Estrogen Receptor alpha / Q000378:metabolism; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D006801:Humans; D061986:MCF-7 Cells; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D010936:Plant Extracts / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry; D029771:Rhodiola / Q000737:chemistry; D018874:Spheroids, Cellular / Q000187:drug effects; D015533:Transcriptional Activation; D051176:beta Catenin / Q000378:metabolism
chemical_list: C495270:CTNNB1 protein, human; D047628:Estrogen Receptor alpha; D004967:Estrogens; D010936:Plant Extracts; D051176:beta Catenin
keywords: Continuous treatment; ER+ Breast cancer; In vivo; Phytoestrogens; Rhodiola crenulata; β-catenin activity