title: Silencing NOTCH signaling causes growth arrest in both breast cancer stem cells and breast cancer cells.
abstract: BACKGROUND
  Breast cancer stem cells (BCSCs) are characterized by high aldehyde dehydrogenase (ALDH) enzyme activity and are refractory to current treatment modalities, show a higher risk for metastasis, and influence the epithelial to mesenchymal transition (EMT), leading to a shorter time to recurrence and death. In this study, we focused on examination of the mechanism of action of a small herbal molecule, psoralidin (Pso) that has been shown to effectively suppress the growth of BSCSs and breast cancer cells (BCCs), in breast cancer (BC) models.
  
  
  METHODS
  ALDH(-) and ALDH(+) BCCs were isolated from MDA-MB-231 cells, and the anticancer effects of Pso were measured using cell viability, apoptosis, colony formation, invasion, migration, mammosphere formation, immunofluorescence, and western blot analysis.
  
  
  RESULTS
  Psoralidin significantly downregulated NOTCH1 signaling, and this downregulation resulted in growth inhibition and induction of apoptosis in both ALDH(-) and ALDH(+) cells. Molecularly, Pso inhibited NOTCH1 signaling, which facilitated inhibition of EMT markers (β-catenin and vimentin) and upregulated E-cadherin expression, resulting in reduced migration and invasion of both ALDH(-) and ALDH(+) cells.
  
  
  CONCLUSIONS
  Together, our results suggest that inhibition of NOTCH1 by Pso resulted in growth arrest and inhibition of EMT in BCSCs and BCCs. Psoralidin appears to be a novel agent that targets both BCSCs and BCCs.
authors.affiliation: Department of Biomedical Sciences, Paul L Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX, USA.
authors.forename: S
authors.initials: S
authors.lastname: Suman
authors.forename: T P
authors.initials: TP
authors.lastname: Das
authors.forename: C
authors.initials: C
authors.lastname: Damodaran
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D001572:Benzofurans / Q000494:pharmacology; D001943:Breast Neoplasms / Q000235:genetics / Q000473:pathology*; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D049109:Cell Proliferation; D003374:Coumarins / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics; D005260:Female; D020868:Gene Silencing; D006801:Humans; D009361:Neoplasm Invasiveness; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D051881:Receptor, Notch1 / Q000037:antagonists & inhibitors / Q000235:genetics*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D014407:Tumor Cells, Cultured
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D001572:Benzofurans; D003374:Coumarins; C497761:NOTCH1 protein, human; D051881:Receptor, Notch1; C102768:psoralidin