title: Correlation between Slug transcription factor and miR-221 in MDA-MB-231 breast cancer cells.
abstract: BACKGROUND
  Breast cancer and its metastatic progression is mainly directed by epithelial to mesenchymal transition (EMT), a phenomenon supported by specific transcription factors and miRNAs.
  
  
  METHODS
  In order to investigate a possible correlation between Slug transcription factor and miR-221, we performed Slug gene silencing in MDA-MB-231 breast cancer cells and evaluated the expression of genes involved in supporting the breast cancer phenotype, using qRT-PCR and Western blot analysis. Chromatin immunoprecipitation and wound healing assays were employed to determine a functional link between these two molecules.
  
  
  RESULTS
  We showed that Slug silencing significantly decreased the level of miR-221 and vimentin, reactivated Estrogen Receptor α and increased E-cadherin and TRPS1 expression. We demonstrated that miR-221 is a Slug target gene, and identified a specific region of miR-221 promoter that is transcriptionally active and binds the transcription factor Slug "in vivo". In addition, we showed that in Slug-silenced cells, wich retained residual miR-221 (about 38%), cell migration was strongly inhibited. Cell migration was inhibited, but to a less degree, following complete knockdown of miR-221 expression by transfection with antagomiR-221.
  
  
  CONCLUSIONS
  We report for the first time evidence of a correlation between Slug transcription factor and miR-221 in breast cancer cells. These studies suggest that miR-221 expression is, in part, dependent on Slug in breast cancer cells, and that Slug plays a more important role than miR-221 in cell migration and invasion.
authors.affiliation: Department of Biomedical and Specialty Surgical Sciences, University of Ferrara, Ferrara, 44121, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Lambertini
authors.forename: Andrea
authors.initials: A
authors.lastname: Lolli
authors.forename: Federica
authors.initials: F
authors.lastname: Vezzali
authors.forename: Letizia
authors.initials: L
authors.lastname: Penolazzi
authors.forename: Roberto
authors.initials: R
authors.lastname: Gambari
authors.forename: Roberta
authors.initials: R
authors.lastname: Piva
mesh_terms: D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D047369:Chromatin Immunoprecipitation; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D020868:Gene Silencing; D006801:Humans; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014162:Transfection
chemical_list: D035683:MicroRNAs; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; C525709:MIR221, human; C000604407:SNAI1 protein, human