title: Androgen receptor splice variants contribute to prostate cancer aggressiveness through induction of EMT and expression of stem cell marker genes.
abstract: BACKGROUND
  The mechanism(s) by which androgen receptor (AR) splice variants contribute to castration-resistant prostate cancer (CRPC) is still lacking.
  
  
  METHODS
  Expressions of epithelial-to-mesenchymal transition (EMT) and stem cell markers were molecularly tested using prostate cancer (PCa) cells transfected with AR and AR3 (also known as AR-V7) plasmids or siRNA, and also cultured cells under androgen deprivation therapy (ADT) condition. Cell migration, clonogenicity, sphere-forming capacity was assessed using PCa cells under all experimental conditions and 3,3'-diindolylmethane (DIM; BR-DIM) treatment. Human PCa samples from BR-DIM untreated or treated patients were also used for assessing the expression of AR3 and stem cell markers.
  
  
  RESULTS
  Overexpression of AR led to the induction of EMT phenotype, while overexpression of AR3 not only induced EMT but also led to the expression of stem cell signature genes. More importantly, ADT enhanced the expression of AR and AR3 concomitant with up-regulated expression of EMT and stem cell marker genes. Dihydrotestosterone (DHT) treatment decreased the expression of AR and AR3, and reversed the expression of these EMT and stem cell marker genes. BR-DIM administered to PCa patients prior to radical prostatectomy inhibited the expression of cancer stem cell markers consistent with inhibition of self-renewal of PCa cells after BR-DIM treatment.
  
  
  CONCLUSIONS
  AR variants could contribute to PCa progression through induction of EMT and acquisition of stem cell characteristics, which could be attenuated by BR-DIM, suggesting that BR-DIM could become a promising agent for the prevention of CRPC and/or for the treatment of PCa.
authors.affiliation: Department of Pathology, Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan.
authors.forename: Dejuan
authors.initials: D
authors.lastname: Kong
authors.forename: Seema
authors.initials: S
authors.lastname: Sethi
authors.forename: Yiwei
authors.initials: Y
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Wael A
authors.initials: WA
authors.lastname: Sakr
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Heath
authors.forename: Fazlul H
authors.initials: FH
authors.lastname: Sarkar
mesh_terms: D045744:Cell Line, Tumor; D058750:Epithelial-Mesenchymal Transition / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D009361:Neoplasm Invasiveness / Q000235:genetics / Q000473:pathology; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D020033:Protein Isoforms / Q000096:biosynthesis* / Q000235:genetics; D011944:Receptors, Androgen / Q000096:biosynthesis* / Q000235:genetics; D012189:Retrospective Studies
chemical_list: C410798:AR protein, human; D020033:Protein Isoforms; D011944:Receptors, Androgen
keywords: 3,3′-diindolylmethane; androgen receptor splice variants; cancer stem cells; self-renewal