Androgen receptor as a regulator of ZEB2 expression and its implications in epithelial-to-mesenchymal transition in prostate cancer

Endocr Relat Cancer. 2014 May 8;21(3):473-86. doi: 10.1530/ERC-13-0514. Print 2014 Jun.

Abstract

Zinc finger E-box-binding protein 2 (ZEB2) is known to help mediate the epithelial-to-mesenchymal transition, and thereby it facilitates cancer metastasis. This study was initiated to explore whether ZEB2 expression differs in prostate cancer (PCa, n=7) and benign prostatic hyperplasia (BPH, n=7) tissues. In PCa tissues, the levels of both immunoreactive ZEB2 and androgen receptor (AR) were found to be significantly higher (P<0.05) when compared with BPH tissues. Co-regulation of AR and ZEB2 prompted us to investigate the role of androgenic stimuli in ZEB2 expression. ZEB2 expression was found to be significantly (P<0.05) upregulated after androgen stimulation and downregulated following AR silencing in LNCaP cells, an androgen-dependent PCa cell line. This finding suggested AR as a positive regulator of ZEB2 expression in androgen-dependent cells. Paradoxically, androgen-independent (AI) cell lines PC3 and DU145, known to possess low AR levels, showed significantly (P<0.05) higher expression of ZEB2 compared with LNCaP cells. Furthermore, forced expression of AR in PC3 (PC3-AR) and DU145 (DU-AR) cells led to reductions in ZEB2 expression, invasiveness, and migration. These cells also exhibited an increase in the levels of E-cadherin (a transcriptional target of ZEB2). Co-transfection of AR and ZEB2 cDNA constructs prevented the decline in invasiveness and migration to a significant extent. Additionally, ZEB2 downregulation was associated with an increase in miR200a/miR200b levels in PC3-AR cells and with a decrease in miR200a/miR200b levels in AR-silenced LNCaP cells. Thus, AR acts as a positive regulator of ZEB2 expression in androgen-dependent cells and as a negative regulator in AI PCa cells.

Keywords: EMT; ZEB2; androgen receptor; prostate cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Androgens / pharmacology
  • Apoptosis / drug effects
  • Blotting, Western
  • Cell Movement / drug effects
  • Cell Proliferation / drug effects
  • Dihydrotestosterone / pharmacology
  • Epithelial-Mesenchymal Transition*
  • Fluorescent Antibody Technique
  • Gene Expression Regulation, Neoplastic*
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism*
  • Humans
  • Immunoenzyme Techniques
  • Male
  • MicroRNAs / genetics*
  • Neoplasms, Hormone-Dependent / drug therapy
  • Neoplasms, Hormone-Dependent / genetics
  • Neoplasms, Hormone-Dependent / metabolism
  • Neoplasms, Hormone-Dependent / pathology
  • Prostatic Hyperplasia / drug therapy
  • Prostatic Hyperplasia / genetics
  • Prostatic Hyperplasia / metabolism
  • Prostatic Hyperplasia / pathology
  • Prostatic Neoplasms / drug therapy
  • Prostatic Neoplasms / genetics
  • Prostatic Neoplasms / metabolism*
  • Prostatic Neoplasms / pathology*
  • RNA, Messenger / genetics
  • RNA, Small Interfering / genetics
  • Real-Time Polymerase Chain Reaction
  • Receptors, Androgen / chemistry
  • Receptors, Androgen / genetics
  • Receptors, Androgen / metabolism*
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tumor Cells, Cultured
  • Wound Healing
  • Zinc Finger E-box Binding Homeobox 2

Substances

  • AR protein, human
  • Androgens
  • Homeodomain Proteins
  • MIRN200 microRNA, human
  • MicroRNAs
  • RNA, Messenger
  • RNA, Small Interfering
  • Receptors, Androgen
  • Repressor Proteins
  • ZEB2 protein, human
  • Zinc Finger E-box Binding Homeobox 2
  • Dihydrotestosterone