Inhibition of CCN6 (Wnt-1-induced signaling protein 3) down-regulates E-cadherin in the breast epithelium through induction of snail and ZEB1

Academic Article

Abstract

  • The cysteine-rich protein CCN6 [or Wnt-1-induced signaling protein 3 (WISP3)] exerts tumor-suppressive effects in aggressive inflammatory breast cancer. Loss of CCN6 is associated with poorly differentiated phenotypes and increased invasion. Here, we show that reduction of CCN6 expression occurs in 60% of invasive breast carcinomas and is associated with axillary lymph node metastases. Furthermore, low CCN6 expression in invasive carcinoma tissue samples correlates with reduced expression of E-cadherin. In vitro, RNA interference knockdown of CCN6 in two benign human mammary epithelial cell lines (HME and MCF10A) decreased expression of E-cadherin protein and mRNA and reduced activity of the E-cadherin promoter; this reduction was dependent on intact E-box elements. CCN6 knockdown in HME cells resulted in up-regulation of the E-cadherin transcriptional repressors Snail and ZEB1 and enhanced their recruitment and binding to the E-cadherin promoter as analyzed by chromatin immunoprecipitation assays. Small interfering RNA-mediated knockdown of ZEB1 or Snail blocked the down-regulation of E-cadherin caused by CCN6 inhibition. These data show, for the first time, that CCN6 expression is reduced or lost in a substantial number of invasive breast carcinomas and that CCN6 modulates transcriptional repressors of E-cadherin. Together, our results lead to a new hypothesis that Snail and ZEB1 are downstream of CCN6 and play a critical role in CCN6-mediated regulation of E-cadherin in breast cancer. Copyright © American Society for Investigative Pathology.
  • Published In

    Digital Object Identifier (doi)

    Pubmed Id

  • 14678777
  • Author List

  • Huang W; Zhang Y; Varambally S; Chinnaiyan AM; Banerjee M; Merajver SD; Kleer CG
  • Start Page

  • 893
  • End Page

  • 904
  • Volume

  • 172
  • Issue

  • 4