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

Wei Huang, Yanhong Zhang, Sooryanarayana Varambally, Arul M. Chinnaiyan, Mousumi Banerjee, Sofia D. Merajver, Celina G. Kleer

Research output: Contribution to journalArticle

55 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)893-904
Number of pages12
JournalAmerican Journal of Pathology
Volume172
Issue number4
DOIs
StatePublished - Apr 2008
Externally publishedYes

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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