DLG5 suppresses breast cancer stem cell-like characteristics to restore tamoxifen sensitivity by inhibiting TAZ expression

J Cell Mol Med. 2019 Jan;23(1):512-521. doi: 10.1111/jcmm.13954. Epub 2018 Nov 18.

Abstract

Tamoxifen (TAM) is a primary drug for treatment of estrogen receptor positive breast cancer. However, TAM resistance remains a serious threat to breast cancer patients and may be attributed to increased stemness of breast cancer. Here, we show that discs large homolog 5 (DLG5) expression is down-regulated in TAM-resistant breast cancer and cells. DLG5 silencing decreased the sensitivity to TAM and increased the frequency and stemness of CD44+ /CD24- breast cancer stem cells (BCSCs) and TAZ, a transducer of the Hippo pathway, expression in MCF7 cells while DLG5 overexpression had opposite effects. TAZ silencing restored the sensitivity to TAM and reduced the frequency and stemness in TAM-resistant breast cancer cells. Taken together, our data indicate that down-regulated DLG5 expression increases the stemness of breast cancer cells by enhancing TAZ expression, contributing to TAM resistance in breast cancer.

Keywords: DLG5; TAZ; stemness; tamoxifen resistance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents, Hormonal / pharmacology
  • Breast / drug effects
  • Breast / metabolism
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / metabolism*
  • Cell Line, Tumor
  • Down-Regulation / drug effects
  • Down-Regulation / physiology
  • Drug Resistance, Neoplasm / drug effects
  • Drug Resistance, Neoplasm / physiology
  • Female
  • Gene Expression Regulation, Neoplastic / drug effects
  • Gene Expression Regulation, Neoplastic / physiology
  • Gene Silencing / drug effects
  • Gene Silencing / physiology
  • Humans
  • MCF-7 Cells
  • Membrane Proteins / metabolism*
  • Neoplastic Stem Cells / drug effects
  • Neoplastic Stem Cells / metabolism*
  • Protein Serine-Threonine Kinases / metabolism
  • Receptors, Estrogen / metabolism
  • Tamoxifen / pharmacology*
  • Trans-Activators / metabolism*
  • Transcriptional Coactivator with PDZ-Binding Motif Proteins
  • Tumor Suppressor Proteins / metabolism*

Substances

  • Antineoplastic Agents, Hormonal
  • DLG5 protein, human
  • Membrane Proteins
  • Receptors, Estrogen
  • Trans-Activators
  • Transcriptional Coactivator with PDZ-Binding Motif Proteins
  • Tumor Suppressor Proteins
  • WWTR1 protein, human
  • Tamoxifen
  • Protein Serine-Threonine Kinases