lincRNA-RoR and miR-145 regulate invasion in triple-negative breast cancer via targeting ARF6

Mol Cancer Res. 2015 Feb;13(2):330-8. doi: 10.1158/1541-7786.MCR-14-0251. Epub 2014 Sep 24.

Abstract

Triple-negative (ER(-), HER2(-), PR(-)) breast cancer (TNBC) is an aggressive disease with a poor prognosis with no available molecularly targeted therapy. Silencing of microRNA-145 (miR-145) may be a defining marker of TNBC based on molecular profiling and deep sequencing. Therefore, the molecular mechanism behind miR-145 downregulation in TNBC was examined. Overexpression of the long intergenic noncoding RNA regulator of reprogramming, lincRNA-RoR, functions as a competitive endogenous RNA sponge in TNBC. Interestingly, lincRNA-RoR is dramatically upregulated in TNBC and in metastatic disease and knockdown restores miR-145 expression. Previous reports suggest that miR-145 has growth-suppressive activity in some breast cancers; however, these data in TNBC indicate that miR-145 does not affect proliferation or apoptosis but instead, miR-145 regulates tumor cell invasion. Investigation of miR-145-regulated pathways involved in tumor invasion revealed a novel target, the small GTPase ADP-ribosylation factor 6 (Arf6). Subsequent analysis demonstrated that ARF6, a known regulator of breast tumor cell invasion, is dramatically upregulated in TNBC and in breast tumor metastasis. Mechanistically, ARF6 regulates E-cadherin localization and affects cell-cell adhesion. These results reveal a lincRNA-RoR/miR-145/ARF6 pathway that regulates invasion in TNBCs.

Implications: The lincRNA-RoR/miR-145/ARF6 pathway is critical to TNBC metastasis and could serve as biomarkers or therapeutic targets for improving survival.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADP-Ribosylation Factor 6
  • ADP-Ribosylation Factors / genetics*
  • ADP-Ribosylation Factors / metabolism
  • Cell Line, Tumor
  • Cell Movement
  • Cell Proliferation
  • Female
  • HEK293 Cells
  • Humans
  • MCF-7 Cells
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism
  • Neoplasm Invasiveness
  • RNA, Long Noncoding / genetics*
  • RNA, Long Noncoding / metabolism
  • Triple Negative Breast Neoplasms / genetics*
  • Triple Negative Breast Neoplasms / metabolism
  • Triple Negative Breast Neoplasms / pathology*

Substances

  • ADP-Ribosylation Factor 6
  • Linc-RNA-RoR, human
  • MIRN145 microRNA, human
  • MicroRNAs
  • RNA, Long Noncoding
  • ADP-Ribosylation Factors
  • ARF6 protein, human