Dual role for miR-34a in the control of early progenitor proliferation and commitment in the mammary gland and in breast cancer

Paola Bonetti, Montserrat Climent, Fabiana Panebianco, Chiara Tordonato, Angela Santoro, Matteo Jacopo Marzi, Pier Giuseppe Pelicci, Andrea Ventura, Francesco Nicassio

Research output: Contribution to journalArticle

Abstract

The role of the tumour-suppressor miR-34 family in breast physiology and in mammary stem cells (MaSCs) is largely unknown. Here, we revealed that miR-34 family, and miR-34a in particular, is implicated in mammary epithelium homoeostasis. Expression of miR-34a occurs upon luminal commitment and differentiation and serves to inhibit the expansion of the pool of MaSCs and early progenitor cells, likely in a p53-independent fashion. Mutant mice (miR34-KO) and loss-of-function approaches revealed two separate functions of miR-34a, controlling both proliferation and fate commitment in mammary progenitors by modulating several pathways involved in epithelial cell plasticity and luminal-to-basal conversion. In particular, miR-34a acts as endogenous inhibitor of the Wnt/beta-catenin signalling pathway, targeting up to nine upstream regulators at the same time, thus modulating the expansion of the MaSCs/early progenitor pool. These multiple roles of miR-34a are maintained in a model of human breast cancer, in which chronic expression of miR-34a in triple-negative mesenchymal-like cells (enriched in cancer stem cells—CSCs) could promote a luminal-like differentiation programme, restrict the CSC pool, and inhibit tumour propagation. Hence, activation of miR-34a-dependent programmes could provide a therapeutic opportunity for the subset of breast cancers, which are rich in CSCs and respond poorly to conventional therapies.

Original languageEnglish
Pages (from-to)360-374
Number of pages15
JournalOncogene
Volume38
Issue number3
DOIs
Publication statusPublished - Jan 17 2019

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research

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