miR-221/222 control luminal breast cancer tumor progression by regulating different targets

Patrizia Dentelli, Matteo Traversa, Arturo Rosso, Gabriele Togliatto, Cristina Olgasi, Caterina Marchiò, Paolo Provero, Antonio Lembo, Giulia Bon, Laura Annaratone, Anna Sapino, Rita Falcioni, Maria Felice Brizzi

Research output: Contribution to journalArticlepeer-review


α6β4 integrin is an adhesion molecule for laminin receptors involved in tumor progression. We present a link between β4 integrin expression and miR-221/222 in the most prevalent human mammary tumor: luminal invasive carcinomas (Lum-ICs). Using human primary tumors that display different β4 integrin expression and grade, we show that miR-221/222 expression inversely correlates with tumor proliferating index, Ki67. Interestingly, most high-grade tumors express β4 integrin and low miR-221/222 levels. We ectopically transfected miR-221/222 into a human-derived mammary tumor cell line that recapitulates the luminal subtype to investigate whether miR-221/222 regulates β4 expression. We demonstrate that miR-221/222 overexpression results in β4 expression downregulation, breast cancer cell proliferation, and invasion inhibition. The role of miR-221/222 in driving β4 integrin expression is also confirmed via mutating the miR-221/222 seed sequence for β4 integrin 3′UTR. Furthermore, we show that these 2 miRNAs are also key breast cancer cell proliferation and invasion regulators, via the post-transcriptional regulation of signal transducer and activator of transcription 5A (STAT5A) and of a disintegrin and metalloprotease-17 (ADAM-17). We further confirm these data by silencing ADAM-17, using a dominant-negative or an activated STAT5A form. miR-221/222-driven β4 integrin, STAT5A, and ADAM-17 did not occur in MCF-10A cells, denoted "normal" breast epithelial cells, indicating that the mechanism is cancer cell-specific. These results provide the first evidence of a post-transcriptional mechanism that regulates β4 integrin, STAT5A, and ADAM-17 expression, thus controlling breast cancer cell proliferation and invasion. Pre-miR-221/222 use in the aggressive luminal subtype may be a powerful therapeutic anti-cancer strategy.

Original languageEnglish
Pages (from-to)1811-1826
Number of pages16
JournalCell Cycle
Issue number11
Publication statusPublished - Jun 1 2014


  • ADAM-17
  • Breast cancers
  • miR-221/222
  • STAT5A
  • β4 integrin

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology
  • Developmental Biology
  • Medicine(all)


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