miR-126&126* restored expressions play a tumor suppressor role by directly regulating ADAM9 and MMP7 in melanoma

PLoS One. 2013;8(2):e56824. doi: 10.1371/journal.pone.0056824. Epub 2013 Feb 21.

Abstract

The abnormal expression of several microRNAs has a causal role in tumorigenesis with either antineoplastic or oncogenic functions. Here we demonstrated that miR-126 and miR-126* play a tumor suppressor role in human melanoma through the direct or indirect repression of several key oncogenic molecules. The expression levels of miR-126&126* were elevated in normal melanocytes and primary melanoma cell lines, whereas they markedly declined in metastatic cells. Indeed, the restored expression of miR-126&126* in two advanced melanoma cell lines was accompanied by a significant reduction of proliferation, invasion and chemotaxis in vitro as well as of growth and dissemination in vivo. In accordance, the reverse functional effects were obtained by knocking down miR-126&126* by transfecting antisense LNA oligonucleotides in melanoma cells. Looking for the effectors of these antineoplastic functions, we identified ADAM9 and MMP7, two metalloproteases playing a pivotal role in melanoma progression, as direct targets of miR-126&126*. In addition, as ADAM9 and MMP7 share a role in the proteolytic cleavage of the HB-EGF precursor, we looked for the effectiveness of this regulatory pathway in melanoma, confirming the decrease of HB-EGF activation as a consequence of miR-126&126*-dependent downmodulation of ADAM9 and MMP7. Finally, gene profile analyses showed that miR-126&126* reexpression was sufficient to inactivate other key signaling pathways involved in the oncogenic transformation, as PI3K/AKT and MAPK, and to restore melanogenesis, as indicated by KIT/MITF/TYR induction. In view of this miR-126&126* wide-ranging action, we believe that the replacement of these microRNAs might be considered a promising therapeutic approach.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADAM Proteins / genetics*
  • ADAM Proteins / metabolism
  • Animals
  • Base Pairing
  • Base Sequence
  • Cell Line, Tumor
  • Disease Progression
  • Gene Expression Profiling
  • Gene Expression Regulation, Neoplastic*
  • Genes, Tumor Suppressor*
  • Heparin-binding EGF-like Growth Factor
  • Humans
  • Intercellular Signaling Peptides and Proteins / metabolism
  • Matrix Metalloproteinase 7 / genetics*
  • Matrix Metalloproteinase 7 / metabolism
  • Melanocytes / metabolism
  • Melanoma / genetics*
  • Melanoma / metabolism
  • Membrane Proteins / genetics*
  • Membrane Proteins / metabolism
  • Mice
  • MicroRNAs / genetics*
  • Osteopontin / genetics
  • Osteopontin / metabolism
  • Proteolysis
  • RNA Interference
  • Skin Neoplasms / genetics*
  • Skin Neoplasms / metabolism
  • Xenograft Model Antitumor Assays

Substances

  • HBEGF protein, human
  • Hbegf protein, mouse
  • Heparin-binding EGF-like Growth Factor
  • Intercellular Signaling Peptides and Proteins
  • MIRN126 microRNA, human
  • Membrane Proteins
  • MicroRNAs
  • Osteopontin
  • ADAM Proteins
  • ADAM9 protein, human
  • Matrix Metalloproteinase 7