MicroRNA-184 antagonizes microRNA-205 to maintain SHIP2 levels in epithelia

Proc Natl Acad Sci U S A. 2008 Dec 9;105(49):19300-5. doi: 10.1073/pnas.0803992105. Epub 2008 Nov 25.

Abstract

Despite their potential to regulate approximately one-third of the whole genome, relatively few microRNA (miRNA) targets have been experimentally validated, particularly in stratified squamous epithelia. Here we demonstrate not only that the lipid phosphatase SHIP2 is a target of miRNA-205 (miR-205) in epithelial cells, but, more importantly, that the corneal epithelial-specific miR-184 can interfere with the ability of miR-205 to suppress SHIP2 levels. This is the first example of a miRNA negatively regulating another to maintain levels of a target protein. Interfering with miR-205 function by using a synthetic antagomir, or by the ectopic expression of miR-184, leads to a coordinated damping of the Akt signaling pathway via SHIP2 induction. This was associated with a marked increase in keratinocyte apoptosis and cell death. Aggressive squamous cell carcinoma (SCC) cells exhibited elevated levels of miR-205. This was associated with a concomitant reduction in SHIP2 levels. Partial knockdown of endogenous miR-205 in SCCs markedly decreased phosphorylated Akt and phosphorylated BAD levels and increased apoptosis. We were able to increase SHIP2 levels in SCC cells after inhibition of miR-205. Therefore, miR-205 might have diagnostic value in determining the aggressivity of SCCs. Blockage of miR-205 activity with an antagomir or via ectopic expression of miR-184 could be novel therapeutic approaches for treating aggressive SCCs.

Publication types

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

MeSH terms

  • Apoptosis / physiology
  • Carcinoma, Squamous Cell / physiopathology
  • Cell Survival / physiology
  • Down-Regulation / genetics
  • Epithelium, Corneal / cytology
  • Gene Expression Regulation, Neoplastic
  • HeLa Cells
  • Humans
  • Keratinocytes / cytology
  • Keratinocytes / physiology*
  • Kidney / cytology
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism*
  • Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases
  • Phosphoric Monoester Hydrolases / physiology*
  • Proto-Oncogene Proteins c-akt / metabolism
  • RNA, Small Interfering
  • STAT1 Transcription Factor / genetics
  • Skin Neoplasms / physiopathology
  • Transfection

Substances

  • MIRN184 microRNA, human
  • MIRN205 microRNA, human
  • MicroRNAs
  • RNA, Small Interfering
  • STAT1 Transcription Factor
  • Proto-Oncogene Proteins c-akt
  • Phosphoric Monoester Hydrolases
  • INPPL1 protein, human
  • Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases