MicroRNA-149*, a p53-responsive microRNA, functions as an oncogenic regulator in human melanoma

Proc Natl Acad Sci U S A. 2011 Sep 20;108(38):15840-5. doi: 10.1073/pnas.1019312108. Epub 2011 Sep 6.

Abstract

The tumor suppressor p53 is activated in response to cellular stress to prevent malignant transformation by activation of the DNA repair machinery to preserve the cell, or by induction of apoptosis to eliminate the cell should the damage prove irrevocable. The gene encoding p53 frequently undergoes inactivating mutations in many human cancers, but WT p53 is often expressed at high levels in melanoma, which, as judged from the malignant nature of the disease, fails to act as an effective tumor suppressor. Here we show that p53 directly up-regulates microRNA-149* (miR-149*) that in turn targets glycogen synthase kinase-3α, resulting in increased expression of Mcl-1 and resistance to apoptosis in melanoma cells. Although deficiency in miR-149* undermined survival of melanoma cells and inhibited melanoma growth in a mouse xenograft model, elevated expression of miR-149* was found in fresh human metastatic melanoma isolates, which was associated with decreased glycogen synthase kinase-3α and increased Mcl-1. These results reveal a p53-dependent, miR-149*-mediated pathway that contributes to survival of melanoma cells, provides a rational explanation for the ineffectiveness of p53 to suppress melanoma, and identifies the expression of miR-149* as a mechanism involved in the increased expression of Mcl-1 in melanoma cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / genetics
  • Blotting, Western
  • Cell Line
  • Cell Line, Tumor
  • Glycogen Synthase Kinase 3 / genetics
  • Glycogen Synthase Kinase 3 / metabolism
  • HCT116 Cells
  • Humans
  • Male
  • Melanoma / genetics*
  • Melanoma / metabolism
  • Melanoma / pathology
  • Mice
  • Mice, Nude
  • MicroRNAs / genetics*
  • Myeloid Cell Leukemia Sequence 1 Protein
  • Neoplasm Transplantation
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Proto-Oncogenes / genetics*
  • RNA Interference
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction
  • Transplantation, Heterologous
  • Tumor Suppressor Protein p53 / genetics*
  • Tumor Suppressor Protein p53 / metabolism
  • Up-Regulation

Substances

  • MIRN149 microRNA, human
  • Mcl1 protein, mouse
  • MicroRNAs
  • Myeloid Cell Leukemia Sequence 1 Protein
  • Proto-Oncogene Proteins c-bcl-2
  • Tumor Suppressor Protein p53
  • Glycogen Synthase Kinase 3
  • glycogen synthase kinase 3 alpha