mTORC1 activation blocks BrafV600E-induced growth arrest but is insufficient for melanoma formation

Cancer Cell. 2015 Jan 12;27(1):41-56. doi: 10.1016/j.ccell.2014.11.014.

Abstract

Braf(V600E) induces benign, growth-arrested melanocytic nevus development, but also drives melanoma formation. Cdkn2a loss in Braf(V600E) melanocytes in mice results in rare progression to melanoma, but only after stable growth arrest as nevi. Immediate progression to melanoma is prevented by upregulation of miR-99/100, which downregulates mTOR and IGF1R signaling. mTORC1 activation through Stk11 (Lkb1) loss abrogates growth arrest of Braf(V600E) melanocytic nevi, but is insufficient for complete progression to melanoma. Cdkn2a loss is associated with mTORC2 and Akt activation in human and murine melanocytic neoplasms. Simultaneous Cdkn2a and Lkb1 inactivation in Braf(V600E) melanocytes results in activation of both mTORC1 and mTORC2/Akt, inducing rapid melanoma formation in mice. In this model, activation of both mTORC1/2 is required for Braf-induced melanomagenesis.

Publication types

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

MeSH terms

  • AMP-Activated Protein Kinases
  • Animals
  • Cell Line, Tumor
  • Cell Proliferation
  • Cyclin-Dependent Kinase Inhibitor p16 / genetics
  • Cyclin-Dependent Kinase Inhibitor p16 / metabolism
  • Humans
  • Mechanistic Target of Rapamycin Complex 1
  • Mechanistic Target of Rapamycin Complex 2
  • Melanocytes / metabolism
  • Melanoma, Experimental / metabolism
  • Melanoma, Experimental / pathology*
  • Mice
  • MicroRNAs / metabolism
  • Molecular Sequence Data
  • Multiprotein Complexes / metabolism*
  • Mutation
  • Nevus / metabolism*
  • Nevus / pathology
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • Proto-Oncogene Proteins B-raf / metabolism*
  • Signal Transduction
  • Skin Neoplasms / metabolism*
  • Skin Neoplasms / pathology
  • TOR Serine-Threonine Kinases / metabolism*

Substances

  • Cdkn2a protein, mouse
  • Cyclin-Dependent Kinase Inhibitor p16
  • MicroRNAs
  • Mirn100 microRNA, mouse
  • Mirn99 microRNA, mouse
  • Multiprotein Complexes
  • Braf protein, mouse
  • Mechanistic Target of Rapamycin Complex 1
  • Mechanistic Target of Rapamycin Complex 2
  • Protein Serine-Threonine Kinases
  • Proto-Oncogene Proteins B-raf
  • Stk11 protein, mouse
  • TOR Serine-Threonine Kinases
  • AMP-Activated Protein Kinases

Associated data

  • GEO/GSE61750