Human cutaneous melanomas lacking MITF and melanocyte differentiation antigens express a functional Axl receptor kinase

J Invest Dermatol. 2011 Dec;131(12):2448-57. doi: 10.1038/jid.2011.218. Epub 2011 Jul 28.


Axl, a member of the TAM (Tyro3, Axl, Mer) family of receptor tyrosine kinases, displays an increasingly important role in carcinogenesis. Analysis of 58 cutaneous melanoma lines indicated that Axl was expressed in 38% of them, with significant overrepresentation in NRAS- compared with BRAF-mutated tumors. Axl activation could be induced by autocrine production of its ligand, Gas6, in a significant fraction of Axl-positive tumors. Pearson's correlation analysis on expression data from five data sets of melanoma lines identified several transcripts correlating positively or negatively with Axl. By functionally grouping genes, those inversely correlated were involved in melanocyte development and pigmentation, whereas those positively correlated were involved in motility, invasion, and microenvironment interactions. Accordingly, Axl-positive melanomas did not express microphthalmia transcription factor (MITF) and melanocyte differentiation antigens (MDAs) such as MART-1 and gp100 and possessed a greater in vitro invasive potential compared with Axl-negative ones. Motility, invasivity, and ability to heal a wound or to migrate across an endothelial barrier were inhibited in vitro by Axl knockdown. Pharmacological inhibition of Axl using the selective inhibitor R428 had comparable effects in reducing migration and invasion. These results suggest that targeted inhibition of Axl signaling in the subset of melanomas lacking MITF and MDAs may represent a novel therapeutic strategy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Differentiation / metabolism
  • Axl Receptor Tyrosine Kinase
  • Benzocycloheptenes / pharmacology
  • Cell Line, Tumor
  • Cell Movement / genetics
  • Enzyme Inhibitors / pharmacology
  • Gene Knockdown Techniques
  • Humans
  • Melanoma / genetics
  • Melanoma / metabolism*
  • Melanoma / pathology
  • Melanoma-Specific Antigens / genetics
  • Melanoma-Specific Antigens / metabolism*
  • Microphthalmia-Associated Transcription Factor / metabolism*
  • Mutation
  • Neoplasm Invasiveness
  • Proto-Oncogene Proteins / antagonists & inhibitors
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins B-raf / genetics
  • Receptor Protein-Tyrosine Kinases / antagonists & inhibitors
  • Receptor Protein-Tyrosine Kinases / metabolism*
  • Skin Neoplasms / genetics
  • Skin Neoplasms / metabolism*
  • Skin Neoplasms / pathology
  • Triazoles / pharmacology


  • Antigens, Differentiation
  • Benzocycloheptenes
  • Enzyme Inhibitors
  • MITF protein, human
  • Melanoma-Specific Antigens
  • Microphthalmia-Associated Transcription Factor
  • Proto-Oncogene Proteins
  • Triazoles
  • bemcentinib
  • Receptor Protein-Tyrosine Kinases
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf
  • Axl Receptor Tyrosine Kinase
  • AXL protein, human