Abl kinase regulation by BRAF/ERK and cooperation with Akt in melanoma

Oncogene. 2017 Aug 10;36(32):4585-4596. doi: 10.1038/onc.2017.76. Epub 2017 Apr 3.

Abstract

The melanoma incidence continues to increase, and the disease remains incurable for many due to its metastatic nature and high rate of therapeutic resistance. In particular, melanomas harboring BRAFV600E and PTEN mutations often are resistant to current therapies, including BRAF inhibitors (BRAFi) and immune checkpoint inhibitors. Abl kinases (Abl/Arg) are activated in melanomas and drive progression; however, their mechanism of activation has not been established. Here we elucidate a novel link between BRAFV600E/ERK signaling and Abl kinases. We demonstrate that BRAFV600E/ERK play a critical role in binding, phosphorylating and regulating Abl localization and Abl/Arg activation by Src family kinases. Importantly, Abl/Arg activation downstream of BRAFV600E has functional and biological significance, driving proliferation, invasion, as well as switch in epithelial-mesenchymal-transition transcription factor expression, which is known to be critical for melanoma cells to shift between differentiated and invasive states. Finally, we describe findings of high translational significance by demonstrating that Abl/Arg cooperate with PI3K/Akt/PTEN, a parallel pathway that is associated with intrinsic resistance to BRAFi and immunotherapy, as Abl/Arg and Akt inhibitors cooperate to prevent viability, cell cycle progression and in vivo growth of melanomas harboring mutant BRAF/PTEN. Thus, these data not only provide mechanistic insight into Abl/Arg regulation during melanoma development, but also pave the way for the development of new strategies for treating patients with melanomas harboring mutant BRAF/PTEN, which often are refractory to current therapies.

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Cell Proliferation / physiology
  • Drug Resistance, Neoplasm / genetics
  • Female
  • Humans
  • Melanoma / drug therapy
  • Melanoma / genetics
  • Melanoma / metabolism*
  • Melanoma / pathology
  • Mice
  • Mice, Nude
  • Mutation / drug effects
  • Organic Cation Transport Proteins / biosynthesis
  • PTEN Phosphohydrolase / genetics
  • PTEN Phosphohydrolase / metabolism
  • Phosphorylation / physiology
  • Protein Tyrosine Phosphatases / metabolism*
  • Proto-Oncogene Proteins B-raf / genetics
  • Proto-Oncogene Proteins B-raf / metabolism*
  • Proto-Oncogene Proteins c-abl / genetics
  • Proto-Oncogene Proteins c-abl / metabolism*
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Pyrimidines / therapeutic use
  • RNA, Small Interfering / metabolism
  • Skin Neoplasms / drug therapy
  • Skin Neoplasms / genetics
  • Skin Neoplasms / metabolism*
  • Skin Neoplasms / pathology

Substances

  • Organic Cation Transport Proteins
  • Pyrimidines
  • RNA, Small Interfering
  • solute carrier family 22 (organic cation transporter), member 3
  • Proto-Oncogene Proteins c-abl
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf
  • Proto-Oncogene Proteins c-akt
  • B59 protein, human
  • Protein Tyrosine Phosphatases
  • PTEN Phosphohydrolase
  • PTEN protein, human
  • nilotinib