JAK2 tyrosine kinase inhibitor tyrphostin AG490 downregulates the mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription (STAT) pathways and induces apoptosis in myeloma cells

Br J Haematol. 2000 Jun;109(4):823-8. doi: 10.1046/j.1365-2141.2000.02127.x.


Cytokines of the interleukin 6 (IL-6) family, which activates the signal transducer gp130, are major survival and growth factors for human multiple myeloma (MM) cells. The signal transduction of gp130 involves the Janus tyrosine kinases (JAK) JAK1, JAK2 and Tyk2 and then the downstream effectors comprising the signal transducer and activator of transcription 3 (STAT3) and mitogen-activated protein kinase (MAPK) pathways. We evaluated the effects of the JAK2 inhibitor tyrphostin AG490 on MM cells. We found that AG490 suppressed cell proliferation and induced apoptosis in IL-6-dependent MM cell lines. JAK2 kinase activity, ERK2 and STAT3 phosphorylation were inhibited. These results suggest that the chemical blocking of the gp130 signalling pathway at the JAK level could be a relevant therapeutic approach to MM.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, CD / metabolism
  • Apoptosis / drug effects
  • Cell Division / drug effects
  • Cytokine Receptor gp130
  • DNA-Binding Proteins / metabolism*
  • Depression, Chemical
  • Enzyme Inhibitors / pharmacology
  • Flow Cytometry
  • Humans
  • Immunoblotting
  • Interleukin-6 / metabolism
  • Janus Kinase 2
  • MAP Kinase Signaling System / drug effects
  • Membrane Glycoproteins / metabolism
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Multiple Myeloma / enzymology*
  • Multiple Myeloma / metabolism
  • Phosphorylation
  • Protein-Tyrosine Kinases / antagonists & inhibitors*
  • Proto-Oncogene Proteins*
  • STAT2 Transcription Factor
  • STAT3 Transcription Factor
  • Signal Transduction / drug effects*
  • Trans-Activators / metabolism*
  • Tumor Cells, Cultured
  • Tyrphostins / pharmacology*


  • Antigens, CD
  • DNA-Binding Proteins
  • Enzyme Inhibitors
  • IL6ST protein, human
  • Interleukin-6
  • Membrane Glycoproteins
  • Proto-Oncogene Proteins
  • STAT2 Transcription Factor
  • STAT3 Transcription Factor
  • STAT3 protein, human
  • Trans-Activators
  • Tyrphostins
  • alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide
  • Cytokine Receptor gp130
  • Protein-Tyrosine Kinases
  • JAK2 protein, human
  • Janus Kinase 2
  • Mitogen-Activated Protein Kinase 1