title: The oncogenic TEL/PDGFR beta fusion protein induces cell death through JNK/SAPK pathway.
abstract: The TEL/PDGFR beta (T/P) fusion protein isolated from patients bearing a t(5;12) translocation is transforming when expressed in haematopoietic cells. To examine the signal transduction events activated by this protein, we measured the effect of T/P on activation of the c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) in mouse bone marrow-derived Ba/F3 cells. Significant increase in the activity of JNK/SAPK1 was observed in transient transfection as well as in Ba/F3 cells stably expressing T/P. This activation was abrogated when the T/P-expressing cells were treated with a specific inhibitor of the PDGFR beta tyrosine kinase, indicating that the activity of the PDGFR beta part of the fusion protein was involved in JNK/SAPK activation. Expression of a dominant negative mutant of mitogen-activated protein kinase kinase 4 (MKK4), a direct activator of JNK/SAPK, prevented T/P-induced JNK/SAPK activation. In addition, inhibition of phosphoinositide-3 OH kinase (PI-3 kinase), a promoting survival factor, potentiated the effect of T/P on JNK/SAPK activation. Interestingly, expression of T/P was shown to initiate an apoptotic response that was enhanced by treatment of cells with the PI-3 kinase inhibitor LY294002, suggesting that T/P mediated cell death through activation of JNK/SAPK signalling pathway. Consistent with this hypothesis, expression of the dominant negative mutant of MKK4 decreased T/P-mediated apoptosis, while a dominant-negative mutant of PI-3 kinase enhances cell death. These findings indicate that activation of JNK/SAPK by T/P is related to apoptosis rather than cell proliferation and transformation.
authors.affiliation: INSERM U 482, Hôpital Saint-Antoine, Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Atfi
authors.forename: C
authors.initials: C
authors.lastname: Prunier
authors.forename: A
authors.initials: A
authors.lastname: Mazars
authors.forename: A S
authors.initials: AS
authors.lastname: Défachelles
authors.forename: Y
authors.initials: Y
authors.lastname: Cayre
authors.forename: C
authors.initials: C
authors.lastname: Gespach
authors.forename: M F
authors.initials: MF
authors.lastname: Bourgeade
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000502:physiology*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000502:physiology*; D002460:Cell Line; D002867:Chromones / Q000494:pharmacology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000502:physiology; D006412:Hematopoietic Stem Cells / Q000378:metabolism / Q000473:pathology; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D009025:Morpholines / Q000494:pharmacology; D015514:Oncogene Proteins, Fusion / Q000037:antagonists & inhibitors / Q000235:genetics / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000037:antagonists & inhibitors / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D014162:Transfection
chemical_list: D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002867:Chromones; D004791:Enzyme Inhibitors; D020558:GTP Phosphohydrolases; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D009025:Morpholines; D015514:Oncogene Proteins, Fusion; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D011993:Recombinant Fusion Proteins; C120888:TEL-PDGFRbeta fusion protein, human; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C482559:MAP2K4 protein, human; C482562:Map2k4 protein, mouse