title: Inhibition of MEK5 by BIX02188 induces apoptosis in cells expressing the oncogenic mutant FLT3-ITD.
abstract: Fms-like tyrosine kinase-3 (FLT3) is a growth factor receptor normally expressed on hematopoietic progenitor cells. Approximately one third of all patients with AML carry an activating mutation in FLT3 that drives proliferation and survival of the leukemic cells. The most common activating mutation is the so-called internal tandem duplication (ITD), which involves an in-frame duplication of a segment of varying length in the region of the FLT3 gene that encodes the juxtamembrane domain. The pathways downstream of FLT3-ITD are partially known but further knowledge regarding the downstream signal transduction molecules is important in order to develop alternative strategies for pharmacological intervention. In this paper we have studied the role of MEK/ERK5 in FLT3-ITD mediated transformation. We have found that both wild-type FLT3 and FLT3-ITD activate MEK5 leading to the activation of ERK5. By use of the selective inhibitor of MEK5, BIX02188, we have shown that activation of AKT downstream of FLT3 is partially dependent on ERK5. Furthermore, inhibition of MEK5/ERK5 induces apoptosis of both FLT3-ITD transfected Ba/F3 cells as well as the FLT3-ITD carrying leukemic cell lines MV4-11 and MOLM-13. These results suggest that MEK5/ERK5 is important for FLT3-ITD induced hematopoietic transformation and may thus represent an alternative therapeutic target in the treatment of FLT3-ITD positive leukemia.
authors.affiliation: Experimental Clinical Chemistry, Wallenberg Laboratory, Department of Laboratory Medicine, Lund University, Skåne University Hospital, SE-205 02 Malmö, Sweden.
authors.forename: Elena
authors.initials: E
authors.lastname: Razumovskaya
authors.forename: Jianmin
authors.initials: J
authors.lastname: Sun
authors.forename: Lars
authors.initials: L
authors.lastname: Rönnstrand
mesh_terms: D000814:Aniline Compounds / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D007938:Leukemia / Q000201:enzymology; D008024:Ligands; D048671:MAP Kinase Kinase 5 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D048054:Mitogen-Activated Protein Kinase 7 / Q000378:metabolism*; D015513:Oncogene Proteins / Q000096:biosynthesis* / Q000235:genetics; D010766:Phosphorylation / Q000187:drug effects; D051941:fms-Like Tyrosine Kinase 3 / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000814:Aniline Compounds; C533206:BIX 02188; D007211:Indoles; D008024:Ligands; D015513:Oncogene Proteins; C497970:FLT3 protein, human; D051941:fms-Like Tyrosine Kinase 3; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048054:Mitogen-Activated Protein Kinase 7; D048671:MAP Kinase Kinase 5; C482563:MAP2K5 protein, human