title: Blockade of MEK/ERK signaling enhances sunitinib-induced growth inhibition and apoptosis of leukemia cells possessing activating mutations of the FLT3 gene.
abstract: The FMS-like tyrosine kinase 3 (FLT3) is a cell surface receptor tyrosine kinase. Activating mutations of this gene occur in nearly 30% of acute myelogenous leukemia (AML) patients. These mutations, in part, result in activation of mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathways. In this study, we found that AZD6244 (ARRY-142886), a novel inhibitor of MEK1/2 kinases, effectively inhibited the proliferation of acute biphenotypic leukemia MV4-11 and acute monocytic leukemia MOLM13 cells. The concentrations that inhibited 50% growth were approximately 0.3 and 1.2 microM, respectively, as measured by thymidine uptake on day 2 of culture. AZD6244 potently down-regulated the levels of phospho-ERK1/2 and its downstream effector, p-p70S6K, in the MV4-11 and MOLM13 cells as measured by Western blot analysis. Interestingly, when AZD6244 was combined with sunitinib, a FLT3 kinase inhibitor, growth inhibition and apoptosis of both MV4-11 and MOLM13 cells were synergistically enhanced in association with further down-regulation of phospho-ERK1/2 and p-p70S6K in these cells. Taken together, concomitant blockade of FLT3 and MEK signaling represents a promising treatment strategy for individuals with leukemia who possess activating mutations of FLT3.
authors.affiliation: Department of Hematology and Respiratory Medicine, Kochi University, Kochi 783-8505, Japan.
authors.forename: Chie
authors.initials: C
authors.lastname: Nishioka
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ikezoe
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Ayako
authors.initials: A
authors.lastname: Takeshita
authors.forename: Ayuko
authors.initials: A
authors.lastname: Taniguchi
authors.forename: Naoki
authors.initials: N
authors.lastname: Komatsu
authors.forename: Kazuto
authors.initials: K
authors.lastname: Togitani
authors.forename: H Phillip
authors.initials: HP
authors.lastname: Koeffler
authors.forename: Akihito
authors.initials: A
authors.lastname: Yokoyama
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D001562:Benzimidazoles / Q000627:therapeutic use; D049109:Cell Proliferation / Q000187:drug effects; D005260:Female; D006801:Humans; D007211:Indoles / Q000627:therapeutic use*; D007938:Leukemia / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D007947:Leukemia, Megakaryoblastic, Acute / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D011758:Pyrroles / Q000627:therapeutic use*; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D000077210:Sunitinib; D014407:Tumor Cells, Cultured; D051941:fms-Like Tyrosine Kinase 3 / Q000235:genetics*
chemical_list: C517975:AZD 6244; D001562:Benzimidazoles; D007211:Indoles; D011758:Pyrroles; C497970:FLT3 protein, human; D051941:fms-Like Tyrosine Kinase 3; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; D000077210:Sunitinib