title: Lyn is an important component of the signal transduction pathway specific to FLT3/ITD and can be a therapeutic target in the treatment of AML with FLT3/ITD.
abstract: Fms-like tyrosine kinase 3 (FLT3) is expressed in hematopoietic progenitor cells. An internal tandem duplication (ITD) of FLT3 (FLT3/ITD) is the most frequent mutation in human adult acute myeloid leukemia (AML). FLT3/ITD contributes to the constitutive activation of FLT3 itself and its downstream signal components, mitogen-activated protein kinase and signal transducers and activators of transcription 5 (STAT5), and enables interleukin (IL)-3-dependent cell lines to grow autonomously. In the present study, we showed the specific association of FLT3/ITD with Lyn, which led to the phosphorylation of Lyn in vivo. We also demonstrated that FLT3/ITD receptors displayed a higher affinity to bind to Lyn than wild-type FLT3 receptors in vitro and that this affinity was relative to the intensity of tyrosil phosphorylation of the receptor. Both treatment with small interfering RNA (siRNA) targeting Lyn and the Src family kinase inhibitor PP2 suppressed the IL-3-independent growth of FLT3/ITD-expressing 32D cells (FLT3/ITD-32D), reducing the constitutive phosphorylation of Lyn and STAT5. PP2 treatment of mice transplanted with FLT3/ITD-32D cells blocked the onset of tumors and decreased the size of established tumors. These results demonstrate that Lyn is an important component of the signal transduction pathway specific to FLT3/ITD and can be a therapeutic target in the treatment of AML with FLT3/ITD.
authors.affiliation: 1Department of Hematology and Oncology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Okamoto
authors.forename: F
authors.initials: F
authors.lastname: Hayakawa
authors.forename: Y
authors.initials: Y
authors.lastname: Miyata
authors.forename: K
authors.initials: K
authors.lastname: Watamoto
authors.forename: N
authors.initials: N
authors.lastname: Emi
authors.forename: A
authors.initials: A
authors.lastname: Abe
authors.forename: H
authors.initials: H
authors.lastname: Kiyoi
authors.forename: M
authors.initials: M
authors.lastname: Towatari
authors.forename: T
authors.initials: T
authors.lastname: Naoe
mesh_terms: D000208:Acute Disease; D000595:Amino Acid Sequence; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D002460:Cell Line / Q000187:drug effects / Q000637:transplantation; D015195:Drug Design; D004354:Drug Screening Assays, Antitumor; D005260:Female; D006412:Hematopoietic Stem Cells / Q000187:drug effects; D007951:Leukemia, Myeloid / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics; D008565:Membrane Proteins / Q000494:pharmacology; D051379:Mice; D008809:Mice, Inbred C3H; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D011485:Protein Binding; D025941:Protein Interaction Mapping; D047428:Protein Kinase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D011499:Protein Processing, Post-Translational; D011743:Pyrimidines / Q000494:pharmacology / Q000627:therapeutic use; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000502:physiology; D050799:STAT5 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction; D020080:Tandem Repeat Sequences; D014162:Transfection; D051941:fms-Like Tyrosine Kinase 3 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: C412373:AG 1879; D000970:Antineoplastic Agents; D008565:Membrane Proteins; D050505:Mutant Proteins; D009363:Neoplasm Proteins; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D050799:STAT5 Transcription Factor; C084881:flt3 ligand protein; D019000:Phosphotyrosine; C497970:FLT3 protein, human; D051941:fms-Like Tyrosine Kinase 3; C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases