title: Deregulated Syk inhibits differentiation and induces growth factor-independent proliferation of pre-B cells.
abstract: The nonreceptor protein spleen tyrosine kinase (Syk) is a key mediator of signal transduction in a variety of cell types, including B lymphocytes. We show that deregulated Syk activity allows growth factor-independent proliferation and transforms bone marrow-derived pre-B cells that are then able to induce leukemia in mice. Syk-transformed pre-B cells show a characteristic pattern of tyrosine phosphorylation, increased c-Myc expression, and defective differentiation. Treatment of Syk-transformed pre-B cells with a novel Syk-specific inhibitor (R406) reduces tyrosine phosphorylation and c-Myc expression. In addition, R406 treatment removes the developmental block and allows the differentiation of the Syk-transformed pre-B cells into immature B cells. Because R406 treatment also prevents the proliferation of c-Myc-transformed pre-B cells, our data indicate that endogenous Syk kinase activity may be required for the survival of pre-B cells transformed by other oncogenes. Collectively, our data suggest that Syk is a protooncogene involved in the transformation of lymphocytes, thus making Syk a potential target for the treatment of leukemia.
authors.affiliation: Institute of Biology III, Albert-Ludwigs-University of Freiburg, 79104 Freiburg, and Department of Pediatric Hematology and Oncology, Children's Hospital, Munich, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Wossning
authors.forename: Sebastian
authors.initials: S
authors.lastname: Herzog
authors.forename: Fabian
authors.initials: F
authors.lastname: Köhler
authors.forename: Sonja
authors.initials: S
authors.lastname: Meixlsperger
authors.forename: Yogesh
authors.initials: Y
authors.lastname: Kulathu
authors.forename: Gerhard
authors.initials: G
authors.lastname: Mittler
authors.forename: Akihiro
authors.initials: A
authors.lastname: Abe
authors.forename: Uta
authors.initials: U
authors.lastname: Fuchs
authors.forename: Arndt
authors.initials: A
authors.lastname: Borkhardt
authors.forename: Hassan
authors.initials: H
authors.lastname: Jumaa
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D019264:Adoptive Transfer; D000818:Animals; D001402:B-Lymphocytes / Q000187:drug effects / Q000378:metabolism* / Q000637:transplantation; D001549:Benzamides; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D016044:Fusion Proteins, bcr-abl / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D006801:Humans; D000068877:Imatinib Mesylate; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D007938:Leukemia / Q000235:genetics / Q000473:pathology / Q000628:therapy; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D010078:Oxazines / Q000494:pharmacology; D051966:Phospholipase C gamma / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D010879:Piperazines / Q000494:pharmacology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D011947:Receptors, Antigen, B-Cell / Q000235:genetics; D013154:Spleen / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D000072377:Syk Kinase; D014162:Transfection
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C113939:B cell linker protein; D001549:Benzamides; D004268:DNA-Binding Proteins; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; C510788:N4-(2,2-dimethyl-3-oxo-4H-pyrid(1,4)oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine; D010078:Oxazines; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D016271:Proto-Oncogene Proteins c-myc; D011725:Pyridines; D011743:Pyrimidines; C499308:Rag2 protein, mouse; D011947:Receptors, Antigen, B-Cell; D000068877:Imatinib Mesylate; D011505:Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl; C000606896:SYK protein, human; D000072377:Syk Kinase; C000606897:Syk protein, mouse; D051966:Phospholipase C gamma