Assuntos
Proteínas de Transporte/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Leucemia Promielocítica Aguda/metabolismo , Proteínas Nucleares/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Receptor alfa de Ácido Retinoico/metabolismo , Retinoides/metabolismo , Células-Tronco/metabolismo , Adulto , Cromossomos Humanos Par 15/metabolismo , Cromossomos Humanos Par 17/metabolismo , Proteínas de Ligação a DNA , Humanos , Masculino , Fatores de Transcrição , Translocação Genética/fisiologiaRESUMO
Mutation of KIT receptor tyrosine kinase at residue D816 results in ligand-independent constitutive kinase activity. This mutation occurs in most patients with mastocytosis, a myeloproliferative neoplasm, and is detected at lower frequencies in acute myeloid leukemia and in germ cell tumors. Other KIT mutations occur in gastrointestinal stromal tumors (GIST) and mucosal melanoma. KIT is considered as a bona fide therapeutic target as c-kit mutations are driving oncogenes in these pathologies. However, several evidences suggest that KIT-D816V mutant is not as aggressive as other KIT mutants. Here, we show that an intracellular docking site in the juxtamembrane region of KIT maintains a negative regulation on KIT-D816V transforming potential. Sixteen signaling proteins were shown to interact with this motif. We further demonstrate that mutation of this site results in signaling modifications, altered gene expression profile and increased transforming activity of KIT-D816V mutant. This result was unexpected as mutations of the homologous sites on wild-type (WT) KIT, or on the related oncogenic FLT3-ITD receptor, impair their function. Our results support the hypothesis that, KIT-D816V mutation is a mild oncogenic event that is sufficient to confer partial transforming properties, but requires additional mutations to acquire its full transforming potential.
Assuntos
Mutação de Sentido Incorreto , Proteínas Proto-Oncogênicas c-kit/genética , Sequência de Aminoácidos , Animais , Sítios de Ligação , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Transformação Celular Neoplásica/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos , Camundongos Nus , Dados de Sequência Molecular , Transplante de Neoplasias , Proteínas Proto-Oncogênicas c-kit/química , Transdução de Sinais , TranscriptomaRESUMO
The closely related non-receptor tyrosine kinases FEline Sarcoma (FES) and FEs Related (FER) are activated by cell surface receptors in hematopoietic cells. Despite the early description of oncogenic viral forms of fes, v-fes, and v-fps, the implication of FES and FER in human pathology is not known. We have recently shown that FES but not FER is necessary for oncogenic KIT receptor signaling. Here, we report that both FES and FER kinases are activated in primary acute myeloid leukemia (AML) blasts and in AML cell lines. FES and FER activation is dependent on FLT3 in cell lines harboring constitutively active FLT3 mutants. Moreover, both FES and FER proteins are critical for FLT3-internal tandem duplication (ITD) signaling and for cell proliferation in relevant AML cell lines. FER is required for cell cycle transitions, whereas FES seems necessary for cell survival. We concluded that FES and FER kinases mediate essential non-redundant functions downstream of FLT3-ITD.
