A novel tumour-suppressor function for the Notch pathway in myeloid leukaemia.
Notch signalling is a central regulator of differentiation in a variety of organisms and tissue types. Its activity is controlled by the multi-subunit γ-secretase (γSE) complex. Although Notch signalling can play both oncogenic and tumour-suppressor roles in solid tumours, in the haematopoietic system it is exclusively oncogenic, notably in T-cell acute lymphoblastic leukaemia, a disease characterized by Notch1-activating mutations. Here we identify novel somatic-inactivating Notch pathway mutations in a fraction of patients with chronic myelomonocytic leukaemia (CMML). Inactivation of Notch signalling in mouse haematopoietic stem cells (HSCs) results in an aberrant accumulation of granulocyte/monocyte progenitors (GMPs), extramedullary haematopoieisis and the induction of CMML-like disease. Transcriptome analysis revealed that Notch signalling regulates an extensive myelomonocytic-specific gene signature, through the direct suppression of gene transcription by the Notch target Hes1. Our studies identify a novel role for Notch signalling during early haematopoietic stem cell differentiation and suggest that the Notch pathway can play both tumour-promoting and -suppressive roles within the same tissue.
Pubmed ID: 21562564 RIS Download
Animals | Basic Helix-Loop-Helix Transcription Factors | Cell Differentiation | Cells, Cultured | Gene Expression Profiling | Gene Expression Regulation, Neoplastic | Gene Silencing | Genes, Tumor Suppressor | Granulocyte-Macrophage Progenitor Cells | Hematopoietic Stem Cells | Homeodomain Proteins | Humans | Leukemia, Myelomonocytic, Chronic | Mice | Mice, Inbred C57BL | Mutation | Receptors, Notch | Signal Transduction | Tumor Cells, Cultured