Search

Acute myeloid leukemias (AMLs) result from a series of genetic events occurring in a stem or progenitor hematopoietic cell that gives rise to their clonal expansion and an impaired capacity to differentiate. To circumvent the genetic heterogeneity of AML patient cohorts, we have developed a model system, driven by the MLL-AF9 (MA9) oncogene, to generate multiple human leukemias using progenitor cells from a single healthy donor. Through stepwise RNA-sequencing data generated using this model and AML patients, we have identified consistent changes associated with MA9-driven leukemogenesis and demonstrate that no recurrent secondary mutations are required. We identify 39 biomarkers whose high expression level is specific to this genetic subtype of AML and validate that many of these have diagnostic utility. We further examined one biomarker, the receptor tyrosine kinase (RTK) RET, and show through shRNA knockdowns that its expression is essential for in vivo and in vitro growth of MA9-AML. These results highlight the value of novel human models of AML derived from single donors using specific oncogenic fusions to understand their biology and to uncover potential therapeutic targets.

Interleukin-15 deficiency promotes the development of T-cell acute lymphoblastic leukemia in non-obese diabetes mice with severe combined immunodeficiency

The hematopoietic system produces appropriate levels of blood cells over an individual's lifetime through a careful balance of differentiation, proliferation and self-renewal. The acquisition of genetic and epigenetic alterations leads to deregulation of these processes and the development of acute leukemias. A prerequisite to targeted therapies directed against these malignancies is a thorough understanding of the processes that subvert the normal developmental program of the hematopoietic system. This involves identifying the molecular lesions responsible for malignant transformation, their mechanisms of action and the cell type(s) in which they occur. Over the last 3 decades, significant progress has been made through the identification of recurrent genetic alterations and translocations in leukemic blast populations, and their subsequent functional characterization in cell lines and/or mouse models. Recently, primary human hematopoietic cells have emerged as a complementary means to characterize leukemic oncogenes. This approach enables the process of leukemogenesis to be precisely modeled in the appropriate cellular context: from primary human hematopoietic cells to leukemic stem cells capable of initiating disease in vivo. Here we review the model systems used to study leukemogenesis, and focus particularly on recent advances provided by in vitro and in vivo studies with primary human hematopoietic cells.