Pathogenesis of Cooperating Mutations of Partial Tandem Duplication of MLL Gene in De Novo Acute Myeloid Leukemia (I)

Project: National Science and Technology CouncilNational Science and Technology Council Academic Grants

Project Details


Backgrounds: Acute myeloid leukemia (AML) is a molecularly and clinically heterogeneous myeloid neoplasm. AML with partial tandem duplication of MLL gene (MLL-PTD) is a specific subtype and confers poor outcome. Our preliminary data showed a high frequency of RUNX1 or DNMT3A mutations in de novo MLL-PTD AML patients and they were mutually exclusive with rare exception. The cooperative biological function of MLL-PTD with RUNX1 mutations or DNMT3A mutations is unclear. We hypothesize that MLL-PTD cooperating with RUNX1 mutations or DNMT3A mutations results in AML transformation and they might contribute to leukemogenesis through the same or similar signaling pathways. Aims: Our specific aims are: 1) to determine the cooperative function of MllPTD and RUNX1 mutants in initiating AML in mouse model, validate the expression of target genes in human AML samples, and examine treatment strategies with specific inhibitors; 2) to determine the cooperative biological function of MLL/MllPTD and DNMT3A mutants in the pathogenesis of AML and explore the downstream targets as potential biomarkers and/or therapeutic targets. Materials and Methods: After retroviral or lentiviral-mediated over-expression of RUNX1 or DNMT3A mutants in MllPTD mouse bone marrow cells or human MLL-PTD positive AML cell lines, we will perform colony formation assays, analyze cell growth/proliferation by MTS assay and cellular differentiation by flow cytometry, and examine the dose responsive curve for specific inhibitors. Microarray analysis will be performed to correlate gene expression and DNA methylation status. We will identify differentially expressed genes in the transformed cells or clinical samples harboring MLL-PTD in mRNA and/or protein levels by RT-qPCR and/or Western blot. For in vivo studies, we will perform bone marrow transplantation assay for promising RUNX1 or DNMT3A mutants in irradiated B6 mice to investigate leukemia transformation and generate inducible double knock-in mice with cooperating MllPTD/WT and Runx1Mut/WT driven by LSL-tTA/Vav1-Cre to check AML development. In the future, we might use the double knock-in mouse model for drug treatment strategies. Significance: After accomplishing this project, we will be able to better understand the pathogenesis of de novo MLL-PTD AML and its cooperative roles in leukemogenesis with RUNX1 or DNMT3A mutations, which in turn will provide an opportunity to discover new biomarkers and identify novel therapeutic targets for the pre-clinical approaches

Project IDs

Project ID:PC10309-0064
External Project ID:MOST103-2321-B182-015
Effective start/end date01/08/1431/07/15


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