In vivo modelling of order and hierarchical position of oncogenic mutation in acute myeloid leukemia (AML)
Supervisors: Prof Claus Nerlov and Prof Paresh Vyas
Background and project overview
AML occurs due to the sequential acquisition of somatic mutations by hematopoietic cells of the myeloid lineage, leading to the formation of leukemic stem cells (LSCs), which are ectopically self-renewing myeloid progenitor cells that lack normal differentiation capacity. LSCs expand and eventually supplant the normal stem- and progenitor cells in the bone marrow, leading to hematopoietic failure.
Within AML, there are two hierarchies to consider. First, there is a hierarchy of mutation acquisition. Typically around 5 coding leukemogenic mutations are present in the leukemia at diagnosis. These are acquired sequentially in either linear or branching hierarchies. The second hierarchy is the hierarchy of blood stem progenitor and precursor cells during differentiation. It is likely that initiating and early mutations in a mutational hierarchy are acquired in stem and early progenitor cells to establish a preleukaemic state. Examples of mutations in this class include those in the DNMT3A, TET2 and ASXL1 genes. In contrast, the full complement of leukemogeneic mutations may only be in fully transformed progenitor-like and precursor-like leukemic stem cells and their poorly differentiated progeny. Examples here include mutations in FLT3. Finally, it is also clear that mutations in genes occur in a variety of orders – thus, mutations in IDH1/2 or NPM can be either initiating or be acquired later in the mutational hierarchy.
To date we do not understand the rules that govern how mutations cooperate and whether the order they are acquired influences the biology of the mutant cells and their response to therapy. In this project, we will study these questions through accurate modeling in vivo to develop a greater understanding of the basic biology the impact of mutational order on haemopoiesis with the aim of translating this to improve response to therapy.
We will use advanced mouse genetics to accurately model AML by introducing leukemogenic mutations in the order in which, and into the cell types where, they are normally acquired. This will be achieved using multiple recombinases and newly developed recombinase drivers, allowing the introduction of mutation to be both temporally and hierarchically controlled. The models developed will be used to study the effects of both conventional therapies (i.e. chemotherapy) and targeted therapies (e.g. TET, IDH, FLT3 inhibitors) on the clonal structure of AML, comparing effects on premalignant HSCs and malignant progenitors, thereby determining the cellular basis of their action and of their distinct efficacies in disease eradication. This will involve functional analysis of putative pre-leukemic and leukemic stem cells before and after intervention, as well as single cell-level analysis of the effects of treatment on their mutational profiles and gene expression.
- To develop murine genetic models of AML that allow mutations to be introduced in the sequence and hierarchical positions normally observed in human AML.
- To study the effects of conventional and targeted therapies in the resulting accurate preclinical AML models
- Drissen, R., N. Buza-Vidas, P. Woll, S. Thongjuea, A. Gambardella, A. Giustacchini, E. Mancini, A. Zriwil, M. Lutteropp, A. Grover, A. Mead, E. Sitnicka, S. E. W. Jacobsen and C. Nerlov (2016). "Distinct myeloid progenitor-differentiation pathways identified through single-cell RNA sequencing." Nat Immunol 17(6): 666-676.
- Quek, L., G. W. Otto, C. Garnett, L. Lhermitte, D. Karamitros, B. Stoilova, I. J. Lau, J. Doondeea, B. Usukhbayar, A. Kennedy, M. Metzner, N. Goardon, A. Ivey, C. Allen, R. Gale, B. Davies, A. Sternberg, S. Killick, H. Hunter, P. Cahalin, A. Price, A. Carr, M. Griffiths, P. Virgo, S. Mackinnon, D. Grimwade, S. Freeman, N. Russell, C. Craddock, A. Mead, A. Peniket, C. Porcher and P. Vyas (2016). "Genetically distinct leukemic stem cells in human CD34- acute myeloid leukemia are arrested at a hemopoietic precursor-like stage." J Exp Med 213(8): 1513-1535.
The WIMM has a very important role in training young scientists in Molecular Medicine and Stem Cell Biology and takes on several D.Phil (PhD) students each year. There are currently approximately 120 DPhil students in the WIMM. In addition to training opportunities through the University, in the WIMM we run a course on basic techniques for new students of approximately 20 lectures. There are also courses on Immunology and Bioinformatics and others may be added. Institute Seminars are held on a weekly basis and regularly attract world-class scientists in haematopoiesis research. Informal exchange of ideas in the coffee area is encouraged and is an attractive feature of the WIMM.
The Vyas and Nerlov laboratories have clearly defined protocols to support training in specific experimental techniques. Standard operating procedures are regularly updated to ensure that methods are optimal. The above project utilises a wide range of state of the art molecular and cell biological techniques, advanced genetic technologies and bioinformatics analysis and will consequently provide an excellent foundation for a research career.
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