Étude des gènes de fusion MLL dans les leucémies aigues humaines

Authors: Gil, Laurine
Advisor: Barabé, Frédéric
Abstract: Acute leukemias result from a clonal and malignant proliferation of hematopoietic cells. They arise following an oncogenic event which occurs in a hematopoietic stem cell (HSC) or progenitor cell. This generates instability, causing the accumulation of other genetic and/or epigenetic events leading to the clinical development of the disease. MLL leukemias represent approximately 10 % of acute leukemias, and nowadays more than 70 fusion genes have been characterized. Cord blood is an important source of both HSCs and progenitor cells. Purification of these cells and subsequent transformation into leukemic cells allows us to induce human acute leukemia via MLL fusion genes into NSG immunodeficient mice and thus to study the leukemic potential of different MLL fusion genes. Firstly, four MLL fusion genes were studied: MLL-AF9, MLL-AF4, MLL-ENL and MLL-ELL. In vitro, we are able to transform HSC into leukemic cells which display rapid growth. The in vivo results showed that it is possible to induce leukemia by means of MLL-AF9 and MLL-ENL oncogenes. For the MLL- AF4 and MLL-ELL fusions, although some leukemias have been obtained, several technical difficulties prevented us from having an adequate model for the study of these oncogenes. Secondly, MLL-AF9 acute leukemias were studied in a model where stem cells originate from a single donor. Based on this model, we have determined that the single MLL-AF9 oncogene is sufficient to initiate disease. Indeed, no new mutations were identified during leukemia development. Among the different MLL-AF9 acute myeloid leukemias (AML) generated from this model, a certain number of non-mutated genes, notably the RET, have been identified as potential biomarkers for this specific subgroup of leukemia.
Document Type: Mémoire de maîtrise
Issue Date: 2016
Open Access Date: 24 April 2018
Permalink: http://hdl.handle.net/20.500.11794/27122
Grantor: Université Laval
Collection:Thèses et mémoires

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