Phenotypic and Functional Characterization of NK and T Cells in a Murine Model of Acute Myeloid Leukemia

Abstract

Acute Myeloid Leukemia (AML) is a hematologic malignancy characterized by a malignant clonal disorder affecting the bone marrow due to the proliferation and expansion of leukemic stem cells (LSC) of the myeloid lineage. These cells undergo a blockage in their differentiation, impairing normal hematopoiesis and resulting in conditions such as anemia, granulocytopenia or thrombocytopenia. The proliferative advantage of LSC is attributed to genetic mutations that occur in normal hematopoietic stem cells (HSC), among which the FLT3 gene mutation is recurrent and associated with a worse prognosis. The FLT3 oncoprotein leads to a dependence on FLT3 gene signaling in leukemic cells by altering cell signaling pathways in AML, seeking to sustain survival and resistance to the immune system. AML blasts play a crucial role in immune evasion by modulating the bone marrow microenvironment through immunosuppressive activity, identified by the accumulation of regulatory cells such as regulatory T lymphocytes (Treg) and the presence of myeloid-derived suppressor cells (MDSC) that protect leukemic blasts. Previously published data from our research group demonstrate a decrease in the frequency of total and cytotoxic NK cells in patients diagnosed with AML, especially in AML with FLT3-ITD mutation, emphasizing the need to understand the immune dysfunction presented in AML with this genetic alteration and to assist in elucidating the mechanisms that contribute to the resistance of this leukemia. Thus, we propose the evaluation and determination of how the leukemic microenvironment regulates and modulates NK and T cells using the murine model Flt3-ITDki/Mx1-Tet2f/f, which closely resembles AML in humans. To study this hypothesis we will conduct immunophenotypic analyses by flow cytometry and functional assays for cytotoxicity and activation of NK and T cells. We hope to generate results that contribute to an increased understanding of the immune dysfunction observed in cases of AML with FLT3-ITD mutation, consequently evaluate the mutation's effects on immune cells, especially in the NK/T interaction.