Impact of Acute Myeloid Leukemia-Derived Extracellular Vesicles on Expression of CTNNB1, TGF-β, and VEGF Genes in Bone Marrow Mesenchymal Stem Cells: Insights into Leukemia Pathogenesis.

Objective: Acute myeloid leukemia (AML) is a heterogeneous malignancy driven by disruptions in the bone marrow microenvironment (BME). Extracellular vesicles (EVs) are crucial communicators and effectors in the BME, facilitating interactions between leukemic cells and stromal components to promote leukemogenesis. Elucidating these EVmediated processes is essential for developing novel therapeutic strategies. This study sought to clarify the effects of EVs derived from newly diagnosed non-M3 AML patients on bone marrow mesenchymal stromal cells (BMSCs), focusing on proliferation, survival, apoptosis, and expression of CTNNB1, TGF-β, and VEGF genes, which are pivotal in leukemia progression.

Materials and methods: In this experimental study, AML-derived EVs were isolated from 30 newly diagnosed non-M3 AML patients and characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), Bradford assay, and flow cytometry. BMSCs were isolated from healthy BM aspirates and were co-cultured with EVs at concentrations of 10, 40, and 60 μg/ml for 24, 48, and 72 hours. Outcomes were assessed using quantitative reverse transcription polymerase chain reaction (RT-PCR), (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliuom bromide (MTT) assay, flow cytometry [for apoptosis, reactive oxygen species (ROS), and Ki67], and Western blot analyses.

Results: AML-derived EVs at 40 μg/ml significantly suppressed apoptosis, enhanced cell survival, and upregulated CTNNB1, TGF-β, and VEGF gene expression in BMSCs via the Wnt/β-catenin signaling pathway, as confirmed by increased β-catenin protein levels. However, a 60 μg/ml dose increased apoptosis and reduced gene expression.

Conclusion: These findings can suggest that AML-derived EVs modulate the BME by promoting BMSC survival and upregulating pro-leukemic genes at an optimal dose, offering a potential therapeutic target for AML treatment.