the impact of acute myeloblastic leukemia-derived small extracellular vesicles on the bone marrow mesenchymal stem cells: expression of g1 cell cycle progression genes

Background: leukemia progression is intricately linked to interactions with neighboring cells within the bone marrow microenvironment (bmm), and small extracellular vesicles (sevs) emerge as vital mediators in facilitating these interactions. objectives: this study examined the proliferation effects of sevs-derived from acute myeloid leukemia (aml) in the hl60 cell line on the cell cycle progression of bone marrow mesenchymal stem cells (bm-mscs), a key element of the bmm. methods: small extracellular vesicles were isolated from the hl60 cell line supernatant, using the exocib kit, and characterized through flow cytometry, transmission electron microscopy (tem), dynamic light scattering (dls), and bicinchoninic acid (bca) protein assay. bone marrow mesenchymal stem cells were cultured and treated with various concentrations (20 μg/ml, 50 μg/ml, and 80 μg/ml) of aml-derived sevs for 24, 48, and 72 hours. the effects on cell proliferation and viability were assessed, using methylthiazole tetrazolium test (mtt) and ki-67 assays, while cell cycle progression and apoptosis were analyzed via flow cytometry. rt-qpcr was performed to evaluate the expression levels of ccnd1, cdk4, cdk6, and akt1 genes. results: the proliferation effects of aml-derived sevs on bm-mscs were both dose- and time-dependent, with optimal effects observed at 50 μg/ml after 48 hours. flow cytometry analysis revealed a significant increase in the g1 phase, showing a 1.8-fold change compared to the control group (p < 0.0001). rt-qpcr results demonstrated a significant upregulation of ccnd1 (3.5-fold, p < 0.0001), cdk4 (3.2-fold, p < 0.0001), cdk6 (2.5-fold, p < 0.0001), and akt1 (3.2-fold, p < 0.0001) expression levels, along with increased ki-67 (2.3-fold, p < 0.0001) levels. moreover, treatment with 50 μg/ml of aml-derived sevs resulted in a notable reduction in bm-msc apoptosis (0.57-fold decrease, p < 0.0001). conclusions: our findings revealed that aml extracellular vesicles could alter the gene expression associated with the proliferation of bmscs to increase their proliferation by stimulating the cell cycle of mscs through the g1 phase.