MicroRNA‐34a‐mediated death of acute myeloid leukemia stem cells through apoptosis induction and exosome shedding inhibition via histone deacetylase 2 targeting

We investigated the role of leukemia stem cells in chemoresistance and recurrence of acute myeloid leukemia. Total RNA was isolated from cells or tissues using TRIzol reagent. Cell viability was assessed with the tetrazolium assay. MicroRNA-34a (miR-34a), which acts on cell death regulation pathways, was noticeably downregulated in non-M3 acute myeloid leukemia stem cells compared with normal hematopoietic stem cells. Furthermore, inhibition of miR-34a-mediated suppression in leukemia stem cells was associated with poor clinical outcomes and impaired treatment efficacy in acute myeloid leukemia. Transfection with a miR-34a mimic triggered leukemia stem cell death and prevented leukemia. Bioinformatics analysis and a dual-luciferase reporter assay showed that miR-34a targeted the 3'-untranslated region of histone deacetylase 2, and the reinforced expression of miR-34a remarkably stimulated the expression of histone deacetylase 2 in leukemia stem cells. Ectopic miR-34a expression triggered death of leukemia stem cells via pathways involving the Janus kinase 1-signal transducer and activator of transcription 2-p53 axis. Targeting leukemia stem cells to trigger cell death through upregulation of miR-34a expression could be used to diagnose and treat acute myeloid leukemia.