LAUSR

Decitabine (5‐aza‐2‐deoxycytidine, DAC), a DNA‐hypomethylating agent, has been one of the frontline therapies for clonal hematopoietic stem cell disorders, such as myelodysplastic syndrome and acute myeloid leukemia, but DAC‐resistance often occurs and leads to treatment failure. Therefore, elucidating the mechanisms of DAC resistance is important for improving its therapeutic efficacy. The extracellular vesicles and particles (EVPs) have been reported to be involved in mediating drug resistance by transporting diverse bioactive components. In this study, we established the DAC‐resistant cell line (KG1a‐DAC) from its parental human leukemia‐derived cell line KG1a and observed that EVPs released from KG1a‐DAC can promote DAC‐resistant in KG1a cells. Moreover, treatment with KG1a‐DAC EVPs reduced the expression of cyclin‐dependent kinase inhibitor 2B (CDKN2B) in KG1a cells. miRNA‐Seq analysis revealed that miR‐4755‐5p is overexpressed in EVPs from KG1a‐DAC. Dual‐luciferase reporter assay and flow cytometry analysis confirmed that miR‐4755‐5p rendered KG1a cells resistant to the DAC by targeting CDKN2B gene. Taken together, miR‐4755‐5p in EVPs released from the DAC‐resistant cells plays an essential role in inducing DAC‐resistance, and is a potential therapeutic target for suppression of DAC resistance.