Increased release of microvesicles containing mitochondria is associated with the myeloid differentiation of AML-M5 leukaemia cells

Extensive literature has demonstrated that acute myeloid leukaemia (AML) cells show enhanced mitochondrial biogenesis and increased reliance on oxidative phosphorylation (OXPHOS) compared with normal hematopoietic progenitors, and one hallmark of AML leukaemia blasts is myeloid differentiation blockade. However, relatively few reports have linked these processes. Recent studies have indicated that therapies that overcome differentiation arrest represent an effective treatment strategy. Here, we identified that the disruption of the mitochondrial mass and energy metabolism promotes leukaemia cellular myeloid differentiation. In this study, we showed that acute monocytic leukaemia (AML-M5) cells package mitochondria in microvesicles (MVs) when MVs shed from membranes. Additionally, during myeloid differentiation, we report for the first time that differentiated leukaemia cells release more MVs than undifferentiated leukaemia cells. Targeting the formation of MVs using a specific inhibitor (Y-27632) restrained myeloid differentiation, suggesting that the increased release level of MVs plays an important role in regulating myeloid differentiation. Furthermore, the intracellular mitochondria and ATP levels were decreased after leukaemia cells overcame the differentiation blockade. Moreover, rotenone, which is used to inhibit the respiratory chain and ATP production, had a strong effect on myeloid differentiation in monocytic leukaemia cells. Collectively, these studies uncovered the relationship between mitochondrial function and myeloid differentiation and may provide more insight into the diagnosis and treatment of AML.