ROS regulate the transfer of mitochondria from BMSC to AML blasts. (A) Primary AML and BMSC were prestained with MitoTracker green FM for 1 hour and then cultured together before 24-hour drug treatment. Flow cytometry was used to detect MitoTracker green FM in the AML blast. (B) Primary AML (n = 7) and BMSC were prestained with MitoTracker green FM for 1 hour and then cultured together before 24-hour NAC (5 mM) and glutathione (5 mM) treatment. Flow cytometry was used to detect MitoTracker green FM in the AML blast. (C) Primary AML (n = 10) and BMSC were prestained with MitoTracker green FM for 1 hour and then cultured together before 24-hour H₂O₂ (50 µM). Flow cytometry was used to detect MitoTracker green FM in the AML blast. (D) Nonmalignant CD34⁺ cells (n = 7) and BMSC were prestained with MitoTracker green FM for 1 hour and then cultured together before 24-hour H₂O₂ (50 µM). Flow cytometry was used to detect MitoTracker green FM in the nonmalignant CD34⁺ cells. (E) BMSC cultured alone and in coculture with AML or treated with H₂O₂ (50 µM). AML were removed and BMSC were stained for ROS, using CellROX. BMSC were visualized for ROS, using fluorescence microscopy. (F) BMSC cultured alone and in coculture with AML or treated with H₂O₂ (50 µM) were stained for ROS, using H2DCFDA (10 µM). BMSC were visualized for ROS, using fluorescence microscopy. (G-H) BMSC cultured alone and in coculture with AML (G) or nonmalignant CD34⁺ cells (H) were stained for ROS, using H2DCFDA (10 µM), and levels were analyzed by flow cytometry.