*2.10. ROS Detection*

Detection of ROS was performed, as described previously [18]. Cells were treated with 1 µmol/L 20 ,70dichlorodihydrofluorescein diacetate (DCF-DA; Invitrogen, MA, USA) for 30 min, followed by a 1× PBS wash for 2 times. The reduced DCF-DA was oxidized by intracellular ROS and converted into fluorescent 20 , 70 -dichlorofluorescein (DCF). Fluorescent signals were detected by the *FACSCanto*™ flow cytometer (BD). A total of 10,000 cells were analyzed per sample.
