Figure 3.

Autophagy reduces the ROS level of cancer cells. (a) Rapa reduces replication stress-induced ROS level of cancer cells. HT1080 cells and U2OS cells were treated with 20 nM Rapa or cotreated with 200 μM HU for 24 h. Cellular ROS level was determined by flow cytometry. (b) Rapa reduces X-ray-induced ROS level of cancer cells. HT1080 cells and U2OS cells were pretreated with or without Rapa (20 nM) for 6 h and then were treated with 5 Gy X-ray. Cellular ROS level was tested at 24 h after X-ray treatment using flow cytometry. (c, d) Another autophagy activator Torin1 (50 nM) for verification in HT1080 cells and U2OS cells, which has the same treatment as (a) and (b). Each experiment was repeated three times. ^∗P < 0.05, ^∗∗P < 0.01, ^∗∗∗P < 0.001, and ^∗∗∗∗P < 0.0001. ROS: reactive oxygen species.