Fig. 5

High tolerance to oxidative stress was associated with ICC cell resistance. (A) SOD2 expression was upregulated after exposure to GEM. (B) SOD2 expression in parental and GEM-resistant cells. (C) Detection of the levels of ROS in parental and resistant ICC cells with or without GEM treatment. Δ value = (median value with GEM) – (median value without GEM). (D) Inhibition of SOD2 expression by si-RNA enhanced the resistance of ICC cells to GEM treatment. *P<0.05; **P<0.01 versus the negative group.