Figure 6.

CTX1 induced p38 MAPK phosphorylation in HL-60 cells via the Ca²⁺/NOX4/ROS axis. Without specific indication, HL-60 cells were treated with 800 nM CTX1 for 3 h (for measuring [Ca²⁺]i) or 4 h (for measuring ROS level, cell viability, NOX4 expression, and p-p38 MAPK level). On the other hand, HL-60 cells were pretreated with 10 μM BAPTA-AM or 10 μM GLX351322 for 1 h and then incubated with 800 nM CTX1 for 3 h (for measuring [Ca²⁺]i) or for 4 h (for measuring ROS level, cell viability, NOX4 expression, and p-p38 MAPK level). (A) CTX1 induced HL-60 cell death in a concentration-dependent manner. CTX1 induced (B) ROS generation and (C) an elevation of [Ca²⁺]i in HL-60 cells. HL-60 cells were treated with 800 nM CTX1 for indicated time periods. (D) Effect of BAPTA−AM and GLX351322 on CTX1-induced ROS generation (mean ± SD, * p < 0.05). (E) Effect of BAPTA−AM and GLX351322 on the viability of CTX1-treated HL-60 cells (mean ± SD, * p < 0.05). (F) CTX1 induced phosphorylation of p38 MAPK in HL-60 cells (* p < 0.05, CTX1-treated cells compared to untreated control cells). Effect of (G) BAPTA−AM and (H) GLX351322 on CTX1-induced p38 MAPK phosphorylation (* p < 0.05, BAPTA−AM/CTX1-treated cells compared to CTX1-treated cells; * p < 0.05, GLX351322/CTX1-treated cells compared to CTX1-treated cells). Effect of BAPTA−AM on NOX4 protein (I) and mRNA (J) expression in CTX1-treated cells (* p < 0.05, BAPTA−AM/CTX1-treated cells compared to CTX1-treated cells).