Figure 5

Cd²⁺-induced reactive oxygen species (ROS) formation in kidney PTC induces up-regulation of CHOP, but has no effect on Wnt signaling. (A) When used, the ROS scavenger α-tocopherol was pre-incubated for 1 h. Cells were loaded with 20 μM carboxy-H₂DCFDA. Cell suspensions were incubated with Cd²⁺ ± α-tocopherol and fluorescent signals were measured immediately at 500/535 nm. Graph shows means ± SEM of 4-7 experiments. (B) β-catenin immunoblot of WKPT-0293 Cl.2 cells ± α-tocopherol (TOCO) (100 μM) ± 25 μM Cd²⁺ for 6 h. (C) Expression of CHOP mRNA in WKPT-0293 Cl.2 cells without (ctl) or with 25 μM Cd²⁺ by RT-PCR. (D) Prevention of Cd²⁺-mediated increase in CHOP mRNA expression by α-tocopherol. (E) Association of CHOP with TCF4 is increased in WKPT-0293 Cl.2 cells incubated with 25 μM Cd²⁺ for 6 h when compared to controls (ctl). (F) Effect of CHOP overexpression on Cd²⁺-induced expression of c-Myc by RT-PCR. PTC transiently transfected with full length human CHOP (CHOP) or empty vector (vector) were exposed to 25 μM Cd²⁺.