Figure 5.

Effects of specific MAPK inhibitors on AP-1 activity and viability of TET-R Jurkat and CEM cells treated with TET. (A) TET-R Jurkat cells (3×10⁵ cells/mL) were incubated in 96-well plates or 10-cm cell culture dishes and treated with or without 20 μmol/L SP600125 (a specific JNK inhibitor) for 24 h in the presence or absence of 5 μmol/L TET in the medium. The DNA-binding activity of AP-1 was detected with an EMSA; USF-2 served as a loading control. Cell viability and TET toxicity were analysed by performing MTT and LDH assays, respectively. (B) TET-R Jurkat cells were treated with or without 40 μmol/L PD98059 (a specific ERK inhibitor) for 24 h in the presence or absence of 5 μMmol/L TET in the medium. AP-1 activity was detected with an EMSA. The data represent the mean±SD of 3 separate experiments. ^*P<0.05 vs control; paired Student's t-test. (C) The effect of ERK inhibition by 40 μmol/L PD98059 was verified by performing an immunoprecipitation kinase assay. (D, E) An EMSA of DNA-binding activity of AP-1 and NF-κB in nuclear extracts from CEM cells treated with 10 μmol/L TET for 2, 6, 12, 18 and 24 h is shown. Quantitative densitometry data are expressed as the mean±SD (n=2). ^*P<0.05 vs control.