Figure 9.

Sp-1 is induced by TGZ via MEK-1/Erk pathway. T98G cells were treated with TGZ at indicated time points. Total or phospho-Erk1/2 expression was measured by Western blot analysis (A). T98G cells were pretreated with different amounts of PD98059 for 1h prior to the addition of TGZ for 15 min (p-Erks) or 16h (Sp-1). Sp-1 or phospho-Erk1/2 expression was measured by Western blot analysis (B). T98G cells were pretreated with or without 20 µM PD98059 for 1h, then co-treated with TGZ or Control for 16h. The immunoprecipitated proteins were subjected to Western blot analysis with anti-phosphothreonine or anti-Sp-1 antibody (C). The pEP4-3 or pGL3 and Sp-1 plasmid were co-transfected into T98G cells. After 24h incubation, the cells were pretreated with or without PD98059 at different concentrations for 1h, and then co-treated with TGZ for 24h (D). *P<0.01, significant compared with Control; †P<0.01, significant compared with TGZ treatment. The bar graphs represent mean ± S.D. of RLU of three experiments. The pEP4-3 or pGL3 and pcDNA3.1, wild Sp-1 or mThr⁴⁵³/mThr⁷³⁹ Sp-1 expression plasmid were co-transfected into T98G cells for 24h, then treated with TGZ for 24h (E). The bar graphs represent mean ± S.D. of RLU of three experiments. *P<0.001, significant compared with pcDNA3.1; †P<0.01, significant compared with Sp-1.