Figure 5.

AP-1 and Sp1 inhibitors suppress xylosyltransferase-1 (XT-1) expression in nucleus pulposus (NP) cells. A–C: Effect of AP-1 inhibitor tanshinone IIA (Tan IIA) (A) and Sp1 inhibitors WP631 (B) and mithramycin A (Mith A) (C) on XT-1 mRNA expression in rat NP cells. Real-time RT-PCR analysis showed that the inhibitors significantly suppress XT-1 mRNA in a dose-dependent manner. D: Western blot analysis of rat NP cells treated with the inhibitors WP631, Mith A, and Tan IIA. XT-1 protein levels decreased with inhibitor treatment. E: Multiple blots shown in experiment D were quantified by densitometric analysis. β-Tubulin was used as a loading control and to calculate relative expression levels to untreated control (Ctr). Values shown are means ± SEM of three independent experiments. ^∗P < 0.05. DMSO, dimethyl sulfoxide.