Figure 1. Celastrol is a potent p536 inhibitor.

(A)VCaP cells were treated with different NF-κB inhibitors for 18 h. Western blot shows that Celastrol 2 µM for 18 h treatment can significantly inhibit p536 expression while 481407 (2 µM) and MG132 (2.5 µM) almost had no impact on p536 expression. In addition to p536, dramatically decreased AR and ERG expression at protein levels were seen in Celastrol treated group, but they are not decreased by other two inhibitors. Duplicate wells are shown for each group. β-actin was used as control. (B) VCaP cells were treated with different concentration of celastrol for 2 h. Significant decreased p536 expression was seen in all groups by western blot, including the lowest concentration group of 0.05 µM, strongly suggesting Celastrol is a potent p536 inhibitor. β-actin was the control.