Figure 4From: Development and characterization of a novel C-terminal inhibitor of Hsp90 in androgen dependent and independent prostate cancer cells Native Size Exclusion Chromatography (SEC) fractionation of Hsp90 complexes and inhibition of Hsp90 dependent luciferase refolding activity. Vehicle or 25 μM KU174 treated (24h) SEC fractions were probed by SDS-PAGE Western blot. For each protein in Figure 4A, a vehicle control treated (Figure 4A, panel C) and a KU174 treated (Figure 4A, panel T) are depicted. Pooled vehicle fractions (9-16) showed the ability to refold thermally denatured luciferase and this activity was inhibited by KU174 (Figure 4B). In a follow-up study, PC3-MM2 cells treated with or without KU174 (0.1 μM) were fractionated by SEC and fractions 9-16 of each sample were pooled and chaperone activity was tested as a function of luciferase refolding (Figure 4C). The chaperone refolding activity of 0.1 μM KU174 treated samples is reduced to ~50% of vehicle (see left axis segment) and was further inhibited by novobiocin. These data suggest KU174 directly inhibits Hsp90 complex refolding activity.Back to article page