Figure 5

Hsp90 inhibition induced over-expression of survivin through post-transcriptional mechanisms in A549 cells. (A) Hsp90 inhibition induced over-expression of survivin partially through the process of protein translation. A549 cells were pre-incubated with/without 500 nM of cycloheximide for 1 hour and subsequently treated with DMSO or various concentrations (100 nM, 250 nM and 500 nM) of 17-AAG 24 hours. The expression of survivin was revealed by Western blot analysis. Actin was used as an internal control. Relative ratio of expression was shown. (B) 17-AAG reduced the rate of survivin protein degradation in A549 cells. A549 cells were pre-incubated with 500 nM of cycloheximide for 1 hour and subsequently treated with/without 250 nM of 17-AAG for various time. The expression of survivin was revealed by Western blot analysis. Actin was used as an internal control. Relative ratio of expression was shown. (C) The amount of survivin presented in un-treated A549 cells was less than that in 17-AAG-treated cells after 4 hours of protein synthesis inhibition. A549 cells were pre-incubated with 500 nM of cycloheximide for 1 hour and subsequently treated with/without 250 nM of 17-AAG for 2 hours and 4 hours. The expression of survivin was revealed by Western blot analysis. Actin was used as an internal control. Relative ratio of expression was shown.