Figure 7. A proteasome inhibitor suppressed HSP90 inhibitor-mediated p53 down-regulation.

(A) JMN-1B or (B) NCI-H226 cells which were treated with MG-132(10 μM) or lactacystin (10 μM) were examined for ubiquitinated proteins and p53 expression with Western blot analysis. Tubulin-α and actin are used as a loading control. (C) JMN-1B cells were treated or untreated with MG-132 (10 μM) for 12 hours and then treated with 17-AAG (1 μM) or 17-DMAG (0.1 μM). The cell lysate was examined for ubiquitinated proteins and actin is used as a loading control. (D) JMN-1B cells uninfected or infected with Ad-p53 (3 × 10⁴ vp/cell) were treated or untreated with 17-AAG (1 μM), 17-DMAG (0.1 μM) and/or MG-132(10 μM) for 48 hours. The cell lysates were examined for p53 expression. Actin was used as loading control.