Effects of combined treatment with SBHA and proteasome inhibitors on p53 expression in breast cancer cells. MCF-7 cells were exposed to SBHA (40 μM), Bortezomib (5 nM), and MG-132 (250 nM), alone or in combination, for 72 h and p53 expression changes were examined. (A) Western blot analysis of p53 protein. Representative blots of three independent experiments with similar results are shown. (B) Representative gel images of RT-PCR analysis of p53 transcript are shown. Lanes 2-6: control, SBHA, Bortezomib, SBHA + Bortezomib, MG-132, and SBHA + MG-132 group, respectively.