Figure S6. IRC117539’s effect on proteasomes, its subunits and ER stress.
(A) mRNA levels of various proteasome subunits were determined by q-PCR in LNCaP cells treated with the IRC117539 (1 μM) compound for indicated times. Expression levels were normalized to GAPDH mRNA. (B) Cycloheximide (CHX) chase experiment indicates enhanced turnover and diminished half-life of proteasome subunits in cells treated with IRC117539 (1 μM). Western blot analyses of protein levels and quantifications are shown (n = 2). (C) Western blot analyses of CHOP and BiP expression in AR-positive LNCaP and AR-negative PC3 cells treated with 1 μM IRC117539. Global ubiquitin conjugates are also shown. MG132, a potent ER stress inducer, was used at 1 μM as a positive control. (D) IC50 values are shown for comparison of IRC117539-induced changes in LNCaP cells (treatment: 24 h). IRC117539 achieves AR degradation and impairs AR signaling and prostate cancer cell survival at comparable doses.