A, PC-3 cells were treated with vehicle, orlistat (25 µmol/L), bortezomib (5 nmol/L) or the combination of bortezomib and orlistat. Total RNA was collected with TRIzol and RT-PCR was performed with oligonucleotides specific for XBP-1 and β-actin. XBP-1 (us) is indicated by the 473 bp product and XBP-1 (s) is indicated by the 447 bp fragment. PC-3 cells were treated for one hour with thapsigargin (1 µmol/L) as a positive control. B, PC-3 cells were treated with vehicle, orlistat (25 µmol/L), bortezomib (5 nmol/L), or the combination of bortezomib and orlistat. Nuclear lysates were collected as described in Experimental Methods for immunoblot analysis with antibodies specific for XBP-1 and Lamin A/C. Immunoblot indicates the 55 kD XBP-1 (s) protein. Asterisk denotes higher molecular weight nonspecific band. C, PC-3 cells were treated with vehicle, bortezomib (5 nmol/L), C75 (9 µg/ml), or the combination of bortezomib and C75. Asterisk denotes higher molecular weight nonspecific band. Images represent cropped immunoblots. Full length scans available in supplementary data figure 4.