Figure 5. Vorinostat-induced immunogenic modulation is mediated by the unfolded protein response.

MDA-MB-231 cells were exposed to siRNA control or targeting ERN1 or PERK for 24 h prior to being exposed to vehicle (DMSO) or vorinostat (3 μM) as described in Materials and Methods. A. and B. At the end of treatment, total cell lysates were examined by Western blotting to determine expression of ERN1 (A) or PERK (B). GAPDH was used as internal control for total protein levels. Silencing ratio denotes target protein expression relative to GAPDH, further normalized to protein levels after treatment in the presence of silencing RNA control. C. and D. At the end of treatment, MDA-MB-231 cells were used as targets in a CTL lysis assay using CEA-specific CD8⁺ T cells as effectors (E:T = 30:1). Results are presented as mean ± S.E.M. from 6 replicate wells, and are representative of 2-3 independent experiments. Asterisks denote statistical significance relative to controls (P < 0.0001).