Figure 4.
NH125 treatment leads to CHOP-mediated synergy with low-dose TRAIL, and a decrease In C-FLIPL and Survlvln In GSC. A, T4213 transfected with either nontargeting or CHOP-specific pooled siRNAs were treated with either 0.1% DMSO or 2.5 μmol/L NH125 for 24 hours. An absence of CHOP leads to diminished DR5 expression following NH125 treatment despite intact ATF4 and ATF3. B, T4213, NS039, and U251 cells were treated with increasing concentrations of NH125 for 20 hours, and then co-incubated with 5 ng/mL of TRAIL for 4 hours. Raw viability data were normalized to cells treated with 0.1% DMSO, and means and SDs from biological triplicates are presented. Addition of 5 ng/mL of TRAIL produces a synergistic decrease in viability at nanomolar and low micromolar concentrations of NH125 in T4213 and NS039 (*** indicates combination index <0.5, see Supplementary Table S3). This synergistic decrease in viability is not observed in U251. C, A dose-dependent decrease in the long isoform of C-FLIP and Survivin is seen in NH125-treated T4213 and NS039 after 24 hours. A marginal decrease in C-FLIP and Survivin is observed in NH125-treated U251 after 24 hours.