Fig. 7.

Functional roles of IRE1α, GRP78/BiP, and GADD34 in regulating GST-MDA-7/IL-24-mediated cell death in leukemia cells. A, U937 cells were infected with lentiviruses carrying shRNA constructs against IRE1α, GRP78/BiP, GADD34, or their control GFP counterparts and selected with puromycin for 2 weeks, after which Western blot analysis was performed to monitor the level of knockdown of these proteins. B, these cells were treated with GST-MDA-7/IL-24 (150 nM) for 48 h, after which the extent of apoptosis was monitored using Annexin V/PI analysis assay. Values represent the means for three separate experiments ± S.D. *, significantly higher that values for shGFP-transfected cells (p < 0.05 in each case).