Fig. 1: Tunicamycin specifically sensitizes mouse cells to TRAIL-induced apoptosis.

a Cell death profiles of MEFs treated with 20 ng/ml recombinant mouse SuperKillerTRAIL (mTRAIL SK), 1 μg/ml tunicamycin (TU), or the combination of both. The percentage of cell death was measured over time using a Fluostar Omega fluorescence plate reader analyzing the SYTOX Green-positive cells. Error bars represent S.E.M. of three independent experiments. *P < 0.05; **P < 0.01. b MEFs were stimulated with TU in presence or absence of 20 ng/ml mTRAIL-SK for 15 h, and cell lysates were immunoblotted as indicated. Caspase cleavage products are indicated by arrowheads. Representative images of two independent experiments. c Cell death profile of MEFs pretreated with 20 μM Z-VAD-FMK (Z-VAD) or control (CTRL) followed by treatment with either mTRAIL-SK (20 ng/ml), TU, or TU + mTRAIL-SK for 18 h. Cell death was measured using a Fluostar Omega fluorescence plate reader. Error bars represent S.E.M. of two independent experiments. d Cell death profiles of MEFs stimulated with TU in combination or not with increasing doses (6, 20, and 200 ng/ml) of mTRAIL SK or mTRAIL for 20 h. Cell death was measured using a Fluostar Omega fluorescence plate reader. Error bars represent S.E.M. of two independent experiments. e Cell death profiles of MEF cells stimulated with 20 ng/ml mTRAIL-SK in combination or not with increasing doses of TU for 20 h. Cell death was measured using a Fluostar Omega fluorescence plate reader. Error bars represent S.E.M. of two independent experiments. f, g Cell death profiles of MEFs exposed to f 1 μM thapsigargin (THAP) or THAP + 20 ng/ml mTRAIL-SK; or g 0.5 μM brefeldin A (BFA) or BFA + 20 ng/ml mTRAIL-SK for 16 h and 20 h. Cell death was measured using a Fluostar Omega fluorescence plate reader. Error bars represent S.E.M. of three independent experiments. h MEFs were incubated with TU, THAP, or BFA for 4 and 6 h, and cell lysates were immunoblotted as indicated. Representative images of two independent experiments. i Cell death profiles of MEFs exposed to TU or 1.5 μg/ml translation inhibitor cycloheximide (CHX) in combination or not with 20 ng/ml of human (h) or mouse (m) TNF for 20 h. Cell death was measured using a Fluostar Omega fluorescence plate reader. Error bars represent S.E.M. of two independent experiments. j Cell death profiles of MEFs exposed to TU or 1.5 μg/ml CHX in combination or not with 20 ng/ml mTRAIL-SK or hFas Ligand (hFasL) for 16 h. Cell death was measured using a Fluostar Omega fluorescence plate reader. Results are representative of two independent experiments. Error bars represent S.E.M. of triplicates from a representative experiment. k Cell death profiles of HT22 cells treated for 24 h with 20 ng/ml mTRAIL-SK, or with TU or THAP in combination or not with mTRAIL-SK. Cell death was measured using a Fluostar Omega fluorescence plate reader. Error bars represent S.E.M. of two independent experiments. l Cell death profiles of 3T3 cells treated with mTRAIL-SK or with TU or THAP, in combination or not with mTRAIL-SK. Cell death was measured using an Incucyte ZOOM® system. Results are representative of two independent experiments. Error bars represent S.E.M. of duplicates from a representative experiment