Fig. 6: Delayed activation of apoptosis in multicellular tumor spheroids upon ER stress. | Cell Death & Disease

Fig. 6: Delayed activation of apoptosis in multicellular tumor spheroids upon ER stress.

From: cFLIP downregulation is an early event required for endoplasmic reticulum stress-induced apoptosis in tumor cells

Fig. 6

A Cultures of HCT116 cells growing in 2D or as spheroids (10-days) were treated with TG (100 nM) for the indicated times. Caspase-8 processing was determined in whole-cell extracts by western blotting. Caspase-8 processing at 24 h of TG treatment was quantified using GAPDH as protein-loading control with Image LabTM 6.0 software and graphed relative to 2D- or 3D-untreated controls. Blots are representative of three independent experiments. B 2D or 3D cultures of HCT116 cells were treated with or without TG (100 nM) for 24 h and caspase-8 activity determined by an enzymatic specific assay as described in “Material and methods” and graphed relative to 2D- or 3D-untreated conditions (*p ≤ 0.05. Multiple t-test. Holm–Sidak method). C 2D or 3D cultures of HCT116 cells were treated with or without TG (100 nM) in the presence or absence of pan-caspase inhibitor Q-VD-OPh (20 μM) for 3 days. Cell viability was analyzed after staining with Annexin V-FITC and PI by flow cytometry (ns = not statistically significant; ****p ≤ 0.0001; two-way ANOVA. Tukey’s multiple comparisons test).

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