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. 2015 Oct 22;7(4):4356–4368. doi: 10.18632/oncotarget.5374

Figure 1. Niacin inhibits TRAIL-induced apoptosis in HCT116 cells.

Figure 1

HCT116 cells were pretreated with niacin (400–1,600 μM) for 12 h and then incubated with recombinant TRAIL (100 ng/ml) for an additional 2 h. A. Cells were photographed under light microscopy (×200). B, C. Viable cells were stained with crystal violet. Viability of control cells was set at 100%, and viability relative to the control was estimated. Results are representative of three independent experiments. D. Release of LDH into the cell culture supernatant. E. HCT116 cells were pretreated with niacin for 12 h, and then further co-incubated with or without recombinant TRAIL protein (100 ng/ml) for an additional 2 h. Whole cell lysates were subjected to western blot analysis of caspase-8 and caspase-3. β-actin was used as a loading control. *p < 0.05, **p < 0.001; significant differences between control and each treatment group. adj. volume, adjustment of volume (band volume minus background volume).