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. Author manuscript; available in PMC: 2013 Jun 10.
Published in final edited form as: Cancer Discov. 2012 Jul 19;2(8):722–735. doi: 10.1158/2159-8290.CD-12-0014

Figure 6.

Figure 6

IDO-dependent potentiation of IL6 production. (A) Supernatant from U937 cells stimulated for 24 hours with IFNγ (100 ng/ml) and/or LPS (100 ng/ml) was analyzed for kynurenine and IL6. Results from triplicate wells are plotted as the means ± SEM. Methyl thiohydantoin tryptophan (MTH-Trp, 100 µmol/l) was included during induction where indicated and significance relative to the corresponding induced level without MTH-Trp was determined by two-tailed Student’s t test (**; P ≤ 0.0001). (B) Supernatant from HL-60 cells stimulated for 24 hours with IFNγ (100 ng/ml) and LPS (100 ng/ml) was analyzed for kynurenine and IL6. Results from duplicate wells are plotted as the means ± SEM. Methyl thiohydantoin tryptophan (MTH-Trp, 100 µmol/l) was included during induction where indicated and significance relative to the corresponding induced level without MTH-Trp was determined by two-tailed Student’s t test (*; P < 0.05). (C) HL-60 cells treated in triplicate with Ido1-targeting (si-Ido1) or non-targeting (si-Gapdh) siRNAs were stimulated for 24 hours with IFNγ (100 ng/ml) and LPS (100 ng/ml). Pooled cell lysates were analyzed by Western blot analysis for IDO1 and β-actin (left panel). IDO1 induction was suppressed by approximately 89.7% as assessed by densitometry analysis and normalization to actin. Individual cell supernatants were analyzed for IL6 (right panel). The IL6 data are plotted as the means ± SEM with the significance of the difference between specific Ido1-targeting versus non-targeting results determined by two-tailed Student’s t test (**; P < 0.0001).