Fig. 2.

Dose-dependent reduction of kynurenine production in IDO1 or TDO2 LNA-modified ASO-treated cancer cells. Cancer cells (a, b EFO-21, c, d MDA-MB-453) were treated with different concentrations of IDO1-specific (a, b), TDO2-specific (c, d) ASOs or the control oligo 2 (a, b concentration: 3 µM) or the control oligo 1 (c, d concentration: 10 µM) for 3 days without the use of a transfection reagent. Afterwards, medium was replaced and supplemented with tryptophan (concentration: 100 µM). Supernatants were harvested 24 h after medium replacement and kynurenine levels were determined by ELISA. Relative kynurenine levels as compared to mock-treated cells (set to 1) are depicted. IDO1 mRNA (b) or TDO2 mRNA expression (d) was analyzed in cells 24 h after medium replacement and relative mRNA expression is depicted compared to mock-treated cells (set to 1). a, b The mean ± SD of two independent experiments run in duplicates is shown. c, d The mean of duplicates ± SD from an experiment is shown. a, b Significant differences compared to mock-treated cells were determined using one-way ANOVA followed by Dunnett’s multiple comparison test