The Indoleamine-2,3-Dioxygenase (IDO) Inhibitor 1-Methyl-D-tryptophan Upregulates IDO1 in Human Cancer Cells
Figure 1
SKOV-3 ovarian carcinoma cells constitutively degrade trp via indoleamine-2,3-dioxygenase-1 (IDO1).
(A) Relative mRNA expression of the three trp-degrading enzymes IDO1, IDO2 and tryptophan-2,3-dioxygenase (TDO) (white bars) and kyn production (black bar) of SKOV-3 cells, measured by quantitative RT-PCR and high performance liquid chromatography (HPLC). (B) Knockdown of IDO1 mRNA by siRNA measured by qRT-PCR. (C) Western blot analysis showing IDO1 protein expression in SKOV-3 cells with siRNA mediated knockdown of IDO1 in comparison to controls. (D) Immunocytochemistry (red, IDO1 staining; blue, DAPI nuclear staining) of control SKOV-3 cells and SKOV-3 cells with IDO1 knockdown. (E) Kyn release of SKOV-3 cells after knockdown of IDO1 in comparison to controls. Experiments were performed at least in triplicate. Data are mean ± SEM. * (p<0.05).