Pharmacologic dual inhibition of TDO2/IDO reduces ovarian cancer cell growth and TRP catabolism. OVCAR3 cells were treated with vehicle or increasing concentrations of epacadostat (A), 680c91 (B), AT-0174 (C), or StemRegenin (D). After 72 hours, cells were fixed and stained with crystal violet to assess viability. E, TRP and KYN metabolomics were performed on conditioned media from cells treated with 10 µmol/L epacadostat, 10 µmol/L 680c91, 10 µmol/L AT-0174, or 10 µmol/L StemRegenin. F, Cells were pretreated with increasing concentrations of epacadostat, 680c91, AT-0174, or StemRegenin for 168 hours, then cell growth over time was measured using an IncuCyte Live Cell Imaging system. Statistical test, multicomparison two-way ANOVA (E and F).