Figure 3.

Tryptophan-derived one-carbon units are incorporated into serine and purine nucleotides in pancreatic cancer cells

(A and B) CFPAC-1 cells were grown with or without human IFNγ (1 ng/mL) or with IFNγ and IDO1 inhibitor epacadostat for 24 h (A), or in 2D versus 3D conditions for 24 h (B), in the presence of ¹³C₁₁-tryptophan. Intracellular metabolites were analyzed by LC-MS and corrected for natural background ¹³C abundance. y axis = ¹³C labeled fraction for the stated isotopologues. Labeled isotopologues are defined as mass + n (m+n), where n = number of ¹³C incorporated. The potential positions of tryptophan-derived carbons are labeled in red in the structural diagrams.

See Figure S3C for explanation of labeling in acetyl-CoA. n = 3 biological replicates, error bars are SDs.