Extended Data Fig. 10: D-Cys clearance by D-amino acid oxidase and its lack of adverse effects.
From: d-cysteine impairs tumour growth by inhibiting cysteine desulfurase NFS1
a, Immunodeficient mice were administered 200 μL of D-Cys (15 mg/mL in PBS) intraperitoneally, vehicle only (Veh), or the D-amino acid oxidase (DAAO) inhibitor 6-hydroxy-2-(naphthalen-1-ylmethyl)-1,2,4-triazine -3,5(2H,4H)-dione (ref. 69) (DAAO inh, 30 mg/kg, orally). A fourth group received both D-Cys and the DAAO inhibitor. Blood samples were collected from the tail at 1 and 2 h post-administration for the analysis of L-cystine and D-cystine levels via chiral chromatography (n = 2 each). b–e, Immunodeficient mice were fed a chow diet supplemented with either L-cystine or D-cystine for 28 days. Additionally, daily intraperitoneal (IP) and subcutaneous (SC) injections of D-cystine or vehicle were administered as detailed in Methods. Body weight was monitored throughout the experimental protocol (b). Twenty-eight days after starting the diet, mice were euthanized, and samples were collected for the measurement of creatinine (c), alanine aminotransferase (ALAT; d), and aspartate aminotransferase (ASAT; e). Data obtained from individual animals are presented as mean ± SD for control and D-Cys-treated groups (n = 10 each). Statistical analyses were performed using unpaired, two-tailed Student’s t-tests. ref. 69.
