Figure 5

Arginine depletion by ADI-PEG 20 reduces argininosuccinate and inhibits cellular proliferation in FH-deficient cells. (A) Arginine levels determined in the media of the indicated cell lines after the incubation for 4 hours with 125 ng/mL ADI-PEG 20. (B) Excreted and intracellular levels of argininosuccinate after treatment with ADI-PEG 20, as in (A), were detected by LC-MS. (C) Representative images of a colony survival assay after treatment with either 125 ng/mL (mouse cells) or 50 ng/mL (human cells) ADI-PEG 20 for 8 days. The media was replaced and cells were left to grow for a further 4 days before fixation and staining. All the results were obtained from three independent cultures and expressed as average ± SEM. FH, fumarate hydratase; LC-MS, liquid chromatography-mass spectrometry; SEM, standard error of the mean.