Figure 3. Impact of polyamine metabolism on cysteine starvation sensitivity.
(a) Cell lines were grown in complete medium (Control) or matched medium lacking cysteine (-Cysteine) supplemented with putrescine (Putr), spermidine (Spd) or spermine (Spe), all 20uM, for 28h. (b) Cell lines were grown in complete medium (with 13C515N1-methionine 0.2mM substituted for methionine) for 3h. Metabolites were extracted and analysed by LCMS. (c) Cell lines were grown in complete medium (with 13C515N1-methionine 0.2mM substituted for methionine) or matched medium lacking cysteine for 16h. Metabolites were extracted and analysed by LCMS. (d) MDA-MB-231 cells were treated with AMD1 inhibitor sardomozide 20μM for 16h, followed by 20h cysteine starvation (without sardomozide), then cells were fixed, stained and counted. Representative images were taken using a light microscope. Scale bars = 100μm (e) Cell lines were grown in complete medium (with 13C515N1-methionine 0.2mM substituted for methionine) supplemented with 4-methylthio-2-oxobutanoic acid (MTOB) 0.1mM, or sardomozide 20μM for 5h. Metabolites were extracted and analysed by LCMS. All data are averages of n=3 biological replicates, error bars are SD.