Figure 1: 14C-cystine uptake assay on 4T1 cancer cells and TM40A mammary epithelial cells, both derived from BALB/c mice.

(A) Cystine uptake by 4T1 cells was more than 3-fold higher than TM40A cells (P = 0.032). (B) 200 μM SSZ caused a decrease in TM40A cystine uptake to 0.39-fold (P < 0.001) and a decrease in 4T1 cystine uptake to 0.25-fold (P < 0.001). Results are represented as means from 3 experiments (performed in duplicates) ± SEM. Statistical significance was assessed through one-tailed Student t-tests. *P < 0.05. ***P < 0.001.