Figure 3.

ASCT2 knock-out does not phenocopy LAT1 knock-out in vitro. A, cell proliferation of WT (white), ASCT2^KO (light and dark gray, two independent clones), and LAT1^KO (black) cells of LS174T and A549 cell lines. Cells were cultivated for 72 h in DMEM, 0.3×, or 0.1× media (Table S2). The media were replaced every day to maintain constant AA concentrations. Proliferation rates are presented as -fold increase (see “Experimental Procedures” for detailed description). These data represent the average of at least three independent experiments. *, significant compared with WT (ANOVA, p < 0.05), #, significant compared with LAT1^KO (p < 0.05). B, clonal growth of WT, ASCT2^KO (#1 and #2), and LAT1^KO cells of LS174T and A549 cell lines. Cells were cultivated for 15 days in DMEM, 0.3× or 0.1× media (Table S1). The media were replaced every 2 days to maintain constant AA concentrations and colored for visualization using Giemsa. C, cell proliferation of LS174T and A549 WT (white) and ASCT2^KO (light and dark gray, two independent clones) cells cultivated for 72 h in glutamine-free DMEM. These data represent the average of at least three independent experiments. *, significant compared with WT (ANOVA, p < 0.05); #, significant compared with DMEM (+) glutamine (p < 0.05).