Figure 2.
Effect of ammonium supplementation on MCTS growth. (A) HeLa and (B) MDA-MB-231 cells (2 × 104 cells/mL) were seeded in 2% (wt/vol) agarose-coated culture dishes in DMEM with 0 (■), 0.5 (•), 1 (▴), 5 (♦), and 10 (▾) mM NH4Cl. Spheroid micrographs were taken at day 20 (HeLa) or day 15 (MDA-MB-231); bars represent 200 μm. Fresh DMEM medium was replaced every 3 days. The spheroid growth was determined at the indicated times by measuring MCTS diameter. Data shown represent the mean ± SD of at least 30 MCTS (10 MCTS from each preparation), n = 3 different preparations. Statistical analysis was performed using one-way ANOVA with Scheffé comparison test. *P < 0.01 vs. non-treated MCTS.