Glutamine uptake assay

Glutamine uptake was determined using a glutamine assay kit (colorimetric) (ab197011, Abcam) following the manufacturer’s instructions. According to the principle of glutamine conversion into glutamic acid and ammonia, the amount of glutamine was calculated by measuring the amount of ammonia. The relative glutamine uptake was calculated to the ratio of control cells and normalized by the protein amount of each group. Experiments were performed in triplicate and repeated three times.