Figure 3.

MDA-MB-231 human cancer cell line exhibits enhanced glycolysis and reduced TCA cycle activity. (A) MDA-MB-231 cells were plated at 3000 cells/cm² in 6-well plates in normal medium. Culture medium was replaced after 18 h with normal medium (◊), or a medium containing 1 mM Glc+4 mM Gln (□) or 25 mM Glc+0.5 mM Gln (▵). Then, the cells were collected and counted at indicate time points. (B) Extracellular uptake of Glc and Gln and secretion of Lac and Glu after 54 h. (C) Ratio of Glc uptake to Gln uptake. (D) MID of Fum, Mal, and Asp in cells cultured in the presence of [U-¹³C₅]glutamine. (E) Ratio of PDH flux to Glc uptake. Error bars indicate s.e.m. (n=3) using propagation of error.