<p>(A) MTX (10 nM) treatment strongly elevates CerS6 in p53<sup>+/+</sup> but not p53<sup>-/-</sup> cells. (B) Antifolate lometrexol (LTX) bypasses p53 and does not affect CerS6: <i>left panel</i>, LTX inhibits both p53<sup>+/+</sup> and p53<sup>-/-</sup> A549 cells (Experiments were performed three times with six wells per concentration point in each experiment; error bars, SD) no statistically significant differences between p53<sup>+/+</sup> and p53<sup>-/-</sup> cells were observed (p>0.1); <i>right panel</i>, levels of p53 and CerS6 (Western blot) in the cells after LTX treatment. Cells were exposed to LTX for 48 h.</p
