Persistence of RUNX1 expression after transient inhibition of its proteolytic degradation. (A) Nontransfected 293T cells were treated with the indicated drug or vehicle (DMSO) for 24 hours. Immediately afterward, protein lysates were subjected to western blot detection of endogenous RUNX1 compared with β-actin control. (B) Average fold change of endogenous RUNX1 mRNA expression relative to vehicle treatment, for drugs corresponding to panel A. (C) Nontransfected 293T cells were treated with the indicated drug or vehicle for 24 hours. At 24, 48, and 72 hours after the conclusion of drug treatment, protein lysates from aliquots were subjected to western blot detection of endogenous RUNX1 compared with β-actin control. (D) Average fold change of endogenous RUNX1 mRNA expression relative to vehicle treatment, for drugs corresponding to panel C. Error bars show standard deviation. *P < .05; **P < .01; ***P < .001, using a 2-tailed Student t test assuming unequal variance.