Drug screening to rescue RUNX1-deficient megakaryocyte agonist response. shNT- (A) and shRX (B) megakaryocytes were treated with the indicated drugs from day 5 to day 11 of differentiation. Expression of P-selectin levels was measured by flow cytometry after staining with human CD62P in day 11 megakaryocytes exposed to various concentrations of TRAP as indicated. Mean ± 1 SD is shown. N = 3. ∗P ≤ .05, ∗∗P ≤ .01, and ∗∗∗P ≤ .001 by 1-way ANOVA comparing each shRX data point to its shNT comparative.