Results of p53 immunoblotting in sensitive and resistant primary AML blasts after MI219 or Nutlin3 treatment or external irradiation. AML blasts were purified through negative selection and either left untreated or treated for 8 hours with MI219 (5μM), Nutlin 3 (5μM), or one-time external irradiation (5 Gy). After 8 hours, cells were lysed and protein fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Each gel was also loaded with an aliquot of a MOLM13 AML cell line lysate as an internal standard (loaded as 1.25, 2.5, and 5 μg of MI219-treated lysate or 5 μg of untreated lysate [UT], respectively). Protein was transferred to membrane and prepared for immunoblotting with an anti-p53 and anti-actin antibody. Films for both p53 and actin were developed together. IC₅₀ values for MI219 are indicated in brackets.