KPT-185 and Nutlin-3a synergistically induce p53. (A) OCI-AML-3 cells were treated with 50 nM KPT-185 and/or 2.5 µM Nutlin-3a. KPT-185 synergizes with Nutlin-3a to induce p53. p53 expression levels were expressed as mean fluorescence intensity ratio (MFIR) calculated by the following formula: MFIR = (MFI for anti-p53 antibody)/(MFI for isotypic control). (B) MOLM-13 and MV4;11 cells expressing control shRNA (shC) or p53-specific shRNA (shp53) were treated with 50 nM KPT-185 and/or 2.5 µM Nutlin-3a for 6 hours. Results are expressed as fold change (mean ± SD) relative to the MFIR value in untreated negative control shRNA-expressing cells. Similar results were obtained in 2 other independent experiments. *P < .05; **P < .01; ***P < .001.