CDDO-mediated increase of active CEBPA protein and signs of differentiation in primary blasts from patients with AML. (A) AML blasts were cultured for 24 hours in the presence or absence of CDDO at different concentrations as indicated and subjected to Western blotting using an anti-CEBPA antibody. Anti–β-actin (AML nos. 1,2), anti-eIF2α (AML no. 3), or anti–beta-tubulin (AML nos. 4-6) antibodies were used for loading controls. Information about the type of AML and the karyotype and/or a CEBPA mutation are given below the blots. The densitometric units of p42/p30 are indicated as numbers above the Western blots. (B) Patients with refractory or relapsed AML were treated with CDDO (RTA401) during a phase 1 clinical trial, and cells were collected from the peripheral blood (PB) or bone marrow (BM) and assessed for expression of surface markers CD11b, CD14, and CD34 by flow cytometry at the indicated times (see also Table 2). Three of 5 patients (patients nos. 301, 304, 305) showed alterations of these parameters during the observed period. PB baseline percentages are not available from patient no. 301, therefore, BM percentages are provided.