Simultaneous inhibition of XIAP and MDM2 enhances cell death in samples from AML patients and cell death is enhanced by the combination even when they are protected by MSCs. (A) Mononucleocytes from blasts of AML patients were treated with 1396-11, nutlin-3a, or both for 24 hours, in suspension or cocultured with MS-5. Cell death was determined in the CD34⁺ population by annexin V/7-AAD staining. The CI of the combination for each patient is shown under the graph. 1396 indicates 1396-11; N3a, nutlin-3a. (B) Mononuclear cells from blasts of AML patients were treated with nutlin-3a for 24 hours. Cell death was determined by annexin V/PI staining and proteins by Western blot.