Palmitate demonstrates therapeutic efficacy on AML growing in vitro and in vivo. (A) CD34⁺ AML cells, normal bulk hematopoietic cells, and CD34⁺ normal hematopoietic cells were treated with increasing concentrations of palmitate (stock concentration of 2 mM palmitate conjugated with 0.17 mM bovine serum albumin). A total of 24 hours after treatment, cell viability was measured by Annexin V/PI staining. (B) Primary AML (n = 3) and normal hematopoietic cells (n = 3) were treated with 50 μM palmitate for 24 hours and were plated in clonogenic growth assays. The number of resultant colonies was counted, including CFU-GM, BFU-E, and CFU-L colony-forming units. The mean percentage of colonies obtained ± SD compared with buffer control–treated cells is shown. (C) Normal hematopoietic cells and primary AML samples were treated with increasing concentrations of palmitate. After 4 hours of treatment, levels of ROS were measured by staining with MitoSOX and flow cytometry. (D) Primary AML and Lin⁻ CD34⁺-enriched human cord blood cells were treated with 50 μM palmitate or buffer control for 24 hours. After treatment, equal cell numbers were injected into the right femurs of irradiated NOD/SCID mice preconditioned with anti-CD122. Eight weeks later, the percentage of human CD45⁺CD33⁺CD19⁻ cells in the noninjected femurs was measured by FACS. ***P < .0001 as determined by the unpaired Student t test. (E) NOD/SCID mice were injected subcutaneously with OCI- AML-2 leukemia cells. After tumors were palpable (day 7), mice were treated with palmitate or vehicle control as described in Materials and Methods. Tumor volume was measured with time and tumor mass was measured at the end of the experiment. Data represent mean ± SD. **P < .001, by Student t test. (F) Sublethally irradiated NOD/SCID mice preconditioned with anti-mouse CD122 were injected intrafemorally with primary AML cells. Six days after injection, mice were treated with palmitate or vehicle control as described in Materials and methods. Engraftment of human AML cells into the mouse marrow was assessed by determining the percentage of human CD45⁺CD33⁺CD19⁻ cells by flow cytometry. *P < .01 by Student t test.