Targeting of TAK1 impairs expansion of primary AML CD34⁺ cells. (A) Primary AML CD34⁺ cells were incubated with various concentrations of AZ-TAK1 for 24 hours and cell death was quantified by annexin V staining. (B) NF-κB activity of primary AML CD34⁺ cells treated with 100 nM AZ-TAK1. NF-κB activity was measured by p65 DNA binding enzyme-linked immunosorbent assay. (C) Growth of primary AML CD34⁺ cells treated with 100 nM AZ-TAK1. AZ-TAK1 was added after initial growth was observed and added at the indicated time points (↓). (D) Growth of primary AML CD34⁺ cells transduced with hairpins targeting TAK1 or control hairpins.