TAK1 inhibition induces apoptosis in AML cells. (A) HL60, OCI-M3, and MOLM13 cells were incubated with various concentrations of TAK1 inhibitors 5z-7-oxozeaenol and AZ-TAK1, alone, or in combination with TNFα, and apoptosis was quantified by using annexin V staining. (B) Relative expression of TAK1 in HL60 cells using 2 independent hairpins targeting TAK1. (C) Relative TAK1 protein expression of short hairpin TAK1 (shTAK1) or scrambled transduced HL60 cells. (D) Cell growth of MOLM13 cells transduced with TAK1 hairpins or scrambled hairpin. (E) Annexin V staining of the shTAK1 or scrambled transduced MOLM13 cells. (F) Cleaved caspase-8 protein expression of shTAK1 and scrambled transduced HL60 cells at day 1 after transduction. UNT, untransduced.