TLR1/TLR2 activation induces differentiation of AML cells in an NFκB-dependent manner and apoptosis in a p38 MAPK-dependent manner. (A) In MA9 cells treated with Pam3CSK4 for 24 hours, GSEA identified an enriched NFκB signature relative to nontreated cells (control). (B-D) Histograms depicting phospho-flow cytometric analysis of phosphorylated (B) AKT, (C) NFκB, and (D) p38 MAPK in Pam3CSK4-treated (20 minutes) MA9 cells (blue) compared with control treated cells (gray) and isotype control (purple line). (E) Percentage of CD14⁺ cells after preincubation with the IκB kinase-inhibitor TPCA1 at 1 or 3 μM, or DMSO control for 10 minutes, before being treated with Pam3CSK4 (1 μg/mL) for 3 days (n = 3). (F) Percentage of cleaved (active) Caspase 3⁺ cells and (G) percentage of Annexin V⁺ cells after preincubation with the p38 MAPK inhibitor SB203580 at 1 or 10 μM, or DMSO control for 10 minutes, before being treated with Pam3CSK4 (at the indicated concentrations) for 2 days (n = 3). Mean values and SDs are shown. **P < .01; ****P < .0001.