Targeting elevated NF-kB signaling substantially reduces chronic phase and blast crisis chronic myeloid leukemia stem cells. (A) Gene set enrichment analysis (GSEA) of published expression data set GSE40721 comparing CML CD34+;CD38+ progenitor cells with CML CD34+;CD38- stem cells for the ‘HALLMARK_TNFA_SIGNALING_VIA_NFKB’ gene set. (B) Colony-forming unit (CFU) assays using primary patient-derived CD34+ bone marrow (BM) cells after being treated for 72 hours (h) using LY2409881 (LY) (10 mM), nilotinib (NIL) (50 nM), LY + NIL or DMSO control, in the presence of TNF (1 ng/mL). (C) CFU counts upon serial-plating using cells obtained in (B), without any further treatment. (D) Analysis of apoptotic and CFSEMax/Annexin V CD34+ chronic phase chronic myeloid leukemia (CML-CP) patient-derived BM cells after being treated for 72 h using LY (10 mM), NIL (50 nM), LY + NIL, or DMSO control, in the presence of TNF (1 ng/mL). Shown is 1 of 3 representative results. (E) GSEA of published expression data set GSE47927 comparing CML-CP hematopoietic stem cells (HSC) with blast crisis CML (CML-BC) HSC analyzed for the ‘HALLMARK_TNFA_SIGNALING_VIA_NFKB’-gene set. (F) CFU assays of BC-CML-derived mononucleated (MNC) BM cells being treated for 72 h using LY (10 mM), NIL (50 nM), LY + NIL, or DMSO control in the presence of TNF (1 ng/mL). Significance was calculated using one or two-way ANOVA; mean ± standard deviation; *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001.