NF-κB activity in marrow cells. (A) Bone marrow mononuclear cells (BMMCs) from healthy controls (shown are representative results from 1 of 3 marrows) and patients with MDS were treated with either TNF-α or TRAIL at the indicated concentrations for 20 hours. Nuclear extracts were isolated, and ³²P NF-κB gel shift was performed. Unlabeled probe (Cold) was used for competitive inhibition. Shown are representative examples from patients with refractory anemia with ringed sideroblasts (RARS; tested were marrows from patients 10 and 11; shown are results from patient 10); chronic myelomonocytic leukemia (CMML; tested were patients 23 and 25; shown is patient 23) and RA with excess blasts (RAEB; tested were patients 13, 17, and 20; shown is patient 17). (B) EMSA for NF-κB using nuclear extracts from purified CD34⁺ and CD34^- marrow cells compared with unfractioned BMMCs from primary MDS cells; equal amounts of protein were loaded for each patient (healthy controls and patients with CMML and RAEB are the same as in panel A; RA patients tested were 2, 5, and 7; shown are results in patient 7).