Longer blockade of anergic signaling induces apoptosis in the pERK(+) subset. (A) Leukemic cells were left untreated or treated for 48 hours with 10μM U0126, and cell viability was measured with the use of a luminescent-based cell viability assay. Each value from treated samples was normalized to the untreated control, and samples were grouped on the basis of the ERK1/2 activation status. Data were analyzed by using Mann-Whitney U test (P value is indicated). (B) Leukemic cells were left untreated or treated for 48 hours with 10μM CI1040, and cell viability was measured with a luminescent-based cell viability assay. Each value from treated samples was normalized to the untreated control, and samples were grouped on the basis of the ERK1/2 activation status. Data were analyzed by using Mann-Whitney U test (P value is indicated). (C) Leukemic cells were left untreated or treated for 48 hours with 10μM NMS6E and cell viability was measured by the use of a luminescent-based cell viability assay. Each value from treated samples was normalized to the untreated control, and samples were grouped on the basis of ERK1/2 activation status. Data were analyzed by using Mann-Whitney U test (P value is indicated). (D-E) Leukemic cells were left untreated or treated for 48 hours with 10μM 11R-VIVIT, and cell viability was measured by the use of luminescent-based cell viability assay. Each value from treated samples was normalized to the untreated control, and samples were grouped on the basis of ERK1/2 (D) or NF-ATc1 (E) activation status. Data were analyzed with the Mann-Whitney U test (P value is indicated). (F) ERK1/2 and NF-ATc1 inhibitors do not exert any synergistic effect. Samples from 9 anergic CLL patients were treated with 10μM each inhibitor (U0126, NMS6E, VIVIT) or with a MAPK inhibitor in combination with VIVIT for 48 hours, and cell viability was measured. Viability is expressed as percentage of the untreated control.