Obinutuzumab counteracts microenvironment-dependent loss of priming through NF-κB inhibition and Bcl-x_L downregulation in primary MCL cells. (A) Immunoblotting of indicated proteins in primary MCL cells cocultured on L-40L for 6 hours in the presence or absence of the NF-κB inhibitor Bay11-7082 (Bay11: 5 µM) or proteasome inhibitor BTZ (50 nM). (B) Immunoblotting analysis of the indicated proteins in CD20^High or CD20^Low primary MCL cells in the presence or absence of OBN (48 hours; 5 µg/mL). (C) qRT-PCR analysis of NF-κB targets (IL2RG, PLEK, and CD74)³⁵  in CD20^High or CD20^Low primary cells. (D) CD20 expression levels measured by fluorescence-activated cell sorting analysis on CD19⁺CD5⁺ primary MCL cells. (E) qRT-PCR analysis of BCLXL gene in CD20^High (black bars) or CD20^Low (gray bars). L-40L+Ck cocultured primary MCL cells in the presence or absence of OBN (24 hours; 5 µg/mL). (F-G) qRT-PCR analysis of BCLXL, BCL-2, and MCL-1 (F) and immunoblotting of Bcl-x_L (G) in Z138 and Maver-1 cells cocultured or not on L-40L cells in the presence or absence of OBN (24 hours; 5 µg/mL). (H) BH3-profiling of Z138 and Maver-1 cells cocultured on L-40L+Ck in the presence or absence of OBN (24 hours; 0.5 µg/mL), was performed as described in “Methods.”