Graded constitutive NF-κB signaling in B cells drives SLL/CLL-like lymphomagenesis and overcomes microenvironment dependence

Many lymphoma- as well as microenvironment-associated alterations mediating enhanced NF-κB signaling occur upstream of the IκB Kinase complex and its key kinase IKK2, therefore affecting additional pathways. Here, we specifically investigated the effects of graded canonical NF-κB activation in mouse B cells, induced through the expression of one or two copies of a constitutively active IKK2 variant (IKK2ca).

Strong canonical NF-κB signaling drives an early expansion of B1a cells, culminating in lethal lymphomagenesis with complete penetrance. These B cell malignancies resemble human small lymphocytic lymphoma (SLL) and chronic lymphocytic leukemia (CLL) with respect to disease course, gene expression and stereotypic B cell receptor clonality. Mice with less pronounced canonical NF-κB activation presented delayed, more heterogeneous lymphomagenesis with lower penetrance, highlighting NF-κB dose-dependent effects.