Constitutive NF-kappaB and NFAT activation in aggressive B-cell lymphomas synergistically activates the CD154 gene and maintains lymphoma cell survival

Authors:
Pham LV, Tamayo AT, Yoshimura LC, Lin-Lee YC and Ford RJ
In:
Source: Blood
Publication Date: (2005)
Issue: 106(12): 3940-3947
Research Area:
Immunotherapy / Hematology
Cells used in publication:
B cell, human
Species: human
Tissue Origin: blood
T cell, human peripheral blood unstim.
Species: human
Tissue Origin: blood
Platform:
Nucleofectorâ„¢ I/II/2b
Experiment
Nucleofectected luciferase reporter (driven by CD154 promoter) into LBCL line and treated with NF-κB or NFAT inhibitors to examine effect on expression. Co-nucleofected expression plasmid with plasmids expressing dominant negative form of IκBαM or NFAT into LBCL cells. Nucleofected LBCL cells with siRNA against NFATc1 or c-rel (which reduced cell growth by 47-57%).
Abstract
Abnormalities in B-lymphocyte CD40 ligand (CD154) expression have been described for a number of immunologic diseases, including B-cell lymphomas. Although functional analysis of the CD154 gene and protein has been extensive, little is known about the mechanisms controlling CD154 expression in activated T cells, and even less is known for normal and malignant B cells. In this study we describe the transcriptional mechanism controlling CD154 expression in large B cell lymphoma (LBCL). We show that the nuclear factor of activated T cells (NFAT) transcription factor is also constitutively activated in LBCL. We demonstrate that the constitutively active NFATc1 and c-rel members of the NFAT and NF-kappaB families of transcription factors, respectively, directly interact with each other, bind to the CD154 promoter, and synergistically activate CD154 gene transcription. Down-regulation of NFATc1 or c-rel with small interfering RNA (siRNA) or chemical inhibitors inhibits CD154 gene transcription and lymphoma cell growth. These findings suggest that targeting NF-kappaB and NFAT, by inhibiting the expression of these transcription factors, or interdicting their interaction may provide a therapeutic rationale for patients with non-Hodgkin's lymphoma of B-cell origin, and possibly other disorders that display dysregulated CD154 expression.