Transactivation of CCL20 Gene by CD30 in Hodgkin’s Lymphoma.

Hodgkin’s lymphoma (HL) is characterized by a minority of neoplastic cells, the so-called Hodgkin/Reed-Sternberg (H/RS) cells, and an admixture of reactive cells including lymphocytes, plasma cells, eosinophils, and histiocytes. Chemokines produced by H/RS cells play a major role in leukocyte trafficking. These molecules with specific receptor affinities contribute to the maintenance of a favorable environment for survival of H/RS cells. The C-C chemokine CCL20 is expected to play a crucial role in the initiation of immune responses and tumor growth. However, expression of CCL20 in HL has not been studied. We found that in lymph nodes from patients with HL, CCL20 was expressed in H/RS cells by immunohistochemistry. CCL20 was expressed in HL cell lines KM-H2 and L428 established from B-cell type HL patients, but not in cell lines L540 and HDLM-2 established from T-cell type HL patients. CD30 was identified in H/RS cells of HL and has attracted much interest as a molecular marker of HL. All four H/RS cell lines expressed CD30, but not CD30 ligand. CD30 induced CCL20 mRNA expression. Analysis of the CCL20 promoter showed the importance of NF-κB binding site for CD30-induced CCL20 expression. Coexpression of IκB, IKK, NIK, and TRAF dominant-negative constructs with CD30 inhibited CD30-induced activation of CCL20 promoter, suggesting that CD30 induces CCL20 via NF-κB signaling. Electrophoretic mobility shift assay showed the NF-κB complexes that consisted of p50, p65, and c-Rel in KM-H2 and L428 cells. In contrast, the NF-κB complexes contained p50 homodimer that was transcriptionally repressive in L540 and HDLM-2 cells. The CCL20 promoter was activated by the C-terminal region of CD30, which activated NF-κB signaling. A decoy CD30 lacking the cytoplasmic region inhibited CCL20 promoter activity in KM-H2 and L428 cells. Thus, in B-cell derived H-RS cells, ligand-independent activation of CD30 signaling activates NF-κB and this leads to constitutive CCL20 expression.