Lymphotoxin-β receptor activation by lymphotoxin-α(1)β(2) and LIGHT promotes tumor growth in an NFκB-dependent manner.
Lymphotoxin beta receptor (LTβR) activation on mouse fibrosarcoma cells (BFS-1) results in enhanced solid tumor growth paralleled by increased angiogenesis induced by the expression of pro-angiogenic CXCL2. In our study, we demonstrate that both functional ligands of the LTβR, namely LTα(1) β(2) and LIGHT, are involved in the activation of LTβR in solid fibrosarcomas. To identify whether the lymphocyte population is involved in the activation of LTβR in these fibrosarcoma tumors, we used conditional LTβ-deficient mice that specifically lack LTβ expression either on T cells (T-LTβ(-/-)) or on B cells (B-LTβ(-/-)). Solid tumor growth was reduced in both mouse strains when compared to tumor growth in wild-type mice, indicating the participation of both T and B host lymphocytes in the activation of LTβR in these tumors. Tumor growth was also reduced in LIGHT-deficient mice, suggesting a contribution of this ligand to the activation of LTβR in BFS-1 fibrosarcomas. LTβR signaling can involve IκBα and/or NFκB-inducing kinase (NIK) for subsequent NFκB activation in different types of cells. Expression of a dominant negative form of IκBα or of a dominant negative mutant of NIK resulted in decreased activation of NFκB signaling and reduced expression of pro-angiogenic CXCL2 in vitro. Moreover, expression of dominant negative form of NIK or an IκBα repressor in these fibrosarcoma cells resulted in reduced solid tumor growth in vivo, suggesting that both IκBα and NIK are involved in pro-angiogenic signaling after LTβR activation. Our data support the idea that the ablation of LTβR signaling should be considered for cancer treatment.
Daller
Barbara
B
Institute of Immunology, University of Regensburg, Regensburg, Germany.
Müsch
Werner
W
Röhrl
Johann
J
Tumanov
Alexei V
AV
Nedospasov
Sergei A
SA
Männel
Daniela N
DN
Schneider-Brachert
Wulf
W
Hehlgans
Thomas
T
D000818:Animals; D017209:Apoptosis; D001402:B-Lymphocytes / Q000378:metabolism / Q000473:pathology; D015153:Blotting, Western; D049109:Cell Proliferation; D002478:Cells, Cultured; D054426:Chemokine CXCL2 / Q000378:metabolism; D005260:Female; D005354:Fibrosarcoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D005434:Flow Cytometry; D053361:Lymphotoxin alpha1, beta2 Heterotrimer / Q000378:metabolism*; D053259:Lymphotoxin beta Receptor / Q000378:metabolism*; D053308:Lymphotoxin-beta / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism / Q000473:pathology; D053326:Tumor Necrosis Factor Ligand Superfamily Member 14 / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D054426:Chemokine CXCL2; C404915:Cxcl2 protein, mouse; D053361:Lymphotoxin alpha1, beta2 Heterotrimer; D053259:Lymphotoxin beta Receptor; D053308:Lymphotoxin-beta; D016328:NF-kappa B; D012333:RNA, Messenger; C505915:Tnfsf14 protein, mouse; D053326:Tumor Necrosis Factor Ligand Superfamily Member 14; D014409:Tumor Necrosis Factor-alpha